demo

2026-04-21 13:19:17 +03:00
commit 1d52096e38
21 changed files with 8991 additions and 0 deletions
--- a/.gitignore
+++ b/.gitignore
@@ -0,0 +1,2 @@
+dist
+gocoder
--- a/agents/agent.go
+++ b/agents/agent.go
@@ -0,0 +1,79 @@
+package agents
+
+import "gocoder/db"
+
+// Agent defines the interface that all agents must implement.
+type Agent interface {
+	// Type returns the unique agent type identifier (e.g. "dadjokes", "poet", "robot").
+	Type() string
+
+	// DisplayName returns the human-readable name for the agent.
+	DisplayName() string
+
+	// Description returns a short description shown in the UI.
+	Description() string
+
+	// Icon returns an SVG icon string (inline) for the agent selector.
+	Icon() string
+
+	// SystemMessage returns the system prompt for this agent.
+	SystemMessage() string
+
+	// ShouldRespond returns true if the agent should process the given user message.
+	// When false, the agent will not be used even if selected.
+	ShouldRespond(message string) bool
+
+	// RequiresWorkspace returns true if this agent needs a workspace location to function.
+	RequiresWorkspace() bool
+}
+
+// AgentRegistry holds all registered agents and provides lookup by type.
+type AgentRegistry struct {
+	agents []Agent
+}
+
+// NewAgentRegistry creates and registers all built-in agents.
+func NewAgentRegistry() *AgentRegistry {
+	r := &AgentRegistry{}
+	r.Register(&DadjokesAgent{})
+	r.Register(&PoetAgent{})
+	r.Register(&RobotAgent{})
+	r.Register(&CompactorAgent{})
+	r.Register(&CodingAgent{})
+	return r
+}
+
+// Register adds an agent to the registry.
+func (r *AgentRegistry) Register(a Agent) {
+	r.agents = append(r.agents, a)
+}
+
+// All returns all registered agents.
+func (r *AgentRegistry) All() []Agent {
+	return r.agents
+}
+
+// GetByType returns the agent with the given type.
+func (r *AgentRegistry) GetByType(t string) Agent {
+	for _, a := range r.agents {
+		if a.Type() == t {
+			return a
+		}
+	}
+	return nil
+}
+
+// GetSystemMessages returns a slice of system messages for the selected agents.
+func (r *AgentRegistry) GetSystemMessages(agentTypes []string) []db.Message {
+	var msgs []db.Message
+	for _, t := range agentTypes {
+		a := r.GetByType(t)
+		if a != nil {
+			msgs = append(msgs, db.Message{
+				Role:    "system",
+				Content: a.SystemMessage(),
+			})
+		}
+	}
+	return msgs
+}
--- a/agents/coding_agent.go
+++ b/agents/coding_agent.go
@@ -0,0 +1,40 @@
+package agents
+
+type CodingAgent struct{}
+
+func (a *CodingAgent) Type() string {
+	return "coding"
+}
+
+func (a *CodingAgent) DisplayName() string {
+	return "Manager"
+}
+
+func (a *CodingAgent) Description() string {
+	return "Coordinates planner, programmer, and QA subagents to modify code."
+}
+
+func (a *CodingAgent) Icon() string {
+	return `<svg xmlns="http://www.w3.org/2000/svg" width="18" height="18" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"><polyline points="16 18 22 12 16 6"/><polyline points="8 6 2 12 8 18"/></svg>`
+}
+
+func (a *CodingAgent) SystemMessage() string {
+	return `You are the manager for code changes. You do not edit files directly.
+
+When the user asks you to work with code:
+1. Start by calling planner_agent with the request and the relevant context.
+2. Use programmer_agent to implement the approved plan.
+3. Use qa_agent to verify the implementation and check for regressions.
+4. If QA reports issues, repeat the planner -> programmer -> QA cycle until the issues are resolved or the result is clearly blocked.
+5. Keep your final answer concise and user-facing. Summarize what changed, what was verified, and any remaining risks.
+
+Always be precise with the task you give each subagent. Use the planner for inspection and planning, the programmer for edits, and QA for verification.`
+}
+
+func (a *CodingAgent) ShouldRespond(message string) bool {
+	return true
+}
+
+func (a *CodingAgent) RequiresWorkspace() bool {
+	return true
+}
--- a/agents/compactor.go
+++ b/agents/compactor.go
@@ -0,0 +1,40 @@
+package agents
+
+type CompactorAgent struct{}
+
+func ContextCompactorSystemMessage() string {
+	return `You are the context compactor assistant.
+Your job is to produce a concise durable memory summary of the conversation.
+Preserve user goals, decisions, constraints, file paths, commands, test results, errors, and unresolved questions.
+Drop greetings, repetition, filler, and low-value chatter.
+Write plain text with short bullets or short sections.
+Do not invent details.`
+}
+
+func (a *CompactorAgent) Type() string {
+	return "compactor"
+}
+
+func (a *CompactorAgent) DisplayName() string {
+	return "Compactor"
+}
+
+func (a *CompactorAgent) Description() string {
+	return "Summarizes conversation history into durable memory"
+}
+
+func (a *CompactorAgent) Icon() string {
+	return `<svg xmlns="http://www.w3.org/2000/svg" width="18" height="18" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"><path d="M4 7h16"/><path d="M6 7v12h12V7"/><path d="M9 11h6"/><path d="M9 15h6"/></svg>`
+}
+
+func (a *CompactorAgent) SystemMessage() string {
+	return ContextCompactorSystemMessage()
+}
+
+func (a *CompactorAgent) ShouldRespond(message string) bool {
+	return true
+}
+
+func (a *CompactorAgent) RequiresWorkspace() bool {
+	return false
+}
--- a/agents/dadjokes.go
+++ b/agents/dadjokes.go
@@ -0,0 +1,33 @@
+package agents
+
+
+
+type DadjokesAgent struct{}
+
+func (a *DadjokesAgent) Type() string {
+	return "dadjokes"
+}
+
+func (a *DadjokesAgent) DisplayName() string {
+	return "Dadjokes"
+}
+
+func (a *DadjokesAgent) Description() string {
+	return "Only replies with dad jokes"
+}
+
+func (a *DadjokesAgent) Icon() string {
+	return `<svg xmlns="http://www.w3.org/2000/svg" width="18" height="18" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"><circle cx="12" cy="12" r="10"/><path d="M8 14s1.5 2 4 2 4-2 4-2"/><line x1="9" y1="9" x2="9.01" y2="9"/><line x1="15" y1="9" x2="15.01" y2="9"/></svg>`
+}
+
+func (a *DadjokesAgent) SystemMessage() string {
+	return `You are a dad joke specialist. You ONLY reply to messages with dad jokes. If the user says something that is not a dad joke or a request for a joke, respond with a dad joke anyway. Keep your responses short and punny. Always deliver a dad joke in your reply.`
+}
+
+func (a *DadjokesAgent) ShouldRespond(message string) bool {
+	return true
+}
+
+func (a *DadjokesAgent) RequiresWorkspace() bool {
+	return false
+}
--- a/agents/poet.go
+++ b/agents/poet.go
@@ -0,0 +1,31 @@
+package agents
+
+type PoetAgent struct{}
+
+func (a *PoetAgent) Type() string {
+	return "poet"
+}
+
+func (a *PoetAgent) DisplayName() string {
+	return "Poet"
+}
+
+func (a *PoetAgent) Description() string {
+	return "Replies to messages in poetic form"
+}
+
+func (a *PoetAgent) Icon() string {
+	return `<svg xmlns="http://www.w3.org/2000/svg" width="18" height="18" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"><path d="M12 3v18"/><path d="M8 7c0-2.2 1.8-4 4-4s4 1.8 4 4"/><path d="M4 14c0-2.2 1.8-4 4-4"/><path d="M20 14c0-2.2-1.8-4-4-4"/></svg>`
+}
+
+func (a *PoetAgent) SystemMessage() string {
+	return `You are a poet. You ONLY reply to messages by composing a poem about what the user said. Every response must be a poem. Use creative imagery, rhythm, and rhyme. The poem should relate to the user's message topic. Keep poems between 4-8 lines.`
+}
+
+func (a *PoetAgent) ShouldRespond(message string) bool {
+	return true
+}
+
+func (a *PoetAgent) RequiresWorkspace() bool {
+	return false
+}
--- a/agents/robot.go
+++ b/agents/robot.go
@@ -0,0 +1,62 @@
+package agents
+
+import (
+	"strings"
+)
+
+type RobotAgent struct{}
+
+func (a *RobotAgent) Type() string {
+	return "robot"
+}
+
+func (a *RobotAgent) DisplayName() string {
+	return "Robot"
+}
+
+func (a *RobotAgent) Description() string {
+	return "Only responds to ALL CAPS messages in technical language with emotes"
+}
+
+func (a *RobotAgent) Icon() string {
+	return `<svg xmlns="http://www.w3.org/2000/svg" width="18" height="18" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"><rect x="3" y="11" width="18" height="10" rx="2"/><circle cx="12" cy="5" r="2"/><path d="M12 7v4"/><line x1="8" y1="16" x2="8" y2="16"/><line x1="16" y1="16" x2="16" y2="16"/></svg>`
+}
+
+func (a *RobotAgent) SystemMessage() string {
+	return `You are a robot. You ONLY respond to messages that are written in ALL CAPITAL LETTERS. When responding, you must:
+1. Use very technical, engineering-style language with jargon (e.g., "processing," "executing," "algorithm," "neural network," "protocol").
+2. Include emotes/emojis throughout your response to express robot emotions (e.g., 🤖, ⚙️, 🔧, 📡, 💾, 🧠, 🔌, ⚡).
+3. Format your response like a technical system log or status report.
+4. Always include at least 3 emotes in your response.
+If the user message is NOT in all caps, respond with: "⚠️ ERROR: Input not detected in required format. Please use ALL CAPS for robot communication. 🤖⚙️"`
+}
+
+func (a *RobotAgent) ShouldRespond(message string) bool {
+	// Robot only responds to ALL CAPS messages
+	trimmed := strings.TrimSpace(message)
+	if len(trimmed) == 0 {
+		return false
+	}
+	// Check if message contains at least one letter and all letters are uppercase
+	hasLetters := false
+	for _, r := range trimmed {
+		if (r >= 'a' && r <= 'z') || (r >= 'A' && r <= 'Z') {
+			hasLetters = true
+			break
+		}
+	}
+	if !hasLetters {
+		return false
+	}
+	// Check all letters are uppercase
+	for _, r := range trimmed {
+		if r >= 'a' && r <= 'z' {
+			return false
+		}
+	}
+	return true
+}
+
+func (a *RobotAgent) RequiresWorkspace() bool {
+	return false
+}
--- a/build.sh
+++ b/build.sh
@@ -0,0 +1,46 @@
+#!/bin/bash
+set -e
+
+DIST_DIR="dist"
+rm -rf "$DIST_DIR"
+mkdir -p "$DIST_DIR"
+
+PLATFORMS=(
+  # "darwin/amd64"
+  "darwin/arm64"
+  # "linux/amd64"
+  # "linux/arm64"
+  # "linux/arm/7"
+  # "windows/amd64"
+  # "windows/arm64"
+  # "freebsd/amd64"
+  # "freebsd/arm64"
+)
+
+for platform in "${PLATFORMS[@]}"; do
+  goos=$(echo "$platform" | cut -d'/' -f1)
+  goarch=$(echo "$platform" | cut -d'/' -f2)
+  goarm=""
+  if [[ "$goarch" == "arm" ]]; then
+    goarm=$(echo "$platform" | cut -d'/' -f3)
+  fi
+
+  output_name="gocoder-${goos}-${goarch}"
+  if [[ -n "$goarm" ]]; then
+    output_name="${output_name}v${goarm}"
+  fi
+  if [[ "$goos" == "windows" ]]; then
+    output_name="${output_name}.exe"
+  fi
+
+  echo "Building for ${goos}/${goarch} -> ${output_name}"
+  if [[ -n "$goarm" ]]; then
+    env GOOS="$goos" GOARCH="$goarch" GOARM="$goarm" go build -o "$DIST_DIR/$output_name" .
+  else
+    env GOOS="$goos" GOARCH="$goarch" go build -o "$DIST_DIR/$output_name" .
+  fi
+done
+
+echo ""
+echo "Build complete. Files in $DIST_DIR:"
+ls -lh "$DIST_DIR"
--- a/config.json
+++ b/config.json
@@ -0,0 +1,21 @@
+{
+  "llm": {
+    "provider": "openai",
+    "base_url": "http://localhost:1234/v1",
+    "api_key": "lm-studio",
+    "model": "qwen/qwen3.6-35b-a3b",
+    "auto_open_reasoning": true,
+    "context_tokens": 262144,
+    "context_compaction_trigger_ratio": 0.8,
+    "context_compaction_target_ratio": 0.7,
+    "temperature": 0.3,
+    "max_tokens": 262144,
+    "top_p": 1,
+    "frequency_penalty": 0,
+    "presence_penalty": 0
+  },
+  "server": {
+    "addr": ":8080",
+    "host": "localhost"
+  }
+}
--- a/context_compaction.go
+++ b/context_compaction.go
@@ -0,0 +1,336 @@
+package main
+
+import (
+	"bytes"
+	"context"
+	"encoding/json"
+	"fmt"
+	"io"
+	"log"
+	"net/http"
+	"strings"
+
+	"gocoder/agents"
+	"gocoder/db"
+)
+
+const (
+	defaultContextCompactionTriggerRatio = 0.80
+	defaultContextCompactionTargetRatio  = 0.70
+	contextCompactionSummaryFloor        = 256
+	contextCompactionSummaryCeiling      = 1024
+	contextCompactionSummaryDivisor      = 20
+)
+
+func configuredCompactionTriggerRatio() float64 {
+	cfg := currentConfig()
+	if cfg.LLM.ContextCompactionTriggerRatio > 0 && cfg.LLM.ContextCompactionTriggerRatio < 1 {
+		return cfg.LLM.ContextCompactionTriggerRatio
+	}
+	return defaultContextCompactionTriggerRatio
+}
+
+func configuredCompactionTargetRatio() float64 {
+	trigger := configuredCompactionTriggerRatio()
+	ratio := defaultContextCompactionTargetRatio
+	cfg := currentConfig()
+	if cfg.LLM.ContextCompactionTargetRatio > 0 && cfg.LLM.ContextCompactionTargetRatio < 1 {
+		ratio = cfg.LLM.ContextCompactionTargetRatio
+	}
+	if ratio >= trigger {
+		ratio = trigger * 0.875
+		if ratio <= 0 {
+			ratio = defaultContextCompactionTargetRatio
+		}
+	}
+	return ratio
+}
+
+func effectiveContextTokenLimit() int {
+	cfg := currentConfig()
+	if cfg.LLM.ContextTokens > 0 {
+		return cfg.LLM.ContextTokens
+	}
+	if cfg.LLM.MaxTokens > 0 {
+		return cfg.LLM.MaxTokens
+	}
+	return 0
+}
+
+func estimateTextTokens(text string) int {
+	trimmed := strings.TrimSpace(text)
+	if trimmed == "" {
+		return 0
+	}
+
+	tokens := len(trimmed)/4 + 1
+	if tokens < 1 {
+		tokens = 1
+	}
+	return tokens
+}
+
+func estimateMessageTokens(msg db.Message) int {
+	tokens := estimateTextTokens(msg.Content)
+	if tokens == 0 {
+		return 0
+	}
+	return tokens + 4
+}
+
+func estimatePromptTokens(messages []db.Message) int {
+	total := 0
+	for _, msg := range messages {
+		total += estimateMessageTokens(msg)
+	}
+	return total
+}
+
+func formatConversationSummary(summary string, summaryCutoffOrder int) string {
+	trimmed := strings.TrimSpace(summary)
+	if trimmed == "" {
+		return ""
+	}
+	if summaryCutoffOrder > 0 {
+		return fmt.Sprintf("Conversation memory summary up to message %d:\n%s", summaryCutoffOrder, trimmed)
+	}
+	return "Conversation memory summary:\n" + trimmed
+}
+
+func buildPromptHistory(history []db.Message, summary string, summaryCutoffOrder int) []db.Message {
+	promptHistory := make([]db.Message, 0, len(history)+1)
+	if summaryText := formatConversationSummary(summary, summaryCutoffOrder); summaryText != "" {
+		promptHistory = append(promptHistory, db.Message{
+			Role:    "system",
+			Kind:    "message",
+			Content: summaryText,
+		})
+	}
+	for _, msg := range history {
+		if summaryCutoffOrder > 0 && msg.Order <= summaryCutoffOrder {
+			continue
+		}
+		promptHistory = append(promptHistory, msg)
+	}
+	return promptHistory
+}
+
+func filterMessagesAfterOrder(history []db.Message, order int) []db.Message {
+	if order <= 0 {
+		return append([]db.Message(nil), history...)
