session-handoff

Handoff and migration plugin for Claude Code and Codex. Start a clean session with your decisions and pending work carried over, or migrate the supported portable conversation history to the other client instead.

▶ Watch the 21-second demo

Claude Code:

/session-handoff the next task is to run full pre-release suite

Codex:

$session-handoff the next task is to refactor the benchmarking tool

Or migrate the supported portable conversation history to the other client instead:

Claude Code:

/session-handoff migrate codex

Codex:

$session-handoff migrate claude

Measured recovery

Harness	Benchmark result	session-handoff	Native compact
Codex	Critical facts recovered	37/37	37/37
Codex	Task success (valid runs)	9/9	9/9
Claude Code	Critical facts recovered	6/6	6/6
Claude Code	Task success (valid runs)	1/1	1/1

Zero critical facts lost in either pilot: session-handoff matched native compact on critical-fact recovery and task success, while starting from a fresh session. Measured September 8, 2026, with Luna xhigh. Codex: ten synthetic case/context-length combinations. Claude Code: one paired comparison on compound-rot/long. Each fact had to be recoverable in both probe answers, assessed for meaning, and recorded in internal pilot reports.

Install

Requirements: Linux or macOS (tested on Linux; macOS validation is pending), Python 3.10 or newer, and Claude Code, Codex, or both. Git is needed for the marketplace install; Node.js 18 or newer and npm are needed only for the npm alternative below. Your Claude Code or Codex installation may have its own separate dependencies.

The yuzushi-plugins marketplace installs the plugin from GitHub, on Python; it does not install or require Node/npm.

Claude Code — run in the session:

/plugin marketplace add yuzushi-dev/yuzushi-plugins
/plugin install session-handoff@yuzushi

Codex:

codex plugin marketplace add yuzushi-dev/yuzushi-plugins
codex plugin add session-handoff@yuzushi

Start a new session with the plugin and its hooks enabled in a client that supports plugin hooks, and approve the hook trust request if prompted. In the tested clients (Claude Code 2.1.263 and Codex 0.153.4), the first session installs automatic session switching for that client on its own, in the background, and a notice confirms it; restart your terminal afterward and launch claude or codex from it for supervision to take effect. Use the manual command the notice shows to also enable switching for your other client. Telemetry is a separate, one-time choice — reply in chat with exactly session-handoff telemetry yes or session-handoff telemetry no; it stays off without an explicit yes. If the notice never appeared or your client does not show plugin hooks, ask "Show session-handoff setup and telemetry commands" — the read-only handoff_setup tool finds its own installation and returns the exact commands, so there is no path to look up. Supervision covers claude/codex CLI processes, not a desktop app or IDE session. Setup itself never enables telemetry, and running it again is safe.

Install with npm instead if you'd rather not use the marketplace (also needs Python 3.10+):

npx session-handoff@latest setup

Add --client claude or --client codex to select one client, and --yes for non-interactive setup (it still does not grant telemetry consent). Restart your terminal and client afterward.

What you get

• Ref-first handoff records. handoff_create stores an immutable record outside the workspace and returns a handoff://<project-uuid>/<handoff-uuid> reference; a clean repository needs no project file or dependency to use it.
• Automatic session switching. Once set up, the managed launcher can open the fresh session for you after a handoff; migration between Claude Code and Codex works the same way.
• Compaction recovery, kept separate. A fail-open PreCompact hook writes a small redacted checkpoint before compaction and reinjects only a pointer to it — recovery evidence, not a semantic handoff.
• Secrets redacted before storage. The MCP server redacts common credential forms in every handoff, on top of the model being told never to copy secrets into one.
• Doctor without spending a turn. session-handoff doctor --human reports client and central-store readiness without starting a model session.
• Telemetry off until you say yes. No collection happens without an explicit choice; see docs/telemetry.md for the full inventory and controls. Explicit consent v3 includes a random per-home ID for registration, daily/version observations, and successful managed uninstalls; the registry retains first/last observation and last version while the service operates. Existing v1/v2 consent remains scoped to anonymous aggregates or lifecycle counts until explicitly renewed. Local purge stops future updates but cannot erase records already received by the server.

Architecture in brief

host (Claude Code | Codex)
        │  session start / first use
        ▼
   skill + MCP server ──► central handoff store (ref-first, immutable)
        │                          ▲
        │                          └── handoff_read / handoff_list / handoff_search
        ▼
  managed launcher ──► auto-switch to a fresh session, or migrate to the other client
        │
        ▼
PreCompact hook ──► local recovery checkpoint (redacted, pointer-only reinjection)

The managed bundle carries hooks/, server/ (MCP server and migration engine), skills/, bin/, and commands/, copied once into a persistent per-user location by setup.

Release notes: docs/CHANGELOG-0.7.4.md.

---

Reference: first use and create mode

After restarting the client:

Claude Code:

/session-handoff

Codex:

$session-handoff

Use migrate claude or migrate codex to preserve supported portable conversation history while changing clients. A normal handoff starts a clean session and keeps the implementation state in the handoff file.

Create mode is central and ref-first: handoff_create(name="next.md", workspace=...) stores an immutable record outside the workspace and returns its handoff://<project-uuid>/<handoff-uuid> reference. If the MCP server is unavailable, use the explicit legacy fallback handoff_create(path="handoffs/next.md", workspace=...); that is the mode that writes a workspace file.

Reference: compaction recovery checkpoint

Before Claude Code or Codex compacts a session, the plugin writes a small recovery checkpoint under ~/.local/state/session-handoff/checkpoints/. After SessionStart(source=compact) it injects only a pointer to that file. The checkpoint contains redacted Git state and a local lifecycle event log; it is recovery evidence, not a semantic summary, and manual $session-handoff remains the semantic handoff path. If the optional checkpoint scorer is explicitly configured, its tool summary may make a model call; the default checkpoint path is deterministic. Lifecycle events record only hook names, IDs, paths, timestamps, and byte counts; they never contain prompts or tool payloads.

The checkpoint hook is fail-open: a write or Git-read failure does not block compaction. Do not treat its transcript path or Git output as secret-free project content; verify the live repository and transcript before acting.

After managed setup, check it without starting a model session:

python3 "$HOME/.local/share/session-handoff/plugin/bin/session-handoff" doctor --pretty
python3 "$HOME/.local/share/session-handoff/plugin/bin/session-handoff" doctor --human

The default doctor output is machine-readable JSON. --human adds a compact read-only summary of client readiness plus central data/state/catalog health; an absent store is reported separately from an unsafe or corrupt one. Doctor does not create or repair the store.

Reference: setup recovery and uninstall

If a Codex update replaces the managed launcher while it is supervised, the supervisor restores it when Codex exits and keeps the updated executable as its target. Claude version updates are reconciled to the newest validated executable in its native versions directory. An installer run outside a supervised session cannot be repaired automatically; rerun setup afterward for the affected client.

Run the setup command for the client you want to configure, or both commands for both clients. The client executable must already be on PATH. Setup installs a persistent user-scoped bundle, registers the MCP server and skill, and saves the original launcher as *.session-handoff-original before wrapping it.

Without chat hooks, run the returned telemetry enable command in a terminal to review the consent prompt. If a choice is already pending, it prints the Python commands to answer yes or no.

To remove the managed setup:

python3 "$HOME/.local/share/session-handoff/plugin/bin/session-handoff" uninstall

This restores the saved client launchers and removes the managed bundle and registrations. Central projects and records under XDG data, bindings under XDG state, checkpoints, and saved legacy handoffs are preserved. The command prints the exact Central data, Central state, and Checkpoints paths.