docs(gate): assertion-strength audit of the live compiled bundle

[myselfsiddharth]

Closes #61.

Summary

Audits every step of artifacts/compiled/traj-gate-live-create-stat-dashboard-from-testdata-9.5.21.bundle.json against the audit's central question: if this step silently did nothing, would its assertion fail? No assertion or strength label is changed — this is the audit, strengthening is follow-up work.

• Load-bearing count: 6/12 (steps 0, 1, 3, 7, 10, 11) — matches the compiler's existing strong/weak split exactly under a table-only reading. Reproducible via node scripts/assertion-audit.mjs.
• Every weak step (2, 4, 5, 6, 8, 9) mapped to a docs/gate/compiler.md blind spot, with a strengthen / needs richer fingerprint / inherently weak recommendation each. Two are novel, code-grounded findings: step 8 already has an unused new-landmark signal (newLandmarks() is computed but never used as the assertion target when a click has its own locator — src/compiler/assertions.ts:286); step 2 has an unused dom_digest diff the compiler's own priority-8 fallback could use instead of a non-discriminating "is the clicked button still visible" check.

Empirical verification (required by the issue)

Ran against a freshly booted, freshly seeded 9.5.21 testbed (npm run testbed -- --version 9.5.21), through the unmodified ReplayRunner / evaluateAssertion / bundleToProgram — no product code patched. Method: swap the target step's compiled_action for a genuine { type: "wait" } no-op, leave the assertion untouched, run.

• Steps 0 and 1 (both "would catch a no-op," both url-matches, strong): confirmed. Neutered runs produced ASSERTION_FAILED with the expected URL mismatch in both cases — satisfies the issue's "at least two claims verified empirically."
• Step 3 (also "strong," ADR-0007 hide-on-select case): confirmed NOT load-bearing today. Both the real click and the neutered no-op produced PASS. Root cause: the assertion's target is a recorded structural/positional CSS path that resolves to zero elements on a fresh, unmodified 9.5.21 instance — the same version it was recorded on, no version bump involved. This is exactly the "is the structural locator stable run-to-run" question ADR-0006 left open for Record the ADR-0006 gate task live against the seeded base version #24, now answered empirically: no, at least not for this row.
• Step 4 (weak fill): the same structural-locator defect makes it fail unconditionally — confirmed the real, correctly-executed fill still times out after 5000ms. So this row isn't just "weak" (fails to discriminate), it's currently non-functional regardless of what the step does.
• Steps 5, 6, 8, 9 were not independently tested; flagged as sharing the same assertion shape, not claimed as confirmed.

This cuts both ways on any published number: step 3 would currently score a no-op step as valid, while steps 2/4-shaped rows would currently score a correct execution as a failure. The doc's "Statement of consequence" section spells this out for whoever writes the gate memo, as the issue requires.

A smaller, secondary finding (documented, not fixed): url-matches in src/runner/assertions.ts reads page.url() once with no poll loop despite carrying timeout_ms, unlike element-visible. Grafana 9.5.21 appends ?orgId=1 to /dashboard/new client-side ~500ms after domcontentloaded (confirmed manually), so a fresh full-page navigate races that evaluator — worked around in the verification harness by settling manually, not fixed in product code.

Test plan

• npm run lint:docs — clean (46 docs)
• npm run ci — clean (secret-scan, contracts, lint, typecheck, unit + integration tests all pass)
• node scripts/assertion-audit.mjs reproduces the 6 strong / 6 weak / 6-load-bearing counts mechanically from the committed bundle
• Live empirical check against a real 9.5.21 testbed instance (see above) — container torn down afterward, no scratch files committed

Checklist (from the issue)

• Every step in the compiled bundle has a row (12/12)
• Load-bearing step count stated as a plain fraction, derived mechanically from the artifact
• At least two "would catch a no-op" claims verified empirically (steps 0, 1) — plus a third tested and found to disprove itself (step 3), reported in full rather than dropped
• Every weak step mapped to a blind spot or follow-up issue
• Consequence for the gate memo stated explicitly
• No assertion or strength label changed in this PR
• docs/README.md index row added
• Branch track1/b3-assertion-audit

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[myselfsiddharth]

@copilot review this PR

[Copilot]

@copilot review this PR

I reviewed this PR and found no high-confidence issues requiring changes.

