session-time-machine

Requirements. Mods are on by default in Claude Code 2.1.287+.

/timemachine draws the session as a timeline: every prompt, tool call and turn end, read from the session's own transcript. Press a point, type what you want done differently, and the mod writes a copy of the session cut at that point under a new session id and gives you the command that continues it. The session you are in is not touched, so you can try the other approach and still go back.

⏱ Time machine
 9 points  3 prompts  5 calls
──────────────────────────────────────
  1 ┏ ● prompt 1  add a retry to the upload client
  2 ┃ ◆ Read  src/upload.ts
  3 ┃ ◆ Edit  src/upload.ts                  <- armed (highlighted row)
  4 ┃ ◆ Bash  npm test
  5 ┗ ■ turn end  Tests pass, retry added with backoff.
╭────────────────────────────────────╮
│ Fork from #3                       │
│ after: src/upload.ts               │
│ Type the new instruction after     │
│ /timemachine fork 3 and press Enter│
╰────────────────────────────────────╯
↑ older   ↓ newer   ⟳ reload   ✕ clear

Colors mark the kind: blue prompts, violet turn ends, and a glyph per tool (green Bash, amber Edit/Write, teal Read/Grep/Glob, orange Web, pink Agent, lilac MCP). The armed row is highlighted and rows light up under the pointer.

> /timemachine fork 3 keep the retry but use the existing queue helper instead
Forked at point 3 (Edit src/upload.ts): 41 rows kept.
New session 7c1e…, resume command copied. In a new terminal:
cd '/home/me/app' && claude --resume 7c1e… 'keep the retry but use the existing queue helper instead'

Usage

Points are of three kinds. ▸ prompt: the fork keeps everything before that prompt, so the instruction replaces it. · tool call: the fork keeps the conversation up to and including that call's result. ■ turn end: the fork keeps the whole turn. The timeline refreshes when a turn completes; the pane's reload button re-reads it on demand, and ⤢ expand adds a second line with more of each point's text. Row width follows the pane's own width.

How it forks, and what it cannot do

The mod API has no call that forks or rewinds the live session, so the fork is a new session, not a branch inside the one you are in. What the mod does around that to make it one click:

1. Snapshots. While the mod is loaded it commits the whole working tree (tracked, modified and untracked files, .gitignore honored) with a throwaway git index: before each prompt, after each Edit/Write/Bash call and at each turn end. Your index, branch and stash are never touched; each snapshot is pinned by refs/time-machine/<session-id>/<point>.
2. Fork here (or /timemachine fork <n> [instruction]) then
   • creates a git worktree on its own branch time-machine/<id> at the snapshot of that point, under .claude/worktrees/,
   • reads ~/.claude/projects/<project>/<session-id>.jsonl (or under CLAUDE_CONFIG_DIR), follows the parentUuid chain from the last row (dropping rewound branches and subagent sidechains), keeps the rows up to the point, closes any tool_use left without its tool_result,
   • writes them under a new session id for the worktree, with a first message that tells the model the files live in the worktree,
   • opens it in Claude Desktop (claude --desktop --resume <new-id>, macOS), or in a new Terminal window when you gave an instruction (it travels as the resume command's message) or Desktop cannot take it, running in that worktree. Elsewhere, or if the window cannot open, the command is copied to the clipboard instead.

Your checkout and the session you are in are not touched.

Limits:

• macOS only. The fork opens through claude --desktop, or Terminal; elsewhere you paste the command.
• Snapshots only exist from when the mod was loaded. A point without one forks the conversation only, and the pane says so before you press.
• Git projects only. Outside a git repository there is no file snapshot.
• Bash side effects outside the repo (installed packages, databases) are not part of a snapshot.
• 4 MiB. $.fs.read rejects files over 4 MiB, so a very long transcript shows an error in the pane instead of a timeline.
• Rows only. The timeline is the transcript's prompts, tool calls and turn ends; thinking and attachments are kept in the fork but not listed.
• Pane not drawn in claude -p. /timemachine list and fork work there; the pane needs the terminal UI.

Options

snapshots (boolean, default true) and openTerminal (boolean, default true) are declared next to copyCommand in plugin.json.

Read from user settings, keyed by the plugin's full id:

{ "pluginConfigs": { "session-time-machine@skills-dir": { "options": { "copyCommand": false } } } }

Install

npx claude-code-templates@latest --mod productivity/session-time-machine

Hooks: session.start (registers /timemachine), command.run, turn.complete, ui.render on Pane. Calls: $.fs.read, $.fs.write, $.env.get (HOME, CLAUDE_CONFIG_DIR), $.session.cwd, $.session.id, $.prompt.fill, $.ui.copy. No network, no process spawn.

Tests: claude plugin test productivity/session-time-machine cover the transcript parsing, the cut points, the tool-pair closing, the resume command, and mount the pane on the terminal and desktop surfaces to press a point.