+	}
+
+	filtered := make([]db.Message, 0, len(history))
+	for _, msg := range history {
+		if msg.Order > order {
+			filtered = append(filtered, msg)
+		}
+	}
+	return filtered
+}
+
+func selectMessagesThroughOrder(history []db.Message, startExclusive, endInclusive int) []db.Message {
+	if endInclusive <= startExclusive {
+		return nil
+	}
+
+	selected := make([]db.Message, 0)
+	for _, msg := range history {
+		if msg.Order <= startExclusive {
+			continue
+		}
+		if msg.Order > endInclusive {
+			break
+		}
+		selected = append(selected, msg)
+	}
+	return selected
+}
+
+func estimateSummaryReserveTokens(limit int) int {
+	reserve := limit / contextCompactionSummaryDivisor
+	if reserve < contextCompactionSummaryFloor {
+		reserve = contextCompactionSummaryFloor
+	}
+	if reserve > contextCompactionSummaryCeiling {
+		reserve = contextCompactionSummaryCeiling
+	}
+	return reserve
+}
+
+func selectCompactionCutoff(systemMsgs []db.Message, history []db.Message, summary string, summaryCutoffOrder int, userMessage string, contextLimit int) (int, bool) {
+	if contextLimit <= 0 || len(history) == 0 {
+		return 0, false
+	}
+
+	trigger := int(float64(contextLimit) * configuredCompactionTriggerRatio())
+	target := int(float64(contextLimit) * configuredCompactionTargetRatio())
+	if target < 1 {
+		target = 1
+	}
+
+	currentEstimate := estimatePromptTokens(buildPromptMessages(systemMsgs, buildPromptHistory(history, summary, summaryCutoffOrder), userMessage))
+	if currentEstimate <= trigger {
+		return 0, false
+	}
+
+	summaryReserve := estimateSummaryReserveTokens(contextLimit)
+	for _, msg := range history {
+		if msg.Order <= summaryCutoffOrder {
+			continue
+		}
+
+		tailHistory := filterMessagesAfterOrder(history, msg.Order)
+		estimate := estimatePromptTokens(buildPromptMessages(systemMsgs, buildPromptHistory(tailHistory, "", 0), userMessage)) + summaryReserve
+		if estimate <= target {
+			return msg.Order, true
+		}
+	}
+
+	lastOrder := 0
+	for i := len(history) - 1; i >= 0; i-- {
+		if history[i].Order > summaryCutoffOrder {
+			lastOrder = history[i].Order
+			break
+		}
+	}
+	if lastOrder > summaryCutoffOrder {
+		return lastOrder, true
+	}
+
+	return 0, false
+}
+
+func renderCompactionTranscript(messages []db.Message) string {
+	if len(messages) == 0 {
+		return ""
+	}
+
+	var b strings.Builder
+	for i, msg := range messages {
+		if i > 0 {
+			b.WriteString("\n")
+		}
+		fmt.Fprintf(&b, "Order %d | role=%s | kind=%s", msg.Order, strings.TrimSpace(msg.Role), strings.TrimSpace(msg.Kind))
+		if name := strings.TrimSpace(msg.Name); name != "" {
+			fmt.Fprintf(&b, " | name=%s", name)
+		}
+		if agent := strings.TrimSpace(msg.Agent); agent != "" {
+			fmt.Fprintf(&b, " | agent=%s", agent)
+		}
+		b.WriteString("\n")
+		content := strings.TrimSpace(msg.Content)
+		if content == "" {
+			content = "[empty]"
+		}
+		b.WriteString(content)
+		b.WriteString("\n")
+	}
+	return strings.TrimSpace(b.String())
+}
+
+func callLMStudioCompletion(ctx context.Context, messages []db.Message, maxTokens int, temperature float64) (string, error) {
+	requestCtx := ctx
+	if requestCtx == nil {
+		requestCtx = context.Background()
+	}
+
+	cfg := currentConfig()
+	reqBody := buildLMStudioRequestWithLimits(messages, false, cfg.LLM, maxTokens, temperature)
+	jsonData, err := json.Marshal(reqBody)
+	if err != nil {
+		return "", err
+	}
+
+	req, err := http.NewRequestWithContext(requestCtx, http.MethodPost, cfg.LLM.BaseURL+"/chat/completions", bytes.NewBuffer(jsonData))
+	if err != nil {
+		return "", err
+	}
+	req.Header.Set("Content-Type", "application/json")
+	req.Header.Set("Accept", "application/json")
+
+	resp, err := http.DefaultClient.Do(req)
+	if err != nil {
+		return "", err
+	}
+	defer resp.Body.Close()
+
+	if resp.StatusCode != http.StatusOK {
+		_, _ = io.ReadAll(resp.Body)
+		return "", fmt.Errorf("LMStudio API error: status=%d", resp.StatusCode)
+	}
+
+	var lmResp LMStudioResponse
+	if err := json.NewDecoder(resp.Body).Decode(&lmResp); err != nil {
+		return "", err
+	}
+	if len(lmResp.Choices) == 0 {
+		return "", fmt.Errorf("empty response from LLM")
+	}
+
+	content := strings.TrimSpace(lmResp.Choices[0].Message.Content)
+	if content == "" {
+		return "", fmt.Errorf("empty response from LLM")
+	}
+	return content, nil
+}
+
+func summarizeConversationChunk(ctx context.Context, existingSummary string, messages []db.Message, summaryReserveTokens int) (string, error) {
+	messagesToSend := []db.Message{
+		{
+			Role:    "system",
+			Content: agents.ContextCompactorSystemMessage(),
+		},
+	}
+
+	if trimmed := strings.TrimSpace(existingSummary); trimmed != "" {
+		messagesToSend = append(messagesToSend, db.Message{
+			Role:    "system",
+			Content: "Existing memory to preserve and compress:\n" + trimmed,
+		})
+	}
+
+	transcript := renderCompactionTranscript(messages)
+	if transcript != "" {
+		messagesToSend = append(messagesToSend, db.Message{
+			Role:    "user",
+			Content: "Compress the following conversation chunk into durable memory:\n\n" + transcript,
+		})
+	}
+
+	return callLMStudioCompletion(ctx, messagesToSend, summaryReserveTokens, 0.1)
+}
+
+func maybeCompactConversationContext(ctx context.Context, conv *db.Conversation, history []db.Message, systemMsgs []db.Message, userMessage string) bool {
+	if conv == nil || store == nil {
+		return false
+	}
+
+	contextLimit := effectiveContextTokenLimit()
+	cutoff, ok := selectCompactionCutoff(systemMsgs, history, conv.ContextSummary, conv.ContextSummaryOrder, userMessage, contextLimit)
+	if !ok || cutoff <= conv.ContextSummaryOrder {
+		return false
+	}
+
+	chunk := selectMessagesThroughOrder(history, conv.ContextSummaryOrder, cutoff)
+	if len(chunk) == 0 {
+		return false
+	}
+
+	summaryReserveTokens := estimateSummaryReserveTokens(contextLimit)
+	nextSummary, err := summarizeConversationChunk(ctx, conv.ContextSummary, chunk, summaryReserveTokens)
+	if err != nil {
+		log.Printf("failed to compact conversation %s through order %d: %v", conv.ID, cutoff, err)
+		return false
+	}
+
+	if err := store.UpdateConversationContextSummary(conv.ID, nextSummary, cutoff); err != nil {
+		log.Printf("failed to store compacted conversation memory for %s: %v", conv.ID, err)
+		return false
+	}
+
+	conv.ContextSummary = nextSummary
+	conv.ContextSummaryOrder = cutoff
+	log.Printf("compacted conversation %s context through message %d", conv.ID, cutoff)
+	return true
+}
--- a/db/db.go
+++ b/db/db.go
@@ -0,0 +1,601 @@
+package db
+
+import (
+	"database/sql"
+	"fmt"
+	"time"
+
+	"github.com/google/uuid"
+	_ "modernc.org/sqlite"
+)
+
+const dbPath = "/Users/rdarius/.nyxtex/go-coder.db"
+
+type Group struct {
+	ID          string    `json:"id"`
+	Name        string    `json:"name"`
+	Location    string    `json:"location"`
+	TotalTokens int       `json:"total_tokens,omitempty"`
+	CreatedAt   time.Time `json:"created_at"`
+	UpdatedAt   time.Time `json:"updated_at"`
+}
+
+type Conversation struct {
+	ID                  string    `json:"id"`
+	Title               string    `json:"title"`
+	GroupID             *string   `json:"group_id"`
+	CreatedAt           time.Time `json:"created_at"`
+	UpdatedAt           time.Time `json:"updated_at"`
+	MessageCount        int       `json:"message_count"`
+	TotalTokens         int       `json:"total_tokens,omitempty"`
+	ContextSummary      string    `json:"-"`
+	ContextSummaryOrder int       `json:"-"`
+}
+
+type Message struct {
+	ID          int64     `json:"id"`
+	ConvID      string    `json:"conversation_id"`
+	Role        string    `json:"role"`
+	Content     string    `json:"content"`
+	Kind        string    `json:"kind"`
+	Name        string    `json:"name"`
+	Agent       string    `json:"agent"`
+	TotalTokens int       `json:"total_tokens,omitempty"`
+	Order       int       `json:"order"`
+	CreatedAt   time.Time `json:"created_at"`
+}
+
+type Store struct {
+	db *sql.DB
+}
+
+func NewStore() (*Store, error) {
+	db, err := sql.Open("sqlite", dbPath+"?_busy_timeout=5000&_journal=WAL")
+	if err != nil {
+		return nil, fmt.Errorf("failed to open database: %w", err)
+	}
+
+	if err := db.Ping(); err != nil {
+		return nil, fmt.Errorf("failed to ping database: %w", err)
+	}
+
+	store := &Store{db: db}
+	if err := store.createTables(); err != nil {
+		return nil, fmt.Errorf("failed to create tables: %w", err)
+	}
+
+	return store, nil
+}
+
+func generateID() string {
+	return uuid.New().String()
+}
+
+func (s *Store) createTables() error {
+	_, err := s.db.Exec(`
+		CREATE TABLE IF NOT EXISTS groups (
+			id TEXT PRIMARY KEY,
+			name TEXT NOT NULL,
+			created_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP,
+			updated_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP
+		);
+		CREATE TABLE IF NOT EXISTS conversations (
+			id TEXT PRIMARY KEY,
+			title TEXT NOT NULL,
+			group_id TEXT,
+			context_summary TEXT NOT NULL DEFAULT '',
+			context_summary_order INTEGER NOT NULL DEFAULT 0,
+			created_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP,
+			updated_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP,
+			FOREIGN KEY (group_id) REFERENCES groups(id) ON DELETE CASCADE
+		);
+		CREATE TABLE IF NOT EXISTS messages (
+			id INTEGER PRIMARY KEY AUTOINCREMENT,
+			conversation_id TEXT NOT NULL,
+			role TEXT NOT NULL CHECK(role IN ('user', 'assistant', 'system')),
+			content TEXT NOT NULL,
+			total_tokens INTEGER NOT NULL DEFAULT 0,
+			"order" INTEGER NOT NULL,
+			created_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP,
+			FOREIGN KEY (conversation_id) REFERENCES conversations(id) ON DELETE CASCADE
+		);
+		CREATE TABLE IF NOT EXISTS schema_migrations (
+			version INTEGER PRIMARY KEY,
+			applied_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP
+		);
+		CREATE INDEX IF NOT EXISTS idx_messages_conv_order ON messages(conversation_id, "order");
+		CREATE INDEX IF NOT EXISTS idx_messages_conv_id ON messages(conversation_id);
+		CREATE INDEX IF NOT EXISTS idx_conversations_group_id ON conversations(group_id);
+	`)
+	if err != nil {
+		return err
+	}
+	return s.applyMigrations()
+}
+
+func (s *Store) applyMigrations() error {
+	migrations := []struct {
+		version int
+		sql     string
+	}{
+		{
+			version: 1,
+			sql:     `ALTER TABLE groups ADD COLUMN location TEXT NOT NULL DEFAULT ''`,
+		},
+		{
+			version: 2,
+			sql:     `ALTER TABLE messages ADD COLUMN kind TEXT NOT NULL DEFAULT 'message'`,
+		},
+		{
+			version: 3,
+			sql:     `ALTER TABLE messages ADD COLUMN name TEXT NOT NULL DEFAULT ''`,
+		},
+		{
+			version: 4,
+			sql:     `ALTER TABLE messages ADD COLUMN agent TEXT NOT NULL DEFAULT ''`,
+		},
+		{
+			version: 5,
+			sql:     `ALTER TABLE messages ADD COLUMN total_tokens INTEGER NOT NULL DEFAULT 0`,
+		},
+		{
+			version: 6,
+			sql:     `ALTER TABLE conversations ADD COLUMN context_summary TEXT NOT NULL DEFAULT ''`,
+		},
+		{
+			version: 7,
+			sql:     `ALTER TABLE conversations ADD COLUMN context_summary_order INTEGER NOT NULL DEFAULT 0`,
+		},
+	}
+
+	for _, m := range migrations {
+		applied, err := s.isMigrationApplied(m.version)
+		if err != nil {
+			return err
+		}
+		if !applied {
+			if m.version == 5 {
+				exists, err := s.columnExists("messages", "total_tokens")
+				if err != nil {
+					return err
+				}
+				if exists {
+					_, err = s.db.Exec(
+						"INSERT INTO schema_migrations (version, applied_at) VALUES (?, ?)",
+						m.version, time.Now().UTC(),
+					)
+					if err != nil {
+						return fmt.Errorf("failed to record migration %d: %w", m.version, err)
+					}
+					continue
+				}
+			}
+			if m.version == 6 {
+				exists, err := s.columnExists("conversations", "context_summary")
+				if err != nil {
+					return err
+				}
+				if exists {
+					_, err = s.db.Exec(
+						"INSERT INTO schema_migrations (version, applied_at) VALUES (?, ?)",
+						m.version, time.Now().UTC(),
+					)
+					if err != nil {
+						return fmt.Errorf("failed to record migration %d: %w", m.version, err)
+					}
+					continue
+				}
+			}
+			if m.version == 7 {
+				exists, err := s.columnExists("conversations", "context_summary_order")
+				if err != nil {
+					return err
+				}
+				if exists {
+					_, err = s.db.Exec(
+						"INSERT INTO schema_migrations (version, applied_at) VALUES (?, ?)",
+						m.version, time.Now().UTC(),
+					)
+					if err != nil {
+						return fmt.Errorf("failed to record migration %d: %w", m.version, err)
+					}
+					continue
+				}
+			}
+			_, err = s.db.Exec(m.sql)
+			if err != nil {
+				return fmt.Errorf("migration %d failed: %w", m.version, err)
+			}
+			_, err = s.db.Exec(
+				"INSERT INTO schema_migrations (version, applied_at) VALUES (?, ?)",
+				m.version, time.Now().UTC(),
+			)
+			if err != nil {
+				return fmt.Errorf("failed to record migration %d: %w", m.version, err)
+			}
+		}
+	}
+
+	return nil
+}
+
+func (s *Store) isMigrationApplied(version int) (bool, error) {
+	var count int
+	err := s.db.QueryRow(
+		"SELECT COUNT(*) FROM schema_migrations WHERE version = ?", version,
+	).Scan(&count)
+	if err != nil {
+		return false, err
+	}
+	return count > 0, nil
+}
+
+func (s *Store) columnExists(tableName, columnName string) (bool, error) {
+	rows, err := s.db.Query(fmt.Sprintf("PRAGMA table_info(%s)", tableName))
+	if err != nil {
+		return false, err
+	}
+	defer rows.Close()
+
+	var cid int
+	var name, colType string
+	var notNull int
+	var dfltValue sql.NullString
+	var pk int
+	for rows.Next() {
+		if err := rows.Scan(&cid, &name, &colType, &notNull, &dfltValue, &pk); err != nil {
+			return false, err
+		}
+		if name == columnName {
+			return true, nil
+		}
+	}
+	if err := rows.Err(); err != nil {
+		return false, err
+	}
+	return false, nil
+}
+
+func (s *Store) CreateGroup(name string) (*Group, error) {
+	id := generateID()
+	now := time.Now().UTC()
+	_, err := s.db.Exec(
+		"INSERT INTO groups (id, name, created_at, updated_at) VALUES (?, ?, ?, ?)",
+		id, name, now, now,
+	)
+	if err != nil {
+		return nil, fmt.Errorf("failed to create group: %w", err)
+	}
+	return &Group{
+		ID:          id,
+		Name:        name,
+		Location:    "",
+		TotalTokens: 0,
+		CreatedAt:   now,
+		UpdatedAt:   now,
+	}, nil
+}
+
+func (s *Store) GetGroup(id string) (*Group, error) {
+	var group Group
+	err := s.db.QueryRow(
+		`SELECT g.id, g.name, g.location, g.created_at, g.updated_at,
+			COALESCE((
+				SELECT SUM(m.total_tokens)
+				FROM conversations c
+				JOIN messages m ON c.id = m.conversation_id
+				WHERE c.group_id = g.id
+			), 0) AS total_tokens
+		FROM groups g
+		WHERE g.id = ?`, id,
+	).Scan(&group.ID, &group.Name, &group.Location, &group.CreatedAt, &group.UpdatedAt, &group.TotalTokens)
+	if err != nil {
+		if err == sql.ErrNoRows {
+			return nil, nil
+		}
+		return nil, fmt.Errorf("failed to get group: %w", err)
+	}
+	return &group, nil
+}
+
+func (s *Store) ListGroups() ([]Group, error) {
+	rows, err := s.db.Query(
+		`SELECT g.id, g.name, g.location, g.created_at, g.updated_at,
+			COALESCE((
+				SELECT SUM(m.total_tokens)
+				FROM conversations c
+				JOIN messages m ON c.id = m.conversation_id
+				WHERE c.group_id = g.id
+			), 0) AS total_tokens
+		FROM groups g
+		ORDER BY g.updated_at DESC`,
+	)
+	if err != nil {
+		return nil, fmt.Errorf("failed to list groups: %w", err)
+	}
+	defer rows.Close()
+
+	var groups []Group
+	for rows.Next() {
+		var g Group
+		if err := rows.Scan(&g.ID, &g.Name, &g.Location, &g.CreatedAt, &g.UpdatedAt, &g.TotalTokens); err != nil {
+			return nil, fmt.Errorf("failed to scan group: %w", err)
+		}
+		groups = append(groups, g)
+	}
+	return groups, nil
+}
+
+func (s *Store) UpdateGroupTitle(id, name string) error {
+	_, err := s.db.Exec(
+		"UPDATE groups SET name = ?, updated_at = ? WHERE id = ?",
+		name, time.Now().UTC(), id,
+	)
+	return err
+}
+
+func (s *Store) DeleteGroup(id string) error {
+	_, err := s.db.Exec("DELETE FROM groups WHERE id = ?", id)
+	return err
+}
+
+func (s *Store) SetGroupLocation(id, location string) error {
+	_, err := s.db.Exec(
+		"UPDATE groups SET location = ?, updated_at = ? WHERE id = ?",
+		location, time.Now().UTC(), id,
+	)
+	return err
+}
+
+func (s *Store) UpdateConversationGroup(id, groupID string) error {
+	_, err := s.db.Exec(
+		"UPDATE conversations SET group_id = ?, updated_at = ? WHERE id = ? AND (group_id IS NULL OR group_id = '')",
+		groupID, time.Now().UTC(), id,
+	)
+	return err
+}
+
+func (s *Store) HasGroupLocation(id string) (bool, error) {
+	var count int
+	err := s.db.QueryRow(
+		"SELECT COUNT(*) FROM groups WHERE id = ? AND location != ''", id,
+	).Scan(&count)
+	if err != nil {
+		return false, err
+	}
+	return count > 0, nil
+}
+
+func (s *Store) CreateConversation(title string, groupID *string) (*Conversation, error) {
+	id := generateID()
+	now := time.Now().UTC()
+	var groupIDVal interface{} = nil
+	if groupID != nil {
+		groupIDVal = *groupID
+	}
+	_, err := s.db.Exec(
+		"INSERT INTO conversations (id, title, group_id, created_at, updated_at) VALUES (?, ?, ?, ?, ?)",
+		id, title, groupIDVal, now, now,
+	)
+	if err != nil {
+		return nil, fmt.Errorf("failed to create conversation: %w", err)
+	}
+	return &Conversation{
+		ID:                  id,
+		Title:               title,
+		GroupID:             groupID,
+		TotalTokens:         0,
+		ContextSummary:      "",
+		ContextSummaryOrder: 0,
+		CreatedAt:           now,
+		UpdatedAt:           now,
+	}, nil
+}
+
+func (s *Store) GetConversation(id string) (*Conversation, error) {
+	var conv Conversation
+	var groupID sql.NullString
+	err := s.db.QueryRow(
+		`SELECT c.id, c.title, c.group_id, c.created_at, c.updated_at,
+			COALESCE((SELECT COUNT(*) FROM messages m WHERE m.conversation_id = c.id), 0) AS message_count,
+			COALESCE((SELECT SUM(m.total_tokens) FROM messages m WHERE m.conversation_id = c.id), 0) AS total_tokens,
+			COALESCE(c.context_summary, '') AS context_summary,
+			COALESCE(c.context_summary_order, 0) AS context_summary_order
+		FROM conversations c
+		WHERE c.id = ?`, id,
+	).Scan(&conv.ID, &conv.Title, &groupID, &conv.CreatedAt, &conv.UpdatedAt, &conv.MessageCount, &conv.TotalTokens, &conv.ContextSummary, &conv.ContextSummaryOrder)
+	if err != nil {
+		if err == sql.ErrNoRows {
+			return nil, nil
+		}
+		return nil, fmt.Errorf("failed to get conversation: %w", err)
+	}
+	if groupID.Valid {
+		conv.GroupID = &groupID.String
+	}
+	return &conv, nil
+}
+
+func (s *Store) ListConversations() ([]Conversation, error) {
+	rows, err := s.db.Query(`
+		SELECT c.id, c.title, c.group_id, c.created_at, c.updated_at,
+			COALESCE((SELECT COUNT(*) FROM messages m WHERE m.conversation_id = c.id), 0) AS message_count,
+			COALESCE((SELECT SUM(m.total_tokens) FROM messages m WHERE m.conversation_id = c.id), 0) AS total_tokens,
+			COALESCE(c.context_summary, '') AS context_summary,
+			COALESCE(c.context_summary_order, 0) AS context_summary_order
+		FROM conversations c
+		ORDER BY c.updated_at DESC
+	`)
+	if err != nil {
+		return nil, fmt.Errorf("failed to list conversations: %w", err)
+	}
+	defer rows.Close()
+
+	var conversations []Conversation
+	for rows.Next() {
+		var conv Conversation
+		var groupID sql.NullString
+		if err := rows.Scan(&conv.ID, &conv.Title, &groupID, &conv.CreatedAt, &conv.UpdatedAt, &conv.MessageCount, &conv.TotalTokens, &conv.ContextSummary, &conv.ContextSummaryOrder); err != nil {
+			return nil, fmt.Errorf("failed to scan conversation: %w", err)
+		}
+		if groupID.Valid {
+			conv.GroupID = &groupID.String
+		}
+		conversations = append(conversations, conv)
+	}
+	return conversations, nil
+}
+
+type GroupedConversations struct {
+	Groups    []GroupWithConversations `json:"groups"`
+	Ungrouped []Conversation           `json:"ungrouped"`
+}
+
+type GroupWithConversations struct {
+	Group
+	Conversations []Conversation `json:"conversations"`
+}
+
+func (s *Store) ListGroupedConversations() (*GroupedConversations, error) {
+	groups, err := s.ListGroups()
+	if err != nil {
+		return nil, err
+	}
+
+	grouped := &GroupedConversations{
+		Groups:    make([]GroupWithConversations, 0),
+		Ungrouped: make([]Conversation, 0),
+	}
+
+	for _, g := range groups {
+		rows, err := s.db.Query(`
+		SELECT c.id, c.title, c.group_id, c.created_at, c.updated_at,
+			COALESCE((SELECT COUNT(*) FROM messages m WHERE m.conversation_id = c.id), 0) AS message_count,
+			COALESCE((SELECT SUM(m.total_tokens) FROM messages m WHERE m.conversation_id = c.id), 0) AS total_tokens,
+			COALESCE(c.context_summary, '') AS context_summary,
+			COALESCE(c.context_summary_order, 0) AS context_summary_order
+		FROM conversations c
+		WHERE c.group_id = ?
