fix: use first cwd as launch dir for worktree sessions

docs/agent/plan-issue-62-claude-launch-dir.md

@@ -0,0 +1,45 @@
+# Plan: issue #62 — Claude resume launch directory for worktree sessions
+
+## Goal
+
+Resume Claude sessions correctly when the transcript's tail `cwd` points to a
+`.claude/worktrees/` path, while preserving existing behavior for non-worktree
+sessions.
+
+## Root cause
+
+`parseJSONL` uses last-wins semantics for `cwd`. When a session starts in the
+project root and then work moves into a worktree, the last `cwd` is the worktree
+path. `launcher.Claude` does `os.Chdir(cwd)` before `claude --resume <id>`.
+Claude Code resolves transcript storage from the launch directory namespace, so
+it searches a namespace that contains no transcript.
+
+## Solution
+
+Separate two concepts in `source.Session`:
+
+- `CWD` — last non-empty `cwd` from the transcript (display/filter, unchanged)
+- `LaunchDir` — first non-empty `cwd` from the transcript (the directory from
+  which the session was originally started; used by `launcher.Claude`)
+
+For sessions that never changed directory, `LaunchDir == CWD`.
+
+## Files changed
+
+| File | Change |
+|------|--------|
+| `source/session.go` | Add `LaunchDir string` field |
+| `source/metacache.go` | Add `LaunchDir string` to `MetaEntry` |
+| `source/claude.go` | `parseJSONL` returns 4 values (title, cwd, launchDir, msgCount); `parseOne` and `ReloadSession` populate `Session.LaunchDir` |
+| `source/claude_test.go` | New tests: `TestParseJSONL_LaunchDirIsFirstCWD`, `TestParseJSONL_LaunchDirEqualsDisplayCWD_WhenNoWorktreeChange`, `TestSession_LaunchDir_SetFromFirstCWD` |
+| `main.go` | Use `session.LaunchDir` (fallback `session.CWD`) as the `dir` arg to launcher |
+
+## Non-goals
+
+- Changing path-filter logic (still uses `CWD`)
+- Changing `CWDDisplay` (still uses `CWD`)
+- Handling Opencode or Codex worktree patterns (not observed)
+
+## Verification
+
+`go test ./...` passes. The three new tests exercise the invariant directly.

main.go

@@ -178,8 +178,12 @@ func runInteractiveStreaming(cfg cmd.Config, from, until *time.Time) {
 		os.Exit(0)
 	}
 
-	if !dirExists(session.CWD) {
-		fmt.Fprintf(os.Stderr, "Error: directory not found: %s\n", session.CWD)
+	launchDir := session.LaunchDir
+	if launchDir == "" {
+		launchDir = session.CWD
+	}
+	if !dirExists(launchDir) {
+		fmt.Fprintf(os.Stderr, "Error: directory not found: %s\n", launchDir)
 		os.Exit(1)
 	}
 
@@ -193,11 +197,11 @@ func runInteractiveStreaming(cfg cmd.Config, from, until *time.Time) {
 
 	switch session.Client {
 	case source.ClientClaude:
-		mustLaunch(launcher.Claude(session.ID, session.CWD, launchOpts))
+		mustLaunch(launcher.Claude(session.ID, launchDir, launchOpts))
 	case source.ClientCodex:
-		mustLaunch(launcher.Codex(session.ID, session.CWD, launchOpts))
+		mustLaunch(launcher.Codex(session.ID, launchDir, launchOpts))
 	default:
-		mustLaunch(launcher.Opencode(session.ID, session.CWD, launchOpts))
+		mustLaunch(launcher.Opencode(session.ID, launchDir, launchOpts))
 	}
 }
 

source/claude.go

@@ -139,28 +139,33 @@ func parseOne(jsonlFile, dirName, home, pathFilter string, strictMatch, verbose
 	sessionID := strings.TrimSuffix(filepath.Base(jsonlFile), ".jsonl")
 	projectPath := filepath.Dir(jsonlFile)
 
-	var title, cwd string
+	var title, cwd, launchDir string
 	var msgCount int
 
 	if entry, hit := cache.Lookup(jsonlFile, mtime, size); hit {
 		title = entry.Title
 		cwd = entry.CWD
+		launchDir = entry.LaunchDir
 		msgCount = entry.MsgCount
 	} else {
-		title, cwd, msgCount = parseJSONL(jsonlFile, verbose)
+		title, cwd, launchDir, msgCount = parseJSONL(jsonlFile, verbose)
 		if cwd == "" {
 			decoded, err := url.PathUnescape(dirName)
 			if err != nil || !strings.HasPrefix(decoded, "/") {
 				return Session{}, false
 			}
 			cwd = decoded
 		}
+		if launchDir == "" {
+			launchDir = cwd
+		}
 		cache.Store(jsonlFile, MetaEntry{
-			Mtime:    mtime,
-			Size:     size,
-			Title:    title,
-			CWD:      cwd,
-			MsgCount: msgCount,
+			Mtime:     mtime,
+			Size:      size,
+			Title:     title,
+			CWD:       cwd,
+			LaunchDir: launchDir,
+			MsgCount:  msgCount,
 		})
 	}
 
