| name | skill-counterfactual-audit |
| description | Audit a skill by running a paired probe — the same task once with the skill loaded and once without — segment both traces into goal-directed phases, align phases, and emit a SIP report (surface anchoring, template copy, excess planning, task recovery, off-task artifact). Use whenever a skill is created, modified, or proposed for retirement. Pass-rate is BLIND to most skill effects: CTA (arxiv 2605.11946v1) shows a single skill can produce 522 measurable behavioural changes across 49 tasks while pass-rate moves only +0.3%. Triggers: "audit this skill", "is this skill helping", "retire skill", "before shipping skill", "behavioural impact of skill X", or any skill review event.
|
| user-invocable | true |
| version | 1.0.0 |
| format | "2025-10-02T00:00:00.000Z" |
| triggers | ["audit this skill","is this skill helping","behavioural impact of skill","retire this skill","before shipping a skill"] |
| updated | "2026-05-16T00:00:00.000Z" |
| status | ACTIVE |
| source | arxiv 2605.11946v1 (Counterfactual Trace Audit / CTA) |
Skill Counterfactual Audit
Why
When you ship a skill, pass-rate is the easy metric — and it's blind to almost everything that matters. CTA (arxiv 2605.11946v1) shows a single skill can produce 522 measurable behavioural changes across 49 tasks while pass-rate moves only +0.3%. The interesting effects (surface anchoring on the skill's vocabulary, template copy without adaptation, excess planning loops, recovery from off-task drift, generation of off-task artifacts) live entirely below pass-rate.
The remedy is a paired-trace audit: run the same probe task twice, with and without the skill, and compare the behaviours directly rather than the headline metric.
How
For each skill under audit:
- Curate a probe-task bank (3-5 small tasks per skill domain). Each task should have:
- A clear goal (a single instruction)
- An expected category of behaviour
- A "phase decomposition" (rough segmentation rules)
- Run paired — same prompt, same task, run A with skill loaded, run B without.
- Segment each trace — phases like {plan, retrieve, edit, verify, fix-loop, summary}.
- Align phases — match B phases to A phases; mark new/dropped/displaced phases.
- Classify SIP (Skill Influence Pattern) — for each aligned phase, label the effect:
- surface-anchoring — A copies vocabulary/structure from the skill itself
- template-copy — A reproduces a skill template literally without adaptation
- excess-planning — A adds extra planning steps absent in B
- task-recovery — A recovers from drift that B falls into
- off-task-artifact — A produces artifacts unrelated to the goal
- Emit report to
.planning/patterns/skill-audits/<skill>-<timestamp>.md with phase comparison table + SIP distribution + retire/refine/keep recommendation.
Recommendation rule of thumb
| Dominant SIP | Verdict |
|---|
| task-recovery + correct artifacts | keep (genuine value) |
| surface-anchoring with no task-recovery | refine (skill is leaking style, not capability) |
| template-copy on most tasks | refine (lower template specificity) |
| off-task-artifact on >25% of probes | retire (skill is causing distraction) |
| excess-planning with no completion delta | refine (skill adds ceremony) |
When to skip
- The skill is a workflow guide that doesn't directly shape output (e.g.,
loop, schedule) — audit dominant SIPs would always be "task-recovery" trivially.
- No probe-task bank exists for the domain (build one first; defer audit).
- The skill was just created and has no historical baseline. Run the audit when the skill has been active for ≥3 sessions.
Integration
done-retirement — required gate before retiring a skill.gsd-cleanup — sweeps audits on a milestone-close cadence.- Companion to
simplify, code-review — those audit code; this audits skill behaviour.
Cross-references
- Rosetta concept #9 (Execution-Grounded Selection) — paired-trace audit is the skill-domain instantiation
- College:
agent-systems / integration-evaluation / agent-paired-trace-audit
- Related skills:
skill-integration (manages the skill lifecycle that this audits)
