v0.0.5: context compaction, minimal config, retry/search/code symbols/diff/status/test commands

README.md

@@ -44,19 +44,10 @@ providers:
   loveuer:
     base_url: https://ai.loveuer.com
     api_key: ${AGENTU_API_KEY}
-    model: deepseek-v4-flash
     models:
-      - deepseek-v4-flash
+      - id: deepseek-v4-flash
-    thinking: none
+        thinking: none
-    thinking_param: thinking
+        context: 256000
-
-agent:
-  system_prompt: |
-    You are agentu, a concise local agent. Answer simple conversation directly.
-    Use tools only when the user's request needs local project context or local
-    command execution.
-  working_dir: .
-  tool_timeout: 30s
 ```
 
 Web tools are enabled by default with a built-in no-key backend. agentu exposes
@@ -67,18 +58,26 @@ Provider names are the keys under `providers`. At startup, agentu selects the
 first provider by name. Use `/model provider <name>` to switch providers for the
 current session.
 
-`models` is optional. If present, `/model model <name>` is restricted to that
+`models` is required. `/model model <name>` is restricted to that list. Each
-list. If omitted, any model name is accepted for that provider.
+entry is an object with:
 
-`thinking` is optional. Supported values are:
+- `id`: model name sent to the provider.
+- `thinking`: optional default thinking level for that model.
+- `context`: optional context-window token count used for auto-compaction.
+
+If `model` is omitted, agentu uses the first `models` entry. The `agent` block
+is optional: `working_dir`, `tool_timeout`, `system_prompt`, and
+`max_context_tokens` all have defaults. `max_context_tokens` overrides the
+selected model's `context` when set.
+
+Supported thinking values are:
 
 ```text
 none, middle, high, xhigh, max
 ```
 
 When configured or changed with `/model thinking ...`, the value is sent as a
-top-level OpenAI-compatible request field. `thinking_param` controls that field
+top-level OpenAI-compatible request field named `thinking`.
-name and defaults to `thinking`.
 
 ## CLI Flags
 
@@ -90,6 +89,7 @@ go run ./cmd/agentu [flags]
 - `--theme light|dark` selects the TUI theme. Default: `light`.
 - `--plain` uses the simple line-based REPL instead of the TUI.
 - `--yolo` enables automatic file writes and shell execution.
+- `--resume <id>` resumes a saved session from `~/.agentu/sessions`.
 
 ## TUI Controls
 
@@ -103,10 +103,18 @@ go run ./cmd/agentu [flags]
 Slash commands:
 
 - `/clear` resets conversation history.
+- `/compact` summarizes older conversation history and keeps recent context.
+- `/status` shows changed files with `git status --short`.
+- `/diff [--stat] [path...]` shows the unstaged git diff.
+- `/test [command...]` runs a project test command; defaults to `go test ./...` for Go modules or `npm test` for Node projects.
 - `/model` shows current provider, model, thinking, and switch usage.
 - `/model provider <name>` switches provider for the current session.
 - `/model model <name>` or `/model <name>` switches model for the current session.
 - `/model thinking <none|middle|high|xhigh|max>` changes thinking for the current session.
+- `/sessions` lists saved sessions.
+- `/resume [id]` resumes by ID or opens an interactive picker.
+- `/rename <name>` renames the current session.
+- `/new` saves the current session and starts a fresh one.
 - `/exit` or `/quit` exits.
 
 ## Local Tools
@@ -115,7 +123,8 @@ Read-only tools are available by default:
 
 - `file_read`
 - `file_list`
-- `file_search`
+- `file_search` with optional `context_lines` and `max_results`
+- `code_symbols` for Go packages, imports, types, functions, and methods
 
 Web tools are also available in read-only mode:
 

agentu.example.yaml

@@ -2,16 +2,7 @@ providers:
   loveuer:
     base_url: https://ai.loveuer.com
     api_key: ${AGENTU_API_KEY}
-    model: deepseek-v4-flash
     models:
-      - deepseek-v4-flash
+      - id: deepseek-v4-flash
-    thinking: none
+        thinking: none
-    thinking_param: thinking
+        context: 256000
-
-agent:
-  system_prompt: |
-    You are agentu, a concise local agent. Answer simple conversation directly.
-    Use tools only when the user's request needs local project context or local
-    command execution.
-  working_dir: .
-  tool_timeout: 30s

cmd/agentu/main.go

@@ -20,6 +20,20 @@ import (
 	"agentu/internal/tui"
 )
 
+const defaultConfigContent = `# agentu configuration
+# Replace the placeholder values below with your actual provider settings.
+# See agentu.example.yaml for the full reference.
+providers:
+  default:
+    base_url: https://api.openai.com
+    api_key: YOUR_API_KEY_HERE
+    models:
+      - id: gpt-4o
+        context: 128000
+      - id: gpt-4o-mini
+        context: 128000
+`
+
 func main() {
 	if err := run(); err != nil {
 		fmt.Fprintln(os.Stderr, "agentu:", err)
@@ -43,11 +57,10 @@ func run() error {
 	cfg, err := config.Load(*configPath)
 	if err != nil {
 		if errors.Is(err, os.ErrNotExist) {
-			resolvedPath, resolveErr := config.ResolvePath(*configPath)
+			if bootstrapErr := bootstrapConfig(*configPath); bootstrapErr != nil {
-			if resolveErr != nil {
+				return bootstrapErr
-				return resolveErr
 			}
-			return fmt.Errorf("config not found at %s; create ~/.agentu/config.yaml from agentu.example.yaml and set AGENTU_API_KEY", resolvedPath)
+			return fmt.Errorf("created default config at %s; edit it to set your API key and provider, then restart agentu", *configPath)
 		}
 		return err
 	}
@@ -65,17 +78,22 @@ func run() error {
 	registry.Register(tools.NewBuiltinSearchTool(http.DefaultClient))
 	registry.Register(tools.NewBuiltinFetchTool(http.DefaultClient))
 	systemPrompt := strings.TrimSpace(cfg.Agent.SystemPrompt + "\n\n" + tools.AgentInstructions(cfg.Agent.WorkingDir, *yolo))
+	maxContextTokens := cfg.Agent.MaxContextTokens
+	if maxContextTokens == 0 {
+		maxContextTokens = providerConfig.ContextTokens
+	}
 
 	assistant := agent.New(agent.Options{
-		Provider:        provider,
+		Provider:         provider,
-		ProviderName:    providerName,
+		ProviderName:     providerName,
-		Model:           providerConfig.Model,
+		Model:            providerConfig.Model,
-		Thinking:        providerConfig.Thinking,
+		Thinking:         providerConfig.Thinking,
-		ThinkingParam:   providerConfig.ThinkingParam,
+		ThinkingParam:    providerConfig.ThinkingParam,
-		ThinkingEnabled: providerConfig.ThinkingConfigured,
+		ThinkingEnabled:  providerConfig.ThinkingConfigured,
-		SystemPrompt:    systemPrompt,
+		SystemPrompt:     systemPrompt,
-		ToolRegistry:    registry,
+		ToolRegistry:     registry,
-		ToolTimeout:     cfg.Agent.ToolTimeout,
+		ToolTimeout:      cfg.Agent.ToolTimeout,
+		MaxContextTokens: maxContextTokens,
 	})
 
 	// Initialize session store
@@ -114,6 +132,7 @@ func run() error {
 			Yolo:         *yolo,
 			ThemeMode:    themeMode,
 			ModelManager: modelManager,
+			WorkingDir:   cfg.Agent.WorkingDir,
 		})
 		printExitSession(modelManager)
 		return err
@@ -122,12 +141,27 @@ func run() error {
 	return repl(ctx, assistant, modelManager)
 }
 
+func bootstrapConfig(configPath string) error {
+	resolved, err := config.ResolvePath(configPath)
+	if err != nil {
+		return fmt.Errorf("resolve config path: %w", err)
+	}
+	dir := filepath.Dir(resolved)
+	if err := os.MkdirAll(dir, 0o755); err != nil {
+		return fmt.Errorf("create config directory: %w", err)
+	}
+	if err := os.WriteFile(resolved, []byte(defaultConfigContent), 0o644); err != nil {
+		return fmt.Errorf("write default config: %w", err)
+	}
+	return nil
+}
+
 func repl(ctx context.Context, assistant *agent.Agent, modelManager *session.Manager) error {
 	scanner := bufio.NewScanner(os.Stdin)
 	scanner.Buffer(make([]byte, 0, 64*1024), 1024*1024)
 
 	fmt.Println("agentu")
-	fmt.Println("Type /exit to quit, /clear to reset context.")
+	fmt.Println("Type /exit to quit, /clear to reset context, /compact to compress context.")
 	for {
 		fmt.Print("> ")
 		if !scanner.Scan() {
@@ -150,6 +184,16 @@ func repl(ctx context.Context, assistant *agent.Agent, modelManager *session.Man
 			assistant.Clear()
 			fmt.Println("context cleared")
 			continue
+		case "/compact":
+			if err := assistant.Compact(ctx); err != nil {
+				fmt.Fprintln(os.Stderr, "compact error:", err)
+			} else {
+				fmt.Println("context compacted")
+				if modelManager != nil {
+					_ = modelManager.Save()
+				}
+			}
+			continue
 		}
 
 		if err := assistant.RunTurn(ctx, input, os.Stdout, os.Stderr); err != nil {

internal/agent/agent.go

@@ -13,20 +13,36 @@ import (
 	"agentu/internal/tools"
 )
 
-const defaultMaxToolIterations = 8
+const (
+	defaultMaxToolRounds  = 50
+	doomLoopThreshold     = 3
+	compactRecentMessages = 6
+	summaryMessageLimit   = 8000
+	contextSummaryPrefix  = "[context summary]"
+
+	summarizerSystemPrompt = "You are a conversation summarizer. Summarize the following conversation history into a concise but detailed summary. Preserve:\n" +
+		"- Key facts, decisions, and conclusions\n" +
+		"- File paths and code changes made\n" +
+		"- Tool call results (especially errors)\n" +
+		"- Current task state and next steps\n\n" +
+		"Do NOT include: tool call syntax, raw JSON, or verbatim file contents.\n" +
+		"Output only the summary, no preamble."
+)
 
 type Agent struct {
-	provider          llm.Provider
+	provider         llm.Provider
-	providerName      string
+	providerName     string
-	model             string
+	model            string
-	thinking          string
+	thinking         string
-	thinkingParam     string
+	thinkingParam    string
-	thinkingEnabled   bool
+	thinkingEnabled  bool
-	systemPrompt      string
+	systemPrompt     string
-	toolRegistry      *tools.Registry
+	toolRegistry     *tools.Registry
-	toolTimeout       time.Duration
+	toolTimeout      time.Duration
-	maxToolIterations int
+	maxToolRounds    int
-	messages          []llm.Message
+	maxContextTokens int
+	lastUsage        *llm.Usage
+	messages         []llm.Message
 }
 
 type Options struct {
@@ -40,47 +56,52 @@ type Options struct {
 	ToolRegistry      *tools.Registry
 	ToolTimeout       time.Duration
 	MaxToolIterations int
+	MaxContextTokens  int
 }
 
 func New(opts Options) *Agent {
-	maxToolIterations := opts.MaxToolIterations
+	maxToolRounds := opts.MaxToolIterations
-	if maxToolIterations <= 0 {
+	if maxToolRounds <= 0 {
-		maxToolIterations = defaultMaxToolIterations
+		maxToolRounds = defaultMaxToolRounds
 	}
 	toolTimeout := opts.ToolTimeout
 	if toolTimeout <= 0 {
 		toolTimeout = 30 * time.Second
 	}
 	a := &Agent{
-		provider:          opts.Provider,
+		provider:         opts.Provider,
-		providerName:      opts.ProviderName,
+		providerName:     opts.ProviderName,
-		model:             opts.Model,
+		model:            opts.Model,
-		thinking:          opts.Thinking,
+		thinking:         opts.Thinking,
-		thinkingParam:     opts.ThinkingParam,
+		thinkingParam:    opts.ThinkingParam,
-		thinkingEnabled:   opts.ThinkingEnabled,
+		thinkingEnabled:  opts.ThinkingEnabled,
-		systemPrompt:      opts.SystemPrompt,
+		systemPrompt:     opts.SystemPrompt,
-		toolRegistry:      opts.ToolRegistry,
+		toolRegistry:     opts.ToolRegistry,
-		toolTimeout:       toolTimeout,
+		toolTimeout:      toolTimeout,
-		maxToolIterations: maxToolIterations,
+		maxToolRounds:    maxToolRounds,
+		maxContextTokens: opts.MaxContextTokens,
 	}
 	a.Clear()
 	return a
 }
 
 type RuntimeOptions struct {
-	Provider        llm.Provider
+	Provider         llm.Provider
-	ProviderName    string
+	ProviderName     string
-	Model           string
+	Model            string
-	Thinking        string
+	Thinking         string
-	ThinkingParam   string
+	ThinkingParam    string
-	ThinkingEnabled bool
+	ThinkingEnabled  bool
+	MaxContextTokens int
 }
 
 type RuntimeInfo struct {
-	ProviderName    string
+	ProviderName     string
-	Model           string
+	Model            string
-	Thinking        string
+	Thinking         string
-	ThinkingEnabled bool
+	ThinkingEnabled  bool
+	ContextTokens    int
+	MaxContextTokens int
 }
 
 func (a *Agent) SetRuntime(opts RuntimeOptions) {
@@ -96,18 +117,22 @@ func (a *Agent) SetRuntime(opts RuntimeOptions) {
 	a.thinking = opts.Thinking
 	a.thinkingParam = opts.ThinkingParam
 	a.thinkingEnabled = opts.ThinkingEnabled
+	a.maxContextTokens = opts.MaxContextTokens
 }
 
 func (a *Agent) RuntimeInfo() RuntimeInfo {
 	return RuntimeInfo{
-		ProviderName:    a.providerName,
+		ProviderName:     a.providerName,
-		Model:           a.model,
+		Model:            a.model,
-		Thinking:        a.thinking,
+		Thinking:         a.thinking,
-		ThinkingEnabled: a.thinkingEnabled,
+		ThinkingEnabled:  a.thinkingEnabled,
+		ContextTokens:    llm.EstimateTokens(a.messages, a.toolDefinitions()),
+		MaxContextTokens: a.maxContextTokens,
 	}
 }
 
 func (a *Agent) Clear() {
+	a.lastUsage = nil
 	a.messages = nil
 	if strings.TrimSpace(a.systemPrompt) != "" {
 		a.messages = append(a.messages, llm.Message{
@@ -129,14 +154,161 @@ func (a *Agent) SetMessages(messages []llm.Message) {
 	a.messages = append([]llm.Message(nil), messages...)
