| name | checkpoint |
| description | Persist bounded mid-task progress as a kernel.checkpoint/v1 JSON manifest so a fresh session or context reset can resume at the exact position without a full handoff. Triggers: checkpoint, save progress, context reset, compact soon, long task. |
| user-invocable | true |
| allowed-tools | Read, Bash, Grep, Glob, Write |
| kernel | {"kind":"state_transition","version":1,"side_effects":"writes_meta","confirmation":"none","produces":["kernel.checkpoint/v1"]} |
The small resumable manifest. A handoff transfers a whole session; a checkpoint records
bounded progress INSIDE a long-running task so work can continue after a context reset
with a fresh, minimal context instead of an inherited transcript.
When to fire (EXP-L21: attention efficiency decays to ~11% late-session; a reset from a
checkpoint restores the flat ~50-70k load-bearing line):
- a long task crosses a natural boundary (a commit lands, a phase completes)
- context is about to compact, or the session is degrading (anchor-drift, I0.13)
- the manifest's execution.checkpoints list says so
Checkpoint vs handoff: same task + same session continuation → checkpoint.
Ending the session / transferring to a future session with decisions and policy → handoff.
1. Gather provenance:
```bash
git branch --show-current && git rev-parse HEAD && git status --short
```
-
Write _meta/checkpoints/{task}-{timestamp}.json per
schemas/kernel.checkpoint.v1.schema.json:
- task: goal + handoff_ref/contract_ref if they exist
- steps_completed: each with EVIDENCE (commit sha, test output, command result),
never intent. Receipts describe intent; files describe reality.
- current_outputs: files produced so far
- provenance.dirty_tree_sha256: when dirty, sha256 of
git diff --binary HEAD
- pending_steps: what remains, in order
- resume: position (exact place in the work), entrypoint (skill to re-enter),
next_operation (the LITERAL first action — "retarget tests/run-tests.sh lines
~1250 registration tests", not "continue the migration")
- context (optional): required selectors + budget if the resume should be bounded
Quote every sha/commit string (all-digit shas parse as integers and fail validation).
-
Validate — MANDATORY:
"${CLAUDE_PLUGIN_ROOT:-.}/orchestration/manifest/kernel-manifest" validate _meta/checkpoints/{file}.json
-
Record:
agentdb write-end '{"skill":"checkpoint","saved_to":"_meta/checkpoints/{file}.json","position":"..."}'
Resume path: /kernel:ingest discovers the newest manifest automatically
(kernel-manifest latest — checkpoints and handoffs share discovery), or accepts an
explicit path.
<hard_stops>
- steps_completed without evidence → not a checkpoint, a hope. Add evidence or move the
step to pending_steps.
- unvalidated json → does not exist. Validate before reporting done.
</hard_stops>