[myselfsiddharth]

Review

Docs-only PR (no product code touched): a new docs/gate/assertion-audit.md, a reproducibility script scripts/assertion-audit.mjs, and one index row in docs/README.md. Closes #61.

What it does

Per-step audit of all 12 rows in the committed traj-gate-live-create-stat-dashboard-from-testdata-9.5.21.bundle.json, answering "would this assertion catch a silent no-op?" per row, a mechanically-reproducible load-bearing count, a blind-spot mapping for every weak row, and a live empirical check against a real 9.5.21 testbed for the required "at least two" no-op claims (delivered three, including one that disproves itself).

Verification performed

I checked this PR's claims against the actual repo rather than taking the prose at face value:

• Ran scripts/assertion-audit.mjs against the real bundle in this checkout — it reproduces the stated 6 strong / 6 weak, 6/12 load-bearing exactly, with the same step indices (0, 1, 3, 7, 10, 11).
• Confirmed src/runner/assertions.ts's url-matches case does read page.url() once with no waitFor/poll loop, unlike the element-visible branch — Finding 2 is accurate.
• Confirmed src/compiler/assertions.ts:286 (const locator = primary ?? landmarkAsLocator(landmarkPick);) — newLandmarks()-derived locator is only ever used when primary is undefined, exactly as claimed for the step 8 recommendation.
• Confirmed the step 2 dom_digest pair (006b965317eacdbc → dee4609c1269959d) and the step 8 landmark diff ([main, navigation, banner] → [..., form]) against experiments/gate-v1/trajectories/grafana-create-stat-dashboard-from-testdata-9.5.21.json — both match the doc exactly.
• Confirmed every blind-spot number cited (1, 3, 8) matches docs/gate/compiler.md's actual "Known blind spots" list.
• Confirmed the frontmatter and the ## Open questions / what I could not verify header satisfy scripts/lint-docs.mjs's required keys/allowed values.
• Confirmed all StepOutcome values used in the empirical table (ASSERTION_FAILED, TIMEOUT, REPAIR_EXHAUSTED, PASS) are real members of the type in src/metrics/types.ts.

Everything checked out. This is unusually well fact-checked for a docs PR — every specific code reference, line number, and data value I spot-checked was accurate rather than approximate.

Issue-checklist compliance

Matches issue #61's "before you open the PR" checklist item-for-item: every step has a row, the fraction is derived mechanically (not hand-counted), every weak step maps to a blind spot, the gate-memo consequence is stated explicitly and in plain language, no strength label or assertion was touched, the README index row was added, and the branch name matches.

Minor observations (non-blocking)

• Scope creep, disclosed correctly. Finding 1 (structural-locator staleness) and Finding 2 (url-matches polling gap) are runner/locator bugs, not assertion-strength findings — but the doc is explicit that both are out of scope for this PR and attributes Finding 1 to the already-open Record the ADR-0006 gate task live against the seeded base version #24 rather than silently fixing or filing redundantly. No action needed, just noting it's the right call.
• LOAD_BEARING_STEP_INDICES in scripts/assertion-audit.mjs is a hardcoded judgment call, not derived from the bundle — this is unavoidable (the question "would this fail on a no-op" isn't mechanically computable from the JSON alone) and the script's own comment says so plainly, plus it prints a divergence warning if strong-count and load-bearing-count ever split. Reasonable given the constraint.
• The doc's empirical table shows step 0's "real action" column as "(see caveat below)" — this forward-reference is resolved by Finding 2 later in the doc, but a reader skimming just the table might be momentarily confused before reaching that section. Not worth restructuring for.

Risk

Very low. No product code changed; the two runner-level bugs surfaced (locator staleness, url-matches polling) are documented as follow-up work, not silently patched. The one real risk is that the audit's central finding — that the section 9 gate number can currently be inflated and deflated simultaneously by locator staleness — needs to actually get picked up by whoever writes the gate memo. The doc states this plainly, which is what the issue required.

Recommendation: approve.