 }
 
+// LastUsage returns a copy of the most recent provider token usage data.
+func (a *Agent) LastUsage() *llm.Usage {
+	if a.lastUsage == nil {
+		return nil
+	}
+	usage := *a.lastUsage
+	return &usage
+}
+
+// SetLastUsage restores the most recent provider token usage data.
+func (a *Agent) SetLastUsage(usage *llm.Usage) {
+	if usage == nil {
+		a.lastUsage = nil
+		return
+	}
+	copy := *usage
+	a.lastUsage = &copy
+}
+
+// Compact summarizes older conversation messages while preserving the system
+// prompt and recent messages intact.
+func (a *Agent) Compact(ctx context.Context) error {
+	if len(a.messages) < 4 {
+		return nil
+	}
+	if a.provider == nil {
+		return fmt.Errorf("provider is not configured")
+	}
+
+	prefixEnd := 0
+	if a.messages[0].Role == llm.RoleSystem {
+		prefixEnd = 1
+	}
+	if len(a.messages)-prefixEnd <= compactRecentMessages {
+		return nil
+	}
+
+	recentStart := len(a.messages) - compactRecentMessages
+	if recentStart <= prefixEnd {
+		return nil
+	}
+	middle := append([]llm.Message(nil), a.messages[prefixEnd:recentStart]...)
+	if len(middle) == 0 {
+		return nil
+	}
+
+	summary, usage, err := a.summarizeMessages(ctx, middle)
+	if err != nil {
+		return fmt.Errorf("compact context: %w", err)
+	}
+	summary = strings.TrimSpace(summary)
+	if summary == "" {
+		return fmt.Errorf("compact context: summary was empty")
+	}
+
+	compressed := make([]llm.Message, 0, prefixEnd+1+len(a.messages[recentStart:]))
+	compressed = append(compressed, a.messages[:prefixEnd]...)
+	compressed = append(compressed, llm.Message{
+		Role:    llm.RoleAssistant,
+		Content: contextSummaryPrefix + "\n" + summary,
+	})
+	compressed = append(compressed, a.messages[recentStart:]...)
+	a.messages = compressed
+	if usage != nil {
+		a.lastUsage = usage
+	}
+	return nil
+}
+
+func (a *Agent) shouldCompact() bool {
+	if a.maxContextTokens <= 0 {
+		return false
+	}
+	if a.lastUsage != nil && a.lastUsage.TotalTokens >= a.maxContextTokens {
+		return true
+	}
+	return llm.EstimateTokens(a.messages, a.toolDefinitions()) >= a.maxContextTokens
+}
+
+func (a *Agent) summarizeMessages(ctx context.Context, messages []llm.Message) (string, *llm.Usage, error) {
+	req := llm.ChatRequest{
+		Model: a.model,
+		Messages: []llm.Message{
+			{Role: llm.RoleSystem, Content: summarizerSystemPrompt},
+			{Role: llm.RoleUser, Content: formatMessagesForSummary(messages)},
+		},
+	}
+
+	var summary strings.Builder
+	var usage *llm.Usage
+	if err := a.provider.ChatStream(ctx, req, func(event llm.StreamEvent) error {
+		if event.Content != "" {
+			summary.WriteString(event.Content)
+		}
+		if event.Usage != nil {
+			copy := *event.Usage
+			usage = &copy
+		}
+		return nil
+	}); err != nil {
+		return "", nil, err
+	}
+
+	return strings.TrimSpace(summary.String()), usage, nil
+}
+
+func formatMessagesForSummary(messages []llm.Message) string {
+	var b strings.Builder
+	b.WriteString("Conversation history to summarize:\n\n")
+	for index, msg := range messages {
+		fmt.Fprintf(&b, "Message %d (%s):\n", index+1, msg.Role)
+		if msg.ToolCallID != "" {
+			fmt.Fprintf(&b, "tool_call_id: %s\n", msg.ToolCallID)
+		}
+		if msg.Content != "" {
+			fmt.Fprintf(&b, "%s\n", compact(msg.Content, summaryMessageLimit))
+		}
+		for _, call := range msg.ToolCalls {
+			fmt.Fprintf(&b, "tool_call: %s %s\n", call.Function.Name, compact(call.Function.Arguments, summaryMessageLimit))
+		}
+		b.WriteByte('\n')
+	}
+	return b.String()
+}
+
+// roundSignature returns a deterministic signature for a set of tool calls
+// in a single round, used for doom loop detection.
+func roundSignature(calls []llm.ToolCall) string {
+	var b strings.Builder
+	for _, c := range calls {
+		b.WriteString(c.Function.Name)
+		b.WriteByte('\x00')
+		b.WriteString(strings.TrimSpace(c.Function.Arguments))
+		b.WriteByte('\x00')
+	}
+	return b.String()
+}
+
 func (a *Agent) RunTurn(ctx context.Context, input string, out io.Writer, logs io.Writer) error {
 	input = strings.TrimSpace(input)
 	if input == "" {
 		return nil
 	}
 	a.messages = append(a.messages, llm.Message{Role: llm.RoleUser, Content: input})
+	if a.shouldCompact() {
+		if err := a.Compact(ctx); err != nil {
+			if logs != nil {
+				fmt.Fprintf(logs, "[compact] warning: %v\n", err)
+			}
+		}
+	}
 
-	for iteration := 0; iteration <= a.maxToolIterations; iteration++ {
+	var recentSignatures []string
+
+	for round := 0; round < a.maxToolRounds; round++ {
 		content, calls, err := a.streamAssistant(ctx, out)
 		if err != nil {
 			return err
@@ -158,6 +330,40 @@ func (a *Agent) RunTurn(ctx context.Context, input string, out io.Writer, logs i
 			fmt.Fprintln(out)
 		}
 
+		// Doom loop detection: check if the last N rounds all called
+		// the exact same tools with the exact same arguments.
+		sig := roundSignature(calls)
+		recentSignatures = append(recentSignatures, sig)
+		if len(recentSignatures) > doomLoopThreshold {
+			recentSignatures = recentSignatures[len(recentSignatures)-doomLoopThreshold:]
+		}
+
+		if len(recentSignatures) == doomLoopThreshold {
+			allSame := true
+			for i := 1; i < len(recentSignatures); i++ {
+				if recentSignatures[i] != recentSignatures[0] {
+					allSame = false
+					break
+				}
+			}
+			if allSame {
+				toolNames := make([]string, 0, len(calls))
+				for _, c := range calls {
+					toolNames = append(toolNames, c.Function.Name)
+				}
+				msg := fmt.Sprintf(
+					"error: doom loop detected — the same tool call (%s) with identical arguments has been repeated %d times. Stopping. Try a different approach or break the task into smaller steps.",
+					strings.Join(toolNames, ", "),
+					doomLoopThreshold,
+				)
+				a.messages = append(a.messages, llm.Message{
+					Role:    llm.RoleAssistant,
+					Content: msg,
+				})
+				return fmt.Errorf("%s", msg)
+			}
+		}
+
 		for _, call := range calls {
 			result := a.executeTool(ctx, call, logs)
 			a.messages = append(a.messages, llm.Message{
@@ -168,7 +374,7 @@ func (a *Agent) RunTurn(ctx context.Context, input string, out io.Writer, logs i
 		}
 	}
 
-	return fmt.Errorf("tool iteration limit reached: %d", a.maxToolIterations)
+	return fmt.Errorf("tool round limit reached after %d rounds; the task may be too complex for a single turn", a.maxToolRounds)
 }
 
 func (a *Agent) streamAssistant(ctx context.Context, out io.Writer) (string, []llm.ToolCall, error) {
@@ -192,6 +398,9 @@ func (a *Agent) streamAssistant(ctx context.Context, out io.Writer) (string, []l
 	}
 
 	err := a.provider.ChatStream(ctx, req, func(event llm.StreamEvent) error {
+		if event.Usage != nil {
+			a.SetLastUsage(event.Usage)
+		}
 		if event.Content != "" {
 			content.WriteString(event.Content)
 			if out != nil {

internal/agent/agent_test.go

@@ -3,6 +3,7 @@ package agent
 import (
 	"context"
 	"encoding/json"
+	"fmt"
 	"strings"
 	"testing"
 
@@ -96,6 +97,134 @@ func (p *contentProvider) ChatStream(ctx context.Context, req llm.ChatRequest, e
 	return emit(llm.StreamEvent{Content: p.text})
 }
 
+type compactProvider struct {
+	summaryCalls int
+	answerCalls  int
+	lastSummary  string
+}
+
+func (p *compactProvider) ChatStream(ctx context.Context, req llm.ChatRequest, emit func(llm.StreamEvent) error) error {
+	if len(req.Messages) == 2 && req.Messages[0].Role == llm.RoleSystem && req.Messages[0].Content == summarizerSystemPrompt {
+		p.summaryCalls++
+		p.lastSummary = req.Messages[1].Content
+		if err := emit(llm.StreamEvent{Content: "old work summarized"}); err != nil {
+			return err
+		}
+		return emit(llm.StreamEvent{Usage: &llm.Usage{PromptTokens: 10, CompletionTokens: 2, TotalTokens: 12}})
+	}
+
+	p.answerCalls++
+	return emit(llm.StreamEvent{Content: "done"})
+}
+
+func TestAgentCompact(t *testing.T) {
+	provider := &compactProvider{}
+	a := New(Options{Provider: provider, Model: "test", SystemPrompt: "system"})
+	a.SetMessages(longConversation())
+
+	if err := a.Compact(context.Background()); err != nil {
+		t.Fatal(err)
+	}
+
+	messages := a.Messages()
+	if len(messages) != 8 {
+		t.Fatalf("messages = %d, want 8", len(messages))
+	}
+	if messages[0].Role != llm.RoleSystem || messages[0].Content != "system" {
+		t.Fatalf("system message = %#v", messages[0])
+	}
+	if messages[1].Role != llm.RoleAssistant || !strings.HasPrefix(messages[1].Content, contextSummaryPrefix) {
+		t.Fatalf("summary message = %#v", messages[1])
+	}
+	if !strings.Contains(messages[1].Content, "old work summarized") {
+		t.Fatalf("summary content = %q", messages[1].Content)
+	}
+	if !strings.Contains(provider.lastSummary, "old-user-0") {
+		t.Fatalf("summary input did not include old history: %q", provider.lastSummary)
+	}
+	if messages[len(messages)-1].Content != "recent-answer-2" {
+		t.Fatalf("last recent message = %#v", messages[len(messages)-1])
+	}
+	if usage := a.LastUsage(); usage == nil || usage.TotalTokens != 12 {
+		t.Fatalf("usage = %#v", usage)
+	}
+}
+
+func TestAgentAutoCompact(t *testing.T) {
+	provider := &compactProvider{}
+	a := New(Options{
+		Provider:          provider,
+		Model:             "test",
+		SystemPrompt:      "system",
+		MaxContextTokens:  1,
+		ToolRegistry:      tools.NewRegistry(),
+		MaxToolIterations: 1,
+	})
+	a.SetMessages(longConversation())
+
+	var out strings.Builder
+	if err := a.RunTurn(context.Background(), "new question", &out, nil); err != nil {
+		t.Fatal(err)
+	}
+	if provider.summaryCalls != 1 {
+		t.Fatalf("summaryCalls = %d, want 1", provider.summaryCalls)
+	}
+	if provider.answerCalls != 1 {
+		t.Fatalf("answerCalls = %d, want 1", provider.answerCalls)
+	}
+	if out.String() != "done" {
+		t.Fatalf("out = %q", out.String())
+	}
+	if !strings.Contains(joinMessageContents(a.Messages()), contextSummaryPrefix) {
+		t.Fatalf("messages missing summary: %#v", a.Messages())
+	}
+}
+
+func TestAgentCompactSkipsShortHistory(t *testing.T) {
+	provider := &contentProvider{text: "unused"}
+	a := New(Options{Provider: provider, Model: "test", SystemPrompt: "system"})
+	a.SetMessages([]llm.Message{
+		{Role: llm.RoleSystem, Content: "system"},
+		{Role: llm.RoleUser, Content: "question"},
+		{Role: llm.RoleAssistant, Content: "answer"},
+	})
+
+	if err := a.Compact(context.Background()); err != nil {
+		t.Fatal(err)
+	}
+	if provider.called {
+		t.Fatal("provider should not be called for short history")
+	}
+	if len(a.Messages()) != 3 {
+		t.Fatalf("messages = %d, want 3", len(a.Messages()))
+	}
+}
+
+func longConversation() []llm.Message {
+	messages := []llm.Message{{Role: llm.RoleSystem, Content: "system"}}
+	for i := 0; i < 3; i++ {
+		messages = append(messages,
+			llm.Message{Role: llm.RoleUser, Content: fmt.Sprintf("old-user-%d", i)},
+			llm.Message{Role: llm.RoleAssistant, Content: fmt.Sprintf("old-answer-%d", i)},
+		)
+	}
+	for i := 0; i < 3; i++ {
+		messages = append(messages,
+			llm.Message{Role: llm.RoleUser, Content: fmt.Sprintf("recent-user-%d", i)},
+			llm.Message{Role: llm.RoleAssistant, Content: fmt.Sprintf("recent-answer-%d", i)},
+		)
+	}
+	return messages
+}
+
+func joinMessageContents(messages []llm.Message) string {
+	var b strings.Builder
+	for _, msg := range messages {
+		b.WriteString(msg.Content)
+		b.WriteByte('\n')
+	}
+	return b.String()
+}
 func TestAgentLetsProviderDecideShellRequestWhenShellDisabled(t *testing.T) {
 	provider := &contentProvider{text: "shell is disabled"}
 	a := New(Options{
@@ -137,3 +266,77 @@ func TestAgentDoesNotBlockFileRequest(t *testing.T) {
 		t.Fatalf("out = %q", out.String())
 	}
 }
+
+// alwaysToolProvider always returns a tool call with the same args on every request.
