# CCD Checkpoint — Extended Details

Load this reference for detailed field descriptions, recovery snapshot format, or when the compact instructions are insufficient.

## Detailed Field Descriptions

The checkpoint response contains:

- `session_delta.skip_stats`: how many tracked surfaces were skipped versus refreshed since the session baseline.
- `projection_telemetry.delta`: skip-vs-refresh summary from current projection digests.
- `projection_telemetry.token_counts`: estimated token spend by source-data surface and projection format (`narrative`, `symbolic`, `bundle`).
- `projection_telemetry.cadence.current.*.cache_status`: whether each projection format was a cache hit or miss.
- `work_stream_decay`: repeated `no_progress` run endings recorded through `ccd host-hook --hook on-agent-end`.
- `candidate_updates.handoff`: handoff refresh candidates from staleness (#570) and milestone-progression (#598) detectors.

Fields that **must be absent** (handover-only): `evaluation`, `approval_steps`, `approval_intents`, `repo_native_checks`, `candidate_updates.memory`. If any appear, treat as contract regression.

## Recovery Snapshot

If the session is at a natural pause point or context pressure is building, persist:

```bash
echo '{"origin": "checkpoint", "checkpoint": {"summary": "...", "immediate_actions": [...], "key_files": [...]}, "working_buffer": {"summary_lines": [...]}}' | ccd recovery write --path .
```
