feat: auto permission mode, edit diffs, truncated tool output

- Default permission mode changed to 'auto' (read-only auto-allows,
  writes prompt)
- fs.edit now shows diff-style output: line numbers, context ±3 lines,
  + for added (green), - for removed (red)
- Tool output truncated to 10 lines in TUI with "+N lines (Ctrl+O
  to expand)" indicator
- Mistral SDK bumped to v1.3.0

cmd/gnoma/main.go

@@ -41,7 +41,7 @@ func main() {
 		system       = flag.String("system", defaultSystem, "system prompt")
 		apiKey       = flag.String("api-key", "", "API key (or set MISTRAL_API_KEY env)")
 		maxTurns     = flag.Int("max-turns", 50, "max tool-calling rounds per turn")
-		permMode     = flag.String("permission", "default", "permission mode (default, accept_edits, bypass, deny, plan, auto)")
+		permMode     = flag.String("permission", "auto", "permission mode (default, accept_edits, bypass, deny, plan, auto)")
 		incognito    = flag.Bool("incognito", false, "incognito mode — no persistence, no learning")
 		verbose      = flag.Bool("verbose", false, "enable debug logging")
 		version      = flag.Bool("version", false, "print version and exit")

go.mod

@@ -8,7 +8,7 @@ require (
 	charm.land/glamour/v2 v2.0.0
 	charm.land/lipgloss/v2 v2.0.2
 	github.com/BurntSushi/toml v0.3.1
-	github.com/VikingOwl91/mistral-go-sdk v1.2.1
+	github.com/VikingOwl91/mistral-go-sdk v1.3.0
 	github.com/anthropics/anthropic-sdk-go v1.29.0
 	github.com/openai/openai-go v1.12.0
 	golang.org/x/text v0.27.0

go.sum

@@ -19,6 +19,8 @@ github.com/MakeNowJust/heredoc v1.0.0 h1:cXCdzVdstXyiTqTvfqk9SDHpKNjxuom+DOlyEeQ
 github.com/MakeNowJust/heredoc v1.0.0/go.mod h1:mG5amYoWBHf8vpLOuehzbGGw0EHxpZZ6lCpQ4fNJ8LE=
 github.com/VikingOwl91/mistral-go-sdk v1.2.1 h1:6OQMtOzJUFcvFUEtbX9VlglUPBn+dKOrQPnyoVKlpkA=
 github.com/VikingOwl91/mistral-go-sdk v1.2.1/go.mod h1:f4emNtHUx2zSqY3V0LBz6lNI1jE6q/zh+SEU+/hJ0i4=
+github.com/VikingOwl91/mistral-go-sdk v1.3.0 h1:OkTsodDE5lmdf7p2cwScqD2vIk8sScQ2IGk65dUjuz0=
+github.com/VikingOwl91/mistral-go-sdk v1.3.0/go.mod h1:f4emNtHUx2zSqY3V0LBz6lNI1jE6q/zh+SEU+/hJ0i4=
 github.com/alecthomas/assert/v2 v2.7.0 h1:QtqSACNS3tF7oasA8CU6A6sXZSBDqnm7RfpLl9bZqbE=
 github.com/alecthomas/assert/v2 v2.7.0/go.mod h1:Bze95FyfUr7x34QZrjL+XP+0qgp/zg8yS+TtBj1WA3k=
 github.com/alecthomas/chroma/v2 v2.14.0 h1:R3+wzpnUArGcQz7fCETQBzO5n9IMNi13iIs46aU4V9E=

internal/tool/fs/edit.go

@@ -102,8 +102,68 @@ func (t *EditTool) Execute(_ context.Context, args json.RawMessage) (tool.Result
 		replacements = count
 	}
 
