Willow Context Sentinel

Use when you need to check whether the current session is approaching context limits and decide whether to compact, hand off, or continue. Implements a cascading model protocol for Willow/OpenClaw stacks on Linux — monitoring prompt_count as a context proxy and routing to strategic-compact or willow_task_submit as needed.

Monitor session context usage and apply a cascading relief protocol before context exhaustion silently degrades response quality.

Output	Meaning
STATUS_OK	prompt_count < 15 — session is healthy, continue normally
COMPACT_NOW	prompt_count 15–25 — approaching limit, invoke strategic-compact
HANDOFF_NOW	prompt_count > 25 — near ceiling, invoke handoff + willow_task_submit
POSTGRES_DOWN	session_anchor.json reports postgres as down — fix infra before proceeding

When to use

• Heartbeat: run at the start of every session and every ~10 prompts
• Before large tasks: check before any operation that will generate many tool calls or long output
• Proactively: if responses feel slower, less coherent, or you notice unusual hedging, run this check immediately
• After a branch merge or plan execution: context spikes are common at transition points

Step 1 — Run the sentinel script

bash

bash {baseDir}/scripts/check_context.sh

The script reads two Willow state files:

• ~/.willow/anchor_state.json — prompt_count field (context proxy)
• ~/.willow/session_anchor.json — postgres status field

Step 2 — Interpret the output

Run the script and act on the single-line output:

STATUS_OK

No action needed. Session is healthy.

text

STATUS_OK

Continue with the current task. Optionally note the prompt_count in a heartbeat log entry.

COMPACT_NOW

text

COMPACT_NOW

Context is filling. Invoke the strategic-compact skill immediately before proceeding:

text

/strategic-compact

After compact completes, re-run the sentinel. If it still reports COMPACT_NOW or escalates to HANDOFF_NOW, proceed to the handoff protocol below.

HANDOFF_NOW

text

HANDOFF_NOW

Session is near the context ceiling. Invoke the handoff skill and submit the next task to Willow:

1. Run /handoff to produce a structured handoff document
2. Call willow_task_submit with the next bite as the task body
3. End the session cleanly — do not attempt further large operations

POSTGRES_DOWN

text

POSTGRES_DOWN

Willow's backing store is unreachable. KB reads and writes will fail silently. Do not proceed with memory-dependent tasks. Check the Willow server status:

bash

willow status
# or
systemctl status willow-postgres

Resolve the infra issue before resuming work.

Step 3 — Integration with HEARTBEAT.md

Add a sentinel call to your heartbeat template so it runs automatically. Minimal example:

markdown

## Heartbeat — {timestamp}

**Sentinel:** `bash ~/.openclaw/skills/willow-context-sentinel/scripts/check_context.sh`

| Check    | Result    |
| -------- | --------- |
| Context  | STATUS_OK |
| Postgres | up        |

Next bite: {next_task}

If the sentinel output is anything other than STATUS_OK, record the output and the action taken before moving on.

Cascading protocol reference

text

Claude Sonnet 4.6
    │
    ├─ prompt_count ≥ 15  →  COMPACT_NOW  →  /strategic-compact
    │                              │
    │                              └─ still ≥ 15 after compact
    │                                         │
    └─ prompt_count > 25  →  HANDOFF_NOW  →  /handoff + willow_task_submit

Relief valves are applied in order. Skip to HANDOFF_NOW if compact has already been run in this session and context remains high.

Notes

• prompt_count is a proxy, not a direct token count. Actual context consumption varies by response length. Treat thresholds as conservative triggers, not hard limits.
• Both state files (anchor_state.json, session_anchor.json) are written by the Willow server. If either file is missing, the script outputs STATUS_OK and logs a warning to stderr — it fails open, not closed.
• This skill does not modify any state files. It is read-only and safe to run at any time.