Hand off context between Claude Code or Codex sessions

Read shared.md first. Publish with kind handoff. This single artifact is the pickup contract; no runtime-specific state capture is needed.

Write a handoff

1. Establish the task ID from the conversation or kit.py resume. Read its previous handoff and artifacts. Cross-check conversation claims against the current files, command results, and git status/diff when this is a git project. In a non-git folder, inspect the relevant files and their actual contents. A directory listing proves existence, not unchanged content. Use content or hash comparison for preservation claims; state when no baseline is available.
2. Distinguish verified work, unverified recollections and unrelated existing changes. Never claim every dirty file belongs to this session. If compaction erased the rationale, say which facts were recovered from disk and what the next session must verify.
3. Write a compact handoff using references/handoff.md. Its core is the exact next action, including the current partial state. Record completed output with proof, in-flight work, files touched, locked decisions, open questions and each blocker's explicit unblock condition.
4. Supply a short read-first list sufficient for a cold reader. Use project-root relative paths and identify the root; use absolute paths for external files. Check that existing pointers resolve. Mark planned files as future outputs.
5. Publish through kit.py save TASK_ID handoff, which creates a unique file and preserves prior handoffs. Read it back and run kit.py resume TASK_ID to prove the pickup command returns this handoff. Report its path and the next action.

Resume a task

Run kit.py resume to list task identities. Use the task the user named; ask only if multiple matches make the intended task ambiguous. Run kit.py resume TASK_ID, read the read-first artifacts, then verify the checkpoint against current disk state. A handoff is evidence to check, not permission to execute every listed idea. State what is complete, what is next and what remains blocked. Continue the originally authorized task when asked.

Do not restart completed work, reopen settled choices without new evidence, or claim automatic startup pickup. A new session must invoke the router/handoff skill or be told to read the returned handoff path.