Willow Context Sentinel

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name: willow-context-sentinel version: "1.0.0" description: 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. metadata: { "openclaw": { "emoji": "🧭", "os": ["linux"], "requires": { "bins": ["bash"] } } }

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Willow Context Sentinel

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 {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.

STATUS_OK

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

COMPACT_NOW

COMPACT_NOW

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

/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

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

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:

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:

## 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

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.

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.