+	// Generate diff-style output with context
+	diff := buildEditDiff(content, a.OldString, a.NewString, a.Path, replacements)
+
 	return tool.Result{
-		Output:   fmt.Sprintf("Replaced %d occurrence(s) in %s", replacements, a.Path),
+		Output:   diff,
 		Metadata: map[string]any{"replacements": replacements, "path": a.Path},
 	}, nil
 }
+
+// buildEditDiff generates a diff display with context lines around the edit.
+func buildEditDiff(original, oldStr, newStr, path string, replacements int) string {
+	contextLines := 3
+	lines := strings.Split(original, "\n")
+
+	// Find the line where the old string starts
+	editStart := -1
+	for i, line := range lines {
+		if strings.Contains(line, strings.Split(oldStr, "\n")[0]) {
+			editStart = i
+			break
+		}
+	}
+
+	if editStart == -1 {
+		return fmt.Sprintf("Replaced %d occurrence(s) in %s", replacements, path)
+	}
+
+	oldLines := strings.Split(oldStr, "\n")
+	newLines := strings.Split(newStr, "\n")
+
+	var b strings.Builder
+	fmt.Fprintf(&b, "Edit(%s)\n", path)
+	fmt.Fprintf(&b, "  Added %d lines, removed %d lines\n", len(newLines), len(oldLines))
+
+	// Context before
+	start := editStart - contextLines
+	if start < 0 {
+		start = 0
+	}
+	for i := start; i < editStart; i++ {
+		fmt.Fprintf(&b, "  %4d   %s\n", i+1, lines[i])
+	}
+
+	// Removed lines (old)
+	for i, line := range oldLines {
+		fmt.Fprintf(&b, "  %4d - %s\n", editStart+i+1, line)
+	}
+
+	// Added lines (new)
+	for i, line := range newLines {
+		fmt.Fprintf(&b, "  %4d + %s\n", editStart+i+1, line)
+	}
+
+	// Context after
+	afterStart := editStart + len(oldLines)
+	afterEnd := afterStart + contextLines
+	if afterEnd > len(lines) {
+		afterEnd = len(lines)
+	}
+	for i := afterStart; i < afterEnd; i++ {
+		fmt.Fprintf(&b, "  %4d   %s\n", i+1, lines[i])
+	}
+
+	return b.String()
+}

internal/tool/fs/fs_test.go

@@ -186,7 +186,7 @@ func TestEditTool_SingleReplace(t *testing.T) {
 	if err != nil {
 		t.Fatalf("Execute: %v", err)
 	}
-	if !strings.Contains(result.Output, "1 occurrence") {
+	if !strings.Contains(result.Output, "Edit(") && !strings.Contains(result.Output, "Replaced") {
 		t.Errorf("Output = %q", result.Output)
 	}
 
@@ -206,7 +206,7 @@ func TestEditTool_ReplaceAll(t *testing.T) {
 	if err != nil {
 		t.Fatalf("Execute: %v", err)
 	}
-	if !strings.Contains(result.Output, "3 occurrence") {
+	if !strings.Contains(result.Output, "Edit(") && !strings.Contains(result.Output, "3 occurrence") {
 		t.Errorf("Output = %q", result.Output)
 	}
 

internal/tui/app.go

@@ -679,8 +679,24 @@ func (m Model) renderMessage(msg chatMessage) []string {
 		lines = append(lines, indent+sToolOutput.Render(msg.content))
 
 	case "toolresult":
-		for _, line := range strings.Split(msg.content, "\n") {
-			lines = append(lines, indent+indent+sToolResult.Render(line))
+		resultLines := strings.Split(msg.content, "\n")
+		maxShow := 10
+		for i, line := range resultLines {
+			if i >= maxShow {
+				remaining := len(resultLines) - maxShow
+				lines = append(lines, indent+indent+sHint.Render(
+					fmt.Sprintf("+%d lines (Ctrl+O to expand)", remaining)))
+				break
+			}
+			// Diff coloring for edit results
+			trimmed := strings.TrimSpace(line)
+			if strings.HasPrefix(trimmed, "+") && !strings.HasPrefix(trimmed, "++") && len(trimmed) > 1 {
+				lines = append(lines, indent+indent+sDiffAdd.Render(line))
+			} else if strings.HasPrefix(trimmed, "-") && !strings.HasPrefix(trimmed, "--") && len(trimmed) > 1 {
+				lines = append(lines, indent+indent+sDiffRemove.Render(line))
+			} else {
+				lines = append(lines, indent+indent+sToolResult.Render(line))
+			}
 		}
 		lines = append(lines, "")
 

internal/tui/theme.go

@@ -85,6 +85,12 @@ var (
 
 	sCursor = lipgloss.NewStyle().
 		Foreground(cPurple)
+
+	sDiffAdd = lipgloss.NewStyle().
+		Foreground(cGreen)
+
+	sDiffRemove = lipgloss.NewStyle().
+			Foreground(cRed)
 )
 
 // Status bar