@@ -178,6 +183,7 @@ func parseOne(jsonlFile, dirName, home, pathFilter string, strictMatch, verbose
 		Title:       title,
 		CWD:         cwd,
 		CWDDisplay:  abbreviateHome(cwd, home),
+		LaunchDir:   launchDir,
 		ProjectPath: projectPath,
 		Time:        mtime,
 		MsgCount:    msgCount,
@@ -200,7 +206,7 @@ func ReloadSession(jsonlFile string, verbose bool) (Session, error) {
 
 	projectPath := filepath.Dir(jsonlFile)
 	sessionID := strings.TrimSuffix(filepath.Base(jsonlFile), ".jsonl")
-	title, cwd, msgCount := parseJSONL(jsonlFile, verbose)
+	title, cwd, launchDir, msgCount := parseJSONL(jsonlFile, verbose)
 
 	if cwd == "" {
 		dirName := filepath.Base(projectPath)
@@ -210,25 +216,32 @@ func ReloadSession(jsonlFile string, verbose bool) (Session, error) {
 		}
 		cwd = decoded
 	}
+	if launchDir == "" {
+		launchDir = cwd
+	}
 
 	return Session{
 		Client:      ClientClaude,
 		ID:          sessionID,
 		Title:       title,
 		CWD:         cwd,
 		CWDDisplay:  abbreviateHome(cwd, home),
+		LaunchDir:   launchDir,
 		ProjectPath: projectPath,
 		Time:        info.ModTime(),
 		MsgCount:    msgCount,
 		jsonlPath:   jsonlFile,
 	}, nil
 }
 
-// parseJSONL extracts title, cwd, and message count from a JSONL session file.
-func parseJSONL(path string, verbose bool) (title, cwd string, msgCount int) {
+// parseJSONL extracts title, cwd, launchDir, and message count from a JSONL session file.
+// cwd is the last non-empty cwd seen (latest working directory, for display/filter).
+// launchDir is the first non-empty cwd seen (the directory Claude should be launched from).
+// For sessions that never left their original directory, launchDir == cwd.
+func parseJSONL(path string, verbose bool) (title, cwd, launchDir string, msgCount int) {
 	f, err := os.Open(path)
 	if err != nil {
-		return "Untitled", "", 0
+		return "Untitled", "", "", 0
 	}
 	defer f.Close()
 
@@ -253,10 +266,13 @@ func parseJSONL(path string, verbose bool) (title, cwd string, msgCount int) {
 			continue
 		}
 
-		// Extract cwd — last value wins (early records may carry launcher dir)
+		// Extract cwd: first non-empty becomes launchDir; last non-empty becomes cwd.
 		if raw, ok := rec["cwd"]; ok {
 			var s string
 			if json.Unmarshal(raw, &s) == nil && s != "" {
+				if launchDir == "" {
+					launchDir = s
+				}
 				cwd = s
 			}
 		}
@@ -323,24 +339,24 @@ func parseJSONL(path string, verbose bool) (title, cwd string, msgCount int) {
 
 	// Priority: agent-name > custom-title > ai-title > summary > last-prompt > first user text > Untitled
 	if lastAgentName != "" {
-		return lastAgentName, cwd, msgCount
+		return lastAgentName, cwd, launchDir, msgCount
 	}
 	if lastCustomTitle != "" {
-		return lastCustomTitle, cwd, msgCount
+		return lastCustomTitle, cwd, launchDir, msgCount
 	}
 	if lastAiTitle != "" {
-		return lastAiTitle, cwd, msgCount
+		return lastAiTitle, cwd, launchDir, msgCount
 	}
 	if lastSummary != "" {
-		return lastSummary, cwd, msgCount
+		return lastSummary, cwd, launchDir, msgCount
 	}
 	if lastPrompt != "" {
-		return lastPrompt, cwd, msgCount
+		return lastPrompt, cwd, launchDir, msgCount
 	}
 	if firstUserMsgTitle != "" {
-		return firstUserMsgTitle, cwd, msgCount
+		return firstUserMsgTitle, cwd, launchDir, msgCount
 	}
-	return "Untitled", cwd, msgCount
+	return "Untitled", cwd, launchDir, msgCount
 }
 
 // IsRealUserMsg returns true for user records that count as a user turn.