+type alwaysToolProvider struct {
+	calls int
+}
+
+func (p *alwaysToolProvider) ChatStream(ctx context.Context, req llm.ChatRequest, emit func(llm.StreamEvent) error) error {
+	p.calls++
+	return emit(llm.StreamEvent{ToolCalls: []llm.ToolCallDelta{
+		{Index: 0, ID: fmt.Sprintf("call_%d", p.calls), Type: "function", Name: "test_echo", Arguments: `{"text":"loop"}`},
+	}})
+}
+
+func TestAgentStopsOnDoomLoop(t *testing.T) {
+	provider := &alwaysToolProvider{}
+	a := New(Options{
+		Provider:          provider,
+		Model:             "test",
+		SystemPrompt:      "system",
+		ToolRegistry:      tools.NewRegistry(echoTool{}),
+		MaxToolIterations: 50, // High hard limit — doom loop should trigger first
+	})
+
+	var out strings.Builder
+	err := a.RunTurn(context.Background(), "loop forever", &out, nil)
+	if err == nil {
+		t.Fatal("expected error when doom loop is detected")
+	}
+	if !strings.Contains(err.Error(), "doom loop detected") {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	// Should have stopped at doomLoopThreshold (3) rounds, not reached hard limit.
+	if provider.calls != doomLoopThreshold {
+		t.Fatalf("calls = %d, want %d (doom loop threshold)", provider.calls, doomLoopThreshold)
+	}
+}
+
+// varyingToolProvider alternates between different tool calls to avoid doom loop detection.
+type varyingToolProvider struct {
+	calls int
+}
+
+func (p *varyingToolProvider) ChatStream(ctx context.Context, req llm.ChatRequest, emit func(llm.StreamEvent) error) error {
+	p.calls++
+	// Vary the arguments each round to avoid doom loop detection.
+	return emit(llm.StreamEvent{ToolCalls: []llm.ToolCallDelta{
+		{Index: 0, ID: fmt.Sprintf("call_%d", p.calls), Type: "function", Name: "test_echo",
+			Arguments: fmt.Sprintf(`{"text":"round-%d"}`, p.calls)},
+	}})
+}
+
+func TestAgentHardLimitStopsVaryingCalls(t *testing.T) {
+	provider := &varyingToolProvider{}
+	const limit = 5
+	a := New(Options{
+		Provider:          provider,
+		Model:             "test",
+		SystemPrompt:      "system",
+		ToolRegistry:      tools.NewRegistry(echoTool{}),
+		MaxToolIterations: limit,
+	})
+
+	var out strings.Builder
+	err := a.RunTurn(context.Background(), "vary forever", &out, nil)
+	if err == nil {
+		t.Fatal("expected error when hard limit is reached")
+	}
+	if !strings.Contains(err.Error(), "tool round limit reached") {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if provider.calls != limit {
+		t.Fatalf("calls = %d, want %d", provider.calls, limit)
+	}
+}

internal/config/config.go

@@ -21,37 +21,50 @@ type Config struct {
 
 type ProviderConfig struct {
 	Name               string
-	BaseURL            string   `yaml:"base_url"`
+	BaseURL            string
-	Model              string   `yaml:"model"`
+	Model              string
-	Models             []string `yaml:"models"`
+	Models             []string
-	APIKey             string   `yaml:"api_key"`
+	ModelConfigs       map[string]ModelConfig
-	Thinking           string   `yaml:"thinking"`
+	ContextTokens      int
-	ThinkingParam      string   `yaml:"thinking_param"`
+	APIKey             string
+	Thinking           string
+	ThinkingParam      string
 	ThinkingConfigured bool
 }
 
+type ModelConfig struct {
+	ID            string `yaml:"id"`
+	Thinking      string `yaml:"thinking"`
+	ContextTokens int    `yaml:"context"`
+}
+
 type AgentConfig struct {
-	SystemPrompt string        `yaml:"system_prompt"`
+	SystemPrompt     string        `yaml:"system_prompt"`
-	WorkingDir   string        `yaml:"working_dir"`
+	WorkingDir       string        `yaml:"working_dir"`
-	ToolTimeout  time.Duration `yaml:"tool_timeout"`
+	ToolTimeout      time.Duration `yaml:"tool_timeout"`
+	MaxContextTokens int           `yaml:"max_context_tokens"`
 }
 
 type rawConfig struct {
 	Providers map[string]rawProviderConfig `yaml:"providers"`
 	Agent     struct {
-		SystemPrompt string `yaml:"system_prompt"`
+		SystemPrompt     string `yaml:"system_prompt"`
-		WorkingDir   string `yaml:"working_dir"`
+		WorkingDir       string `yaml:"working_dir"`
-		ToolTimeout  string `yaml:"tool_timeout"`
+		ToolTimeout      string `yaml:"tool_timeout"`
+		MaxContextTokens int    `yaml:"max_context_tokens"`
 	} `yaml:"agent"`
 }
 
 type rawProviderConfig struct {
-	BaseURL       string   `yaml:"base_url"`
+	BaseURL string           `yaml:"base_url"`
-	Model         string   `yaml:"model"`
+	Models  []rawModelConfig `yaml:"models"`
-	Models        []string `yaml:"models"`
+	APIKey  string           `yaml:"api_key"`
-	APIKey        string   `yaml:"api_key"`
+}
-	Thinking      *string  `yaml:"thinking"`
+
-	ThinkingParam string   `yaml:"thinking_param"`
+type rawModelConfig struct {
+	ID            string `yaml:"id"`
+	Thinking      string `yaml:"thinking"`
+	ContextTokens int    `yaml:"context"`
 }
 
 func Load(path string) (*Config, error) {
@@ -76,8 +89,9 @@ func Load(path string) (*Config, error) {
 	cfg := &Config{
 		Providers: normalizeProviders(raw),
 		Agent: AgentConfig{
-			SystemPrompt: raw.Agent.SystemPrompt,
+			SystemPrompt:     raw.Agent.SystemPrompt,
-			WorkingDir:   raw.Agent.WorkingDir,
+			WorkingDir:       raw.Agent.WorkingDir,
+			MaxContextTokens: raw.Agent.MaxContextTokens,
 		},
 	}
 
@@ -142,8 +156,8 @@ func (c *Config) Validate() error {
 		if strings.TrimSpace(provider.BaseURL) == "" {
 			missing = append(missing, prefix+".base_url")
 		}
-		if strings.TrimSpace(provider.Model) == "" {
+		if len(provider.Models) == 0 {
-			missing = append(missing, prefix+".model")
+			missing = append(missing, prefix+".models")
 		}
 		if strings.TrimSpace(provider.APIKey) == "" {
 			missing = append(missing, prefix+".api_key")
@@ -151,6 +165,19 @@ func (c *Config) Validate() error {
 		if len(missing) > 0 {
 			return fmt.Errorf("missing required config: %s", strings.Join(missing, ", "))
 		}
+		for _, model := range provider.Models {
+			if strings.TrimSpace(model) == "" {
+				return fmt.Errorf("%s.models.id is required", prefix)
+			}
+		}
+		for _, model := range provider.ModelConfigs {
+			if model.ContextTokens < 0 {
+				return fmt.Errorf("%s.models.context must be greater than or equal to zero", prefix)
+			}
+			if model.Thinking != "" && !IsThinkingLevel(model.Thinking) {
+				return fmt.Errorf("%s.models.thinking must be one of: %s", prefix, strings.Join(ThinkingLevels(), ", "))
+			}
+		}
 		if provider.ThinkingConfigured && !IsThinkingLevel(provider.Thinking) {
 			return fmt.Errorf("%s.thinking must be one of: %s", prefix, strings.Join(ThinkingLevels(), ", "))
 		}
@@ -158,6 +185,9 @@ func (c *Config) Validate() error {
 	if c.Agent.ToolTimeout <= 0 {
 		return errors.New("agent.tool_timeout must be greater than zero")
 	}
+	if c.Agent.MaxContextTokens < 0 {
+		return errors.New("agent.max_context_tokens must be greater than or equal to zero")
+	}
 	return nil
 }
 
@@ -187,27 +217,59 @@ func normalizeProviders(raw rawConfig) map[string]ProviderConfig {
 }
 
 func normalizeProvider(name string, raw rawProviderConfig) ProviderConfig {
+	models, modelConfigs := normalizeModelConfigs(raw.Models)
 	provider := ProviderConfig{
-		Name:          name,
+		Name:         name,
-		BaseURL:       raw.BaseURL,
+		BaseURL:      raw.BaseURL,
-		Model:         raw.Model,
+		Models:       models,
-		Models:        append([]string(nil), raw.Models...),
+		ModelConfigs: modelConfigs,
-		APIKey:        raw.APIKey,
+		APIKey:       raw.APIKey,
-		ThinkingParam: raw.ThinkingParam,
 	}
-	if provider.Model == "" && len(provider.Models) > 0 {
+	if len(provider.Models) > 0 {
 		provider.Model = provider.Models[0]
 	}
-	if raw.Thinking != nil {
+	applyModelDefaults(&provider)
-		provider.Thinking = strings.ToLower(strings.TrimSpace(*raw.Thinking))
+	if provider.ThinkingConfigured && provider.ThinkingParam == "" {
-		provider.ThinkingConfigured = true
+		provider.ThinkingParam = "thinking"
-		if provider.ThinkingParam == "" {
-			provider.ThinkingParam = "thinking"
-		}
 	}
 	return provider
 }
 
+func normalizeModelConfigs(rawModels []rawModelConfig) ([]string, map[string]ModelConfig) {
+	models := make([]string, 0, len(rawModels))
+	configs := make(map[string]ModelConfig, len(rawModels))
+	for _, raw := range rawModels {
+		model := ModelConfig{
+			ID:            strings.TrimSpace(raw.ID),
+			Thinking:      strings.ToLower(strings.TrimSpace(raw.Thinking)),
+			ContextTokens: raw.ContextTokens,
+		}
+		models = append(models, model.ID)
+		if model.ID != "" {
+			configs[model.ID] = model
+		}
+	}
+	return models, configs
+}
+
+func applyModelDefaults(provider *ProviderConfig) {
+	model, ok := provider.ModelConfigs[provider.Model]
+	if !ok {
+		return
+	}
+	provider.ContextTokens = model.ContextTokens
+	if model.Thinking != "" {
+		provider.Thinking = model.Thinking
+		provider.ThinkingConfigured = true
+	}
+}
+
+func (p ProviderConfig) WithModel(model string) ProviderConfig {
+	p.Model = strings.TrimSpace(model)
+	applyModelDefaults(&p)
+	return p
+}
+
 func ThinkingLevels() []string {
 	return []string{"none", "middle", "high", "xhigh", "max"}
 }

internal/config/config_test.go

@@ -16,8 +16,9 @@ func TestLoadExpandsEnvAndDefaults(t *testing.T) {
 providers:
   test:
     base_url: https://example.com
-    model: test-model
     api_key: ${AGENTU_TEST_KEY}
+    models:
+      - id: test-model
 agent:
   working_dir: .
