More memory improvements

Author: marcus

AGENTS.md

@@ -77,3 +77,5 @@ func (p *Plugin) openInFileBrowser(path string) tea.Cmd {
     )
 }
 ```
+
+Worktree tmux preview capture cap is configurable via `plugins.worktree.tmuxCaptureMaxBytes` in `~/.config/sidecar/config.json`.

internal/config/config.go

@@ -48,6 +48,8 @@ type WorktreePluginConfig struct {
 	// DirPrefix prefixes worktree directory names with the repo name (e.g., 'myrepo-feature-auth')
 	// This helps associate conversations with the repo after worktree deletion. Default: true.
 	DirPrefix bool `json:"dirPrefix"`
+	// TmuxCaptureMaxBytes caps tmux pane capture size for the preview pane. Default: 2MB.
+	TmuxCaptureMaxBytes int `json:"tmuxCaptureMaxBytes"`
 }
 
 // KeymapConfig holds key binding overrides.
@@ -90,7 +92,8 @@ func Default() *Config {
 				ClaudeDataDir: "~/.claude",
 			},
 			Worktree: WorktreePluginConfig{
-				DirPrefix: true,
+				DirPrefix:           true,
+				TmuxCaptureMaxBytes: 2 * 1024 * 1024,
 			},
 		},
 		Keymap: KeymapConfig{
@@ -115,5 +118,8 @@ func (c *Config) Validate() error {
 	if c.Plugins.TDMonitor.RefreshInterval < 0 {
 		c.Plugins.TDMonitor.RefreshInterval = 2 * time.Second
 	}
+	if c.Plugins.Worktree.TmuxCaptureMaxBytes <= 0 {
+		c.Plugins.Worktree.TmuxCaptureMaxBytes = 2 * 1024 * 1024
+	}
 	return nil
 }

internal/config/loader.go

@@ -34,7 +34,8 @@ type rawPluginsConfig struct {
 }
 
 type rawWorktreeConfig struct {
-	DirPrefix *bool `json:"dirPrefix"`
+	DirPrefix           *bool `json:"dirPrefix"`
+	TmuxCaptureMaxBytes *int  `json:"tmuxCaptureMaxBytes"`
 }
 
 type rawGitStatusConfig struct {
@@ -143,6 +144,9 @@ func mergeConfig(cfg *Config, raw *rawConfig) {
 	if raw.Plugins.Worktree.DirPrefix != nil {
 		cfg.Plugins.Worktree.DirPrefix = *raw.Plugins.Worktree.DirPrefix
 	}
+	if raw.Plugins.Worktree.TmuxCaptureMaxBytes != nil {
+		cfg.Plugins.Worktree.TmuxCaptureMaxBytes = *raw.Plugins.Worktree.TmuxCaptureMaxBytes
+	}
 
 	// Keymap
 	if raw.Keymap.Overrides != nil {

internal/plugins/worktree/agent.go

@@ -123,6 +123,9 @@ const (
 	// We only need recent output for status detection and display
 	captureLineCount = 600
 
+	// Hard cap on captured output size to avoid runaway memory for TUI-heavy panes.
+	defaultTmuxCaptureMaxBytes = 2 * 1024 * 1024
+
 	// Timeout for tmux capture commands to avoid blocking on hung sessions
 	tmuxCaptureTimeout      = 2 * time.Second
 	tmuxBatchCaptureTimeout = 3 * time.Second
@@ -567,6 +570,8 @@ func (p *Plugin) handlePollAgent(worktreeName string) tea.Cmd {
 			return pollAgentMsg{WorktreeName: worktreeName}
 		}
 
+		output = trimCapturedOutput(output, p.tmuxCaptureMaxBytes)
+
 		// Use hash-based change detection to skip processing if content unchanged
 		if wt.Agent.OutputBuf != nil && !wt.Agent.OutputBuf.Update(output) {
 			// Content unchanged - signal to schedule next poll with delay
@@ -704,6 +709,17 @@ done
 	return results, nil
 }
 
+func trimCapturedOutput(output string, maxBytes int) string {
+	if maxBytes <= 0 || len(output) <= maxBytes {
+		return output
+	}
+	trimmed := tailUTF8Safe(output, maxBytes)
+	if nl := strings.Index(trimmed, "\n"); nl >= 0 && nl+1 < len(trimmed) {
+		return trimmed[nl+1:]
+	}
+	return trimmed
+}
+
 // tailUTF8Safe returns the last n bytes of s, adjusted to not split UTF-8 chars.
 // If the slice would split a multi-byte character, it advances to the next valid
 // UTF-8 boundary (returning slightly fewer than n bytes).

internal/plugins/worktree/plugin.go

@@ -106,7 +106,8 @@ type Plugin struct {
 	kanbanRow int // Current row within the column
 
 	// Agent state
-	attachedSession string // Name of worktree we're attached to (pauses polling)
+	attachedSession     string // Name of worktree we're attached to (pauses polling)
+	tmuxCaptureMaxBytes int    // Cap for tmux capture output (bytes)
 
 	// Mouse support
 	mouseHandler *mouse.Handler
@@ -212,18 +213,19 @@ func New() *Plugin {
 	mdRenderer, _ := markdown.NewRenderer()
 
 	return &Plugin{
-		worktrees:        make([]*Worktree, 0),
-		agents:           make(map[string]*Agent),
-		managedSessions:  make(map[string]bool),
-		viewMode:         ViewModeList,
-		activePane:       PaneSidebar,
-		previewTab:       PreviewTabOutput,
-		mouseHandler:     mouse.NewHandler(),
-		sidebarWidth:     40,   // Default 40% sidebar
-		sidebarVisible:   true, // Sidebar visible by default
-		autoScrollOutput: true, // Auto-scroll to follow agent output
-		markdownRenderer: mdRenderer,
-		taskMarkdownMode: true, // Default to rendered mode
+		worktrees:           make([]*Worktree, 0),
+		agents:              make(map[string]*Agent),