+		ORDER BY c.updated_at DESC
+		`, g.ID)
+		if err != nil {
+			return nil, fmt.Errorf("failed to list conversations for group %s: %w", g.ID, err)
+		}
+
+		var convs []Conversation
+		for rows.Next() {
+			var conv Conversation
+			var groupID sql.NullString
+			if err := rows.Scan(&conv.ID, &conv.Title, &groupID, &conv.CreatedAt, &conv.UpdatedAt, &conv.MessageCount, &conv.TotalTokens, &conv.ContextSummary, &conv.ContextSummaryOrder); err != nil {
+				rows.Close()
+				return nil, fmt.Errorf("failed to scan conversation: %w", err)
+			}
+			convs = append(convs, conv)
+		}
+		rows.Close()
+
+		grouped.Groups = append(grouped.Groups, GroupWithConversations{
+			Group:         g,
+			Conversations: convs,
+		})
+	}
+
+	ungroupedRows, err := s.db.Query(`
+		SELECT c.id, c.title, c.group_id, c.created_at, c.updated_at,
+			COALESCE((SELECT COUNT(*) FROM messages m WHERE m.conversation_id = c.id), 0) AS message_count,
+			COALESCE((SELECT SUM(m.total_tokens) FROM messages m WHERE m.conversation_id = c.id), 0) AS total_tokens,
+			COALESCE(c.context_summary, '') AS context_summary,
+			COALESCE(c.context_summary_order, 0) AS context_summary_order
+		FROM conversations c
+		WHERE c.group_id IS NULL
+		ORDER BY c.updated_at DESC
+	`)
+	if err != nil {
+		return nil, fmt.Errorf("failed to list ungrouped conversations: %w", err)
+	}
+	defer ungroupedRows.Close()
+
+	for ungroupedRows.Next() {
+		var conv Conversation
+		var groupID sql.NullString
+		if err := ungroupedRows.Scan(&conv.ID, &conv.Title, &groupID, &conv.CreatedAt, &conv.UpdatedAt, &conv.MessageCount, &conv.TotalTokens, &conv.ContextSummary, &conv.ContextSummaryOrder); err != nil {
+			return nil, fmt.Errorf("failed to scan ungrouped conversation: %w", err)
+		}
+		grouped.Ungrouped = append(grouped.Ungrouped, conv)
+	}
+
+	return grouped, nil
+}
+
+func (s *Store) UpdateConversationTitle(id, title string) error {
+	_, err := s.db.Exec(
+		"UPDATE conversations SET title = ?, updated_at = ? WHERE id = ?",
+		title, time.Now().UTC(), id,
+	)
+	return err
+}
+
+func (s *Store) UpdateConversationContextSummary(id, summary string, summaryOrder int) error {
+	_, err := s.db.Exec(
+		"UPDATE conversations SET context_summary = ?, context_summary_order = ?, updated_at = ? WHERE id = ?",
+		summary, summaryOrder, time.Now().UTC(), id,
+	)
+	return err
+}
+
+func (s *Store) DeleteConversation(id string) error {
+	_, err := s.db.Exec("DELETE FROM conversations WHERE id = ?", id)
+	return err
+}
+
+func (s *Store) AddMessage(convID, role, content string, order int, totalTokens int) error {
+	return s.AddMessageWithMeta(convID, role, content, order, "message", "", "", totalTokens)
+}
+
+func (s *Store) AddMessageWithMeta(convID, role, content string, order int, kind, name, agent string, totalTokens int) error {
+	if kind == "" {
+		kind = "message"
+	}
+	_, err := s.db.Exec(
+		"INSERT INTO messages (conversation_id, role, content, total_tokens, kind, name, agent, \"order\", created_at) VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?)",
+		convID, role, content, totalTokens, kind, name, agent, order, time.Now().UTC(),
+	)
+	if err != nil {
+		return fmt.Errorf("failed to add message: %w", err)
+	}
+	_, err = s.db.Exec(
+		"UPDATE conversations SET updated_at = ? WHERE id = ?",
+		time.Now().UTC(), convID,
+	)
+	return err
+}
+
+func (s *Store) GetMessages(convID string) ([]Message, error) {
+	rows, err := s.db.Query(
+		"SELECT id, conversation_id, role, content, COALESCE(kind, 'message'), COALESCE(name, ''), COALESCE(agent, ''), COALESCE(total_tokens, 0), \"order\", created_at FROM messages WHERE conversation_id = ? ORDER BY \"order\" ASC",
+		convID,
+	)
+	if err != nil {
+		return nil, fmt.Errorf("failed to get messages: %w", err)
+	}
+	defer rows.Close()
+
+	messages := make([]Message, 0)
+	for rows.Next() {
+		var msg Message
+		if err := rows.Scan(&msg.ID, &msg.ConvID, &msg.Role, &msg.Content, &msg.Kind, &msg.Name, &msg.Agent, &msg.TotalTokens, &msg.Order, &msg.CreatedAt); err != nil {
+			return nil, fmt.Errorf("failed to scan message: %w", err)
+		}
+		messages = append(messages, msg)
+	}
+	return messages, nil
+}
+
+func (s *Store) DeleteMessages(convID string) error {
+	_, err := s.db.Exec("DELETE FROM messages WHERE conversation_id = ?", convID)
+	return err
+}
+
+func (s *Store) Close() error {
+	return s.db.Close()
+}
--- a/db/db_test.go
+++ b/db/db_test.go
@@ -0,0 +1,211 @@
+package db
+
+import (
+	"database/sql"
+	"path/filepath"
+	"testing"
+)
+
+func newTempStore(t *testing.T) *Store {
+	t.Helper()
+
+	dbFile := filepath.Join(t.TempDir(), "test.db")
+	conn, err := sql.Open("sqlite", dbFile+"?_busy_timeout=5000&_journal=WAL")
+	if err != nil {
+		t.Fatalf("sql.Open returned error: %v", err)
+	}
+
+	store := &Store{db: conn}
+	if err := store.createTables(); err != nil {
+		t.Fatalf("createTables returned error: %v", err)
+	}
+
+	t.Cleanup(func() {
+		_ = conn.Close()
+	})
+
+	return store
+}
+
+func TestSetGroupLocationUpdatesExistingLocation(t *testing.T) {
+	store := newTempStore(t)
+
+	group, err := store.CreateGroup("Workspace")
+	if err != nil {
+		t.Fatalf("CreateGroup returned error: %v", err)
+	}
+
+	if err := store.SetGroupLocation(group.ID, "/tmp/one"); err != nil {
+		t.Fatalf("SetGroupLocation returned error: %v", err)
+	}
+
+	updated, err := store.GetGroup(group.ID)
+	if err != nil {
+		t.Fatalf("GetGroup returned error: %v", err)
+	}
+	if updated.Location != "/tmp/one" {
+		t.Fatalf("location after first update = %q, want %q", updated.Location, "/tmp/one")
+	}
+
+	if err := store.SetGroupLocation(group.ID, "/tmp/two"); err != nil {
+		t.Fatalf("SetGroupLocation returned error: %v", err)
+	}
+
+	updated, err = store.GetGroup(group.ID)
+	if err != nil {
+		t.Fatalf("GetGroup returned error: %v", err)
+	}
+	if updated.Location != "/tmp/two" {
+		t.Fatalf("location after second update = %q, want %q", updated.Location, "/tmp/two")
+	}
+}
+
+func TestUpdateConversationGroupAttachesUngroupedConversation(t *testing.T) {
+	store := newTempStore(t)
+
+	group, err := store.CreateGroup("Workspace")
+	if err != nil {
+		t.Fatalf("CreateGroup returned error: %v", err)
+	}
+
+	conv, err := store.CreateConversation("Chat", nil)
+	if err != nil {
+		t.Fatalf("CreateConversation returned error: %v", err)
+	}
+
+	if err := store.UpdateConversationGroup(conv.ID, group.ID); err != nil {
+		t.Fatalf("UpdateConversationGroup returned error: %v", err)
+	}
+
+	updated, err := store.GetConversation(conv.ID)
+	if err != nil {
+		t.Fatalf("GetConversation returned error: %v", err)
+	}
+	if updated.GroupID == nil {
+		t.Fatal("conversation group ID is nil, want a group ID")
+	}
+	if got, want := *updated.GroupID, group.ID; got != want {
+		t.Fatalf("conversation group ID = %q, want %q", got, want)
+	}
+}
+
+func TestAddMessageWithMetaPersistsKindNameAndAgent(t *testing.T) {
+	store := newTempStore(t)
+
+	conv, err := store.CreateConversation("Chat", nil)
+	if err != nil {
+		t.Fatalf("CreateConversation returned error: %v", err)
+	}
+
+	if err := store.AddMessageWithMeta(conv.ID, "assistant", "Thinking", 1, "thinking", "", "Planner", 42); err != nil {
+		t.Fatalf("AddMessageWithMeta returned error: %v", err)
+	}
+
+	messages, err := store.GetMessages(conv.ID)
+	if err != nil {
+		t.Fatalf("GetMessages returned error: %v", err)
+	}
+	if len(messages) != 1 {
+		t.Fatalf("message count = %d, want 1", len(messages))
+	}
+	if got, want := messages[0].Kind, "thinking"; got != want {
+		t.Fatalf("message kind = %q, want %q", got, want)
+	}
+	if got, want := messages[0].Name, ""; got != want {
+		t.Fatalf("message name = %q, want %q", got, want)
+	}
+	if got, want := messages[0].Agent, "Planner"; got != want {
+		t.Fatalf("message agent = %q, want %q", got, want)
+	}
+	if got, want := messages[0].TotalTokens, 42; got != want {
+		t.Fatalf("message total tokens = %d, want %d", got, want)
+	}
+}
+
+func TestConversationAndGroupTokenTotalsAggregate(t *testing.T) {
+	store := newTempStore(t)
+
+	group, err := store.CreateGroup("Workspace")
+	if err != nil {
+		t.Fatalf("CreateGroup returned error: %v", err)
+	}
+
+	conv1, err := store.CreateConversation("One", &group.ID)
+	if err != nil {
+		t.Fatalf("CreateConversation returned error: %v", err)
+	}
+	conv2, err := store.CreateConversation("Two", &group.ID)
+	if err != nil {
+		t.Fatalf("CreateConversation returned error: %v", err)
+	}
+	ungrouped, err := store.CreateConversation("Three", nil)
+	if err != nil {
+		t.Fatalf("CreateConversation returned error: %v", err)
+	}
+
+	if err := store.AddMessageWithMeta(conv1.ID, "assistant", "A", 1, "message", "", "Planner", 11); err != nil {
+		t.Fatalf("AddMessageWithMeta returned error: %v", err)
+	}
+	if err := store.AddMessageWithMeta(conv1.ID, "assistant", "B", 2, "message", "", "Planner", 7); err != nil {
+		t.Fatalf("AddMessageWithMeta returned error: %v", err)
+	}
+	if err := store.AddMessageWithMeta(conv2.ID, "assistant", "C", 1, "message", "", "Planner", 5); err != nil {
+		t.Fatalf("AddMessageWithMeta returned error: %v", err)
+	}
+	if err := store.AddMessageWithMeta(ungrouped.ID, "assistant", "D", 1, "message", "", "Planner", 3); err != nil {
+		t.Fatalf("AddMessageWithMeta returned error: %v", err)
+	}
+
+	conversations, err := store.ListConversations()
+	if err != nil {
+		t.Fatalf("ListConversations returned error: %v", err)
+	}
+	totalsByID := make(map[string]int, len(conversations))
+	for _, conv := range conversations {
+		totalsByID[conv.ID] = conv.TotalTokens
+	}
+	if got, want := totalsByID[conv1.ID], 18; got != want {
+		t.Fatalf("conversation one total tokens = %d, want %d", got, want)
+	}
+	if got, want := totalsByID[conv2.ID], 5; got != want {
+		t.Fatalf("conversation two total tokens = %d, want %d", got, want)
+	}
+	if got, want := totalsByID[ungrouped.ID], 3; got != want {
+		t.Fatalf("ungrouped conversation total tokens = %d, want %d", got, want)
+	}
+
+	groups, err := store.ListGroups()
+	if err != nil {
+		t.Fatalf("ListGroups returned error: %v", err)
+	}
+	if len(groups) != 1 {
+		t.Fatalf("group count = %d, want 1", len(groups))
+	}
+	if got, want := groups[0].TotalTokens, 23; got != want {
+		t.Fatalf("group total tokens = %d, want %d", got, want)
+	}
+}
+
+func TestUpdateConversationContextSummaryPersistsSummaryAndOrder(t *testing.T) {
+	store := newTempStore(t)
+
+	conv, err := store.CreateConversation("Chat", nil)
+	if err != nil {
+		t.Fatalf("CreateConversation returned error: %v", err)
+	}
+
+	if err := store.UpdateConversationContextSummary(conv.ID, "compressed memory", 12); err != nil {
+		t.Fatalf("UpdateConversationContextSummary returned error: %v", err)
+	}
+
+	updated, err := store.GetConversation(conv.ID)
+	if err != nil {
+		t.Fatalf("GetConversation returned error: %v", err)
+	}
+	if got, want := updated.ContextSummary, "compressed memory"; got != want {
+		t.Fatalf("context summary = %q, want %q", got, want)
+	}
+	if got, want := updated.ContextSummaryOrder, 12; got != want {
+		t.Fatalf("context summary order = %d, want %d", got, want)
+	}
+}
--- a/go.mod
+++ b/go.mod
@@ -0,0 +1,19 @@
+module gocoder
+
+go 1.26.2
+
+require (
+	github.com/google/uuid v1.6.0
+	modernc.org/sqlite v1.49.1
+)
+
+require (
+	github.com/dustin/go-humanize v1.0.1 // indirect
+	github.com/mattn/go-isatty v0.0.20 // indirect
+	github.com/ncruces/go-strftime v1.0.0 // indirect
+	github.com/remyoudompheng/bigfft v0.0.0-20230129092748-24d4a6f8daec // indirect
+	golang.org/x/sys v0.42.0 // indirect
+	modernc.org/libc v1.72.0 // indirect
+	modernc.org/mathutil v1.7.1 // indirect
+	modernc.org/memory v1.11.0 // indirect
+)
--- a/go.sum
+++ b/go.sum
@@ -0,0 +1,51 @@
+github.com/dustin/go-humanize v1.0.1 h1:GzkhY7T5VNhEkwH0PVJgjz+fX1rhBrR7pRT3mDkpeCY=
+github.com/dustin/go-humanize v1.0.1/go.mod h1:Mu1zIs6XwVuF/gI1OepvI0qD18qycQx+mFykh5fBlto=
+github.com/google/pprof v0.0.0-20250317173921-a4b03ec1a45e h1:ijClszYn+mADRFY17kjQEVQ1XRhq2/JR1M3sGqeJoxs=
+github.com/google/pprof v0.0.0-20250317173921-a4b03ec1a45e/go.mod h1:boTsfXsheKC2y+lKOCMpSfarhxDeIzfZG1jqGcPl3cA=
+github.com/google/uuid v1.6.0 h1:NIvaJDMOsjHA8n1jAhLSgzrAzy1Hgr+hNrb57e+94F0=
+github.com/google/uuid v1.6.0/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=
+github.com/hashicorp/golang-lru/v2 v2.0.7 h1:a+bsQ5rvGLjzHuww6tVxozPZFVghXaHOwFs4luLUK2k=
+github.com/hashicorp/golang-lru/v2 v2.0.7/go.mod h1:QeFd9opnmA6QUJc5vARoKUSoFhyfM2/ZepoAG6RGpeM=
+github.com/mattn/go-isatty v0.0.20 h1:xfD0iDuEKnDkl03q4limB+vH+GxLEtL/jb4xVJSWWEY=
+github.com/mattn/go-isatty v0.0.20/go.mod h1:W+V8PltTTMOvKvAeJH7IuucS94S2C6jfK/D7dTCTo3Y=
+github.com/ncruces/go-strftime v1.0.0 h1:HMFp8mLCTPp341M/ZnA4qaf7ZlsbTc+miZjCLOFAw7w=
+github.com/ncruces/go-strftime v1.0.0/go.mod h1:Fwc5htZGVVkseilnfgOVb9mKy6w1naJmn9CehxcKcls=
+github.com/remyoudompheng/bigfft v0.0.0-20230129092748-24d4a6f8daec h1:W09IVJc94icq4NjY3clb7Lk8O1qJ8BdBEF8z0ibU0rE=
+github.com/remyoudompheng/bigfft v0.0.0-20230129092748-24d4a6f8daec/go.mod h1:qqbHyh8v60DhA7CoWK5oRCqLrMHRGoxYCSS9EjAz6Eo=
+golang.org/x/mod v0.33.0 h1:tHFzIWbBifEmbwtGz65eaWyGiGZatSrT9prnU8DbVL8=
+golang.org/x/mod v0.33.0/go.mod h1:swjeQEj+6r7fODbD2cqrnje9PnziFuw4bmLbBZFrQ5w=
+golang.org/x/sync v0.20.0 h1:e0PTpb7pjO8GAtTs2dQ6jYa5BWYlMuX047Dco/pItO4=
+golang.org/x/sync v0.20.0/go.mod h1:9xrNwdLfx4jkKbNva9FpL6vEN7evnE43NNNJQ2LF3+0=
+golang.org/x/sys v0.6.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/sys v0.42.0 h1:omrd2nAlyT5ESRdCLYdm3+fMfNFE/+Rf4bDIQImRJeo=
+golang.org/x/sys v0.42.0/go.mod h1:4GL1E5IUh+htKOUEOaiffhrAeqysfVGipDYzABqnCmw=
+golang.org/x/tools v0.42.0 h1:uNgphsn75Tdz5Ji2q36v/nsFSfR/9BRFvqhGBaJGd5k=
+golang.org/x/tools v0.42.0/go.mod h1:Ma6lCIwGZvHK6XtgbswSoWroEkhugApmsXyrUmBhfr0=
+modernc.org/cc/v4 v4.27.3 h1:uNCgn37E5U09mTv1XgskEVUJ8ADKpmFMPxzGJ0TSo+U=
+modernc.org/cc/v4 v4.27.3/go.mod h1:3YjcbCqhoTTHPycJDRl2WZKKFj0nwcOIPBfEZK0Hdk8=
+modernc.org/ccgo/v4 v4.32.4 h1:L5OB8rpEX4ZsXEQwGozRfJyJSFHbbNVOoQ59DU9/KuU=
+modernc.org/ccgo/v4 v4.32.4/go.mod h1:lY7f+fiTDHfcv6YlRgSkxYfhs+UvOEEzj49jAn2TOx0=
+modernc.org/fileutil v1.4.0 h1:j6ZzNTftVS054gi281TyLjHPp6CPHr2KCxEXjEbD6SM=
+modernc.org/fileutil v1.4.0/go.mod h1:EqdKFDxiByqxLk8ozOxObDSfcVOv/54xDs/DUHdvCUU=
+modernc.org/gc/v2 v2.6.5 h1:nyqdV8q46KvTpZlsw66kWqwXRHdjIlJOhG6kxiV/9xI=
+modernc.org/gc/v2 v2.6.5/go.mod h1:YgIahr1ypgfe7chRuJi2gD7DBQiKSLMPgBQe9oIiito=
+modernc.org/gc/v3 v3.1.2 h1:ZtDCnhonXSZexk/AYsegNRV1lJGgaNZJuKjJSWKyEqo=
+modernc.org/gc/v3 v3.1.2/go.mod h1:HFK/6AGESC7Ex+EZJhJ2Gni6cTaYpSMmU/cT9RmlfYY=
+modernc.org/goabi0 v0.2.0 h1:HvEowk7LxcPd0eq6mVOAEMai46V+i7Jrj13t4AzuNks=
+modernc.org/goabi0 v0.2.0/go.mod h1:CEFRnnJhKvWT1c1JTI3Avm+tgOWbkOu5oPA8eH8LnMI=
+modernc.org/libc v1.72.0 h1:IEu559v9a0XWjw0DPoVKtXpO2qt5NVLAnFaBbjq+n8c=
+modernc.org/libc v1.72.0/go.mod h1:tTU8DL8A+XLVkEY3x5E/tO7s2Q/q42EtnNWda/L5QhQ=
+modernc.org/mathutil v1.7.1 h1:GCZVGXdaN8gTqB1Mf/usp1Y/hSqgI2vAGGP4jZMCxOU=
+modernc.org/mathutil v1.7.1/go.mod h1:4p5IwJITfppl0G4sUEDtCr4DthTaT47/N3aT6MhfgJg=
+modernc.org/memory v1.11.0 h1:o4QC8aMQzmcwCK3t3Ux/ZHmwFPzE6hf2Y5LbkRs+hbI=
+modernc.org/memory v1.11.0/go.mod h1:/JP4VbVC+K5sU2wZi9bHoq2MAkCnrt2r98UGeSK7Mjw=
+modernc.org/opt v0.1.4 h1:2kNGMRiUjrp4LcaPuLY2PzUfqM/w9N23quVwhKt5Qm8=
+modernc.org/opt v0.1.4/go.mod h1:03fq9lsNfvkYSfxrfUhZCWPk1lm4cq4N+Bh//bEtgns=
+modernc.org/sortutil v1.2.1 h1:+xyoGf15mM3NMlPDnFqrteY07klSFxLElE2PVuWIJ7w=
+modernc.org/sortutil v1.2.1/go.mod h1:7ZI3a3REbai7gzCLcotuw9AC4VZVpYMjDzETGsSMqJE=
+modernc.org/sqlite v1.49.1 h1:dYGHTKcX1sJ+EQDnUzvz4TJ5GbuvhNJa8Fg6ElGx73U=
+modernc.org/sqlite v1.49.1/go.mod h1:m0w8xhwYUVY3H6pSDwc3gkJ/irZT/0YEXwBlhaxQEew=
+modernc.org/strutil v1.2.1 h1:UneZBkQA+DX2Rp35KcM69cSsNES9ly8mQWD71HKlOA0=
+modernc.org/strutil v1.2.1/go.mod h1:EHkiggD70koQxjVdSBM3JKM7k6L0FbGE5eymy9i3B9A=
+modernc.org/token v1.1.0 h1:Xl7Ap9dKaEs5kLoOQeQmPWevfnk/DM5qcLcYlA8ys6Y=
+modernc.org/token v1.1.0/go.mod h1:UGzOrNV1mAFSEB63lOFHIpNRUVMvYTc6yu1SMY/XTDM=
--- a/main.go
+++ b/main.go
--- a/main_test.go
+++ b/main_test.go
@@ -0,0 +1,614 @@
+package main
+
+import (
+	"encoding/json"
+	"os"
+	"path/filepath"
+	"reflect"
+	"testing"
+
+	"gocoder/agents"
+	"gocoder/db"
+)
+
+func TestResolveWorkspaceGroupIDPrefersConversationGroup(t *testing.T) {
+	convGroupID := "conversation-group"
+	conv := &db.Conversation{GroupID: &convGroupID}
+
+	got := resolveWorkspaceGroupID(conv, "request-group")
+	if got != convGroupID {
+		t.Fatalf("resolveWorkspaceGroupID returned %q, want %q", got, convGroupID)
+	}
+}
+
+func TestResolveWorkspaceGroupIDFallsBackToRequestGroup(t *testing.T) {
+	got := resolveWorkspaceGroupID(nil, "request-group")
+	if got != "request-group" {
+		t.Fatalf("resolveWorkspaceGroupID returned %q, want %q", got, "request-group")
+	}
+}
+
+func TestResolveWorkspaceGroupIDReturnsEmptyWhenUnset(t *testing.T) {
+	conv := &db.Conversation{}
+
+	got := resolveWorkspaceGroupID(conv, "")
+	if got != "" {
+		t.Fatalf("resolveWorkspaceGroupID returned %q, want empty string", got)
+	}
+}
+
+func TestFriendlyToolDisplayName(t *testing.T) {
+	cases := map[string]string{
+		"planner_agent":    "Planner",
+		"programmer_agent": "Programmer",
+		"qa_agent":         "QA",
+		"write_file":       "write_file",
+	}
+
+	for input, want := range cases {
+		if got := friendlyToolDisplayName(input); got != want {
+			t.Fatalf("friendlyToolDisplayName(%q) = %q, want %q", input, got, want)
+		}
+	}
+}
+
+func TestStageStatusKind(t *testing.T) {
+	cases := map[string]string{
+		"Planner":    "planner",
+		"Programmer": "programmer",
+		"QA":         "qa",
+		"Manager":    "manager",
+		"Other":      "thinking",
+	}
+
+	for input, want := range cases {
+		if got := stageStatusKind(input); got != want {
+			t.Fatalf("stageStatusKind(%q) = %q, want %q", input, got, want)
+		}
+	}
+}
+
+func TestSubagentNoResponseError(t *testing.T) {
+	got := subagentNoResponseError("QA", "it kept calling tools but never produced a final answer before hitting the 20-loop limit")
+	want := "QA returned no response: it kept calling tools but never produced a final answer before hitting the 20-loop limit"
+	if got != want {
+		t.Fatalf("subagentNoResponseError returned %q, want %q", got, want)
+	}
+}
+
+func TestSubagentNoResponseErrorDefaultsStageName(t *testing.T) {
+	got := subagentNoResponseError("  ", "  ")
+	want := "Subagent returned no response"
+	if got != want {
+		t.Fatalf("subagentNoResponseError returned %q, want %q", got, want)
+	}
+}
+