 `), 0o644); err != nil {
@@ -43,6 +44,115 @@ agent:
 	}
 }
 
+func TestLoadMinimalModelObjectConfig(t *testing.T) {
+	dir := t.TempDir()
+	t.Setenv("AGENTU_TEST_KEY", "sk-test")
+	path := filepath.Join(dir, "agentu.yaml")
+	if err := os.WriteFile(path, []byte(`
+providers:
+  test:
+    base_url: https://example.com
+    api_key: ${AGENTU_TEST_KEY}
+    models:
+      - id: model-a
+        thinking: none
+        context: 256000
+`), 0o644); err != nil {
+		t.Fatal(err)
+	}
+
+	cfg, err := Load(path)
+	if err != nil {
+		t.Fatal(err)
+	}
+	provider := cfg.Providers["test"]
+	if provider.Model != "model-a" {
+		t.Fatalf("model = %q", provider.Model)
+	}
+	if len(provider.Models) != 1 || provider.Models[0] != "model-a" {
+		t.Fatalf("models = %#v", provider.Models)
+	}
+	if provider.ContextTokens != 256000 {
+		t.Fatalf("context tokens = %d", provider.ContextTokens)
+	}
+	if !provider.ThinkingConfigured || provider.Thinking != "none" || provider.ThinkingParam != "thinking" {
+		t.Fatalf("thinking config = %#v", provider)
+	}
+	if cfg.Agent.ToolTimeout != 30*time.Second {
+		t.Fatalf("tool timeout = %s", cfg.Agent.ToolTimeout)
+	}
+	if cfg.Agent.SystemPrompt == "" {
+		t.Fatal("system prompt default was not applied")
+	}
+}
+
+func TestLoadRejectsStringModelEntries(t *testing.T) {
+	dir := t.TempDir()
+	path := filepath.Join(dir, "agentu.yaml")
+	if err := os.WriteFile(path, []byte(`
+providers:
+  test:
+    base_url: https://example.com
+    api_key: sk-test
+    models:
+      - test-model
+`), 0o644); err != nil {
+		t.Fatal(err)
+	}
+
+	_, err := Load(path)
+	if err == nil || !strings.Contains(err.Error(), "cannot unmarshal") {
+		t.Fatalf("err = %v", err)
+	}
+}
+
+func TestLoadMaxContextTokens(t *testing.T) {
+	dir := t.TempDir()
+	path := filepath.Join(dir, "agentu.yaml")
+	if err := os.WriteFile(path, []byte(`
+providers:
+  test:
+    base_url: https://example.com
+    api_key: sk-test
+    models:
+      - id: test-model
+agent:
+  max_context_tokens: 120000
+`), 0o644); err != nil {
+		t.Fatal(err)
+	}
+
+	cfg, err := Load(path)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if cfg.Agent.MaxContextTokens != 120000 {
+		t.Fatalf("max context tokens = %d", cfg.Agent.MaxContextTokens)
+	}
+}
+
+func TestLoadRejectsNegativeMaxContextTokens(t *testing.T) {
+	dir := t.TempDir()
+	path := filepath.Join(dir, "agentu.yaml")
+	if err := os.WriteFile(path, []byte(`
+providers:
+  test:
+    base_url: https://example.com
+    api_key: sk-test
+    models:
+      - id: test-model
+agent:
+  max_context_tokens: -1
+`), 0o644); err != nil {
+		t.Fatal(err)
+	}
+
+	_, err := Load(path)
+	if err == nil || !strings.Contains(err.Error(), "agent.max_context_tokens") {
+		t.Fatalf("err = %v", err)
+	}
+}
+
 func TestLoadUsesDefaultConfigPath(t *testing.T) {
 	dir := t.TempDir()
 	t.Setenv("HOME", dir)
@@ -56,8 +166,9 @@ func TestLoadUsesDefaultConfigPath(t *testing.T) {
 providers:
   test:
     base_url: https://example.com
-    model: test-model
     api_key: ${AGENTU_TEST_KEY}
+    models:
+      - id: test-model
 `), 0o644); err != nil {
 		t.Fatal(err)
 	}
@@ -93,8 +204,9 @@ func TestLoadDefaultSystemPromptDiscouragesEagerTools(t *testing.T) {
 providers:
   test:
     base_url: https://example.com
-    model: test-model
     api_key: ${AGENTU_TEST_KEY}
+    models:
+      - id: test-model
 `), 0o644); err != nil {
 		t.Fatal(err)
 	}
@@ -119,17 +231,15 @@ providers:
   loveuer:
     base_url: https://example.com
     api_key: ${AGENTU_TEST_KEY}
-    model: model-a
     models:
-      - model-a
+      - id: model-a
-      - model-b
+        thinking: xhigh
-    thinking: xhigh
+      - id: model-b
-    thinking_param: thinking
   backup:
     base_url: https://backup.example.com
     api_key: ${AGENTU_TEST_KEY}
     models:
-      - model-c
+      - id: model-c
 `), 0o644); err != nil {
 		t.Fatal(err)
 	}
@@ -162,11 +272,13 @@ providers:
   two:
     base_url: https://two.example.com
     api_key: ${AGENTU_TEST_KEY}
-    model: model-b
+    models:
+      - id: model-b
   one:
     base_url: https://one.example.com
     api_key: ${AGENTU_TEST_KEY}
-    model: model-a
+    models:
+      - id: model-a
 `), 0o644); err != nil {
 		t.Fatal(err)
 	}
@@ -188,9 +300,10 @@ func TestLoadRejectsInvalidThinking(t *testing.T) {
 providers:
   test:
     base_url: https://example.com
-    model: test-model
     api_key: ${AGENTU_TEST_KEY}
-    thinking: huge
+    models:
+      - id: test-model
+        thinking: huge
 `), 0o644); err != nil {
 		t.Fatal(err)
 	}
@@ -224,8 +337,9 @@ func TestLoadRejectsLegacyProviderConfig(t *testing.T) {
 	if err := os.WriteFile(path, []byte(`
 provider:
   base_url: https://example.com
-  model: test-model
   api_key: sk-test
+  models:
+    - id: test-model
 `), 0o644); err != nil {
 		t.Fatal(err)
 	}
@@ -244,8 +358,9 @@ active_provider: loveuer
 providers:
   loveuer:
     base_url: https://example.com
-    model: test-model
     api_key: sk-test
+    models:
+      - id: test-model
 `), 0o644); err != nil {
 		t.Fatal(err)
 	}

internal/llm/openai.go

@@ -10,8 +10,13 @@ import (
 	"io"
 	"net/http"
 	"strings"
+	"time"
 )
 
+const maxChatAttempts = 3
+
+const retryDelay = 100 * time.Millisecond
+
 type OpenAICompatibleClient struct {
 	baseURL    string
 	apiKey     string
@@ -31,34 +36,82 @@ func NewOpenAICompatibleClient(baseURL, apiKey string, httpClient *http.Client)
 
 func (c *OpenAICompatibleClient) ChatStream(ctx context.Context, req ChatRequest, emit func(StreamEvent) error) error {
 	req.Stream = true
+	extra := make(map[string]any, len(req.Extra)+1)
+	for key, value := range req.Extra {
+		extra[key] = value
+	}
+	if _, exists := extra["stream_options"]; !exists {
+		extra["stream_options"] = map[string]any{"include_usage": true}
+	}
+	req.Extra = extra
 	body, err := json.Marshal(req)
 	if err != nil {
 		return fmt.Errorf("marshal chat request: %w", err)
 	}
 
-	httpReq, err := http.NewRequestWithContext(ctx, http.MethodPost, c.baseURL+"/v1/chat/completions", bytes.NewReader(body))
+	var lastErr error
-	if err != nil {
+	for attempt := 1; attempt <= maxChatAttempts; attempt++ {
-		return fmt.Errorf("create chat request: %w", err)
+		httpReq, err := http.NewRequestWithContext(ctx, http.MethodPost, c.baseURL+"/v1/chat/completions", bytes.NewReader(body))
-	}
+		if err != nil {
-	httpReq.Header.Set("Content-Type", "application/json")
+			return fmt.Errorf("create chat request: %w", err)
-	httpReq.Header.Set("Accept", "text/event-stream")
+		}
-	if c.apiKey != "" {
+		httpReq.Header.Set("Content-Type", "application/json")
-		httpReq.Header.Set("Authorization", "Bearer "+c.apiKey)
+		httpReq.Header.Set("Accept", "text/event-stream")
-	}
+		if c.apiKey != "" {
+			httpReq.Header.Set("Authorization", "Bearer "+c.apiKey)
+		}
 
-	resp, err := c.httpClient.Do(httpReq)
+		resp, err := c.httpClient.Do(httpReq)
-	if err != nil {
+		if err != nil {
-		return fmt.Errorf("send chat request: %w", err)
+			lastErr = fmt.Errorf("send chat request: %w", err)
-	}
+			if !shouldRetryRequest(ctx, attempt, 0) {
-	defer resp.Body.Close()
+				return lastErr
+			}
+			if waitErr := waitBeforeRetry(ctx); waitErr != nil {
+				return waitErr
+			}
+			continue
+		}
 
-	if resp.StatusCode < 200 || resp.StatusCode >= 300 {
+		if resp.StatusCode < 200 || resp.StatusCode >= 300 {
-		limit := io.LimitReader(resp.Body, 4096)
+			limit := io.LimitReader(resp.Body, 4096)
-		data, _ := io.ReadAll(limit)
+			data, _ := io.ReadAll(limit)
-		return fmt.Errorf("chat request failed: status=%d body=%s", resp.StatusCode, strings.TrimSpace(string(data)))
+			_ = resp.Body.Close()
-	}
+			lastErr = fmt.Errorf("chat request failed: status=%d body=%s", resp.StatusCode, strings.TrimSpace(string(data)))
+			if !shouldRetryRequest(ctx, attempt, resp.StatusCode) {
+				return lastErr
+			}
+			if waitErr := waitBeforeRetry(ctx); waitErr != nil {
+				return waitErr
+			}
+			continue
+		}
 
-	return readSSE(resp.Body, emit)
+		defer resp.Body.Close()
+		return readSSE(resp.Body, emit)
+	}
+	return lastErr
+}
+
+func shouldRetryRequest(ctx context.Context, attempt int, status int) bool {
+	if ctx.Err() != nil || attempt >= maxChatAttempts {
+		return false
+	}
+	if status == 0 {
+		return true
+	}
+	return status == http.StatusRequestTimeout || status == http.StatusTooManyRequests || status >= 500
+}
+
+func waitBeforeRetry(ctx context.Context) error {
+	timer := time.NewTimer(retryDelay)
+	defer timer.Stop()
+	select {
+	case <-ctx.Done():
+		return ctx.Err()
+	case <-timer.C:
+		return nil
+	}
 }
 
 func readSSE(r io.Reader, emit func(StreamEvent) error) error {
@@ -79,7 +132,7 @@ func readSSE(r io.Reader, emit func(StreamEvent) error) error {
 			if parseErr != nil {
 				return parseErr
 			}
-			if event.Content != "" || len(event.ToolCalls) > 0 || event.FinishReason != "" {
+			if event.Content != "" || len(event.ToolCalls) > 0 || event.FinishReason != "" || event.Usage != nil {
 				if emitErr := emit(event); emitErr != nil {
 					return emitErr
 				}
@@ -100,6 +153,7 @@ type streamPayload struct {
 		} `json:"delta"`
 		FinishReason string `json:"finish_reason"`
 	} `json:"choices"`
+	Usage *Usage `json:"usage,omitempty"`
 	Error *struct {
 		Message string `json:"message"`
 		Type    string `json:"type"`
@@ -127,15 +181,14 @@ func parseStreamPayload(payload string) (StreamEvent, error) {
 		}
 		return StreamEvent{}, fmt.Errorf("provider error: %s", decoded.Error.Message)
 	}
+	event := StreamEvent{Usage: decoded.Usage}
 	if len(decoded.Choices) == 0 {
-		return StreamEvent{}, nil
+		return event, nil
 	}
 
 	choice := decoded.Choices[0]
-	event := StreamEvent{
+	event.Content = choice.Delta.Content
-		Content:      choice.Delta.Content,
+	event.FinishReason = choice.FinishReason
-		FinishReason: choice.FinishReason,
-	}
 	for _, tc := range choice.Delta.ToolCalls {
 		event.ToolCalls = append(event.ToolCalls, ToolCallDelta{
 			Index:     tc.Index,

internal/llm/openai_test.go

@@ -30,6 +30,10 @@ func TestOpenAICompatibleClientStreamsContentAndToolCalls(t *testing.T) {
 		if raw["thinking"] != "high" {
 			t.Fatalf("thinking = %#v", raw["thinking"])
 		}
+		streamOptions, ok := raw["stream_options"].(map[string]any)
+		if !ok || streamOptions["include_usage"] != true {
+			t.Fatalf("stream_options = %#v", raw["stream_options"])
+		}
 		if !req.Stream {
 			t.Fatal("request did not enable stream")
 		}
@@ -66,6 +70,75 @@ func TestOpenAICompatibleClientStreamsContentAndToolCalls(t *testing.T) {
 	}
 }
 
+func TestChatStreamCapturesUsage(t *testing.T) {
+	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		body := mustReadBody(t, r)
+		var raw map[string]any
+		if err := json.NewDecoder(strings.NewReader(body)).Decode(&raw); err != nil {
+			t.Fatal(err)
+		}
+		streamOptions, ok := raw["stream_options"].(map[string]any)
+		if !ok || streamOptions["include_usage"] != true {
+			t.Fatalf("stream_options = %#v", raw["stream_options"])
+		}
+
+		w.Header().Set("Content-Type", "text/event-stream")
+		_, _ = w.Write([]byte(`data: {"choices":[{"delta":{"content":"ok"},"finish_reason":""}]}` + "\n\n"))
+		_, _ = w.Write([]byte(`data: {"choices":[],"usage":{"prompt_tokens":12,"completion_tokens":3,"total_tokens":15}}` + "\n\n"))
+		_, _ = w.Write([]byte("data: [DONE]\n\n"))
+	}))
+	defer server.Close()
+
+	client := NewOpenAICompatibleClient(server.URL, "sk-test", server.Client())
+	var usage *Usage
+	err := client.ChatStream(context.Background(), ChatRequest{Model: "test"}, func(event StreamEvent) error {
+		if event.Usage != nil {
+			usage = event.Usage
+		}
+		return nil
+	})
+	if err != nil {
+		t.Fatal(err)
+	}
+	if usage == nil {
+		t.Fatal("usage was not emitted")
+	}
+	if usage.PromptTokens != 12 || usage.CompletionTokens != 3 || usage.TotalTokens != 15 {
+		t.Fatalf("usage = %#v", usage)
+	}
+}
+
+func TestOpenAICompatibleClientRetriesTransientHTTPError(t *testing.T) {
+	attempts := 0
+	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		attempts++
+		if attempts == 1 {
+			http.Error(w, "temporary", http.StatusBadGateway)
+			return
+		}
+		w.Header().Set("Content-Type", "text/event-stream")
+		_, _ = w.Write([]byte(`data: {"choices":[{"delta":{"content":"ok"},"finish_reason":""}]}` + "\n\n"))
+		_, _ = w.Write([]byte("data: [DONE]\n\n"))
+	}))
+	defer server.Close()
+
+	client := NewOpenAICompatibleClient(server.URL, "sk-test", server.Client())
+	var content strings.Builder
+	err := client.ChatStream(context.Background(), ChatRequest{Model: "test"}, func(event StreamEvent) error {
+		content.WriteString(event.Content)
+		return nil
+	})
+	if err != nil {
+		t.Fatal(err)
+	}
+	if attempts != 2 {
+		t.Fatalf("attempts = %d, want 2", attempts)
+	}
+	if content.String() != "ok" {
+		t.Fatalf("content = %q", content.String())
+	}
+}
+
 func mustReadBody(t *testing.T, r *http.Request) string {
 	t.Helper()
 	data, err := io.ReadAll(r.Body)

internal/llm/token_estimate.go

@@ -0,0 +1,43 @@
+package llm
+
+import "encoding/json"
+
+const tokenEstimateCharRatio = 4
+
+// EstimateTokens estimates the token cost of messages and tool definitions in a
+// chat completion request. It intentionally uses a simple JSON-size heuristic:
+// roughly four UTF-8 bytes per token plus a small per-message framing overhead.
