| name | debug-my-harness |
| description | Diagnose why an agent harness misbehaved by reading the local flight-recorder ledger (.vigiles/runs.jsonl) — which skills fired or got hijacked, which hooks blocked or wrongly allowed, which subagent tool-contract violations happened, and how a skill's trigger rate moved. Use when asked why a skill stopped firing, why a hook didn't block, why the wrong skill ran, or to debug/investigate what the harness actually did. NOT for writing new rules (use strengthen) or editing the spec (use edit-spec). |
Diagnose harness misbehavior from the flight recorder — the local, append-only ledger
at .vigiles/runs.jsonl that vigiles writes as your harness runs. It records what actually
happened, so you debug from evidence instead of guessing.
What's in the ledger
One JSON record per line, each with a kind:
hook — a compiled-hook gate decision: {event, decision: allow|deny|ask, mode: enforce|observe, rule, cmd, reason}.agent — a subagent tool-contract decision: {name, tool, allowed, reason} (a false = the agent went outside its lane).skill — a skill activation: {name, fired}.eval — a measured metric: {name, metric, value} (e.g. trigger-rate recall/precision).capability-diff — a blast-radius change: {pr, added, removed, widened}.
Instructions
Step 1: Read the ledger
Read .vigiles/runs.jsonl (JSONL — one record per line; tolerate a torn last line). If it's
absent or empty, say so — there's nothing recorded yet; suggest running the harness (or
vigiles audit) first. Do NOT fabricate records.
Step 2: Answer the specific question, evidence-first
Match the user's question to the ledger:
- "Why did skill X stop firing / why does the wrong one run?" — count
skill fires by
name over time. If X's fire-rate dropped, look for a sibling that fired on the same kinds
of prompts (a selection collision) and check their descriptions for overlap. Recommend
differentiating or merging the descriptions.
- "Why didn't my hook block that?" — find
hook records for the event. A decision: allow on something that should be denied, or mode: observe (shadow, never blocks), or
the absence of any record, tells you which. Recommend flipping observe→enforce or
fixing the gate logic.
- "Did a subagent misbehave?" — list
agent records with allowed: false: the agent
reached for a tool outside its declared contract. Point at the contract to tighten or widen.
- "Is it getting worse?" — compare
eval metric values (recall/precision) across runs;
a downward trend is drift (often after a harness/model upgrade).
Step 3: Recommend a fix, tied to the evidence
Prefer promoting an ignored-but-decidable rule from prose to a deterministic gate: a
repeated agent violation or a rule the agent keeps breaking → a compiled hook or a tighter
tool-contract (the strengthen skill can help). A description collision → differentiate the
skill descriptions. Always cite the specific records you based the diagnosis on.
Step 4: Offer the next step
If the fix is a spec change, hand off to edit-spec. If it's promoting guidance to a linter
rule, hand off to strengthen. If a behavioral claim needs measuring (does the skill fire
now?), hand off to test-harness (measureTriggerRate).
