Eval framework: skill-activation (trigger) evals + the eval-built prove-need lifecycle (from eliasstravik/skills)

From eliasstravik/skills (MIT, "eval-built agent workflows")

The closest public analog to our eval framework. Its most transferable ideas, prioritized:

1. Skill-activation (trigger) evals — trigger-eval.json (highest leverage)

A flat JSON array of {"query": "...", "should_trigger": true|false} that tests whether a skill activates on the right requests and stays silent on adjacent ones — independent of behavior. For a 60+ skill marketplace, routing is our real failure mode (copywriting vs copy-editing vs ad-creative vs emails; seo-audit vs ai-seo vs schema; pricing vs paywalls). We have no eval for it today.

• Seed 60/40 positive/negative, with adjacent-skill negatives (e.g. "write ad copy" should NOT fire copywriting — it should fire ad-creative; "is my pricing page AI-readable" fires pricing, not ai-seo).
• Elias runs a trigger ratchet that optimizes the skill's description against the query set and applies best_description verbatim. Our per-skill description triggers are exactly what this would harden.

2. The "eval-built" prove-need lifecycle (for NEW skills)

"A skill is not written, it is earned." Before building a skill, run its scenarios against a no-skill baseline; record verbatim failure evidence; saturate (stop when a fresh round adds zero new failure classes). If the baseline doesn't fail, don't ship the skill. Then every skill line traces to a real failure via a failure→assertion traceability table, and the skill starts as a bare core (H1 + one primitive, ≤20 lines) with details earned by observed failures. Strong editorial filter against bloat for a growing library.

3. Harness upgrades

• Execution-cost metrics in grading (tool-call count, errors, output/transcript chars) so a passing-but-expensive skill is caught, not just a failing one.
• Machine-readable failure-classes.json + grading-schema.json (expectations[] / typed claims[] / pass_rate / eval_feedback) — converge these with #484 (the Magister schema work).

The obra complement (completes #479)

Elias saturates the NO-skill baseline (proves the skill is needed). obra/superpowers pressure-tests the WITH-skill artifact (proves it's robust). They're two halves — Elias has no adversarial "try to break the installed skill" round, which is exactly the pressure-test-evals gap already noted on #479. Together = the full picture: prove-need → build → prove-robust.

Credit / license

eliasstravik/skills is MIT — distill-with-credit. Adopt the formats and lifecycle, credit the source. Companion to #479 (framework), #480 (benchmark), #484 (schema convergence).