+func EstimateTokens(messages []Message, tools []Tool) int {
+	if len(messages) == 0 && len(tools) == 0 {
+		return 0
+	}
+
+	payload := struct {
+		Messages []Message `json:"messages,omitempty"`
+		Tools    []Tool    `json:"tools,omitempty"`
+	}{
+		Messages: messages,
+		Tools:    tools,
+	}
+	data, err := json.Marshal(payload)
+	if err != nil {
+		return 0
+	}
+
+	return estimateBytesAsTokens(len(data)) + len(messages)*4
+}
+
+func estimateMessageTokens(msg Message) int {
+	data, err := json.Marshal(msg)
+	if err != nil {
+		return 0
+	}
+	return estimateBytesAsTokens(len(data)) + 4
+}
+
+func estimateBytesAsTokens(n int) int {
+	if n <= 0 {
+		return 0
+	}
+	return (n + tokenEstimateCharRatio - 1) / tokenEstimateCharRatio
+}

internal/llm/token_estimate_test.go

@@ -0,0 +1,45 @@
+package llm
+
+import "testing"
+
+func TestEstimateTokensEmpty(t *testing.T) {
+	if got := EstimateTokens(nil, nil); got != 0 {
+		t.Fatalf("EstimateTokens(nil, nil) = %d, want 0", got)
+	}
+}
+
+func TestEstimateTokens(t *testing.T) {
+	shortMessages := []Message{{Role: RoleUser, Content: "hello"}}
+	short := EstimateTokens(shortMessages, nil)
+	if short <= 4 {
+		t.Fatalf("short estimate = %d, want message framing plus content", short)
+	}
+	if short > 50 {
+		t.Fatalf("short estimate = %d, looks too high for one short message", short)
+	}
+
+	longMessages := []Message{
+		{Role: RoleUser, Content: "hello"},
+		{Role: RoleAssistant, Content: "This is a longer response with enough content to exceed the short estimate."},
+	}
+	long := EstimateTokens(longMessages, nil)
+	if long <= short {
+		t.Fatalf("long estimate = %d, want > short estimate %d", long, short)
+	}
+
+	withTools := EstimateTokens(shortMessages, []Tool{{
+		Type: "function",
+		Function: ToolFunction{
+			Name:        "file_read",
+			Description: "Read a file",
+			Parameters:  []byte(`{"type":"object"}`),
+		},
+	}})
+	if withTools <= short {
+		t.Fatalf("withTools estimate = %d, want > short estimate %d", withTools, short)
+	}
+
+	if msgTokens := estimateMessageTokens(shortMessages[0]); msgTokens <= 4 {
+		t.Fatalf("estimateMessageTokens = %d, want message framing plus content", msgTokens)
+	}
+}

internal/llm/types.go

@@ -79,6 +79,13 @@ type StreamEvent struct {
 	Content      string
 	ToolCalls    []ToolCallDelta
 	FinishReason string
+	Usage        *Usage
+}
+
+type Usage struct {
+	PromptTokens     int `json:"prompt_tokens"`
+	CompletionTokens int `json:"completion_tokens"`
+	TotalTokens      int `json:"total_tokens"`
 }
 
 type ToolCallDelta struct {

internal/session/manager.go

@@ -69,6 +69,7 @@ func (m *Manager) Resume(id string) error {
 	}
 	m.currentSession = sess
 	m.agent.SetMessages(sess.Messages)
+	m.agent.SetLastUsage(sess.LastUsage)
 	return nil
 }
 
@@ -78,6 +79,7 @@ func (m *Manager) Save() error {
 		return nil
 	}
 	m.currentSession.Messages = m.agent.Messages()
+	m.currentSession.LastUsage = m.agent.LastUsage()
 	m.currentSession.Provider = m.providerName
 	m.currentSession.Model = m.provider.Model
 	// Auto-name if empty
@@ -208,11 +210,7 @@ func (m *Manager) Info() string {
 	fmt.Fprintf(&b, "model: %s\n", m.CurrentModel())
 	fmt.Fprintf(&b, "thinking: %s\n", m.CurrentThinking())
 	fmt.Fprintf(&b, "providers: %s\n", strings.Join(m.providerNames(), ", "))
-	if len(m.provider.Models) > 0 {
+	fmt.Fprintf(&b, "models: %s\n", strings.Join(m.provider.Models, ", "))
-		fmt.Fprintf(&b, "models: %s\n", strings.Join(m.provider.Models, ", "))
-	} else {
-		b.WriteString("models: any model name is accepted for this provider\n")
-	}
 	fmt.Fprintf(&b, "thinking levels: %s\n", strings.Join(config.ThinkingLevels(), ", "))
 	b.WriteString("usage: /model provider <name> | /model model <name> | /model thinking <level>")
 	return b.String()
@@ -234,10 +232,10 @@ func (m *Manager) SetModel(model string) (string, error) {
 	if model == "" {
 		return "", fmt.Errorf("model is required")
 	}
-	if len(m.provider.Models) > 0 && !contains(m.provider.Models, model) {
+	if !contains(m.provider.Models, model) {
 		return "", fmt.Errorf("model %q is not configured for provider %q; available: %s", model, m.providerName, strings.Join(m.provider.Models, ", "))
 	}
-	m.provider.Model = model
+	m.provider = m.provider.WithModel(model)
 	m.cfg.Providers[m.providerName] = m.provider
 	m.syncAgent(nil)
 	return "Switched model.\n" + m.summary(), nil
@@ -262,14 +260,22 @@ func (m *Manager) summary() string {
 	return fmt.Sprintf("provider: %s\nmodel: %s\nthinking: %s", m.CurrentProvider(), m.CurrentModel(), m.CurrentThinking())
 }
 
+func (m *Manager) maxContextTokens() int {
+	if m.cfg != nil && m.cfg.Agent.MaxContextTokens > 0 {
+		return m.cfg.Agent.MaxContextTokens
+	}
+	return m.provider.ContextTokens
+}
+
 func (m *Manager) syncAgent(provider llm.Provider) {
 	m.agent.SetRuntime(agent.RuntimeOptions{
-		Provider:        provider,
+		Provider:         provider,
-		ProviderName:    m.providerName,
+		ProviderName:     m.providerName,
-		Model:           m.provider.Model,
+		Model:            m.provider.Model,
-		Thinking:        m.provider.Thinking,
+		Thinking:         m.provider.Thinking,
-		ThinkingParam:   m.provider.ThinkingParam,
+		ThinkingParam:    m.provider.ThinkingParam,
-		ThinkingEnabled: m.provider.ThinkingConfigured,
+		ThinkingEnabled:  m.provider.ThinkingConfigured,
+		MaxContextTokens: m.maxContextTokens(),
 	})
 }
 

internal/session/manager_test.go

@@ -116,6 +116,7 @@ func TestManagerSaveAndResume(t *testing.T) {
 	manager.newSession()
 	var out strings.Builder
 	assistant.RunTurn(context.Background(), "hello world", &out, nil)
+	assistant.SetLastUsage(&llm.Usage{PromptTokens: 10, CompletionTokens: 5, TotalTokens: 15})
 
 	// Save
 	if err := manager.Save(); err != nil {
@@ -153,6 +154,9 @@ func TestManagerSaveAndResume(t *testing.T) {
 	if !hasUser {
 		t.Fatal("resumed session should contain original user message")
 	}
+	if usage := assistant.LastUsage(); usage == nil || usage.TotalTokens != 15 {
+		t.Fatalf("resumed usage = %#v", usage)
+	}
 }
 
 func TestManagerRename(t *testing.T) {
@@ -264,3 +268,66 @@ func TestManagerResumeLatest(t *testing.T) {
 		t.Fatalf("expected %s, got %s", id1, manager.CurrentSessionID())
 	}
 }
+
+type compactingProvider struct {
+	summaryCalls int
+	answerCalls  int
+}
+
+func (p *compactingProvider) ChatStream(ctx context.Context, req llm.ChatRequest, emit func(llm.StreamEvent) error) error {
+	if len(req.Messages) == 2 && req.Messages[0].Role == llm.RoleSystem {
+		p.summaryCalls++
+		return emit(llm.StreamEvent{Content: "summary"})
+	}
+	p.answerCalls++
+	return emit(llm.StreamEvent{Content: "answer"})
+}
+
+func TestManagerUsesModelContextForAgentCompaction(t *testing.T) {
+	provider := &compactingProvider{}
+	cfg := &config.Config{Providers: map[string]config.ProviderConfig{
+		"one": {
+			Name:          "one",
+			BaseURL:       "https://one.example.com",
+			APIKey:        "sk-test",
+			Model:         "model-a",
+			Models:        []string{"model-a"},
+			ModelConfigs:  map[string]config.ModelConfig{"model-a": {ID: "model-a", Thinking: "none", ContextTokens: 1}},
+			ContextTokens: 1,
+		},
+	}}
+	assistant := agent.New(agent.Options{Provider: provider, ProviderName: "one", Model: "model-a"})
+	store, err := NewStore(filepath.Join(t.TempDir(), "sessions"))
+	if err != nil {
+		t.Fatal(err)
+	}
+	manager, err := NewManager(cfg, assistant, nil, store)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if _, err := manager.SetModel("model-a"); err != nil {
+		t.Fatal(err)
+	}
+	assistant.SetMessages([]llm.Message{
+		{Role: llm.RoleSystem, Content: "system"},
+		{Role: llm.RoleUser, Content: "old question 1"},
+		{Role: llm.RoleAssistant, Content: "old answer 1"},
+		{Role: llm.RoleUser, Content: "old question 2"},
+		{Role: llm.RoleAssistant, Content: "old answer 2"},
+		{Role: llm.RoleUser, Content: "recent question 1"},
+		{Role: llm.RoleAssistant, Content: "recent answer 1"},
+		{Role: llm.RoleUser, Content: "recent question 2"},
+		{Role: llm.RoleAssistant, Content: "recent answer 2"},
+	})
+
+	var out strings.Builder
+	if err := assistant.RunTurn(context.Background(), "new question", &out, nil); err != nil {
+		t.Fatal(err)
+	}
+	if provider.summaryCalls != 1 {
+		t.Fatalf("summaryCalls = %d, want 1", provider.summaryCalls)
+	}
+	if provider.answerCalls != 1 {
+		t.Fatalf("answerCalls = %d, want 1", provider.answerCalls)
+	}
+}

internal/session/store.go

@@ -23,6 +23,7 @@ type Session struct {
 	Provider  string        `json:"provider"`
 	Model     string        `json:"model"`
 	Messages  []llm.Message `json:"messages"`
+	LastUsage *llm.Usage    `json:"last_usage,omitempty"`
 }
 
 // SessionMeta is a lightweight summary for listing.