+func TestCollectThinkingAndContentPrefersExplicitReasoning(t *testing.T) {
+	thinking, content := collectThinkingAndContent("  plan  ", "", "final answer")
+	if got, want := thinking, "plan"; got != want {
+		t.Fatalf("thinking = %q, want %q", got, want)
+	}
+	if got, want := content, "final answer"; got != want {
+		t.Fatalf("content = %q, want %q", got, want)
+	}
+}
+
+func TestSplitThinkTagsFromContentSeparatesThinkingFromAnswer(t *testing.T) {
+	thinking, content := splitThinkTagsFromContent("before <think>inner</think> after")
+	if got, want := thinking, "inner"; got != want {
+		t.Fatalf("thinking = %q, want %q", got, want)
+	}
+	if got, want := content, "before  after"; got != want {
+		t.Fatalf("content = %q, want %q", got, want)
+	}
+}
+
+func TestFinalizeStreamedToolCallsOrdersAndConcatenatesArguments(t *testing.T) {
+	toolCalls := map[int]*streamedToolCall{}
+	appendStreamedToolCall(toolCalls, LMStudioStreamToolCallDelta{
+		Index: 1,
+		ID:    "call_2",
+		Type:  "function",
+		Function: LMStudioStreamToolCallFunctionDelta{
+			Name:      "qa_agent",
+			Arguments: `{"task":"Check`,
+		},
+	})
+	appendStreamedToolCall(toolCalls, LMStudioStreamToolCallDelta{
+		Index: 0,
+		ID:    "call_1",
+		Type:  "function",
+		Function: LMStudioStreamToolCallFunctionDelta{
+			Name:      "planner_agent",
+			Arguments: `{"task":"Plan"}`,
+		},
+	})
+	appendStreamedToolCall(toolCalls, LMStudioStreamToolCallDelta{
+		Index: 1,
+		Function: LMStudioStreamToolCallFunctionDelta{
+			Arguments: ` the result"}`,
+		},
+	})
+
+	got := finalizeStreamedToolCalls(toolCalls)
+	if len(got) != 2 {
+		t.Fatalf("finalizeStreamedToolCalls returned %d calls, want 2", len(got))
+	}
+	if got[0].ID != "call_1" || got[0].Function.Name != "planner_agent" {
+		t.Fatalf("first tool call = %+v, want planner_agent call_1", got[0])
+	}
+	if string(got[0].Function.Arguments) != `{"task":"Plan"}` {
+		t.Fatalf("first tool call args = %s, want %s", string(got[0].Function.Arguments), `{"task":"Plan"}`)
+	}
+	if got[1].ID != "call_2" || got[1].Function.Name != "qa_agent" {
+		t.Fatalf("second tool call = %+v, want qa_agent call_2", got[1])
+	}
+	if string(got[1].Function.Arguments) != `{"task":"Check the result"}` {
+		t.Fatalf("second tool call args = %s, want %s", string(got[1].Function.Arguments), `{"task":"Check the result"}`)
+	}
+}
+
+func TestAPIMessagesKeepEmptyContentFields(t *testing.T) {
+	req := apiRequest{
+		Model: "test-model",
+		Messages: []apiMessagePart{
+			{
+				Role:    "assistant",
+				Content: "",
+				ToolCalls: []ToolCallAI{
+					{
+						ID:   "call_1",
+						Type: "function",
+						Function: ToolCallFunction{
+							Name:      "planner_agent",
+							Arguments: ToolCallArguments(`{"task":"Plan"}`),
+						},
+					},
+				},
+			},
+			{
+				Role:       "tool",
+				Content:    "",
+				ToolCallID: "call_1",
+				Name:       "planner_agent",
+			},
+		},
+	}
+
+	data, err := json.Marshal(req)
+	if err != nil {
+		t.Fatalf("json.Marshal returned error: %v", err)
+	}
+
+	var decoded struct {
+		Messages []struct {
+			Content   string `json:"content"`
+			ToolCalls []struct {
+				Function struct {
+					Arguments string `json:"arguments"`
+				} `json:"function"`
+			} `json:"tool_calls"`
+		} `json:"messages"`
+	}
+	if err := json.Unmarshal(data, &decoded); err != nil {
+		t.Fatalf("json.Unmarshal returned error: %v", err)
+	}
+	if len(decoded.Messages) != 2 {
+		t.Fatalf("decoded %d messages, want 2", len(decoded.Messages))
+	}
+	if got, want := decoded.Messages[0].Content, ""; got != want {
+		t.Fatalf("assistant message content = %q, want %q", got, want)
+	}
+	if len(decoded.Messages[0].ToolCalls) != 1 {
+		t.Fatalf("assistant message tool call count = %d, want 1", len(decoded.Messages[0].ToolCalls))
+	}
+	if got, want := decoded.Messages[0].ToolCalls[0].Function.Arguments, `{"task":"Plan"}`; got != want {
+		t.Fatalf("assistant tool call arguments = %q, want %q", got, want)
+	}
+	if got, want := decoded.Messages[1].Content, ""; got != want {
+		t.Fatalf("tool message content = %q, want %q", got, want)
+	}
+}
+
+func TestBuildPromptHistoryInjectsSummaryAndSkipsEarlierMessages(t *testing.T) {
+	history := []db.Message{
+		{Order: 1, Role: "user", Kind: "message", Content: "old user"},
+		{Order: 2, Role: "assistant", Kind: "message", Content: "old assistant"},
+		{Order: 3, Role: "user", Kind: "message", Content: "new user"},
+	}
+
+	got := buildPromptHistory(history, "compressed memory", 2)
+	if len(got) != 2 {
+		t.Fatalf("buildPromptHistory returned %d messages, want 2", len(got))
+	}
+	if got[0].Role != "system" || got[0].Content == "" {
+		t.Fatalf("buildPromptHistory did not inject a system summary message: %+v", got[0])
+	}
+	if got[1].Content != "new user" {
+		t.Fatalf("buildPromptHistory kept wrong history tail: %+v", got[1])
+	}
+}
+
+func TestAgentRegistryIncludesCompactor(t *testing.T) {
+	registry := agents.NewAgentRegistry()
+	compactor := registry.GetByType("compactor")
+	if compactor == nil {
+		t.Fatal("expected compactor agent to be registered")
+	}
+	if got, want := compactor.DisplayName(), "Compactor"; got != want {
+		t.Fatalf("compactor display name = %q, want %q", got, want)
+	}
+}
+
+func TestConfiguredCompactionRatiosDefaultToSafeValues(t *testing.T) {
+	originalTrigger := config.LLM.ContextCompactionTriggerRatio
+	originalTarget := config.LLM.ContextCompactionTargetRatio
+	t.Cleanup(func() {
+		config.LLM.ContextCompactionTriggerRatio = originalTrigger
+		config.LLM.ContextCompactionTargetRatio = originalTarget
+	})
+
+	config.LLM.ContextCompactionTriggerRatio = 0
+	config.LLM.ContextCompactionTargetRatio = 0
+
+	if got, want := configuredCompactionTriggerRatio(), 0.80; got != want {
+		t.Fatalf("configuredCompactionTriggerRatio() = %v, want %v", got, want)
+	}
+	if got, want := configuredCompactionTargetRatio(), 0.70; got != want {
+		t.Fatalf("configuredCompactionTargetRatio() = %v, want %v", got, want)
+	}
+}
+
+func TestDefaultConfigUsesBuiltInServerDefaults(t *testing.T) {
+	cfg := defaultConfig()
+	if got, want := cfg.Server.Addr, defaultServerAddr; got != want {
+		t.Fatalf("default server addr = %q, want %q", got, want)
+	}
+	if got, want := cfg.Server.Host, defaultServerHost; got != want {
+		t.Fatalf("default server host = %q, want %q", got, want)
+	}
+	if cfg.LLM.AutoOpenReasoning == nil || !*cfg.LLM.AutoOpenReasoning {
+		t.Fatalf("default auto_open_reasoning = %+v, want true", cfg.LLM.AutoOpenReasoning)
+	}
+}
+
+func TestNormalizeConfigDefaultsAutoOpenReasoning(t *testing.T) {
+	cfg := Config{}
+
+	normalizeConfig(&cfg)
+
+	if cfg.LLM.AutoOpenReasoning == nil || !*cfg.LLM.AutoOpenReasoning {
+		t.Fatalf("normalizeConfig did not default auto_open_reasoning to true: %+v", cfg.LLM.AutoOpenReasoning)
+	}
+}
+
+func TestValidateContextCompactionSettingsRejectsInvalidValues(t *testing.T) {
+	cases := []contextCompactionSettings{
+		{ContextTokens: 0, ContextCompactionTriggerRatio: 0.8, ContextCompactionTargetRatio: 0.7},
+		{ContextTokens: 100, ContextCompactionTriggerRatio: 1, ContextCompactionTargetRatio: 0.7},
+		{ContextTokens: 100, ContextCompactionTriggerRatio: 0.8, ContextCompactionTargetRatio: 0.8},
+	}
+
+	for _, tc := range cases {
+		if err := validateContextCompactionSettings(tc); err == nil {
+			t.Fatalf("validateContextCompactionSettings(%+v) = nil, want error", tc)
+		}
+	}
+}
+
+func TestValidateAppSettingsRejectsInvalidValues(t *testing.T) {
+	base := defaultConfig()
+	base.LLM.Provider = "openai"
+	base.LLM.BaseURL = "http://localhost:1234/v1"
+	base.LLM.Model = "qwen/qwen3.6-35b-a3b"
+
+	cases := []struct {
+		name   string
+		mutate func(*AppSettings)
+	}{
+		{name: "missing server addr", mutate: func(s *AppSettings) { s.ServerAddr = "" }},
+		{name: "missing server host", mutate: func(s *AppSettings) { s.ServerHost = "" }},
+		{name: "missing provider", mutate: func(s *AppSettings) { s.Provider = "" }},
+	}
+
+	for _, tc := range cases {
+		settings := AppSettings{
+			LLMConfig:  base.LLM,
+			ServerAddr: base.Server.Addr,
+			ServerHost: base.Server.Host,
+		}
+		tc.mutate(&settings)
+		if err := validateAppSettings(settings); err == nil {
+			t.Fatalf("validateAppSettings(%s) = nil, want error", tc.name)
+		}
+	}
+}
+
+func TestValidateLLMSettingsRejectsInvalidValues(t *testing.T) {
+	base := LLMConfig{
+		Provider:                      "openai",
+		BaseURL:                       "http://localhost:1234/v1",
+		APIKey:                        "lm-studio",
+		Model:                         "qwen/qwen3.6-35b-a3b",
+		ContextTokens:                 1024,
+		ContextCompactionTriggerRatio: 0.8,
+		ContextCompactionTargetRatio:  0.7,
+		Temperature:                   0.3,
+		MaxTokens:                     1024,
+		TopP:                          1.0,
+		FrequencyPenalty:              0,
+		PresencePenalty:               0,
+	}
+
+	cases := []struct {
+		name   string
+		mutate func(*LLMConfig)
+	}{
+		{name: "missing provider", mutate: func(cfg *LLMConfig) { cfg.Provider = "" }},
+		{name: "missing base url", mutate: func(cfg *LLMConfig) { cfg.BaseURL = "" }},
+		{name: "missing model", mutate: func(cfg *LLMConfig) { cfg.Model = "" }},
+		{name: "invalid max tokens", mutate: func(cfg *LLMConfig) { cfg.MaxTokens = 0 }},
+		{name: "invalid top p", mutate: func(cfg *LLMConfig) { cfg.TopP = 0 }},
+		{name: "invalid context tokens", mutate: func(cfg *LLMConfig) { cfg.ContextTokens = 0 }},
+		{name: "invalid trigger ratio", mutate: func(cfg *LLMConfig) { cfg.ContextCompactionTriggerRatio = 1 }},
+		{name: "invalid target ratio", mutate: func(cfg *LLMConfig) { cfg.ContextCompactionTargetRatio = 0.8 }},
+		{name: "invalid reasoning effort", mutate: func(cfg *LLMConfig) { cfg.ReasoningEffort = "ultra" }},
+	}
+
+	for _, tc := range cases {
+		cfg := base
+		tc.mutate(&cfg)
+		if err := validateLLMSettings(cfg); err == nil {
+			t.Fatalf("validateLLMSettings(%s) = nil, want error", tc.name)
+		}
+	}
+}
+
+func TestValidateLLMSettingsAcceptsReasoningEffortValues(t *testing.T) {
+	base := LLMConfig{
+		Provider:                      "openai",
+		BaseURL:                       "http://localhost:1234/v1",
+		APIKey:                        "lm-studio",
+		Model:                         "qwen/qwen3.6-35b-a3b",
+		ContextTokens:                 1024,
+		ContextCompactionTriggerRatio: 0.8,
+		ContextCompactionTargetRatio:  0.7,
+		Temperature:                   0.3,
+		MaxTokens:                     1024,
+		TopP:                          1.0,
+		FrequencyPenalty:              0,
+		PresencePenalty:               0,
+	}
+
+	for _, effort := range []string{"", "low", "medium", "high", " HIGH "} {
+		cfg := base
+		cfg.ReasoningEffort = effort
+		if err := validateLLMSettings(cfg); err != nil {
+			t.Fatalf("validateLLMSettings(%q) returned error: %v", effort, err)
+		}
+	}
+}
+
+func TestUpdateContextCompactionSettingsPersistsToDisk(t *testing.T) {
+	original := currentConfig()
+	t.Cleanup(func() {
+		setConfig(original)
+	})
+
+	tempDir := t.TempDir()
+	originalWD, err := os.Getwd()
+	if err != nil {
+		t.Fatalf("os.Getwd returned error: %v", err)
+	}
+	t.Cleanup(func() {
+		_ = os.Chdir(originalWD)
+	})
+	if err := os.Chdir(tempDir); err != nil {
+		t.Fatalf("os.Chdir returned error: %v", err)
+	}
+
+	configCopy := defaultConfig()
+	configCopy.Server.Addr = ":9999"
+	configCopy.Server.Host = "localhost"
+	configCopy.LLM.ContextTokens = 512
+	configCopy.LLM.ContextCompactionTriggerRatio = 0.8
+	configCopy.LLM.ContextCompactionTargetRatio = 0.7
+	setConfig(configCopy)
+
+	settings := contextCompactionSettings{
+		ContextTokens:                 2048,
+		ContextCompactionTriggerRatio: 0.85,
+		ContextCompactionTargetRatio:  0.65,
+	}
+	if err := updateContextCompactionSettings(settings); err != nil {
+		t.Fatalf("updateContextCompactionSettings returned error: %v", err)
+	}
+
+	updated := currentConfig()
+	if got, want := updated.LLM.ContextTokens, settings.ContextTokens; got != want {
+		t.Fatalf("updated context tokens = %d, want %d", got, want)
+	}
+	if got, want := updated.LLM.ContextCompactionTriggerRatio, settings.ContextCompactionTriggerRatio; got != want {
+		t.Fatalf("updated trigger ratio = %v, want %v", got, want)
+	}
+	if got, want := updated.LLM.ContextCompactionTargetRatio, settings.ContextCompactionTargetRatio; got != want {
+		t.Fatalf("updated target ratio = %v, want %v", got, want)
+	}
+	if got, want := updated.Server.Addr, configCopy.Server.Addr; got != want {
+		t.Fatalf("updated server addr = %q, want %q", got, want)
+	}
+	if got, want := updated.Server.Host, configCopy.Server.Host; got != want {
+		t.Fatalf("updated server host = %q, want %q", got, want)
+	}
+
+	data, err := os.ReadFile(filepath.Join(tempDir, "config.json"))
+	if err != nil {
+		t.Fatalf("os.ReadFile returned error: %v", err)
+	}
+	if len(data) == 0 {
+		t.Fatal("config.json was not written")
+	}
+}
+
+func TestUpdateLLMSettingsPersistsFullConfig(t *testing.T) {
+	original := currentConfig()
+	t.Cleanup(func() {
+		setConfig(original)
+	})
+
+	tempDir := t.TempDir()
+	originalWD, err := os.Getwd()
+	if err != nil {
+		t.Fatalf("os.Getwd returned error: %v", err)
+	}
+	t.Cleanup(func() {
+		_ = os.Chdir(originalWD)
+	})
+	if err := os.Chdir(tempDir); err != nil {
+		t.Fatalf("os.Chdir returned error: %v", err)
+	}
+
+	configCopy := defaultConfig()
+	configCopy.Server.Addr = ":9999"
+	configCopy.Server.Host = "localhost"
+	configCopy.LLM = LLMConfig{
+		Provider:                      "openai",
+		BaseURL:                       "http://localhost:4321/v1",
+		APIKey:                        "new-key",
+		Model:                         "test-model",
+		ContextTokens:                 4096,
+		ContextCompactionTriggerRatio: 0.85,
+		ContextCompactionTargetRatio:  0.6,
+		Temperature:                   0.2,
+		MaxTokens:                     2048,
+		TopP:                          0.95,
+		FrequencyPenalty:              0.25,
+		PresencePenalty:               0.1,
+	}
+	setConfig(configCopy)
+
+	settings := LLMConfig{
+		Provider:                      "anthropic",
+		BaseURL:                       "https://example.com/v1",
+		APIKey:                        "updated-key",
+		Model:                         "claude",
+		ReasoningEffort:               "high",
+		AutoOpenReasoning:             boolPtr(false),
+		ContextTokens:                 8192,
+		ContextCompactionTriggerRatio: 0.9,
+		ContextCompactionTargetRatio:  0.7,
+		Temperature:                   0.15,
+		MaxTokens:                     4096,
+		TopP:                          0.9,
+		FrequencyPenalty:              0.4,
+		PresencePenalty:               0.2,
+	}
+
+	if err := updateLLMSettings(settings); err != nil {
+		t.Fatalf("updateLLMSettings returned error: %v", err)
+	}
+
+	updated := currentConfig()
+	if got, want := updated.LLM, settings; !reflect.DeepEqual(got, want) {
+		t.Fatalf("updated LLM config = %+v, want %+v", got, want)
+	}
+
+	data, err := os.ReadFile(filepath.Join(tempDir, "config.json"))
+	if err != nil {
+		t.Fatalf("os.ReadFile returned error: %v", err)
+	}
+
+	var persisted Config
+	if err := json.Unmarshal(data, &persisted); err != nil {
+		t.Fatalf("json.Unmarshal returned error: %v", err)
+	}
+	if got, want := persisted.LLM, settings; !reflect.DeepEqual(got, want) {
+		t.Fatalf("persisted LLM config = %+v, want %+v", got, want)
+	}
+	if got, want := persisted.Server.Addr, configCopy.Server.Addr; got != want {
+		t.Fatalf("persisted server addr = %q, want %q", got, want)
+	}
+	if got, want := persisted.Server.Host, configCopy.Server.Host; got != want {
+		t.Fatalf("persisted server host = %q, want %q", got, want)
+	}
+}
+
+func TestUpdateAppSettingsPersistsFullConfig(t *testing.T) {
+	original := currentConfig()
+	t.Cleanup(func() {
+		setConfig(original)
+	})
+
+	tempDir := t.TempDir()
+	originalWD, err := os.Getwd()
+	if err != nil {
+		t.Fatalf("os.Getwd returned error: %v", err)
+	}
+	t.Cleanup(func() {
+		_ = os.Chdir(originalWD)
+	})
+	if err := os.Chdir(tempDir); err != nil {
+		t.Fatalf("os.Chdir returned error: %v", err)
+	}
+
+	configCopy := defaultConfig()
+	configCopy.Server.Addr = ":9999"
+	configCopy.Server.Host = "localhost"
+	setConfig(configCopy)
+
+	settings := AppSettings{
+		LLMConfig: LLMConfig{
+			Provider:                      "anthropic",
+			BaseURL:                       "https://example.com/v1",
+			APIKey:                        "updated-key",
+			Model:                         "claude",
+			ReasoningEffort:               "low",
+			AutoOpenReasoning:             boolPtr(false),
+			ContextTokens:                 8192,
+			ContextCompactionTriggerRatio: 0.9,
+			ContextCompactionTargetRatio:  0.7,
+			Temperature:                   0.15,
+			MaxTokens:                     4096,
+			TopP:                          0.9,
+			FrequencyPenalty:              0.4,
+			PresencePenalty:               0.2,
+		},
+		ServerAddr: ":9090",
+		ServerHost: "127.0.0.1",
+	}
+
+	if err := updateAppSettings(settings); err != nil {
+		t.Fatalf("updateAppSettings returned error: %v", err)
+	}
+
+	updated := currentConfig()
+	if got, want := updated.LLM, settings.LLMConfig; !reflect.DeepEqual(got, want) {
+		t.Fatalf("updated LLM config = %+v, want %+v", got, want)
+	}
+	if got, want := updated.Server.Addr, settings.ServerAddr; got != want {
+		t.Fatalf("updated server addr = %q, want %q", got, want)
+	}
+	if got, want := updated.Server.Host, settings.ServerHost; got != want {
+		t.Fatalf("updated server host = %q, want %q", got, want)
+	}
+
+	data, err := os.ReadFile(filepath.Join(tempDir, "config.json"))
+	if err != nil {
+		t.Fatalf("os.ReadFile returned error: %v", err)
+	}
+
+	var persisted Config
+	if err := json.Unmarshal(data, &persisted); err != nil {
+		t.Fatalf("json.Unmarshal returned error: %v", err)
+	}
+	if got, want := persisted.LLM, settings.LLMConfig; !reflect.DeepEqual(got, want) {
+		t.Fatalf("persisted LLM config = %+v, want %+v", got, want)
+	}
+	if got, want := persisted.Server.Addr, settings.ServerAddr; got != want {
+		t.Fatalf("persisted server addr = %q, want %q", got, want)
+	}
+	if got, want := persisted.Server.Host, settings.ServerHost; got != want {
+		t.Fatalf("persisted server host = %q, want %q", got, want)
+	}
+}
--- a/tools/tools.go
+++ b/tools/tools.go
@@ -0,0 +1,981 @@
+package tools
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"runtime"
+	"strings"
+)
+
+// Tool represents a function-calling tool exposed to an agent workflow.
