chenhg5/cc-connect · error

%w: %s

Error message

%w: %s

What it means

createTmuxSession runs `tmux new-session` via exec.Command and, when tmux exits non-zero, wraps the combined stdout/stderr output into the returned error. This surfaces any tmux-level failure (bad session name, working dir missing, shell not found, server not running) together with tmux's own diagnostic text. The caller (StartSession) further wraps it as 'tmux: create session %q: %w'.

Source

Thrown at agent/tmux/session.go:225

}

// tmuxWindowExists checks whether a window or pane target (e.g. "sess:win") exists.
func tmuxWindowExists(target string) bool {
	return exec.Command("tmux", "has-session", "-t", target).Run() == nil
}

// createTmuxSession creates a new detached tmux session with the given window name.
func createTmuxSession(name, windowName, workDir, shell string) error {
	args := []string{"new-session", "-d", "-s", name, "-n", windowName}
	if workDir != "" && workDir != "." {
		args = append(args, "-c", workDir)
	}
	if shell != "" {
		args = append(args, shell)
	}
	out, err := exec.Command("tmux", args...).CombinedOutput()
	if err != nil {
		return fmt.Errorf("%w: %s", err, strings.TrimSpace(string(out)))
	}
	// Enable focus events so Claude Code doesn't warn about them being off.
	_ = exec.Command("tmux", "set-option", "-t", name, "-g", "focus-events", "on").Run()
	return nil
}

// createTmuxWindow adds a new window to an existing session.
// Using "session:" (trailing colon) tells tmux to pick the next free index,
// avoiding index collisions when multiple windows are created concurrently.
func createTmuxWindow(session, windowName, workDir string) error {
	args := []string{"new-window", "-d", "-t", session + ":", "-n", windowName}
	if workDir != "" && workDir != "." {
		args = append(args, "-c", workDir)
	}
	out, err := exec.Command("tmux", args...).CombinedOutput()
	if err != nil {
		return fmt.Errorf("%w: %s", err, strings.TrimSpace(string(out)))
	}

View on GitHub (pinned to 4000b2338a)

Solutions

1. Check the tmux error text appended after '%w: %s' — it names the exact tmux failure
2. Verify the work_dir passed in the config exists and is writable
3. Verify the configured shell binary exists in PATH
4. Run `tmux new-session -t <name>` manually to reproduce and see tmux's message
5. Update tmux if the error mentions an unknown option/flag

Example fix

// before
agent, err := tmuxAgent.StartSession(ctx, opts) // work_dir: "/nonexistent"
// tmux: create session "cc": exit status 1: can't establish current working directory

// after
// fix config: work_dir = "/home/user/project" (must exist)
agent, err := tmuxAgent.StartSession(ctx, opts)

if _, err := os.Stat(workDir); err != nil { return fmt.Errorf("work_dir %q unavailable: %w", workDir, err) }
if _, err := exec.LookPath(shellOr("bash")); err != nil { return fmt.Errorf("shell %q not in PATH", shell) }
if err := exec.Command("tmux", "has-session", "-t", name).Run(); err == nil { /* already exists; skip create */ }

if _, err := agent.StartSession(ctx, opts); err != nil {
    var tmuxErr *exec.ExitError
    if errors.As(err, &tmuxErr) { slog.Error("tmux create failed", "stderr", err.Error()) }
    return fmt.Errorf("start tmux session: %w", err)
}

When it happens

Trigger: Calling StartSession with auto_create enabled when the tmux session does not exist and `tmux new-session` fails: e.g. workDir does not exist (-c path invalid), the configured shell is not an executable, duplicate session name due to a race, or tmux server errors.

Common situations: Typo in the agent's work_dir config so `-c` points to a nonexistent directory; shell option set to a binary not installed; tmux version too old for a flag used; two sessions auto-creating the same tmux session name concurrently.

Related errors

• antigravitySession: start: %w
• copilot probe: start: %w
• qoderSession: start: %w
• tmux: create session %q: %w
• tmux: create window %q in session %q: %w

AI-assisted analysis of chenhg5/cc-connect@4000b2338a (2026-09-06). Data as JSON: /api/errors/30bb2f97981bdabc. Report an issue: GitHub.