internal/session/store_test.go

@@ -30,6 +30,7 @@ func TestSaveAndLoad(t *testing.T) {
 			{Role: llm.RoleUser, Content: "hello"},
 			{Role: llm.RoleAssistant, Content: "hi there"},
 		},
+		LastUsage: &llm.Usage{PromptTokens: 10, CompletionTokens: 5, TotalTokens: 15},
 	}
 	if err := store.Save(sess); err != nil {
 		t.Fatalf("save: %v", err)
@@ -51,6 +52,9 @@ func TestSaveAndLoad(t *testing.T) {
 	if loaded.Messages[1].Content != "hello" {
 		t.Errorf("Messages[1].Content = %q, want %q", loaded.Messages[1].Content, "hello")
 	}
+	if loaded.LastUsage == nil || loaded.LastUsage.TotalTokens != 15 {
+		t.Errorf("LastUsage = %#v", loaded.LastUsage)
+	}
 	if loaded.UpdatedAt.IsZero() {
 		t.Error("UpdatedAt should be set")
 	}

internal/tools/code.go

@@ -0,0 +1,219 @@
+package tools
+
+import (
+	"bytes"
+	"context"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"go/ast"
+	"go/parser"
+	"go/printer"
+	"go/token"
+	"io/fs"
+	"os"
+	"path/filepath"
+	"sort"
+	"strings"
+
+	"agentu/internal/llm"
+)
+
+const defaultCodeSymbolFileLimit = 50
+
+type CodeSymbolsTool struct {
+	workingDir string
+}
+
+func NewCodeSymbolsTool(workingDir string) *CodeSymbolsTool {
+	return &CodeSymbolsTool{workingDir: workingDir}
+}
+
+func (t *CodeSymbolsTool) Definition() llm.Tool {
+	return llm.Tool{
+		Type: "function",
+		Function: llm.ToolFunction{
+			Name:        "code_symbols",
+			Description: "List Go code symbols (packages, imports, types, functions, methods) for a file or directory without reading full file contents.",
+			Parameters: JSONSchema(`{
+  "type": "object",
+  "properties": {
+    "path": {"type": "string", "description": "Go file or directory to inspect. Defaults to the configured agent working directory."},
+    "max_files": {"type": "integer", "description": "Maximum number of Go files to inspect when path is a directory. Defaults to 50."}
+  },
+  "additionalProperties": false
+}`),
+		},
+	}
+}
+
+type codeSymbolsArgs struct {
+	Path     string `json:"path"`
+	MaxFiles int    `json:"max_files"`
+}
+
+func (t *CodeSymbolsTool) Execute(ctx context.Context, raw json.RawMessage) (string, error) {
+	var args codeSymbolsArgs
+	if err := json.Unmarshal(raw, &args); err != nil {
+		return "", fmt.Errorf("parse arguments: %w", err)
+	}
+	path, err := resolvePath(t.workingDir, args.Path)
+	if err != nil {
+		return "", err
+	}
+	limit := args.MaxFiles
+	if limit <= 0 {
+		limit = defaultCodeSymbolFileLimit
+	}
+
+	files, err := goFiles(ctx, path, limit)
+	if err != nil {
+		return "", err
+	}
+	if len(files) == 0 {
+		return "no Go files found", nil
+	}
+
+	fset := token.NewFileSet()
+	var out strings.Builder
+	for i, file := range files {
+		if ctxErr := ctx.Err(); ctxErr != nil {
+			return FormatResult(out.String()), ctxErr
+		}
+		if i > 0 {
+			out.WriteString("\n")
+		}
+		if err := appendGoSymbols(&out, fset, file); err != nil {
+			fmt.Fprintf(&out, "%s\nerror: %v\n", file, err)
+		}
+		if out.Len() > MaxToolOutputBytes {
+			break
+		}
+	}
+	return FormatResult(out.String()), nil
+}
+
+func goFiles(ctx context.Context, path string, limit int) ([]string, error) {
+	info, err := os.Stat(path)
+	if err != nil {
+		return nil, err
+	}
+	if !info.IsDir() {
+		if strings.HasSuffix(path, ".go") {
+			return []string{path}, nil
+		}
+		return nil, fmt.Errorf("path is not a Go file: %s", path)
+	}
+
+	var files []string
+	stop := errors.New("file limit reached")
+	err = filepath.WalkDir(path, func(current string, d fs.DirEntry, err error) error {
+		if err != nil {
+			return nil
+		}
+		if ctxErr := ctx.Err(); ctxErr != nil {
+			return ctxErr
+		}
+		if d.IsDir() {
+			switch d.Name() {
+			case ".git", "vendor", "node_modules":
+				return filepath.SkipDir
+			}
+			return nil
+		}
+		if strings.HasSuffix(current, ".go") {
+			files = append(files, current)
+			if len(files) >= limit {
+				return stop
+			}
+		}
+		return nil
+	})
+	if err != nil && !errors.Is(err, stop) {
+		return nil, err
+	}
+	sort.Strings(files)
+	return files, nil
+}
+
+func appendGoSymbols(out *strings.Builder, fset *token.FileSet, path string) error {
+	file, err := parser.ParseFile(fset, path, nil, parser.ImportsOnly|parser.ParseComments)
+	if err != nil {
+		return err
+	}
+	full, err := parser.ParseFile(fset, path, nil, 0)
+	if err != nil {
+		return err
+	}
+
+	fmt.Fprintf(out, "%s\n", path)
+	fmt.Fprintf(out, "  package %s\n", full.Name.Name)
+	if len(file.Imports) > 0 {
+		imports := make([]string, 0, len(file.Imports))
+		for _, imp := range file.Imports {
+			imports = append(imports, strings.Trim(imp.Path.Value, "\""))
+		}
+		fmt.Fprintf(out, "  imports: %s\n", strings.Join(imports, ", "))
+	}
+
+	var types, funcs, methods []string
+	for _, decl := range full.Decls {
+		switch d := decl.(type) {
+		case *ast.GenDecl:
+			if d.Tok != token.TYPE {
+				continue
+			}
+			for _, spec := range d.Specs {
+				if ts, ok := spec.(*ast.TypeSpec); ok {
+					kind := typeKind(ts.Type)
+					types = append(types, fmt.Sprintf("%d: type %s %s", fset.Position(ts.Pos()).Line, ts.Name.Name, kind))
+				}
+			}
+		case *ast.FuncDecl:
+			line := fset.Position(d.Pos()).Line
+			if d.Recv == nil {
+				funcs = append(funcs, fmt.Sprintf("%d: func %s", line, d.Name.Name))
+				continue
+			}
+			methods = append(methods, fmt.Sprintf("%d: method %s.%s", line, receiverName(d.Recv), d.Name.Name))
+		}
+	}
+	appendSymbolGroup(out, "types", types)
+	appendSymbolGroup(out, "funcs", funcs)
+	appendSymbolGroup(out, "methods", methods)
+	return nil
+}
+
+func appendSymbolGroup(out *strings.Builder, title string, values []string) {
+	if len(values) == 0 {
+		return
+	}
+	fmt.Fprintf(out, "  %s:\n", title)
+	for _, value := range values {
+		fmt.Fprintf(out, "    - %s\n", value)
+	}
+}
+
+func typeKind(expr ast.Expr) string {
+	switch expr.(type) {
+	case *ast.StructType:
+		return "struct"
+	case *ast.InterfaceType:
+		return "interface"
+	case *ast.FuncType:
+		return "func"
+	default:
+		return "alias"
+	}
+}
+
+func receiverName(recv *ast.FieldList) string {
+	if recv == nil || len(recv.List) == 0 {
+		return "?"
+	}
+	var b bytes.Buffer
+	if err := printer.Fprint(&b, token.NewFileSet(), recv.List[0].Type); err != nil {
+		return "?"
+	}
+	return b.String()
+}

internal/tools/file.go

@@ -223,7 +223,9 @@ func (t *FileSearchTool) Definition() llm.Tool {
   "properties": {
     "query": {"type": "string", "description": "Text or regular expression to search for."},
     "path": {"type": "string", "description": "Optional directory or file to search. Defaults to the configured agent working directory."},
-    "glob": {"type": "string", "description": "Optional file glob, for example '*.go'."}
+    "glob": {"type": "string", "description": "Optional file glob, for example '*.go'."},
+    "context_lines": {"type": "integer", "description": "Optional number of context lines around each match. Defaults to 0."},
+    "max_results": {"type": "integer", "description": "Optional maximum matches to return. Defaults to 100."}
   },
   "required": ["query"],
   "additionalProperties": false
@@ -233,9 +235,11 @@ func (t *FileSearchTool) Definition() llm.Tool {
 }
 
 type fileSearchArgs struct {
-	Query string `json:"query"`
+	Query        string `json:"query"`
-	Path  string `json:"path"`
+	Path         string `json:"path"`
-	Glob  string `json:"glob"`
+	Glob         string `json:"glob"`
+	ContextLines int    `json:"context_lines"`
+	MaxResults   int    `json:"max_results"`
 }
 
 func (t *FileSearchTool) Execute(ctx context.Context, raw json.RawMessage) (string, error) {
@@ -256,8 +260,31 @@ func (t *FileSearchTool) Execute(ctx context.Context, raw json.RawMessage) (stri
 	return t.walkSearch(ctx, args, path)
 }
 
+func normalizedSearchOptions(args fileSearchArgs) (contextLines int, maxResults int) {
+	contextLines = args.ContextLines
+	if contextLines < 0 {
+		contextLines = 0
+	}
+	if contextLines > 5 {
+		contextLines = 5
+	}
+	maxResults = args.MaxResults
+	if maxResults <= 0 {
+		maxResults = 100
+	}
+	if maxResults > 1000 {
+		maxResults = 1000
+	}
+	return contextLines, maxResults
+}
+
 func (t *FileSearchTool) ripgrep(ctx context.Context, args fileSearchArgs, path string) (string, error) {
 	rgArgs := []string{"--line-number", "--color", "never"}
+	contextLines, maxResults := normalizedSearchOptions(args)
+	if contextLines > 0 {
+		rgArgs = append(rgArgs, "--context", fmt.Sprint(contextLines))
+	}
+	rgArgs = append(rgArgs, "--max-count", fmt.Sprint(maxResults))
 	if args.Glob != "" {
 		rgArgs = append(rgArgs, "--glob", args.Glob)
 	}
@@ -282,7 +309,10 @@ func (t *FileSearchTool) ripgrep(ctx context.Context, args fileSearchArgs, path
 }
 
 func (t *FileSearchTool) walkSearch(ctx context.Context, args fileSearchArgs, root string) (string, error) {
+	contextLines, maxResults := normalizedSearchOptions(args)
 	var out bytes.Buffer
+	matchCount := 0
+	stop := errors.New("result limit reached")
 	err := filepath.WalkDir(root, func(path string, d fs.DirEntry, err error) error {
 		if err != nil {
 			return nil
@@ -312,16 +342,22 @@ func (t *FileSearchTool) walkSearch(ctx context.Context, args fileSearchArgs, ro
 		}
 		lines := strings.Split(string(data), "\n")
 		for i, line := range lines {
-			if strings.Contains(line, args.Query) {
+			if !strings.Contains(line, args.Query) {
-				fmt.Fprintf(&out, "%s:%d:%s\n", path, i+1, line)
+				continue
-				if out.Len() > MaxToolOutputBytes {
+			}
-					return errors.New("output limit reached")
+			matchCount++
-				}
+			appendSearchMatch(&out, path, lines, i, contextLines)
+			if matchCount >= maxResults {
+				fmt.Fprintf(&out, "[stopped after %d matches; narrow path/query or raise max_results]\n", maxResults)
+				return stop
+			}
+			if out.Len() > MaxToolOutputBytes {
+				return stop
 			}
 		}
 		return nil
 	})
-	if err != nil && err.Error() != "output limit reached" {
+	if err != nil && !errors.Is(err, stop) {
 		return "", err
 	}
 	if out.Len() == 0 {
@@ -329,3 +365,18 @@ func (t *FileSearchTool) walkSearch(ctx context.Context, args fileSearchArgs, ro
 	}
 	return FormatResult(out.String()), nil
 }
+
+func appendSearchMatch(out *bytes.Buffer, path string, lines []string, matchIndex int, contextLines int) {
+	start := max(0, matchIndex-contextLines)
+	end := min(len(lines)-1, matchIndex+contextLines)
+	if contextLines > 0 {
+		fmt.Fprintf(out, "-- %s:%d --\n", path, matchIndex+1)
+	}
+	for i := start; i <= end; i++ {
+		marker := ":"
+		if i == matchIndex {
+			marker = "*"
+		}
+		fmt.Fprintf(out, "%s%s%d:%s\n", path, marker, i+1, lines[i])
+	}
+}

internal/tools/paths.go

@@ -1,7 +1,9 @@
 package tools
 
 import (
+	"fmt"
 	"path/filepath"
+	"strings"
 )
 
 func resolvePath(baseDir, path string) (string, error) {
@@ -9,7 +11,22 @@ func resolvePath(baseDir, path string) (string, error) {
 		path = "."
 	}
 	if filepath.IsAbs(path) {
-		return filepath.Clean(path), nil
+		return "", fmt.Errorf("absolute paths are not allowed; use a path relative to the project directory")
 	}
-	return filepath.Abs(filepath.Join(baseDir, path))
+	resolved := filepath.Clean(filepath.Join(baseDir, path))
+	if !isWithinDir(resolved, baseDir) {
+		return "", fmt.Errorf("path escapes the project directory: %s", path)
+	}
+	return resolved, nil
+}
+
+func isWithinDir(path, dir string) bool {
+	rel, err := filepath.Rel(dir, path)
+	if err != nil {
+		return false
+	}
+	if rel == ".." || strings.HasPrefix(rel, ".."+string(filepath.Separator)) {
+		return false
+	}
+	return true
 }

internal/tools/tools.go

@@ -5,12 +5,15 @@ import (
 	"encoding/json"
 	"fmt"
 	"sort"
+	"strings"
 
 	"agentu/internal/llm"
 )
 
 const MaxToolOutputBytes = 64 * 1024
 
+const truncationNoticeBudget = 160
+
 type Tool interface {
 	Definition() llm.Tool
 	Execute(ctx context.Context, args json.RawMessage) (string, error)
@@ -62,11 +65,13 @@ func ReadOnlyBuiltins(workingDir string) *Registry {
 	fileRead := NewFileReadTool(workingDir)
 	fileList := NewFileListTool(workingDir)
 	fileSearch := NewFileSearchTool(workingDir)
+	codeSymbols := NewCodeSymbolsTool(workingDir)
 
-	registry := NewRegistry(fileRead, fileList, fileSearch)
+	registry := NewRegistry(fileRead, fileList, fileSearch, codeSymbols)
 	registry.RegisterAlias("file.read", fileRead)
 	registry.RegisterAlias("file.list", fileList)
 	registry.RegisterAlias("file.search", fileSearch)
+	registry.RegisterAlias("code.symbols", codeSymbols)
 	return registry
 }
 
@@ -83,8 +88,8 @@ func Builtins(workingDir string) *Registry {
 
 func AgentInstructions(workingDir string, yolo bool) string {
 	searchInstructions := webSearchInstructions()
-	readOnlyTools := "file_list, file_read, file_search, web_search, web_fetch"
+	readOnlyTools := "file_list, file_read, file_search, code_symbols, web_search, web_fetch"
-	yoloTools := "file_list, file_read, file_search, file_write, shell_run, web_search, web_fetch"
+	yoloTools := "file_list, file_read, file_search, code_symbols, file_write, shell_run, web_search, web_fetch"
 	if yolo {
 		return fmt.Sprintf(`Local project context:
 - The project working directory is %q.
@@ -92,6 +97,7 @@ func AgentInstructions(workingDir string, yolo bool) string {
 - Do not call tools for greetings, small talk, simple Q&A, or general questions that do not require local project or command context.
 - Do not explore the project preemptively. Do not call file_list just to discover context unless the user asks about project files or the answer truly depends on local files.
 - When the user asks to inspect, list, search, or read project files, use file_list, file_search, and file_read instead of saying you cannot access local files.
+- When the user asks about code structure, symbols, functions, methods, types, or definitions in Go files, use code_symbols before reading whole files.
 - When the user asks to run, execute, test, check, debug, or inspect a shell command, use shell_run. This includes local commands written in backticks, such as go, make, git, pwd, ls, ps, and similar terminal commands.
 - Do not use file tools as a substitute for a command execution request.
 - Do not start interactive or long-running sessions. Prefer bounded, non-interactive local commands with clear completion conditions.
@@ -105,6 +111,7 @@ func AgentInstructions(workingDir string, yolo bool) string {
 - Do not call tools for greetings, small talk, simple Q&A, or general questions that do not require local project context.