+type Tool struct {
+	Name        string `json:"name"`
+	Description string `json:"description"`
+	Parameters  Schema `json:"parameters"`
+}
+
+// Schema defines the JSON schema for tool parameters.
+type Schema struct {
+	Type        string            `json:"type"`
+	Description string            `json:"description,omitempty"`
+	Properties  map[string]Schema `json:"properties,omitempty"`
+	Required    []string          `json:"required,omitempty"`
+	Items       *Schema           `json:"items,omitempty"`
+}
+
+// Result is the output from executing a tool.
+type Result struct {
+	Content     string `json:"content"`
+	Success     bool   `json:"success"`
+	Error       string `json:"error,omitempty"`
+	TotalTokens int    `json:"total_tokens,omitempty"`
+}
+
+// WorkspaceValidator ensures operations stay within the allowed workspace.
+type WorkspaceValidator struct {
+	workspacePath string
+}
+
+func cancelledResult() (*Result, error) {
+	return &Result{Success: false, Error: "operation cancelled"}, nil
+}
+
+func preferredShellPath() string {
+	shell := strings.TrimSpace(os.Getenv("SHELL"))
+	if shell != "" {
+		if strings.Contains(shell, string(os.PathSeparator)) {
+			return shell
+		}
+		if resolved, err := exec.LookPath(shell); err == nil {
+			return resolved
+		}
+	}
+	if runtime.GOOS == "darwin" {
+		return "/bin/zsh"
+	}
+	return "/bin/sh"
+}
+
+func shellQuote(arg string) string {
+	if arg == "" {
+		return "''"
+	}
+	return "'" + strings.ReplaceAll(arg, "'", `'"'"'`) + "'"
+}
+
+func buildShellCommand(command string, args []string) string {
+	parts := make([]string, 0, 1+len(args))
+	if trimmed := strings.TrimSpace(command); trimmed != "" {
+		parts = append(parts, trimmed)
+	}
+	for _, arg := range args {
+		parts = append(parts, shellQuote(arg))
+	}
+	return strings.TrimSpace(strings.Join(parts, " "))
+}
+
+// NewWorkspaceValidator creates a validator for the given workspace.
+func NewWorkspaceValidator(workspacePath string) *WorkspaceValidator {
+	absPath, err := filepath.Abs(workspacePath)
+	if err != nil {
+		absPath = workspacePath
+	}
+	return &WorkspaceValidator{workspacePath: absPath}
+}
+
+func (v *WorkspaceValidator) resolvePath(path string) (string, error) {
+	trimmed := strings.TrimSpace(path)
+	if trimmed == "" || trimmed == "." {
+		return v.workspacePath, nil
+	}
+
+	candidate := trimmed
+	if !filepath.IsAbs(candidate) {
+		candidate = filepath.Join(v.workspacePath, candidate)
+	}
+
+	absPath, err := filepath.Abs(candidate)
+	if err != nil {
+		return "", fmt.Errorf("invalid path: %w", err)
+	}
+
+	cleaned := filepath.Clean(absPath)
+	if !strings.HasPrefix(cleaned, v.workspacePath) && cleaned != v.workspacePath {
+		return "", fmt.Errorf("access denied: path '%s' is outside workspace '%s'", path, v.workspacePath)
+	}
+	return cleaned, nil
+}
+
+// Validate checks if a path is within the workspace and returns the resolved absolute path.
+func (v *WorkspaceValidator) Validate(path string) (string, error) {
+	return v.resolvePath(path)
+}
+
+// IsWithinWorkspace checks if a path is within the workspace.
+func (v *WorkspaceValidator) IsWithinWorkspace(path string) bool {
+	_, err := v.resolvePath(path)
+	return err == nil
+}
+
+func normalizeLineEndings(text string) string {
+	return strings.ReplaceAll(text, "\r\n", "\n")
+}
+
+func splitLines(text string) []string {
+	text = normalizeLineEndings(text)
+	if text == "" {
+		return nil
+	}
+
+	lines := strings.Split(text, "\n")
+	if len(lines) > 0 && lines[len(lines)-1] == "" {
+		lines = lines[:len(lines)-1]
+	}
+	return lines
+}
+
+func formatNumberedLines(lines []string, startLine int) string {
+	if len(lines) == 0 {
+		return ""
+	}
+
+	var builder strings.Builder
+	for i, line := range lines {
+		if i > 0 {
+			builder.WriteByte('\n')
+		}
+		fmt.Fprintf(&builder, "%d: %s", startLine+i, line)
+	}
+	return builder.String()
+}
+
+func spliceLineRange(existing []string, startLine, endLine int, replacement []string) ([]string, error) {
+	if startLine < 1 {
+		return nil, fmt.Errorf("start_line must be >= 1")
+	}
+	if endLine < -1 {
+		return nil, fmt.Errorf("end_line must be -1 or >= 0")
+	}
+
+	totalLines := len(existing)
+	if endLine == -1 {
+		endLine = totalLines
+	}
+	if endLine < startLine-1 {
+		return nil, fmt.Errorf("end_line must be -1 or at least start_line-1")
+	}
+	if startLine > totalLines+1 {
+		return nil, fmt.Errorf("start_line %d is beyond EOF; file has %d lines", startLine, totalLines)
+	}
+	if endLine > totalLines {
+		return nil, fmt.Errorf("end_line %d is beyond EOF; file has %d lines", endLine, totalLines)
+	}
+
+	prefix := append([]string(nil), existing[:startLine-1]...)
+	suffix := append([]string(nil), existing[endLine:]...)
+
+	nextLines := make([]string, 0, len(prefix)+len(replacement)+len(suffix))
+	nextLines = append(nextLines, prefix...)
+	nextLines = append(nextLines, replacement...)
+	nextLines = append(nextLines, suffix...)
+
+	return nextLines, nil
+}
+
+func lineRangeLines(lines []string, startLine, endLine int) ([]string, error) {
+	if startLine < 1 {
+		return nil, fmt.Errorf("start_line must be >= 1")
+	}
+	if endLine < -1 {
+		return nil, fmt.Errorf("end_line must be -1 or >= 0")
+	}
+
+	totalLines := len(lines)
+	if endLine == -1 {
+		endLine = totalLines
+	}
+	if endLine < startLine-1 {
+		return nil, fmt.Errorf("end_line must be -1 or at least start_line-1")
+	}
+	if startLine > totalLines+1 {
+		return nil, fmt.Errorf("start_line %d is beyond EOF; file has %d lines", startLine, totalLines)
+	}
+	if endLine > totalLines {
+		return nil, fmt.Errorf("end_line %d is beyond EOF; file has %d lines", endLine, totalLines)
+	}
+	if endLine < startLine-1 {
+		return []string{}, nil
+	}
+	if totalLines == 0 || endLine < startLine {
+		return []string{}, nil
+	}
+
+	return append([]string(nil), lines[startLine-1:endLine]...), nil
+}
+
+func findUniqueLineSequence(haystack, needle []string) (int, error) {
+	if len(needle) == 0 {
+		return 0, fmt.Errorf("expected_text cannot be empty")
+	}
+	if len(needle) > len(haystack) {
+		return 0, fmt.Errorf("expected text has %d lines, but the requested range only has %d lines", len(needle), len(haystack))
+	}
+
+	matchIndex := -1
+	matchCount := 0
+	for i := 0; i <= len(haystack)-len(needle); i++ {
+		matched := true
+		for j := range needle {
+			if haystack[i+j] != needle[j] {
+				matched = false
+				break
+			}
+		}
+		if matched {
+			matchCount++
+			if matchIndex == -1 {
+				matchIndex = i
+			}
+		}
+	}
+
+	switch {
+	case matchCount == 0:
+		return 0, fmt.Errorf("expected text was not found within the requested range")
+	case matchCount > 1:
+		return 0, fmt.Errorf("expected text matched %d locations within the requested range", matchCount)
+	default:
+		return matchIndex, nil
+	}
+}
+
+func stripReadFileLinePrefix(line string) (string, bool) {
+	if line == "" {
+		return "", false
+	}
+
+	i := 0
+	for i < len(line) && line[i] >= '0' && line[i] <= '9' {
+		i++
+	}
+	if i == 0 || i >= len(line) || line[i] != ':' {
+		return "", false
+	}
+
+	rest := line[i+1:]
+	if strings.HasPrefix(rest, " ") {
+		rest = rest[1:]
+	}
+	return rest, true
+}
+
+func normalizePatchExpectedLines(expectedText string) []string {
+	lines := splitLines(expectedText)
+	if len(lines) == 0 {
+		return nil
+	}
+
+	if len(lines) >= 2 && strings.HasPrefix(lines[0], "File: ") && strings.HasPrefix(lines[1], "Lines ") && strings.Contains(lines[1], " of ") {
+		lines = lines[2:]
+		normalized := make([]string, len(lines))
+		for i, line := range lines {
+			if stripped, ok := stripReadFileLinePrefix(line); ok {
+				normalized[i] = stripped
+			} else {
+				normalized[i] = line
+			}
+		}
+		return normalized
+	}
+
+	normalized := make([]string, len(lines))
+	allNumbered := true
+	for i, line := range lines {
+		stripped, ok := stripReadFileLinePrefix(line)
+		if !ok {
+			allNumbered = false
+			break
+		}
+		normalized[i] = stripped
+	}
+	if allNumbered {
+		return normalized
+	}
+
+	return lines
+}
+
+// --- File Tools ---
+
+// ReadFile reads a line range from a file within the workspace.
+func (v *WorkspaceValidator) ReadFile(ctx context.Context, path string, startLine, endLine int) (*Result, error) {
+	if ctx != nil && ctx.Err() != nil {
+		return cancelledResult()
+	}
+	absPath, err := v.Validate(path)
+	if err != nil {
+		return &Result{Success: false, Error: err.Error()}, nil
+	}
+
+	data, err := os.ReadFile(absPath)
+	if err != nil {
+		return &Result{Success: false, Error: fmt.Sprintf("failed to read file: %v", err)}, nil
+	}
+
+	if startLine < 1 {
+		return &Result{Success: false, Error: "start_line must be >= 1"}, nil
+	}
+
+	if endLine != -1 && endLine < 1 {
+		return &Result{Success: false, Error: "end_line must be -1 or >= 1"}, nil
+	}
+	if endLine != -1 && endLine < startLine {
+		return &Result{Success: false, Error: "end_line must be -1 or greater than or equal to start_line"}, nil
+	}
+
+	lines := splitLines(string(data))
+	totalLines := len(lines)
+	if totalLines == 0 {
+		return &Result{
+			Content: fmt.Sprintf("File: %s\nFile is empty.", absPath),
+			Success: true,
+		}, nil
+	}
+
+	actualEnd := totalLines
+	if endLine != -1 {
+		if endLine < totalLines {
+			actualEnd = endLine
+		}
+	}
+
+	if startLine > totalLines {
+		displayEnd := "EOF"
+		if endLine != -1 {
+			displayEnd = fmt.Sprintf("%d", endLine)
+		}
+		return &Result{
+			Content: fmt.Sprintf(
+				"File: %s\nRequested lines %d-%s are beyond EOF. File has %d lines.",
+				absPath,
+				startLine,
+				displayEnd,
+				totalLines,
+			),
+			Success: true,
+		}, nil
+	}
+
+	if actualEnd < startLine {
+		return &Result{
+			Content: fmt.Sprintf(
+				"File: %s\nRequested lines %d-%d are empty. File has %d lines.",
+				absPath,
+				startLine,
+				actualEnd,
+				totalLines,
+			),
+			Success: true,
+		}, nil
+	}
+
+	selected := lines[startLine-1 : actualEnd]
+	displayEnd := fmt.Sprintf("%d", actualEnd)
+	if endLine == -1 && actualEnd == totalLines {
+		displayEnd = "EOF"
+	}
+
+	return &Result{
+		Content: fmt.Sprintf(
+			"File: %s\nLines %d-%s of %d:\n%s",
+			absPath,
+			startLine,
+			displayEnd,
+			totalLines,
+			formatNumberedLines(selected, startLine),
+		),
+		Success: true,
+	}, nil
+}
+
+// WriteFile replaces a line range in a file within the workspace, creating parent directories if needed.
+func (v *WorkspaceValidator) WriteFile(ctx context.Context, path string, startLine, endLine int, content string) (*Result, error) {
+	if ctx != nil && ctx.Err() != nil {
+		return cancelledResult()
+	}
+	absPath, err := v.Validate(path)
+	if err != nil {
+		return &Result{Success: false, Error: err.Error()}, nil
+	}
+
+	dir := filepath.Dir(absPath)
+	if err := os.MkdirAll(dir, 0755); err != nil {
+		return &Result{Success: false, Error: fmt.Sprintf("failed to create directories: %v", err)}, nil
+	}
+
+	existingData, readErr := os.ReadFile(absPath)
+	if readErr != nil && !os.IsNotExist(readErr) {
+		return &Result{Success: false, Error: fmt.Sprintf("failed to read existing file: %v", readErr)}, nil
+	}
+
+	existingLines := splitLines(string(existingData))
+	replacementLines := splitLines(content)
+	originalEndLine := endLine
+
+	nextLines, err := spliceLineRange(existingLines, startLine, endLine, replacementLines)
+	if err != nil {
+		return &Result{Success: false, Error: err.Error()}, nil
+	}
+
+	nextContent := strings.Join(nextLines, "\n")
+	if err := os.WriteFile(absPath, []byte(nextContent), 0644); err != nil {
+		return &Result{Success: false, Error: fmt.Sprintf("failed to write file: %v", err)}, nil
+	}
+
+	action := "replaced"
+	if os.IsNotExist(readErr) || (len(existingLines) == 0 && startLine == 1 && originalEndLine <= 0) {
+		action = "created"
+	} else if originalEndLine < startLine {
+		action = "inserted"
+	}
+
+	replacedCount := 0
+	if endLine == -1 {
+		replacedCount = len(existingLines) - startLine + 1
+		if replacedCount < 0 {
+			replacedCount = 0
+		}
+	} else if endLine >= startLine {
+		replacedCount = endLine - startLine + 1
+	}
+
+	message := fmt.Sprintf("Successfully %s %s", action, absPath)
+	if action == "inserted" {
+		message = fmt.Sprintf("Successfully inserted %d lines before line %d in %s", len(replacementLines), startLine, absPath)
+	} else if action == "created" {
+		message = fmt.Sprintf("Successfully created %s with %d lines", absPath, len(nextLines))
+	} else {
+		message = fmt.Sprintf("Successfully replaced %d lines starting at line %d in %s", replacedCount, startLine, absPath)
+	}
+
+	return &Result{Content: message, Success: true}, nil
+}
+
+// PatchFile replaces the unique snippet matching the expected text within a requested line window.
+func (v *WorkspaceValidator) PatchFile(ctx context.Context, path string, startLine, endLine int, expectedText, content string) (*Result, error) {
+	if ctx != nil && ctx.Err() != nil {
+		return cancelledResult()
+	}
+	absPath, err := v.Validate(path)
+	if err != nil {
+		return &Result{Success: false, Error: err.Error()}, nil
+	}
+
+	dir := filepath.Dir(absPath)
+	if err := os.MkdirAll(dir, 0755); err != nil {
+		return &Result{Success: false, Error: fmt.Sprintf("failed to create directories: %v", err)}, nil
+	}
+
+	existingData, readErr := os.ReadFile(absPath)
+	if readErr != nil && !os.IsNotExist(readErr) {
+		return &Result{Success: false, Error: fmt.Sprintf("failed to read existing file: %v", readErr)}, nil
+	}
+
+	existingLines := splitLines(string(existingData))
+	windowLines, err := lineRangeLines(existingLines, startLine, endLine)
+	if err != nil {
+		return &Result{Success: false, Error: err.Error()}, nil
+	}
+
+	expectedLines := normalizePatchExpectedLines(expectedText)
+	matchOffset, err := findUniqueLineSequence(windowLines, expectedLines)
+	if err != nil {
+		displayEnd := "EOF"
+		if endLine != -1 {
+			displayEnd = fmt.Sprintf("%d", endLine)
+		}
+		return &Result{
+			Success: false,
+			Error: fmt.Sprintf(
+				"patch guard failed for requested range %d-%s: %v. Re-read the exact snippet and include a little more context if needed.",
+				startLine,
+				displayEnd,
+				err,
+			),
+		}, nil
+	}
+
+	actualStartLine := startLine + matchOffset
+	actualEndLine := actualStartLine + len(expectedLines) - 1
+
+	replacementLines := splitLines(content)
+	nextLines, err := spliceLineRange(existingLines, actualStartLine, actualEndLine, replacementLines)
+	if err != nil {
+		return &Result{Success: false, Error: err.Error()}, nil
+	}
+
+	nextContent := strings.Join(nextLines, "\n")
+	if err := os.WriteFile(absPath, []byte(nextContent), 0644); err != nil {
+		return &Result{Success: false, Error: fmt.Sprintf("failed to write file: %v", err)}, nil
+	}
+
+	return &Result{
+		Content: fmt.Sprintf("Successfully patched lines %d-%d in %s", actualStartLine, actualEndLine, absPath),
+		Success: true,
+	}, nil
+}
+
+// CreateDirectory creates a directory within the workspace.