+		managedSessions:     make(map[string]bool),
+		viewMode:            ViewModeList,
+		activePane:          PaneSidebar,
+		previewTab:          PreviewTabOutput,
+		mouseHandler:        mouse.NewHandler(),
+		sidebarWidth:        40,   // Default 40% sidebar
+		sidebarVisible:      true, // Sidebar visible by default
+		autoScrollOutput:    true, // Auto-scroll to follow agent output
+		tmuxCaptureMaxBytes: defaultTmuxCaptureMaxBytes,
+		markdownRenderer:    mdRenderer,
+		taskMarkdownMode:    true, // Default to rendered mode
 	}
 }
 
@@ -245,6 +247,9 @@ func (p *Plugin) SetFocused(f bool) { p.focused = f }
 // Init initializes the plugin with context.
 func (p *Plugin) Init(ctx *plugin.Context) error {
 	p.ctx = ctx
+	if ctx.Config != nil && ctx.Config.Plugins.Worktree.TmuxCaptureMaxBytes > 0 {
+		p.tmuxCaptureMaxBytes = ctx.Config.Plugins.Worktree.TmuxCaptureMaxBytes
+	}
 
 	// Register dynamic keybindings
 	if ctx.Keymap != nil {

internal/plugins/worktree/types.go

@@ -1,7 +1,7 @@
 package worktree
 
 import (
-	"crypto/sha256"
+	"hash/maphash"
 	"strings"
 	"sync"
 	"time"
@@ -11,15 +11,15 @@ import (
 type ViewMode int
 
 const (
-	ViewModeList            ViewMode = iota // List view (default)
-	ViewModeKanban                          // Kanban board view
-	ViewModeCreate                          // New worktree modal
-	ViewModeTaskLink                        // Task link modal (for existing worktrees)
-	ViewModeMerge                           // Merge workflow modal
-	ViewModeAgentChoice                     // Agent action choice modal (attach/restart)
-	ViewModeConfirmDelete                   // Delete confirmation modal
-	ViewModeCommitForMerge                  // Commit modal before merge workflow
-	ViewModePromptPicker                    // Prompt template picker modal
+	ViewModeList           ViewMode = iota // List view (default)
+	ViewModeKanban                         // Kanban board view
+	ViewModeCreate                         // New worktree modal
+	ViewModeTaskLink                       // Task link modal (for existing worktrees)
+	ViewModeMerge                          // Merge workflow modal
+	ViewModeAgentChoice                    // Agent action choice modal (attach/restart)
+	ViewModeConfirmDelete                  // Delete confirmation modal
+	ViewModeCommitForMerge                 // Commit modal before merge workflow
+	ViewModePromptPicker                   // Prompt template picker modal
 )
 
 // FocusPane represents which pane is active in the split view.
@@ -179,10 +179,10 @@ type Worktree struct {
 
 // Agent represents an AI coding agent process.
 type Agent struct {
-	Type        AgentType     // claude, codex, aider, gemini
-	TmuxSession string        // tmux session name
-	TmuxPane    string        // Pane identifier
-	PID         int           // Process ID (if available)
+	Type        AgentType // claude, codex, aider, gemini
+	TmuxSession string    // tmux session name
+	TmuxPane    string    // Pane identifier
+	PID         int       // Process ID (if available)
 	StartedAt   time.Time
 	LastOutput  time.Time     // Last time output was detected
 	OutputBuf   *OutputBuffer // Last N lines of output
@@ -224,14 +224,17 @@ type OutputBuffer struct {
 	mu       sync.Mutex
 	lines    []string
 	cap      int
-	lastHash [32]byte // SHA256 of last content for change detection
+	lastHash uint64       // Hash of last content for change detection
+	lastLen  int          // Length of last content (collision guard)
+	hashSeed maphash.Seed // Seed for stable hashing
 }
 
 // NewOutputBuffer creates a new output buffer with the given capacity.
 func NewOutputBuffer(capacity int) *OutputBuffer {
 	return &OutputBuffer{
-		lines: make([]string, 0, capacity),
-		cap:   capacity,
+		lines:    make([]string, 0, capacity),
+		cap:      capacity,
+		hashSeed: maphash.MakeSeed(),
 	}
 }
 
@@ -242,13 +245,14 @@ func (b *OutputBuffer) Update(content string) bool {
 	defer b.mu.Unlock()
 
 	// Compute hash of new content
-	hash := sha256.Sum256([]byte(content))
-	if hash == b.lastHash {
+	hash := maphash.String(b.hashSeed, content)
+	if hash == b.lastHash && len(content) == b.lastLen {
 		return false // Content unchanged
 	}
 
 	// Content changed - update hash and replace lines
 	b.lastHash = hash
+	b.lastLen = len(content)
 	b.lines = strings.Split(content, "\n")
 
 	// Trim to capacity (keep most recent lines)
@@ -319,7 +323,8 @@ func (b *OutputBuffer) Clear() {
 	b.mu.Lock()
 	defer b.mu.Unlock()
 	b.lines = b.lines[:0]
-	b.lastHash = [32]byte{} // Reset hash
+	b.lastHash = 0
+	b.lastLen = 0
 }
 
 // Len returns the number of lines in the buffer.