 - Do not explore the project preemptively. Do not call file_list just to discover context unless the user asks about project files or the answer truly depends on local files.
 - When the user asks to inspect, list, search, or read project files, use file_list, file_search, and file_read instead of saying you cannot access local files.
+- When the user asks about code structure, symbols, functions, methods, types, or definitions in Go files, use code_symbols before reading whole files.
 - Shell command execution is disabled in this mode. When the user asks to run, execute, test, check, debug, or inspect a shell command, do not use file tools as a substitute; explain that they need to restart agentu with --yolo to enable shell_run.
 - %s
 - Tool paths should normally be relative to the project working directory.
@@ -120,10 +127,40 @@ func JSONSchema(schema string) json.RawMessage {
 }
 
 func FormatResult(output string) string {
-	if len(output) <= MaxToolOutputBytes {
+	return FormatResultLimit(output, MaxToolOutputBytes)
+}
+
+func FormatResultLimit(output string, limit int) string {
+	if limit <= 0 || len(output) <= limit {
 		return output
 	}
-	return output[:MaxToolOutputBytes] + fmt.Sprintf("\n\n[truncated after %d bytes]", MaxToolOutputBytes)
+	if limit <= truncationNoticeBudget {
+		return output[:limit]
+	}
+	notice := fmt.Sprintf("\n\n[truncated: showing head and tail; omitted %d bytes]\n\n", len(output)-limit)
+	keep := limit - len(notice)
+	if keep <= 0 {
+		return output[:limit]
+	}
+	headLen := keep / 2
+	tailLen := keep - headLen
+	head := trimHeadAtLine(output[:headLen])
+	tail := trimTailAtLine(output[len(output)-tailLen:])
+	return head + notice + tail
+}
+
+func trimHeadAtLine(value string) string {
+	if idx := strings.LastIndexByte(value, '\n'); idx > 0 {
+		return value[:idx+1]
+	}
+	return value
+}
+
+func trimTailAtLine(value string) string {
+	if idx := strings.IndexByte(value, '\n'); idx >= 0 && idx+1 < len(value) {
+		return value[idx+1:]
+	}
+	return value
 }
 
 func FormatError(err error) string {

internal/tools/tools_test.go

@@ -43,6 +43,41 @@ func TestFileTools(t *testing.T) {
 	}
 }
 
+func TestFileSearchSupportsContextAndMaxResults(t *testing.T) {
+	dir := t.TempDir()
+	path := filepath.Join(dir, "notes.txt")
+	content := strings.Join([]string{"before", "needle one", "middle", "needle two", "after"}, "\n")
+	if err := os.WriteFile(path, []byte(content), 0o644); err != nil {
+		t.Fatal(err)
+	}
+	search := NewFileSearchTool(dir)
+	out, err := search.walkSearch(context.Background(), fileSearchArgs{Query: "needle", ContextLines: 1, MaxResults: 1}, dir)
+	if err != nil {
+		t.Fatal(err)
+	}
+	for _, want := range []string{"-- ", "before", "needle one", "middle", "stopped after 1 matches"} {
+		if !strings.Contains(out, want) {
+			t.Fatalf("search output missing %q:\n%s", want, out)
+		}
+	}
+	if strings.Contains(out, "needle two") {
+		t.Fatalf("search should stop after max_results:\n%s", out)
+	}
+}
+
+func TestFormatResultKeepsHeadAndTail(t *testing.T) {
+	input := strings.Join([]string{"head-1", "head-2", strings.Repeat("x", 220), "tail-1", "tail-2"}, "\n")
+	out := FormatResultLimit(input, 220)
+	for _, want := range []string{"head-1", "truncated: showing head and tail", "tail-2"} {
+		if !strings.Contains(out, want) {
+			t.Fatalf("formatted output missing %q:\n%s", want, out)
+		}
+	}
+	if len(out) > 220 {
+		t.Fatalf("formatted output len = %d, want <= 220", len(out))
+	}
+}
+
 func TestShellRunTool(t *testing.T) {
 	dir := t.TempDir()
 	if err := os.WriteFile(filepath.Join(dir, "x.txt"), []byte("x"), 0o644); err != nil {
@@ -69,12 +104,12 @@ func TestReadOnlyBuiltinsExposeOpenAICompatibleNamesAndAliases(t *testing.T) {
 		}
 	}
 
-	for _, want := range []string{"file_list", "file_read", "file_search"} {
+	for _, want := range []string{"file_list", "file_read", "file_search", "code_symbols"} {
 		if !slices.Contains(names, want) {
 			t.Fatalf("definitions missing %s: %#v", want, names)
 		}
 	}
-	for _, alias := range []string{"file.list", "file.read", "file.search"} {
+	for _, alias := range []string{"file.list", "file.read", "file.search", "code.symbols"} {
 		if _, ok := registry.Get(alias); !ok {
 			t.Fatalf("alias missing: %s", alias)
 		}
@@ -84,6 +119,34 @@ func TestReadOnlyBuiltinsExposeOpenAICompatibleNamesAndAliases(t *testing.T) {
 	}
 }
 
+func TestCodeSymbolsToolListsGoSymbols(t *testing.T) {
+	dir := t.TempDir()
+	path := filepath.Join(dir, "sample.go")
+	if err := os.WriteFile(path, []byte(`package sample
+
+import "context"
+
+type Worker struct{}
+type Runner interface{ Run(context.Context) error }
+
+func NewWorker() *Worker { return &Worker{} }
+func (w *Worker) Run(ctx context.Context) error { return nil }
+`), 0o644); err != nil {
+		t.Fatal(err)
+	}
+
+	tool := NewCodeSymbolsTool(dir)
+	out, err := tool.Execute(context.Background(), json.RawMessage(`{"path":"sample.go"}`))
+	if err != nil {
+		t.Fatal(err)
+	}
+	for _, want := range []string{"package sample", "imports: context", "type Worker struct", "type Runner interface", "func NewWorker", "method *Worker.Run"} {
+		if !strings.Contains(out, want) {
+			t.Fatalf("symbols output missing %q:\n%s", want, out)
+		}
+	}
+}
+
 func TestRegistryCanExposeWebSearch(t *testing.T) {
 	registry := ReadOnlyBuiltins(t.TempDir())
 	registry.Register(NewBuiltinSearchTool(nil))
@@ -132,9 +195,65 @@ func TestAgentInstructionsExplainCommandModes(t *testing.T) {
 
 func TestAgentInstructionsExplainWebSearch(t *testing.T) {
 	withSearch := AgentInstructions("/tmp/project", false)
-	for _, want := range []string{"use web_search", "Use web_fetch", "latest information", "source URLs", "Available tools: file_list, file_read, file_search, web_search, web_fetch"} {
+	for _, want := range []string{"use web_search", "Use web_fetch", "latest information", "source URLs", "Available tools: file_list, file_read, file_search, code_symbols, web_search, web_fetch"} {
 		if !strings.Contains(withSearch, want) {
 			t.Fatalf("web search instructions missing %q:\n%s", want, withSearch)
 		}
 	}
 }
+
+func TestResolvePathRejectsAbsolutePaths(t *testing.T) {
+	base := t.TempDir()
+	_, err := resolvePath(base, "/etc/passwd")
+	if err == nil {
+		t.Fatal("expected error for absolute path")
+	}
+	if !strings.Contains(err.Error(), "absolute paths are not allowed") {
+		t.Fatalf("unexpected error: %v", err)
+	}
+}
+
+func TestResolvePathRejectsEscapingBaseDir(t *testing.T) {
+	base := filepath.Join(t.TempDir(), "project")
+	if err := os.MkdirAll(base, 0o755); err != nil {
+		t.Fatal(err)
+	}
+	_, err := resolvePath(base, "../../../etc/passwd")
+	if err == nil {
+		t.Fatal("expected error for path escaping base dir")
+	}
+	if !strings.Contains(err.Error(), "escapes the project directory") {
+		t.Fatalf("unexpected error: %v", err)
+	}
+}
+
+func TestResolvePathAllowsSubdirTraversal(t *testing.T) {
+	base := t.TempDir()
+	if err := os.MkdirAll(filepath.Join(base, "a", "b"), 0o755); err != nil {
+		t.Fatal(err)
+	}
+	if err := os.WriteFile(filepath.Join(base, "a", "target.txt"), []byte("ok"), 0o644); err != nil {
+		t.Fatal(err)
+	}
+	// "a/b/../target.txt" resolves to "a/target.txt" which is within base.
+	resolved, err := resolvePath(base, "a/b/../target.txt")
+	if err != nil {
+		t.Fatal(err)
+	}
+	want := filepath.Join(base, "a", "target.txt")
+	if resolved != want {
+		t.Fatalf("resolved = %q, want %q", resolved, want)
+	}
+}
+
+func TestResolvePathRejectsDotDotThatEscapes(t *testing.T) {
+	base := t.TempDir()
+	sub := filepath.Join(base, "a")
+	if err := os.MkdirAll(sub, 0o755); err != nil {
+		t.Fatal(err)
+	}
+	_, err := resolvePath(sub, "..")
+	if err == nil {
+		t.Fatal("expected error for path escaping via ..")
+	}
+}

internal/tui/app.go

@@ -28,6 +28,7 @@ type Options struct {
 	Yolo         bool
 	ThemeMode    ThemeMode
 	ModelManager ModelManager
+	WorkingDir   string
 }
 
 type ModelManager interface {
@@ -69,13 +70,14 @@ type message struct {
 }
 
 type model struct {
-	ctx       context.Context
+	ctx        context.Context
-	agent     *agent.Agent
+	agent      *agent.Agent
-	modelName string
+	modelName  string
-	yolo      bool
+	yolo       bool
-	models    ModelManager
+	models     ModelManager
-	theme     theme
+	workingDir string
-	styles    styles
+	theme      theme
+	styles     styles
 
 	viewport viewport.Model
 	input    textarea.Model
@@ -84,11 +86,12 @@ type model struct {
 	width  int
 	height int
 
-	messages []message
+	messages     []message
-	status   string
+	status       string
-	running  bool
+	contextUsage string
-	cancel   context.CancelFunc
+	running      bool
-	events   <-chan tea.Msg
+	cancel       context.CancelFunc
+	events       <-chan tea.Msg
 
 	// Session picker state
 	picking      bool
@@ -119,6 +122,7 @@ type slashCommand struct {
 
 var slashCommands = []slashCommand{
 	{Name: "/clear", Description: "reset context"},
+	{Name: "/compact", Description: "compress context"},
 	{Name: "/exit", Description: "quit"},
 	{Name: "/quit", Description: "quit"},
 	{Name: "/model", Description: "model/provider/thinking"},
@@ -126,6 +130,9 @@ var slashCommands = []slashCommand{
 	{Name: "/resume", Description: "resume session"},
 	{Name: "/rename", Description: "rename session"},
 	{Name: "/new", Description: "new session"},
+	{Name: "/status", Description: "show changed files"},
+	{Name: "/diff", Description: "show unstaged diff"},
+	{Name: "/test", Description: "run project tests"},
 }
 
 func newModel(ctx context.Context, assistant *agent.Agent, opts Options) model {
@@ -154,19 +161,22 @@ func newModel(ctx context.Context, assistant *agent.Agent, opts Options) model {
 	vp.Style = st.Viewport
 	vp.SetContent("")
 
-	return model{
+	m := model{
-		ctx:       ctx,
+		ctx:        ctx,
-		agent:     assistant,
+		agent:      assistant,
-		modelName: opts.ModelName,
+		modelName:  opts.ModelName,
-		yolo:      opts.Yolo,
+		yolo:       opts.Yolo,
-		models:    opts.ModelManager,
+		models:     opts.ModelManager,
-		theme:     th,
+		workingDir: opts.WorkingDir,
-		styles:    st,
+		theme:      th,
-		viewport:  vp,
+		styles:     st,
-		input:     input,
+		viewport:   vp,
-		spinner:   spin,
+		input:      input,
-		status:    "ready",
+		spinner:    spin,
+		status:     "ready",
 	}
+	m.refreshContextUsage()
+	return m
 }
 
 func (m model) Init() tea.Cmd {
@@ -272,6 +282,7 @@ func (m model) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
 		if m.models != nil {
 			_ = m.models.Save()
 		}
+		m.refreshContextUsage()
 		m.resize()
 		m.refreshViewport(true)
 		cmds = append(cmds, textarea.Blink)
@@ -338,13 +349,14 @@ func (m *model) submit() (tea.Model, tea.Cmd) {
 		return *m, tea.Quit
 	case "/clear":
 		m.agent.Clear()
+		m.refreshContextUsage()
 		m.messages = []message{{role: roleSystem, content: "Context cleared."}}
 		m.input.SetValue("")
 		m.afterInputChanged()
 		m.status = "ready"
 		m.refreshViewport(true)
 		return *m, nil
-	case "/model":
+	case "/model", "/compact":
 		return m.runLocalCommand(input)
 	}
 
@@ -541,6 +553,9 @@ func (m model) modelMetaView() string {
 			parts = append(parts, "thinking "+currentThinking)
 		}
 	}
+	if m.contextUsage != "" {
+		parts = append(parts, m.contextUsage)
+	}
 	parts = append([]string{modelName, mode}, parts...)