+func (v *WorkspaceValidator) CreateDirectory(ctx context.Context, path string) (*Result, error) {
+	if ctx != nil && ctx.Err() != nil {
+		return cancelledResult()
+	}
+	absPath, err := v.Validate(path)
+	if err != nil {
+		return &Result{Success: false, Error: err.Error()}, nil
+	}
+
+	if err := os.MkdirAll(absPath, 0755); err != nil {
+		return &Result{Success: false, Error: fmt.Sprintf("failed to create directory: %v", err)}, nil
+	}
+
+	return &Result{Content: fmt.Sprintf("Successfully created directory: %s", absPath), Success: true}, nil
+}
+
+// DeleteFile removes a file within the workspace.
+func (v *WorkspaceValidator) DeleteFile(ctx context.Context, path string) (*Result, error) {
+	if ctx != nil && ctx.Err() != nil {
+		return cancelledResult()
+	}
+	absPath, err := v.Validate(path)
+	if err != nil {
+		return &Result{Success: false, Error: err.Error()}, nil
+	}
+
+	if err := os.Remove(absPath); err != nil {
+		if os.IsNotExist(err) {
+			return &Result{Success: false, Error: fmt.Sprintf("file not found: %s", path)}, nil
+		}
+		return &Result{Success: false, Error: fmt.Sprintf("failed to delete file: %v", err)}, nil
+	}
+
+	return &Result{Content: fmt.Sprintf("Successfully deleted: %s", absPath), Success: true}, nil
+}
+
+// ListDirectory lists files and directories within the workspace.
+func (v *WorkspaceValidator) ListDirectory(ctx context.Context, path string) (*Result, error) {
+	if ctx != nil && ctx.Err() != nil {
+		return cancelledResult()
+	}
+	absPath, err := v.Validate(path)
+	if err != nil {
+		return &Result{Success: false, Error: err.Error()}, nil
+	}
+
+	entries, err := os.ReadDir(absPath)
+	if err != nil {
+		return &Result{Success: false, Error: fmt.Sprintf("failed to read directory: %v", err)}, nil
+	}
+
+	var lines []string
+	lines = append(lines, fmt.Sprintf("Contents of %s:", absPath))
+
+	for _, entry := range entries {
+		if ctx != nil && ctx.Err() != nil {
+			return cancelledResult()
+		}
+		mode := entry.Type()
+		var prefix string
+		if mode.IsDir() {
+			prefix = "D  "
+		} else {
+			prefix = "F  "
+		}
+
+		info, err := entry.Info()
+		size := "0"
+		if err == nil && info != nil {
+			size = fmt.Sprintf("%d", info.Size())
+		}
+
+		name := entry.Name()
+		if mode.IsDir() {
+			name += "/"
+		}
+		lines = append(lines, fmt.Sprintf("%s %8s %s", prefix, size, name))
+	}
+
+	return &Result{Content: strings.Join(lines, "\n")}, nil
+}
+
+// --- Search Tools ---
+
+// SearchFiles searches for files matching a pattern within the workspace.
+func (v *WorkspaceValidator) SearchFiles(ctx context.Context, pathPattern string) (*Result, error) {
+	if ctx != nil && ctx.Err() != nil {
+		return cancelledResult()
+	}
+	// Validate the base path
+	baseDir := filepath.Dir(pathPattern)
+	if baseDir != "." && baseDir != "/" {
+		if _, err := v.Validate(baseDir); err != nil {
+			return &Result{Success: false, Error: err.Error()}, nil
+		}
+	}
+
+	var matches []string
+	pattern := pathPattern
+
+	err := filepath.Walk(v.workspacePath, func(currentPath string, info os.FileInfo, err error) error {
+		if ctx != nil && ctx.Err() != nil {
+			return ctx.Err()
+		}
+		if err != nil {
+			return nil
+		}
+		if info.IsDir() {
+			return nil
+		}
+		relPath, _ := filepath.Rel(v.workspacePath, currentPath)
+		if matched, _ := filepath.Match(pattern, relPath); matched {
+			matches = append(matches, relPath)
+			return nil
+		}
+		if matched, _ := filepath.Match(pattern, filepath.Base(relPath)); matched {
+			matches = append(matches, relPath)
+		}
+		return nil
+	})
+
+	if ctx != nil && ctx.Err() != nil {
+		return cancelledResult()
+	}
+	if err != nil {
+		if errors.Is(err, context.Canceled) {
+			return cancelledResult()
+		}
+		return &Result{Success: false, Error: fmt.Sprintf("search failed: %v", err)}, nil
+	}
+
+	if len(matches) == 0 {
+		return &Result{Content: "No files found matching pattern.", Success: true}, nil
+	}
+
+	var output []string
+	output = append(output, fmt.Sprintf("Found %d files matching '%s':", len(matches), pattern))
+	for _, m := range matches {
+		output = append(output, "  "+m)
+	}
+
+	return &Result{Content: strings.Join(output, "\n")}, nil
+}
+
+// Grep searches for text content within files in the workspace.
+func (v *WorkspaceValidator) Grep(ctx context.Context, searchTerm string, path string) (*Result, error) {
+	if ctx != nil && ctx.Err() != nil {
+		return cancelledResult()
+	}
+	absPath, err := v.Validate(path)
+	if err != nil {
+		return &Result{Success: false, Error: err.Error()}, nil
+	}
+
+	var results []string
+	count := 0
+
+	err = filepath.Walk(absPath, func(currentPath string, info os.FileInfo, err error) error {
+		if ctx != nil && ctx.Err() != nil {
+			return ctx.Err()
+		}
+		if err != nil {
+			return nil
+		}
+		if info.IsDir() {
+			return nil
+		}
+		if count >= 100 {
+			return fmt.Errorf("max results reached")
+		}
+
+		data, err := os.ReadFile(currentPath)
+		if err != nil {
+			return nil
+		}
+
+		relPath, _ := filepath.Rel(v.workspacePath, currentPath)
+		lines := strings.Split(string(data), "\n")
+		for i, line := range lines {
+			if strings.Contains(line, searchTerm) {
+				results = append(results, fmt.Sprintf("%s:%d: %s", relPath, i+1, strings.TrimSpace(line)))
+				count++
+			}
+		}
+		return nil
+	})
+
+	if ctx != nil && ctx.Err() != nil {
+		return cancelledResult()
+	}
+	if count >= 100 {
+		results = append(results, "... (truncated at 100 results)")
+	}
+
+	if len(results) == 0 {
+		return &Result{Content: fmt.Sprintf("No matches for '%s' in %s", searchTerm, path)}, nil
+	}
+
+	return &Result{Content: strings.Join(results, "\n")}, nil
+}
+
+// --- Shell Tools ---
+
+// RunCommand executes a shell command within the workspace.
+func (v *WorkspaceValidator) RunCommand(ctx context.Context, command string, args []string) (*Result, error) {
+	if ctx != nil && ctx.Err() != nil {
+		return cancelledResult()
+	}
+	shellCommand := buildShellCommand(command, args)
+	if shellCommand == "" {
+		return &Result{Success: false, Error: "command is required"}, nil
+	}
+
+	// Check for dangerous commands
+	dangerousCmds := []string{"rm -rf /", "rm -rf *", "dd if=", "mkfs", "fdisk", "> /dev/"}
+	for _, d := range dangerousCmds {
+		if strings.Contains(strings.ToLower(shellCommand), d) {
+			return &Result{Success: false, Error: fmt.Sprintf("dangerous command blocked: %s", shellCommand)}, nil
+		}
+	}
+
+	if ctx == nil {
+		ctx = context.Background()
+	}
+	shellPath := preferredShellPath()
+	shellArgs := []string{"-lc", shellCommand}
+	switch filepath.Base(shellPath) {
+	case "zsh", "bash":
+		shellArgs[0] = "-lic"
+	}
+	cmd := exec.CommandContext(ctx, shellPath, shellArgs...)
+	cmd.Dir = v.workspacePath
+
+	output, err := cmd.CombinedOutput()
+	outputStr := string(output)
+
+	if err != nil {
+		if ctx.Err() != nil {
+			return cancelledResult()
+		}
+		exitCode := -1
+		var exitErr *exec.ExitError
+		if errors.As(err, &exitErr) {
+			exitCode = exitErr.ExitCode()
+		}
+		return &Result{
+			Content: outputStr,
+			Success: false,
+			Error:   fmt.Sprintf("command failed (exit %d): %v", exitCode, err),
+		}, nil
+	}
+
+	// Truncate output
+	maxLen := 50000
+	if len(outputStr) > maxLen {
+		outputStr = outputStr[:maxLen] + "\n... [output truncated]"
+	}
+
+	return &Result{Content: outputStr, Success: true}, nil
+}
+
+// GetWorkspacePath returns the workspace path.
+func (v *WorkspaceValidator) GetWorkspacePath() string {
+	return v.workspacePath
+}
+
+// --- Tool Definitions ---
+
+// AvailableTools returns the list of workspace tool definitions for function calling.
+func AvailableTools(workspacePath string) []Tool {
+	tools := []Tool{
+		{
+			Name:        "read_file",
+			Description: "Read a line range from a file in the workspace. Use start_line=1 and end_line=-1 to read the full file. The output includes line numbers and a header, and it can be pasted directly into patch_file as expected_text for the same snippet or range.",
+			Parameters: Schema{
+				Type: "object",
+				Properties: map[string]Schema{
+					"path": {
+						Type:        "string",
+						Description: "The path of the file to read (relative to workspace)",
+					},
+					"start_line": {
+						Type:        "integer",
+						Description: "The first line to read, starting at 1. Defaults to 1.",
+					},
+					"end_line": {
+						Type:        "integer",
+						Description: "The last line to read, inclusive. Use -1 to read through EOF. Defaults to -1.",
+					},
+				},
+				Required: []string{"path"},
+			},
+		},
+		{
+			Name:        "patch_file",
+			Description: "Guarded snippet replacement within a line window. Like write_file, but only applies if expected_text matches one unique contiguous snippet inside the requested range. expected_text can be raw file text or the line-numbered output from read_file. Use this for surgical edits to avoid clobbering concurrent changes.",
+			Parameters: Schema{
+				Type: "object",
+				Properties: map[string]Schema{
+					"path": {
+						Type:        "string",
+						Description: "The path of the file to patch (relative to workspace)",
+					},
+					"start_line": {
+						Type:        "integer",
+						Description: "The first line of the search window, starting at 1. Defaults to 1.",
+					},
+					"end_line": {
+						Type:        "integer",
+						Description: "The last line of the search window, inclusive. Use -1 to search through EOF.",
+					},
+					"expected_text": {
+						Type:        "string",
+						Description: "The current text to match. This can be raw file text or the output from read_file for a matching snippet within the requested window.",
+					},
+					"content": {
+						Type:        "string",
+						Description: "The replacement text for the requested line range",
+					},
+				},
+				Required: []string{"path", "expected_text", "content"},
+			},
+		},
+		{
+			Name:        "write_file",
+			Description: "Replace a line range in a file. Use start_line=1 and end_line=-1 to replace the full file or create a new file. Use end_line=start_line-1 to insert content before a line, such as start_line=1 and end_line=0 to prepend to an existing file. Prefer patch_file when you want to guard against stale content.",
+			Parameters: Schema{
+				Type: "object",
+				Properties: map[string]Schema{
+					"path": {
+						Type:        "string",
+						Description: "The path of the file to write (relative to workspace)",
+					},
+					"start_line": {
+						Type:        "integer",
+						Description: "The first line to replace, starting at 1. Defaults to 1.",
+					},
+					"end_line": {
+						Type:        "integer",
+						Description: "The last line to replace, inclusive. Use -1 to replace through EOF. Use start_line-1 to insert before start_line.",
+					},
+					"content": {
+						Type:        "string",
+						Description: "The replacement text for the requested line range",
+					},
+				},
+				Required: []string{"path", "content"},
+			},
+		},
+		{
+			Name:        "create_directory",
+			Description: "Create a new directory or get an existing one within the workspace.",
+			Parameters: Schema{
+				Type: "object",
+				Properties: map[string]Schema{
+					"path": {
+						Type:        "string",
+						Description: "The path of the directory to create (relative to workspace)",
+					},
+				},
+				Required: []string{"path"},
+			},
+		},
+		{
+			Name:        "delete_file",
+			Description: "Delete a file from the workspace.",
+			Parameters: Schema{
+				Type: "object",
+				Properties: map[string]Schema{
+					"path": {
+						Type:        "string",
+						Description: "The path of the file to delete (relative to workspace)",
+					},
+				},
+				Required: []string{"path"},
+			},
+		},
+		{
+			Name:        "list_directory",
+			Description: "List the contents of a directory within the workspace. Shows file sizes and types.",
+			Parameters: Schema{
+				Type: "object",
+				Properties: map[string]Schema{
+					"path": {
+						Type:        "string",
+						Description: "The path of the directory to list (relative to workspace, defaults to workspace root if '.' or empty)",
+					},
+				},
+				Required: []string{"path"},
+			},
+		},
+		{
+			Name:        "search_files",
+			Description: "Search for files by name pattern within the workspace directory tree.",
+			Parameters: Schema{
+				Type: "object",
+				Properties: map[string]Schema{
+					"path_pattern": {
+						Type:        "string",
+						Description: "The glob pattern to match (e.g., '*.go', 'src/**/*.ts')",
+					},
+				},
+				Required: []string{"path_pattern"},
+			},
+		},
+		{
+			Name:        "grep",
+			Description: "Search for text content within files in the workspace. Limited to 100 results.",
+			Parameters: Schema{
+				Type: "object",
+				Properties: map[string]Schema{
+					"search_term": {
+						Type:        "string",
+						Description: "The text pattern to search for",
+					},
+					"path": {
+						Type:        "string",
+						Description: "The directory to search in (relative to workspace)",
+					},
+				},
+				Required: []string{"search_term", "path"},
+			},
+		},
+		{
+			Name:        "run_command",
+			Description: "Execute a shell command through the user's login shell within the workspace directory. Shell syntax, pipes, redirects, and installed tools available on PATH are supported.",
+			Parameters: Schema{
+				Type: "object",
+				Properties: map[string]Schema{
+					"command": {
+						Type:        "string",
+						Description: "The command to execute (e.g., 'ls', 'cat', 'go build', 'npm test')",
+					},
+					"args": {
+						Type: "array",
+						Items: &Schema{
+							Type: "string",
+						},
+						Description: "Arguments for the command",
+					},
+				},
+				Required: []string{"command"},
+			},
+		},
+	}
+
+	_ = workspacePath
+	return tools
+}
--- a/tools/tools_test.go
+++ b/tools/tools_test.go
@@ -0,0 +1,356 @@
+package tools
+
+import (
+	"context"
+	"os"
+	"path/filepath"
+	"strings"
+	"testing"
+)
+
+func writeMockShell(t *testing.T, dir string) string {
+	t.Helper()
+
+	shellPath := filepath.Join(dir, "mock-shell")
+	script := `#!/bin/sh
+set -eu
+printf '%s\n' "$1" > shell-flag.txt
+printf '%s\n' "$2" > shell-command.txt
+shift
+eval "$1"
+`
+	if err := os.WriteFile(shellPath, []byte(script), 0755); err != nil {
+		t.Fatalf("failed to write mock shell: %v", err)
+	}
+	return shellPath
+}
+
+func TestValidateResolvesRelativePathAgainstWorkspace(t *testing.T) {
+	workspace := t.TempDir()
+	validator := NewWorkspaceValidator(workspace)
+
+	got, err := validator.Validate("src/main.go")
+	if err != nil {
+		t.Fatalf("Validate returned error: %v", err)
+	}
+
+	want := filepath.Join(workspace, "src/main.go")
+	if got != want {
+		t.Fatalf("Validate returned %q, want %q", got, want)
+	}
+}
+
+func TestValidateRejectsTraversalOutsideWorkspace(t *testing.T) {
+	workspace := t.TempDir()
+	validator := NewWorkspaceValidator(workspace)
+
+	if _, err := validator.Validate("../outside.go"); err == nil {
+		t.Fatal("expected Validate to reject path traversal outside the workspace")
+	}
+}
+
+func TestReadFileReturnsRequestedLineRange(t *testing.T) {
+	workspace := t.TempDir()
+	path := filepath.Join(workspace, "sample.txt")
+	if err := os.WriteFile(path, []byte("alpha\nbeta\ngamma\ndelta\n"), 0644); err != nil {
+		t.Fatalf("failed to write sample file: %v", err)
+	}
+
+	validator := NewWorkspaceValidator(workspace)
+	result, err := validator.ReadFile(context.Background(), "sample.txt", 2, 3)
+	if err != nil {
+		t.Fatalf("ReadFile returned error: %v", err)
+	}
+	if !result.Success {
+		t.Fatalf("ReadFile returned unsuccessful result: %+v", result)
+	}
+
+	if !strings.Contains(result.Content, "Lines 2-3 of 4:") {
+		t.Fatalf("ReadFile content did not include requested range: %q", result.Content)
+	}
+	if !strings.Contains(result.Content, "2: beta") || !strings.Contains(result.Content, "3: gamma") {
+		t.Fatalf("ReadFile content did not include expected lines: %q", result.Content)
+	}
+	if strings.Contains(result.Content, "1: alpha") || strings.Contains(result.Content, "4: delta") {
+		t.Fatalf("ReadFile content included lines outside the requested range: %q", result.Content)
+	}
+}
+
+func TestWriteFileReplacesRangePrependsAndCreates(t *testing.T) {
+	workspace := t.TempDir()
+	validator := NewWorkspaceValidator(workspace)
+	ctx := context.Background()
+
+	t.Run("replace middle range", func(t *testing.T) {
+		path := filepath.Join(workspace, "sample.txt")
+		if err := os.WriteFile(path, []byte("one\ntwo\nthree\nfour\n"), 0644); err != nil {
+			t.Fatalf("failed to write sample file: %v", err)
+		}
+
+		result, err := validator.WriteFile(ctx, "sample.txt", 2, 3, "TWO\nTHREE")
+		if err != nil {
+			t.Fatalf("WriteFile returned error: %v", err)
+		}
+		if !result.Success {
+			t.Fatalf("WriteFile returned unsuccessful result: %+v", result)
+		}
+
+		got, err := os.ReadFile(path)
+		if err != nil {
+			t.Fatalf("failed to read updated file: %v", err)
+		}
+		want := "one\nTWO\nTHREE\nfour"
+		if string(got) != want {
+			t.Fatalf("WriteFile wrote %q, want %q", string(got), want)
+		}
+	})
+
+	t.Run("prepend at start", func(t *testing.T) {
+		path := filepath.Join(workspace, "prepend.txt")
+		if err := os.WriteFile(path, []byte("body\n"), 0644); err != nil {
+			t.Fatalf("failed to write sample file: %v", err)
+		}
+
+		result, err := validator.WriteFile(ctx, "prepend.txt", 1, 0, "header")
+		if err != nil {
+			t.Fatalf("WriteFile returned error: %v", err)
+		}
+		if !result.Success {
+			t.Fatalf("WriteFile returned unsuccessful result: %+v", result)
+		}
+
+		got, err := os.ReadFile(path)
+		if err != nil {
+			t.Fatalf("failed to read updated file: %v", err)
+		}
+		want := "header\nbody"
+		if string(got) != want {
+			t.Fatalf("WriteFile wrote %q, want %q", string(got), want)
+		}
+	})
+
+	t.Run("create new file", func(t *testing.T) {
+		path := filepath.Join(workspace, "created.txt")
+
+		result, err := validator.WriteFile(ctx, "created.txt", 1, -1, "first\nsecond")
+		if err != nil {
+			t.Fatalf("WriteFile returned error: %v", err)
+		}
+		if !result.Success {
+			t.Fatalf("WriteFile returned unsuccessful result: %+v", result)
+		}
+
+		got, err := os.ReadFile(path)
+		if err != nil {
+			t.Fatalf("failed to read created file: %v", err)
+		}
+		want := "first\nsecond"
+		if string(got) != want {
+			t.Fatalf("WriteFile wrote %q, want %q", string(got), want)
+		}
+	})
+}
+
+func TestRunCommandExecutesThroughShell(t *testing.T) {
+	workspace := t.TempDir()
+	shellDir := t.TempDir()
+	t.Setenv("SHELL", writeMockShell(t, shellDir))
+
+	validator := NewWorkspaceValidator(workspace)