 	parts = append(parts, "theme "+string(m.theme.Mode))
 	line := fitLine(strings.Join(parts, " · "), max(1, m.width-2))
@@ -700,6 +715,58 @@ func (m model) modelInfo() string {
 	return fmt.Sprintf("model: %s\nmode: %s\ntheme: %s", m.modelName, mode, m.theme.Mode)
 }
 
+func (m *model) refreshContextUsage() {
+	m.contextUsage = contextUsageMeta(m.agent)
+}
+
+func contextUsageMeta(assistant *agent.Agent) string {
+	if assistant == nil {
+		return ""
+	}
+	info := assistant.RuntimeInfo()
+	if info.ContextTokens <= 0 && info.MaxContextTokens <= 0 {
+		return ""
+	}
+	used := formatTokenCount(info.ContextTokens)
+	if info.MaxContextTokens <= 0 {
+		return "ctx ~" + used
+	}
+	return fmt.Sprintf("ctx ~%s/%s (%s)", used, formatTokenCount(info.MaxContextTokens), contextPercent(info.ContextTokens, info.MaxContextTokens))
+}
+
+func contextPercent(used int, limit int) string {
+	if limit <= 0 {
+		return ""
+	}
+	if used <= 0 {
+		return "0%"
+	}
+	percent := used * 100 / limit
+	if percent == 0 {
+		return "<1%"
+	}
+	return fmt.Sprintf("%d%%", percent)
+}
+
+func formatTokenCount(tokens int) string {
+	if tokens < 0 {
+		tokens = 0
+	}
+	if tokens < 1000 {
+		return fmt.Sprintf("%d", tokens)
+	}
+	if tokens < 1_000_000 {
+		if tokens%1000 == 0 {
+			return fmt.Sprintf("%dk", tokens/1000)
+		}
+		return fmt.Sprintf("%.1fk", float64(tokens)/1000)
+	}
+	if tokens%1_000_000 == 0 {
+		return fmt.Sprintf("%dm", tokens/1_000_000)
+	}
+	return fmt.Sprintf("%.1fm", float64(tokens)/1_000_000)
+}
+
 func fitLine(text string, width int) string {
 	width = max(1, width)
 	if lipgloss.Width(text) <= width {
@@ -741,6 +808,7 @@ func (m *model) runLocalCommand(input string) (tea.Model, tea.Cmd) {
 	m.status = status
 	// Rebuild display from agent history (matters after /resume and /new)
 	m.syncMessages()
+	m.refreshContextUsage()
 	// Append command output after synced history
 	m.messages = append(m.messages, message{role: role, content: output})
 	m.refreshViewport(true)
@@ -753,6 +821,8 @@ func (m model) handleLocalCommand(input string) (string, error) {
 		return "", fmt.Errorf("empty command")
 	}
 	switch fields[0] {
+	case "/compact":
+		return m.handleCompactCommand()
 	case "/model":
 		return m.handleModelCommand(fields[1:])
 	case "/sessions":
@@ -763,11 +833,27 @@ func (m model) handleLocalCommand(input string) (string, error) {
 		return m.handleRenameCommand(fields[1:])
 	case "/new":
 		return m.handleNewCommand()
+	case "/status":
+		return m.handleStatusCommand(fields[1:])
+	case "/diff":
+		return m.handleDiffCommand(fields[1:])
+	case "/test":
+		return m.handleTestCommand(fields[1:])
 	default:
 		return "", fmt.Errorf("unknown command: %s", fields[0])
 	}
 }
 
+func (m model) handleCompactCommand() (string, error) {
+	if m.agent == nil {
+		return "", fmt.Errorf("agent is not configured")
+	}
+	if err := m.agent.Compact(m.ctx); err != nil {
+		return "", err
+	}
+	return "Context compacted.", nil
+}
+
 func (m model) handleModelCommand(args []string) (string, error) {
 	if m.models == nil {
 		if len(args) > 0 {

internal/tui/app_test.go

@@ -2,9 +2,15 @@ package tui
 
 import (
 	"context"
+	"os"
+	"os/exec"
+	"path/filepath"
 	"strings"
 	"testing"
 
+	"agentu/internal/agent"
+	"agentu/internal/llm"
+
 	tea "github.com/charmbracelet/bubbletea"
 	"github.com/charmbracelet/lipgloss"
 )
@@ -82,6 +88,20 @@ func TestModelMetaRendersBelowInput(t *testing.T) {
 	}
 }
 
+func TestModelMetaRendersContextUsage(t *testing.T) {
+	assistant := agent.New(agent.Options{Model: "test-model", MaxContextTokens: 1000})
+	assistant.SetMessages([]llm.Message{{Role: llm.RoleUser, Content: strings.Repeat("x", 800)}})
+	m := newModel(context.Background(), assistant, Options{ModelName: "test-model"})
+	next, _ := m.Update(tea.WindowSizeMsg{Width: 120, Height: 30})
+	rendered := next.(model).modelMetaView()
+
+	for _, want := range []string{"ctx ~", "/1k", "%"} {
+		if !strings.Contains(rendered, want) {
+			t.Fatalf("model meta missing %q:\n%s", want, rendered)
+		}
+	}
+}
+
 func TestInitialViewDoesNotRenderTopNote(t *testing.T) {
 	m := newModel(context.Background(), nil, Options{ModelName: "test-model"})
 	next, _ := m.Update(tea.WindowSizeMsg{Width: 100, Height: 30})
@@ -264,13 +284,108 @@ func TestSlashCommandSuggestions(t *testing.T) {
 	m.afterInputChanged()
 
 	rendered := m.View()
-	for _, want := range []string{"/clear reset context", "/exit quit", "/model model/provider/thinking"} {
+	for _, want := range []string{"/clear reset context", "/compact compress context", "/exit quit", "/model model/provider/thinking"} {
 		if !strings.Contains(rendered, want) {
 			t.Fatalf("rendered suggestions missing %q:\n%s", want, rendered)
 		}
 	}
 }
 
+type tuiCompactProvider struct{}
+
+func (tuiCompactProvider) ChatStream(ctx context.Context, req llm.ChatRequest, emit func(llm.StreamEvent) error) error {
+	return emit(llm.StreamEvent{Content: "summary from tui"})
+}
+
+func TestCompactCommand(t *testing.T) {
+	assistant := agent.New(agent.Options{Provider: tuiCompactProvider{}, Model: "test", SystemPrompt: "system"})
+	assistant.SetMessages([]llm.Message{
+		{Role: llm.RoleSystem, Content: "system"},
+		{Role: llm.RoleUser, Content: "old question 1"},
+		{Role: llm.RoleAssistant, Content: "old answer 1"},
+		{Role: llm.RoleUser, Content: "old question 2"},
+		{Role: llm.RoleAssistant, Content: "old answer 2"},
+		{Role: llm.RoleUser, Content: "recent question 1"},
+		{Role: llm.RoleAssistant, Content: "recent answer 1"},
+		{Role: llm.RoleUser, Content: "recent question 2"},
+		{Role: llm.RoleAssistant, Content: "recent answer 2"},
+	})
+	m := newModel(context.Background(), assistant, Options{ModelName: "test-model"})
+
+	out, err := m.handleLocalCommand("/compact")
+	if err != nil {
+		t.Fatal(err)
+	}
+	if out != "Context compacted." {
+		t.Fatalf("output = %q", out)
+	}
+	if !strings.Contains(messageContents(assistant.Messages()), "[context summary]") {
+		t.Fatalf("messages missing summary: %#v", assistant.Messages())
+	}
+}
+
+func messageContents(messages []llm.Message) string {
+	var b strings.Builder
+	for _, msg := range messages {
+		b.WriteString(msg.Content)
+		b.WriteByte('\n')
+	}
+	return b.String()
+}
+
+func TestWorkflowStatusDiffAndTestCommands(t *testing.T) {
+	if _, err := exec.LookPath("git"); err != nil {
+		t.Skip("git not installed")
+	}
+	dir := t.TempDir()
+	runInDir(t, dir, "git", "init")
+	runInDir(t, dir, "git", "config", "user.email", "agentu@example.test")
+	runInDir(t, dir, "git", "config", "user.name", "agentu")
+	if err := os.WriteFile(filepath.Join(dir, "go.mod"), []byte("module example.com/p1\n\ngo 1.26\n"), 0o644); err != nil {
+		t.Fatal(err)
+	}
+	if err := os.WriteFile(filepath.Join(dir, "main_test.go"), []byte("package p1\n\nimport \"testing\"\n\nfunc TestOK(t *testing.T) {}\n"), 0o644); err != nil {
+		t.Fatal(err)
+	}
+	runInDir(t, dir, "git", "add", ".")
+	runInDir(t, dir, "git", "commit", "-m", "init")
+	if err := os.WriteFile(filepath.Join(dir, "main_test.go"), []byte("package p1\n\nimport \"testing\"\n\nfunc TestOK(t *testing.T) { t.Log(\"changed\") }\n"), 0o644); err != nil {
+		t.Fatal(err)
+	}
+
+	m := newModel(context.Background(), nil, Options{ModelName: "test-model", WorkingDir: dir})
+	status, err := m.handleStatusCommand(nil)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !strings.Contains(status, "main_test.go") {
+		t.Fatalf("status missing changed file:\n%s", status)
+	}
+	diff, err := m.handleDiffCommand(nil)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !strings.Contains(diff, "changed") {
+		t.Fatalf("diff missing changed content:\n%s", diff)
+	}
+	out, err := m.handleTestCommand(nil)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !strings.Contains(out, "$ go test ./...") {
+		t.Fatalf("test output missing default command:\n%s", out)
+	}
+}
+
+func runInDir(t *testing.T, dir string, name string, args ...string) {
+	t.Helper()
+	cmd := exec.Command(name, args...)
+	cmd.Dir = dir
+	if output, err := cmd.CombinedOutput(); err != nil {
+		t.Fatalf("%s %v failed: %v\n%s", name, args, err, output)
+	}
+}
+
 func TestModelCommand(t *testing.T) {
 	m := newModel(context.Background(), nil, Options{ModelName: "test-model", Yolo: true})
 	m.input.SetValue("/model")

internal/tui/workflow.go

@@ -0,0 +1,143 @@
+package tui
+
+import (
+	"bytes"
+	"context"
+	"errors"
+	"fmt"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"strings"
+	"time"
+
+	"agentu/internal/tools"
+)
+
+const workflowCommandTimeout = 2 * time.Minute
+
+func (m model) handleStatusCommand(args []string) (string, error) {
+	if len(args) != 0 {
+		return "", fmt.Errorf("usage: /status")
+	}
+	out, err := m.runGitCommand("status", "--short")
+	if err != nil {
+		return out, err
+	}
+	if strings.TrimSpace(out) == "" {
+		return "Working tree clean.", nil
+	}
+	return "Changed files:\n" + out, nil
+}
+
+func (m model) handleDiffCommand(args []string) (string, error) {
+	if len(args) > 0 && args[0] == "--stat" {
+		out, err := m.runGitCommand(append([]string{"diff", "--stat", "--"}, args[1:]...)...)
+		if err != nil {
+			return out, err
+		}
+		if strings.TrimSpace(out) == "" {
+			return "No unstaged diff.", nil
+		}
+		return out, nil
+	}
+	out, err := m.runGitCommand(append([]string{"diff", "--"}, args...)...)
+	if err != nil {
+		return out, err
+	}
+	if strings.TrimSpace(out) == "" {
+		return "No unstaged diff.", nil
+	}
+	return out, nil
+}
+
+func (m model) handleTestCommand(args []string) (string, error) {
+	command := strings.TrimSpace(strings.Join(args, " "))
+	if command == "" {
+		var err error
+		command, err = defaultTestCommand(m.workflowDir())
+		if err != nil {
+			return "", err
+		}
+	}
+	out, err := m.runShellCommand(command)
+	if err != nil {
+		if strings.TrimSpace(out) != "" {
+			return out, err
+		}
+		return "", err
+	}
+	if strings.TrimSpace(out) == "" {
+		return fmt.Sprintf("$ %s\n(no output)", command), nil
+	}
+	return out, nil
+}
+
+func (m model) runGitCommand(args ...string) (string, error) {
+	ctx, cancel := context.WithTimeout(m.ctx, workflowCommandTimeout)
+	defer cancel()
+
+	cmd := exec.CommandContext(ctx, "git", append([]string{"-C", m.workflowDir()}, args...)...)
+	output, err := cmd.CombinedOutput()
+	text := tools.FormatResult(string(output))
+	if errors.Is(ctx.Err(), context.DeadlineExceeded) {
+		return text, fmt.Errorf("git command timed out: %w", ctx.Err())
+	}
+	if err != nil {
+		if strings.TrimSpace(text) != "" {
+			return text, fmt.Errorf("git command failed: %w", err)
+		}
+		return "", fmt.Errorf("git command failed: %w", err)
+	}
+	return text, nil
+}
+
+func (m model) runShellCommand(command string) (string, error) {
+	ctx, cancel := context.WithTimeout(m.ctx, workflowCommandTimeout)
+	defer cancel()
+
+	shell := os.Getenv("SHELL")
+	if shell == "" {
+		shell = "/bin/sh"
+	}
+	cmd := exec.CommandContext(ctx, shell, "-lc", command)
+	cmd.Dir = m.workflowDir()
+
+	var combined bytes.Buffer
+	cmd.Stdout = &combined
+	cmd.Stderr = &combined
+	err := cmd.Run()
+	text := strings.TrimRight(tools.FormatResult(combined.String()), "\n")
+	if text != "" {
+		text = fmt.Sprintf("$ %s\n%s", command, text)
+	}
+	if errors.Is(ctx.Err(), context.DeadlineExceeded) {
+		return text, fmt.Errorf("command timed out: %w", ctx.Err())
+	}
+	if err != nil {
+		return text, fmt.Errorf("command failed: %w", err)
+	}
+	return text, nil
+}
+
+func (m model) workflowDir() string {
+	if strings.TrimSpace(m.workingDir) == "" {
+		return "."
+	}
+	return m.workingDir
+}
+
+func defaultTestCommand(dir string) (string, error) {
+	if fileExists(filepath.Join(dir, "go.mod")) {
+		return "go test ./...", nil
+	}
+	if fileExists(filepath.Join(dir, "package.json")) {
+		return "npm test", nil
+	}
+	return "", fmt.Errorf("no default test command found; use /test <command>")
+}
+
+func fileExists(path string) bool {
+	info, err := os.Stat(path)
+	return err == nil && !info.IsDir()
+}