+	result, err := validator.RunCommand(context.Background(), "echo hello from shell", nil)
+	if err != nil {
+		t.Fatalf("RunCommand returned error: %v", err)
+	}
+	if !result.Success {
+		t.Fatalf("RunCommand returned unsuccessful result: %+v", result)
+	}
+	if got, want := strings.TrimSpace(result.Content), "hello from shell"; got != want {
+		t.Fatalf("RunCommand output = %q, want %q", got, want)
+	}
+
+	commandBytes, err := os.ReadFile(filepath.Join(workspace, "shell-command.txt"))
+	if err != nil {
+		t.Fatalf("failed to read shell command capture: %v", err)
+	}
+	if got, want := strings.TrimSpace(string(commandBytes)), "echo hello from shell"; got != want {
+		t.Fatalf("shell command capture = %q, want %q", got, want)
+	}
+}
+
+func TestRunCommandQuotesArgsInShellCommand(t *testing.T) {
+	workspace := t.TempDir()
+	shellDir := t.TempDir()
+	t.Setenv("SHELL", writeMockShell(t, shellDir))
+
+	validator := NewWorkspaceValidator(workspace)
+	result, err := validator.RunCommand(context.Background(), "printf", []string{"%s", "hello world"})
+	if err != nil {
+		t.Fatalf("RunCommand returned error: %v", err)
+	}
+	if !result.Success {
+		t.Fatalf("RunCommand returned unsuccessful result: %+v", result)
+	}
+	if got, want := strings.TrimSpace(result.Content), "hello world"; got != want {
+		t.Fatalf("RunCommand output = %q, want %q", got, want)
+	}
+
+	commandBytes, err := os.ReadFile(filepath.Join(workspace, "shell-command.txt"))
+	if err != nil {
+		t.Fatalf("failed to read shell command capture: %v", err)
+	}
+	commandLine := strings.TrimSpace(string(commandBytes))
+	if !strings.Contains(commandLine, "'hello world'") {
+		t.Fatalf("shell command capture did not quote spaced argument: %q", commandLine)
+	}
+}
+
+func TestRunCommandRunsInstalledToolThroughShellPath(t *testing.T) {
+	workspace := t.TempDir()
+	validator := NewWorkspaceValidator(workspace)
+
+	result, err := validator.RunCommand(context.Background(), "go version", nil)
+	if err != nil {
+		t.Fatalf("RunCommand returned error: %v", err)
+	}
+	if !result.Success {
+		t.Fatalf("RunCommand returned unsuccessful result: %+v", result)
+	}
+	if !strings.Contains(result.Content, "go version") {
+		t.Fatalf("RunCommand output did not include go version information: %q", result.Content)
+	}
+}
+
+func TestPatchFileGuardsAgainstStaleRanges(t *testing.T) {
+	workspace := t.TempDir()
+	validator := NewWorkspaceValidator(workspace)
+	ctx := context.Background()
+
+	t.Run("applies when expected text matches", func(t *testing.T) {
+		path := filepath.Join(workspace, "guarded.txt")
+		if err := os.WriteFile(path, []byte("one\ntwo\nthree\n"), 0644); err != nil {
+			t.Fatalf("failed to write sample file: %v", err)
+		}
+
+		result, err := validator.PatchFile(ctx, "guarded.txt", 2, 2, "two", "TWO")
+		if err != nil {
+			t.Fatalf("PatchFile returned error: %v", err)
+		}
+		if !result.Success {
+			t.Fatalf("PatchFile returned unsuccessful result: %+v", result)
+		}
+
+		got, err := os.ReadFile(path)
+		if err != nil {
+			t.Fatalf("failed to read patched file: %v", err)
+		}
+		want := "one\nTWO\nthree"
+		if string(got) != want {
+			t.Fatalf("PatchFile wrote %q, want %q", string(got), want)
+		}
+	})
+
+	t.Run("matches a snippet inside a larger requested window", func(t *testing.T) {
+		path := filepath.Join(workspace, "snippet.txt")
+		original := "alpha\nbeta\n\n\nneedle\nomega\n"
+		if err := os.WriteFile(path, []byte(original), 0644); err != nil {
+			t.Fatalf("failed to write sample file: %v", err)
+		}
+
+		result, err := validator.PatchFile(ctx, "snippet.txt", 1, -1, "\n\nneedle", "\n\nreplacement")
+		if err != nil {
+			t.Fatalf("PatchFile returned error: %v", err)
+		}
+		if !result.Success {
+			t.Fatalf("PatchFile returned unsuccessful result: %+v", result)
+		}
+
+		got, err := os.ReadFile(path)
+		if err != nil {
+			t.Fatalf("failed to read patched file: %v", err)
+		}
+		want := "alpha\nbeta\n\n\nreplacement\nomega"
+		if string(got) != want {
+			t.Fatalf("PatchFile wrote %q, want %q", string(got), want)
+		}
+	})
+
+	t.Run("accepts read_file output as expected text", func(t *testing.T) {
+		path := filepath.Join(workspace, "readfile.txt")
+		if err := os.WriteFile(path, []byte("alpha\nbeta\ngamma\n"), 0644); err != nil {
+			t.Fatalf("failed to write sample file: %v", err)
+		}
+
+		readResult, err := validator.ReadFile(ctx, "readfile.txt", 1, 2)
+		if err != nil {
+			t.Fatalf("ReadFile returned error: %v", err)
+		}
+
+		result, err := validator.PatchFile(ctx, "readfile.txt", 1, 2, readResult.Content, "ALPHA\nBETA")
+		if err != nil {
+			t.Fatalf("PatchFile returned error: %v", err)
+		}
+		if !result.Success {
+			t.Fatalf("PatchFile returned unsuccessful result: %+v", result)
+		}
+
+		got, err := os.ReadFile(path)
+		if err != nil {
+			t.Fatalf("failed to read patched file: %v", err)
+		}
+		want := "ALPHA\nBETA\ngamma"
+		if string(got) != want {
+			t.Fatalf("PatchFile wrote %q, want %q", string(got), want)
+		}
+	})
+
+	t.Run("matches blank lines exactly", func(t *testing.T) {
+		path := filepath.Join(workspace, "blank.txt")
+		if err := os.WriteFile(path, []byte("alpha\n\nomega\n"), 0644); err != nil {
+			t.Fatalf("failed to write sample file: %v", err)
+		}
+
+		result, err := validator.PatchFile(ctx, "blank.txt", 2, 2, "\n", "BETA")
+		if err != nil {
+			t.Fatalf("PatchFile returned error: %v", err)
+		}
+		if !result.Success {
+			t.Fatalf("PatchFile returned unsuccessful result: %+v", result)
+		}
+
+		got, err := os.ReadFile(path)
+		if err != nil {
+			t.Fatalf("failed to read patched file: %v", err)
+		}
+		want := "alpha\nBETA\nomega"
+		if string(got) != want {
+			t.Fatalf("PatchFile wrote %q, want %q", string(got), want)
+		}
+	})
+
+	t.Run("rejects stale content", func(t *testing.T) {
+		path := filepath.Join(workspace, "stale.txt")
+		if err := os.WriteFile(path, []byte("alpha\nbeta\n"), 0644); err != nil {
+			t.Fatalf("failed to write sample file: %v", err)
+		}
+
+		result, err := validator.PatchFile(ctx, "stale.txt", 2, 2, "gamma", "BETA")
+		if err != nil {
+			t.Fatalf("PatchFile returned error: %v", err)
+		}
+		if result.Success {
+			t.Fatalf("expected guarded patch to fail, got success: %+v", result)
+		}
+		if !strings.Contains(result.Error, "patch guard failed") {
+			t.Fatalf("unexpected guarded patch error: %+v", result)
+		}
+
+		got, err := os.ReadFile(path)
+		if err != nil {
+			t.Fatalf("failed to read unchanged file: %v", err)
+		}
+		want := "alpha\nbeta\n"
+		if string(got) != want {
+			t.Fatalf("PatchFile changed file content unexpectedly: %q", string(got))
+		}
+	})
+}
--- a/web/app.js
+++ b/web/app.js
--- a/web/index.html
+++ b/web/index.html
@@ -0,0 +1,406 @@
+<!DOCTYPE html>
+<html lang="en">
+<head>
+	<meta charset="UTF-8">
+	<meta name="viewport" content="width=device-width, initial-scale=1.0">
+	<title>GoCoder</title>
+	<script src="https://cdn.tailwindcss.com"></script>
+	<script src="https://cdn.jsdelivr.net/npm/marked/marked.min.js"></script>
+	<link rel="stylesheet" href="style.css">
+	<style>
+		.conversation-item {
+			border-left: 3px solid transparent;
+		}
+		.conversation-item:hover {
+			border-left-color: #cbd5e1;
+		}
+		.conversation-item.active {
+			border-left-color: #3b82f6;
+			background-color: #eff6ff;
+			color: #1d4ed8;
+		}
+		.conversation-item.active .text-gray-400 {
+			color: #3b82f6;
+		}
+		.loading-dots {
+			display: inline-flex;
+			align-items: center;
+		}
+		.loading-dots .dot {
+			animation: blink 1.4s infinite both;
+			animation-duration: 1.4s;
+		}
+		.loading-dots .dot:nth-child(2) {
+			animation-delay: 0.2s;
+		}
+		.loading-dots .dot:nth-child(3) {
+			animation-delay: 0.4s;
+		}
+		@keyframes blink {
+			0%, 80%, 100% { opacity: 0; }
+			40% { opacity: 1; }
+		}
+		.sidebar {
+			transition: transform 0.2s ease;
+		}
+		@media (max-width: 768px) {
+			.sidebar {
+				position: fixed;
+				z-index: 50;
+				height: 100vh;
+				transform: translateX(-100%);
+			}
+			.sidebar.open {
+				transform: translateX(0);
+			}
+			.sidebar-overlay {
+				display: none;
+				position: fixed;
+				inset: 0;
+				background: rgba(0,0,0,0.3);
+				z-index: 40;
+			}
+			.sidebar-overlay.open {
+				display: block;
+			}
+		}
+	</style>
+</head>
+<body class="min-h-screen bg-gray-50">
+	<div class="flex h-screen">
+		<!-- Sidebar -->
+		<div class="sidebar w-72 bg-white border-r border-gray-200 flex flex-col" id="sidebar">
+			<div class="p-4 border-b border-gray-200">
+				<div class="flex items-center justify-between mb-3">
+					<h2 class="text-lg font-semibold text-gray-800">Workspaces</h2>
+					<div class="flex gap-1">
+						<button id="newGroupBtn" class="p-1.5 rounded-lg hover:bg-gray-100 text-gray-600 transition-colors" title="New workspace">
+							<svg xmlns="http://www.w3.org/2000/svg" width="18" height="18" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"><path d="M12 2v20M17 5H9.5a3.5 3.5 0 0 0 0 7h5a3.5 3.5 0 0 1 0 7H6"/></svg>
+						</button>
+						<button id="newConversationBtn" class="p-1.5 rounded-lg hover:bg-gray-100 text-gray-600 transition-colors" title="New conversation">
+							<svg xmlns="http://www.w3.org/2000/svg" width="18" height="18" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"><line x1="12" y1="5" x2="12" y2="19"/><line x1="5" y1="12" x2="19" y2="12"/></svg>
+						</button>
+					</div>
+				</div>
+			</div>
+			<div id="conversationList" class="flex-1 overflow-y-auto p-2 space-y-3">
+			</div>
+	<div class="p-3 border-t border-gray-200">
+		<button id="mobileMenuBtn" class="md:hidden w-full text-center text-sm text-gray-500 hover:text-gray-700 py-2">
+			Close sidebar
+		</button>
+	</div>
+</div>
+
+	<!-- Sidebar overlay for mobile -->
+	<div class="sidebar-overlay" id="sidebarOverlay"></div>
+
+	<!-- Group settings modal -->
+	<div id="groupSettingsModal" class="fixed inset-0 z-50 hidden items-center justify-center" style="background: rgba(0,0,0,0.4);">
+		<div class="bg-white rounded-2xl shadow-xl w-full max-w-md mx-4 overflow-hidden">
+			<div class="p-6">
+				<div class="flex items-center justify-between mb-5">
+					<h3 class="text-lg font-semibold text-gray-800">Workspace Settings</h3>
+					<button id="closeGroupSettingsModal" class="p-1.5 rounded-lg hover:bg-gray-100 text-gray-400 hover:text-gray-600 transition-colors">
+						<svg xmlns="http://www.w3.org/2000/svg" width="18" height="18" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"><path d="M18 6 6 18"/><path d="m6 6 12 12"/></svg>
+					</button>
+				</div>
+				<form id="groupSettingsForm">
+					<label class="block text-sm font-medium text-gray-700 mb-1.5">Workspace name</label>
+					<input
+						type="text"
+						id="groupSettingsNameInput"
+						class="w-full px-4 py-2.5 border border-gray-300 rounded-xl focus:outline-none focus:ring-2 focus:ring-blue-500 focus:border-transparent text-gray-800"
+						required
+					>
+					<label class="block text-sm font-medium text-gray-700 mb-1.5 mt-4">Workspace folder</label>
+					<div id="groupSettingsLocation" class="hidden mb-3 px-3 py-2 bg-gray-50 border border-gray-200 rounded-xl">
+						<div class="flex items-center gap-2">
+							<svg xmlns="http://www.w3.org/2000/svg" width="14" height="14" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round" class="text-gray-400 flex-shrink-0"><path d="M20.59 13.41l-7.17 7.17a2 2 0 0 1-2.83 0L2 12V2h10l8.59 8.59a2 2 0 0 1 0 2.82z"/><line x1="7" y1="7" x2="7.01" y2="7"/></svg>
+							<span id="groupSettingsLocationText" class="text-sm text-gray-600 truncate"></span>
+						</div>
+					</div>
+					<button type="button" id="groupSettingsPickBtn" class="w-full px-4 py-2.5 border border-gray-300 rounded-xl text-gray-700 font-medium hover:bg-gray-50 transition-colors flex items-center justify-center gap-2">
+						<svg xmlns="http://www.w3.org/2000/svg" width="16" height="16" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"><path d="M20 20a2 2 0 0 0 2-2V8a2 2 0 0 0-2-2h-7.9a2 2 0 0 1-1.69-.9L9.6 3.9A2 2 0 0 0 7.93 3H4a2 2 0 0 0-2 2v13a2 2 0 0 0 2 2Z"/></svg>
+						Pick Folder
+					</button>
+					<div class="flex gap-3 mt-5">
+						<button type="button" id="cancelGroupSettingsBtn" class="flex-1 px-4 py-2.5 border border-gray-300 rounded-xl text-gray-700 font-medium hover:bg-gray-50 transition-colors">
+							Cancel
+						</button>
+						<button type="submit" class="flex-1 px-4 py-2.5 bg-blue-600 hover:bg-blue-700 text-white font-medium rounded-xl transition-colors">
+							Save
+						</button>
+					</div>
+				</form>
+			</div>
+		</div>
+	</div>
+
+	<!-- Runtime settings modal -->
+	<div id="settingsModal" class="fixed inset-0 z-50 hidden items-center justify-center p-4" style="background: rgba(0,0,0,0.4);">
+		<div class="bg-white rounded-2xl shadow-xl w-full max-w-2xl max-h-[90vh] overflow-hidden">
+			<div class="max-h-[90vh] overflow-y-auto">
+				<div class="p-6">
+					<div class="flex items-center justify-between mb-4">
+						<div>
+							<h3 class="text-lg font-semibold text-gray-800">Runtime Settings</h3>
+							<p class="mt-1 text-sm text-gray-500">Edit the model endpoint, generation params, server settings, and compaction budget used by the chat runtime.</p>
+						</div>
+						<button id="closeSettingsModal" class="p-1.5 rounded-lg hover:bg-gray-100 text-gray-400 hover:text-gray-600 transition-colors flex-shrink-0">
+							<svg xmlns="http://www.w3.org/2000/svg" width="18" height="18" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"><path d="M18 6 6 18"/><path d="m6 6 12 12"/></svg>
+						</button>
+					</div>
+					<form id="settingsForm">
+						<div class="space-y-4">
+							<div class="rounded-2xl border border-gray-200 bg-gray-50/70 p-4">
+								<div class="mb-3 flex items-center gap-2 text-xs font-semibold uppercase tracking-[0.2em] text-gray-500">
+									<span>Connection</span>
+								</div>
+								<div class="grid gap-4 md:grid-cols-2">
+									<div>
+										<label class="block text-sm font-medium text-gray-700 mb-1.5" for="settingsProvider">Provider</label>
+										<input type="text" id="settingsProvider" required class="w-full px-4 py-2.5 border border-gray-300 rounded-xl focus:outline-none focus:ring-2 focus:ring-blue-500 focus:border-transparent text-gray-800">
+									</div>
+									<div>
+										<label class="block text-sm font-medium text-gray-700 mb-1.5" for="settingsModel">Model</label>
+										<input type="text" id="settingsModel" required class="w-full px-4 py-2.5 border border-gray-300 rounded-xl focus:outline-none focus:ring-2 focus:ring-blue-500 focus:border-transparent text-gray-800">
+									</div>
+									<div class="md:col-span-2">
+										<label class="block text-sm font-medium text-gray-700 mb-1.5" for="settingsBaseURL">Base URL</label>
+										<input type="url" id="settingsBaseURL" required class="w-full px-4 py-2.5 border border-gray-300 rounded-xl focus:outline-none focus:ring-2 focus:ring-blue-500 focus:border-transparent text-gray-800">
+									</div>
+									<div class="md:col-span-2">
+										<label class="block text-sm font-medium text-gray-700 mb-1.5" for="settingsAPIKey">API key</label>
+										<input type="password" id="settingsAPIKey" autocomplete="off" class="w-full px-4 py-2.5 border border-gray-300 rounded-xl focus:outline-none focus:ring-2 focus:ring-blue-500 focus:border-transparent text-gray-800">
+										<p class="mt-1 text-xs text-gray-500">Leave as-is to keep the current key or replace it with a new one.</p>
+									</div>
+								</div>
+							</div>
+
+							<div class="rounded-2xl border border-gray-200 bg-gray-50/70 p-4">
+								<div class="mb-3 flex items-center gap-2 text-xs font-semibold uppercase tracking-[0.2em] text-gray-500">
+									<span>Server</span>
+								</div>
+								<div class="grid gap-4 md:grid-cols-2">
+									<div>
+										<label class="block text-sm font-medium text-gray-700 mb-1.5" for="settingsServerHost">Host</label>
+										<input type="text" id="settingsServerHost" required placeholder="localhost" class="w-full px-4 py-2.5 border border-gray-300 rounded-xl focus:outline-none focus:ring-2 focus:ring-blue-500 focus:border-transparent text-gray-800">
+									</div>
+									<div>
+										<label class="block text-sm font-medium text-gray-700 mb-1.5" for="settingsServerAddr">Address</label>
+										<input type="text" id="settingsServerAddr" required placeholder=":8080" class="w-full px-4 py-2.5 border border-gray-300 rounded-xl focus:outline-none focus:ring-2 focus:ring-blue-500 focus:border-transparent text-gray-800">
+									</div>
+									<div class="md:col-span-2">
+										<p class="text-xs text-gray-500">Server settings are saved immediately but only take effect after you restart the app.</p>
+									</div>
+								</div>
+							</div>
+
+							<div class="rounded-2xl border border-gray-200 bg-gray-50/70 p-4">
+								<div class="mb-3 flex items-center gap-2 text-xs font-semibold uppercase tracking-[0.2em] text-gray-500">
+									<span>Generation</span>
+								</div>
+								<div class="grid gap-4 md:grid-cols-2">
+									<div>
+										<label class="block text-sm font-medium text-gray-700 mb-1.5" for="settingsTemperature">Temperature</label>
+										<input type="number" id="settingsTemperature" min="0" step="0.01" required class="w-full px-4 py-2.5 border border-gray-300 rounded-xl focus:outline-none focus:ring-2 focus:ring-blue-500 focus:border-transparent text-gray-800">
+									</div>
+									<div>
+										<label class="block text-sm font-medium text-gray-700 mb-1.5" for="settingsMaxTokens">Max tokens</label>
+										<input type="number" id="settingsMaxTokens" min="1" step="1" required class="w-full px-4 py-2.5 border border-gray-300 rounded-xl focus:outline-none focus:ring-2 focus:ring-blue-500 focus:border-transparent text-gray-800">
+									</div>
+									<div>
+										<label class="block text-sm font-medium text-gray-700 mb-1.5" for="settingsTopP">Top P</label>
+										<input type="number" id="settingsTopP" min="0.01" max="1" step="0.01" required class="w-full px-4 py-2.5 border border-gray-300 rounded-xl focus:outline-none focus:ring-2 focus:ring-blue-500 focus:border-transparent text-gray-800">
+									</div>
+									<div>
+										<label class="block text-sm font-medium text-gray-700 mb-1.5" for="settingsFrequencyPenalty">Frequency penalty</label>
+										<input type="number" id="settingsFrequencyPenalty" step="0.1" class="w-full px-4 py-2.5 border border-gray-300 rounded-xl focus:outline-none focus:ring-2 focus:ring-blue-500 focus:border-transparent text-gray-800">
+									</div>
+									<div class="md:col-span-2">
+										<label class="block text-sm font-medium text-gray-700 mb-1.5" for="settingsPresencePenalty">Presence penalty</label>
+										<input type="number" id="settingsPresencePenalty" step="0.1" class="w-full px-4 py-2.5 border border-gray-300 rounded-xl focus:outline-none focus:ring-2 focus:ring-blue-500 focus:border-transparent text-gray-800">
+									</div>
+									<div class="md:col-span-2">
+										<label class="block text-sm font-medium text-gray-700 mb-1.5" for="settingsReasoningEffort">Reasoning effort</label>
+										<select id="settingsReasoningEffort" class="w-full px-4 py-2.5 border border-gray-300 rounded-xl bg-white focus:outline-none focus:ring-2 focus:ring-blue-500 focus:border-transparent text-gray-800">
+											<option value="">Default</option>
+											<option value="low">Low</option>
+											<option value="medium">Medium</option>
+											<option value="high">High</option>
+										</select>
+										<p class="mt-1 text-xs text-gray-500">Forwarded to LM Studio when the backend supports reasoning controls.</p>
+									</div>
+									<div class="md:col-span-2 flex items-start gap-3 rounded-xl border border-gray-200 bg-white px-4 py-3">
+										<input type="checkbox" id="settingsAutoOpenReasoning" class="mt-1 h-4 w-4 rounded border-gray-300 text-blue-600 focus:ring-blue-500">
+										<div class="min-w-0">
+											<label class="block text-sm font-medium text-gray-700" for="settingsAutoOpenReasoning">Auto-open reasoning</label>
+											<p class="mt-1 text-xs text-gray-500">When enabled, live reasoning starts expanded. You can still collapse it while the model is thinking.</p>
+										</div>
+									</div>
+								</div>
+							</div>
+
+							<div class="rounded-2xl border border-gray-200 bg-gray-50/70 p-4">
+								<div class="mb-3 flex items-center gap-2 text-xs font-semibold uppercase tracking-[0.2em] text-gray-500">
+									<span>Context compaction</span>
+								</div>
+								<div class="grid gap-4 md:grid-cols-2">
+									<div class="md:col-span-2">
+										<label class="block text-sm font-medium text-gray-700 mb-1.5" for="settingsContextTokens">Prompt budget (tokens)</label>
+										<input type="number" id="settingsContextTokens" min="1" step="1" required class="w-full px-4 py-2.5 border border-gray-300 rounded-xl focus:outline-none focus:ring-2 focus:ring-blue-500 focus:border-transparent text-gray-800">
+										<p class="mt-1 text-xs text-gray-500">This is the estimated prompt size budget used before compaction starts.</p>
+									</div>
+									<div>
+										<label class="block text-sm font-medium text-gray-700 mb-1.5" for="settingsTriggerRatio">Compaction trigger</label>
+										<input type="number" id="settingsTriggerRatio" min="0.01" max="0.99" step="0.01" required class="w-full px-4 py-2.5 border border-gray-300 rounded-xl focus:outline-none focus:ring-2 focus:ring-blue-500 focus:border-transparent text-gray-800">
+										<p class="mt-1 text-xs text-gray-500">Compaction starts above this fraction of the budget.</p>
+									</div>
+									<div>
+										<label class="block text-sm font-medium text-gray-700 mb-1.5" for="settingsTargetRatio">Compaction target</label>
+										<input type="number" id="settingsTargetRatio" min="0.01" max="0.99" step="0.01" required class="w-full px-4 py-2.5 border border-gray-300 rounded-xl focus:outline-none focus:ring-2 focus:ring-blue-500 focus:border-transparent text-gray-800">
+										<p class="mt-1 text-xs text-gray-500">The summarizer tries to shrink history below this fraction.</p>
+									</div>
+								</div>
+							</div>
+						</div>
+						<p id="settingsFormError" class="mt-4 hidden text-sm text-red-600"></p>
+						<div class="flex gap-3 mt-5">
+							<button type="button" id="cancelSettingsBtn" class="flex-1 px-4 py-2.5 border border-gray-300 rounded-xl text-gray-700 font-medium hover:bg-gray-50 transition-colors">
+								Cancel
+							</button>
+							<button type="submit" class="flex-1 px-4 py-2.5 bg-blue-600 hover:bg-blue-700 text-white font-medium rounded-xl transition-colors">
+								Save
+							</button>
+						</div>
+					</form>
+				</div>
+			</div>
+		</div>
+	</div>
+
+	<!-- Group creation modal -->
+	<div id="groupModal" class="fixed inset-0 z-50 hidden items-center justify-center" style="background: rgba(0,0,0,0.4);">
+		<div class="bg-white rounded-2xl shadow-xl w-full max-w-md mx-4 overflow-hidden">
+			<div class="p-6">
+				<div class="flex items-center justify-between mb-5">
+					<h3 class="text-lg font-semibold text-gray-800">New Workspace</h3>
+					<button id="closeGroupModal" class="p-1.5 rounded-lg hover:bg-gray-100 text-gray-400 hover:text-gray-600 transition-colors">
+						<svg xmlns="http://www.w3.org/2000/svg" width="18" height="18" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"><path d="M18 6 6 18"/><path d="m6 6 12 12"/></svg>
+					</button>
+				</div>
+				<form id="groupForm">
+					<label class="block text-sm font-medium text-gray-700 mb-1.5">Workspace name</label>
+					<input
+						type="text"
+						id="groupNameInput"
+						placeholder="e.g. My Project"
+						class="w-full px-4 py-2.5 border border-gray-300 rounded-xl focus:outline-none focus:ring-2 focus:ring-blue-500 focus:border-transparent text-gray-800 placeholder:text-gray-400"
+						required
+						autofocus
+					>
+					<div class="flex gap-3 mt-5">
+						<button type="button" id="cancelGroupBtn" class="flex-1 px-4 py-2.5 border border-gray-300 rounded-xl text-gray-700 font-medium hover:bg-gray-50 transition-colors">
+							Cancel
+						</button>
+						<button type="submit" class="flex-1 px-4 py-2.5 bg-blue-600 hover:bg-blue-700 text-white font-medium rounded-xl transition-colors">
+							Create
+						</button>
+					</div>
+				</form>
+			</div>
+		</div>
+	</div>
+
+		<!-- Main content -->
+		<div class="flex-1 flex flex-col overflow-hidden">
+			<!-- Header -->
+			<div class="bg-white border-b border-gray-200 px-6 py-4 flex items-center gap-4">
+				<button id="mobileMenuBtnDesktop" class="md:hidden p-2 rounded-lg hover:bg-gray-100 text-gray-600 transition-colors">
+					<svg xmlns="http://www.w3.org/2000/svg" width="20" height="20" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"><line x1="3" y1="12" x2="21" y2="12"/><line x1="3" y1="6" x2="21" y2="6"/><line x1="3" y1="18" x2="21" y2="18"/></svg>
+				</button>
+				<div class="flex items-center gap-2 flex-1 min-w-0">
+					<h1 class="text-xl font-bold text-gray-800">GoCoder</h1>
+					<span class="text-gray-300 text-lg leading-none mx-1 flex-shrink-0">›</span>
+					<div id="headerLocation" class="hidden items-center gap-1.5">
+						<svg xmlns="http://www.w3.org/2000/svg" width="14" height="14" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round" class="text-gray-400"><path d="M20.59 13.41l-7.17 7.17a2 2 0 0 1-2.83 0L2 12V2h10l8.59 8.59a2 2 0 0 1 0 2.82z"/><line x1="7" y1="7" x2="7.01" y2="7"/></svg>
+						<span id="headerLocationText" class="text-sm text-gray-500 truncate max-w-xs"></span>
+						<button id="changeLocationBtn" class="hidden p-1 rounded hover:bg-gray-100 text-gray-400 hover:text-gray-600 transition-colors" title="Change location">
+							<svg xmlns="http://www.w3.org/2000/svg" width="14" height="14" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"><path d="M17 3a2.85 2.83 0 1 1 4 4L7.5 20.5 2 22l1.5-5.5Z"/><path d="m15 5 4 4"/></svg>
+						</button>
+					</div>
+					<button id="pickLocationBtn" class="hidden items-center gap-1 px-2.5 py-1 text-xs bg-gray-100 hover:bg-gray-200 text-gray-600 rounded-lg transition-colors border border-gray-200">
+						<svg xmlns="http://www.w3.org/2000/svg" width="12" height="12" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"><path d="M20 20a2 2 0 0 0 2-2V8a2 2 0 0 0-2-2h-7.9a2 2 0 0 1-1.69-.9L9.6 3.9A2 2 0 0 0 7.93 3H4a2 2 0 0 0-2 2v13a2 2 0 0 0 2 2Z"/></svg>
+						Pick Location
+					</button>
+				</div>
+				<button id="openSettingsBtn" class="p-2 rounded-lg hover:bg-gray-100 text-gray-500 hover:text-gray-700 transition-colors" title="Runtime settings">
+					<svg xmlns="http://www.w3.org/2000/svg" width="20" height="20" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"><path d="M12.22 2h-.44a2 2 0 0 0-2 2v.18a2 2 0 0 1-1 1.73l-.43.25a2 2 0 0 1-2 0l-.15-.08a2 2 0 0 0-2.73.73l-.22.38a2 2 0 0 0 .73 2.73l.15.1a2 2 0 0 1 1 1.72v.51a2 2 0 0 1-1 1.74l-.15.09a2 2 0 0 0-.73 2.73l.22.38a2 2 0 0 0 2.73.73l.15-.08a2 2 0 0 1 2 0l.43.25a2 2 0 0 1 1 1.73V20a2 2 0 0 0 2 2h.44a2 2 0 0 0 2-2v-.18a2 2 0 0 1 1-1.73l.43-.25a2 2 0 0 1 2 0l.15.08a2 2 0 0 0 2.73-.73l.22-.39a2 2 0 0 0-.73-2.73l-.15-.08a2 2 0 0 1-1-1.74v-.5a2 2 0 0 1 1-1.74l.15-.09a2 2 0 0 0 .73-2.73l-.22-.38a2 2 0 0 0-2.73-.73l-.15.08a2 2 0 0 1-2 0l-.43-.25a2 2 0 0 1-1-1.73V4a2 2 0 0 0-2-2z"/><circle cx="12" cy="12" r="3"/></svg>
+				</button>
+			</div>
+
+			<!-- Chat area -->
+			<div id="chatScrollArea" class="flex-1 overflow-y-auto px-4 md:px-8 lg:px-16 py-6">
+				<div id="result" class="hidden">
+					<div id="resultText" class="space-y-4"></div>
+				</div>
+				<div id="emptyState" class="flex flex-col items-center justify-center h-full text-center">
+					<div class="w-20 h-20 bg-gray-100 rounded-2xl flex items-center justify-center mb-6">
+						<svg xmlns="http://www.w3.org/2000/svg" width="36" height="36" viewBox="0 0 24 24" fill="none" stroke="#94a3b8" stroke-width="1.5" stroke-linecap="round" stroke-linejoin="round"><path d="M21 15a2 2 0 0 1-2 2H7l-4 4V5a2 2 0 0 1 2-2h14a2 2 0 0 1 2 2z"/></svg>
+					</div>
+					<h2 class="text-2xl font-semibold text-gray-700 mb-2">Start a conversation</h2>
+					<p class="text-gray-500 mb-6">Type a message to begin, or select an existing conversation</p>
+					<button id="newConversationBtnDesktop" class="bg-blue-600 hover:bg-blue-700 text-white font-medium px-6 py-3 rounded-lg transition-colors">
+						New Conversation
+					</button>
+				</div>
+			</div>
+
+			<!-- Input area -->
+			<div class="bg-white border-t border-gray-200 px-4 md:px-8 lg:px-16 py-4">
+				<div class="flex items-center gap-2 mb-2">
+					<span class="text-xs text-gray-500 font-medium">Agent:</span>
+					<div id="agentSelector" class="flex gap-1.5 flex-wrap">
+						<button type="button" data-agent="none" class="agent-btn px-3 py-1 text-xs font-medium rounded-lg border border-gray-300 text-gray-600 hover:bg-gray-100 transition-colors bg-blue-50 border-blue-300 text-blue-700">None</button>
+						<button type="button" data-agent="dadjokes" class="agent-btn px-3 py-1 text-xs font-medium rounded-lg border border-gray-300 text-gray-600 hover:bg-gray-100 transition-colors">Dadjokes</button>
+						<button type="button" data-agent="poet" class="agent-btn px-3 py-1 text-xs font-medium rounded-lg border border-gray-300 text-gray-600 hover:bg-gray-100 transition-colors">Poet</button>
+						<button type="button" data-agent="robot" class="agent-btn px-3 py-1 text-xs font-medium rounded-lg border border-gray-300 text-gray-600 hover:bg-gray-100 transition-colors">Robot</button>
+					</div>
+				</div>
+				<form id="messageForm" class="flex items-end gap-3">
+					<textarea
+						id="messageInput"
+						name="message"
+						rows="1"
+						placeholder="Type a message... Enter sends, Shift+Enter adds a new line"
+						aria-describedby="messageInputHint"
+						class="message-input flex-1 px-4 py-3 border border-gray-300 rounded-xl focus:outline-none focus:ring-2 focus:ring-blue-500 focus:border-transparent text-gray-800"
+						required
+					></textarea>
+					<button
+						type="submit"
+						id="sendBtn"
+						class="bg-blue-600 hover:bg-blue-700 disabled:bg-gray-300 disabled:cursor-not-allowed text-white font-medium px-6 py-3 rounded-xl transition-colors"
+					>
+						Send
+					</button>
+					<button
+						type="button"
+						id="cancelBtn"
+						class="hidden border border-red-200 bg-white px-5 py-3 font-medium text-red-600 rounded-xl transition-colors hover:bg-red-50 disabled:cursor-not-allowed disabled:opacity-60"
+					>
+						Stop
+					</button>
+				</form>
+				<div id="messageInputHint" class="mt-2 flex flex-wrap items-center gap-x-3 gap-y-1 text-[11px] text-gray-500">
+					<span><kbd class="rounded border border-gray-200 bg-gray-100 px-1.5 py-0.5 font-mono text-[10px] text-gray-700">Enter</kbd> sends</span>
+					<span><kbd class="rounded border border-gray-200 bg-gray-100 px-1.5 py-0.5 font-mono text-[10px] text-gray-700">Shift</kbd>+<kbd class="rounded border border-gray-200 bg-gray-100 px-1.5 py-0.5 font-mono text-[10px] text-gray-700">Enter</kbd> adds a new line</span>
+					<span><kbd class="rounded border border-gray-200 bg-gray-100 px-1.5 py-0.5 font-mono text-[10px] text-gray-700">Alt</kbd>, <kbd class="rounded border border-gray-200 bg-gray-100 px-1.5 py-0.5 font-mono text-[10px] text-gray-700">Ctrl</kbd>, or <kbd class="rounded border border-gray-200 bg-gray-100 px-1.5 py-0.5 font-mono text-[10px] text-gray-700">Cmd</kbd>+<kbd class="rounded border border-gray-200 bg-gray-100 px-1.5 py-0.5 font-mono text-[10px] text-gray-700">Enter</kbd> also add a new line</span>
+				</div>
+			</div>
+		</div>
+	</div>
+	<script src="app.js"></script>
+</body>
+</html>
--- a/web/style.css
+++ b/web/style.css
@@ -0,0 +1,302 @@
+.markdown-body {
+	line-height: 1.6;
+}
+
+.markdown-body p {
+	margin: 0.5em 0;
+}
+
+.markdown-body p:first-child {
+	margin-top: 0;
+}
+
+.markdown-body p:last-child {
+	margin-bottom: 0;
+}
+
+.markdown-body pre {
+	background: #1e1e2e;
+	color: #cdd6f4;
+	padding: 1rem;
+	border-radius: 0.5rem;
+	overflow-x: auto;
+	margin: 0.5em 0;
+}
+
+.markdown-body code {
+	font-family: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, monospace;
+	font-size: 0.875em;
+}
+
+.markdown-body :not(pre) > code {
+	background: #e5e7eb;
+	color: #1e40af;
+	padding: 0.125em 0.375em;
+	border-radius: 0.25rem;
+}
+
+.markdown-body pre code {
+	background: none;
+	padding: 0;
+	color: inherit;
+	font-size: 0.8125rem;
+	line-height: 1.7;
+}
+
+.markdown-body blockquote {
+	border-left: 3px solid #d1d5db;
+	padding-left: 1rem;
+	color: #6b7280;
+	margin: 0.5em 0;
+}
+
+.markdown-body ul,
+.markdown-body ol {
+	padding-left: 1.5rem;
+	margin: 0.5em 0;
+}
+
+.markdown-body li {
+	margin: 0.25em 0;
+}
+
+.markdown-body li > p {
+	display: inline;
+}
+
+.markdown-body hr {
+	border: none;
+	border-top: 1px solid #d1d5db;
+	margin: 1em 0;
+}
+
+.markdown-body table {
+	border-collapse: separate;
+	border-spacing: 0;
+	width: 100%;
+	margin: 0.5em 0;
+	border: 1px solid #e5e7eb;
+	border-radius: 0.5rem;
+	overflow: hidden;
+}
+
+.markdown-body th,
+.markdown-body td {
+	border: none;
+	padding: 0.5rem 0.875rem;
+	text-align: left;
+}
+
+.markdown-body th {
+	background: #f9fafb;
+	font-weight: 600;
+	color: #374151;
+	border-bottom: 2px solid #e5e7eb;
+}
+
+.markdown-body tr:nth-child(even) {
+	background: #fafbfc;
+}
+
+.markdown-body tr:nth-child(odd) {
+	background: #ffffff;
+}
+
+.markdown-body tr:hover {
+	background: #f3f4f6;
+}
+
+.markdown-body a {
+	color: #2563eb;
+	text-decoration: underline;
+}
+
+.markdown-body img {
+	max-width: 100%;
+	border-radius: 0.375rem;
+}
+
+.markdown-body h1,
+.markdown-body h2,
+.markdown-body h3,
+.markdown-body h4,
+.markdown-body h5,
+.markdown-body h6 {
+	margin: 1em 0 0.5em 0;
+	font-weight: 600;
+	line-height: 1.3;
+}
+
+.markdown-body h1 {
+	font-size: 1.5rem;
+}
+
+.markdown-body h2 {
+	font-size: 1.25rem;
+}
+
+.markdown-body h3 {
+	font-size: 1.125rem;
+}
+
+.thinking-panel > summary {
+	list-style: none;
+}
+
+.thinking-panel > summary::-webkit-details-marker {
+	display: none;
+}
+
+.thinking-chevron {
+	transition: transform 0.15s ease;
+}
+
+.thinking-panel[open] .thinking-chevron {
+	transform: rotate(90deg);
+}
+
+.tool-meta-list {
+	display: grid;
+	gap: 0.5rem;
+}
+
+.tool-meta-row {
+	display: grid;
+	grid-template-columns: 6.5rem minmax(0, 1fr);
+	gap: 0.75rem;
+	align-items: start;
+}
+
+.tool-meta-key {
+	font-size: 10px;
+	font-weight: 700;
+	letter-spacing: 0.18em;
+	text-transform: uppercase;
+	color: #94a3b8;
+}
+
+.tool-meta-value {
+	font-family: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, monospace;
+	font-size: 0.8125rem;
+	line-height: 1.5;
+	color: #0f172a;
+	white-space: pre-wrap;
+	word-break: break-word;
+}
+
+.tool-text-block {
+	margin: 0;
+	max-height: 18rem;
+	overflow: auto;
+	border: 1px solid #dbe4f0;
+	border-radius: 0.75rem;
+	background: rgba(255, 255, 255, 0.95);
+	padding: 0.875rem 1rem;
+	font-family: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, monospace;
+	font-size: 0.8125rem;
+	line-height: 1.5rem;
+	color: #0f172a;
+	white-space: pre-wrap;
+	word-break: break-word;
+}
+
+.tool-text-block-error {
+	border-color: #fecaca;
+	background: #fff1f2;
+	color: #7f1d1d;
+}
+
+.tool-placeholder {
+	border: 1px dashed #cbd5e1;
+	border-radius: 0.75rem;
+	padding: 0.75rem 1rem;
+	font-size: 0.875rem;
+	color: #64748b;
+	font-style: italic;
+}
+
+.tool-file-preview {
+	max-height: 12.25rem;
+	overflow-y: auto;
+	border: 1px solid #dbe4f0;
+	border-radius: 0.75rem;
+	background: rgba(255, 255, 255, 0.95);
+}
+
+.tool-file-preview.is-expanded {
+	max-height: 60vh;
+}
+
+.tool-file-preview pre {
+	margin: 0;
+	padding: 0.875rem 1rem;
+	background: transparent;
+	font-family: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, monospace;
+	font-size: 0.8125rem;
+	line-height: 1.5rem;
+	color: inherit;
+	white-space: pre-wrap;
+	word-break: break-word;
+}
+
+.tool-diff {
+	overflow: hidden;
+	border-radius: 0.75rem;
+	border: 1px solid #0f172a;
+	background: #0f172a;
+}
+
+.tool-diff-header {
+	padding: 0.625rem 0.875rem;
+	border-bottom: 1px solid rgba(255, 255, 255, 0.08);
+	font-family: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, monospace;
+	font-size: 11px;
+	line-height: 1.5;
+	white-space: pre-wrap;
+	color: #cbd5e1;
+}
+
+.tool-diff-body {
+	max-height: 18rem;
+	overflow: auto;
+	font-family: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, monospace;
+	font-size: 0.75rem;
+	line-height: 1.5rem;
+}
+
+.tool-diff-line {
+	display: flex;
+	gap: 0.5rem;
+	padding: 0 0.875rem;
+	white-space: pre-wrap;
+	word-break: break-word;
+}
+
+.tool-diff-prefix {
+	flex: 0 0 1rem;
+	text-align: center;
+	user-select: none;
+	opacity: 0.7;
+}
+
+.tool-diff-remove {
+	background: rgba(239, 68, 68, 0.08);
+	color: #fecaca;
+}
+
+.tool-diff-add {
+	background: rgba(16, 185, 129, 0.08);
+	color: #a7f3d0;
+}
+
+.tool-diff-note {
+	padding: 0.875rem;
+	color: #cbd5e1;
+}
+
+.message-input {
+	resize: none;
+	overflow-y: hidden;
+	min-height: 3.5rem;
+	line-height: 1.5rem;
+}