fix: meaningful diagnostics, S-first layering, worker retry, representability surfacing

[ryandmonk]

Phase 1 presentation + robustness from the ratified P1+P2 milestone. Feature-detected against dspack-emit 0.7 / dspack-gen 0.4 — no dependency bumps in this PR (bump follows once emit 0.7.0 is on npm).

• Per-instance findings: shared catalogGateFindings() (composer-core) consumes emit 0.7's errorDetails when present — one finding per component instance with an honest Component#id target (the hardcoded a2ui@0.9.1 target is gone), message capped at 3 errors (+N more), full raw strings preserved on finding.evidence. Fallback for emit 0.6 caps the joined message and keeps everything on evidence. Agent twin (project.ts, record-fixture.ts) uses the same helper.
• Build failures: reasons deduped across A2UI versions ("both A2UI versions" target), S-layer findings lead with A-gate cascades collapsed to one summary line, failed-lint-exhausted turns whose last attempt carries representability now surface the emitter refusal instead of "unknown".
• Checks view: errors → warnings → infos; the fidelity wall (193 rows on the shipped shadcn example) collapses to one disclosure line; findings with evidence get a raw-evidence expander.
• Worker: one bounded retry on unusable provider output (the measured-transient 502 class — 4/4 recovered on retry in the field); 429/busy/timeout/kill-switch never retried; fixed a leaked 45s race timer found in passing.
• Fail-first: 7 composer-core + 4 worker failures on pre-change code pasted in the test commit body. composer-core 68, composer 29, agent 44, typecheck green; no e2e edits (testids verified against the suites).

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Status	Name	Latest Commit	Updated (UTC)
✅ Deployment successful! View logs	dspack-studio-composer	a7871e3	Aug 10 2026, 10:17 PM

[Copilot]

Pull request overview

This PR improves diagnostics fidelity and presentation across composer-core, the Composer app, and the hosted Worker by introducing structured, per-instance catalog-gate findings (when available), deduplicating/collapsing build-failure reasons, surfacing representability refusals, and adding a bounded retry for model-output parse failures.

Changes:

• Add catalogGateFindings() to generate per-component-instance A-gate findings with capped messages and full raw evidence, and adopt it in browser + agent emit reporting.
• Improve build-failure summarization (A-gate dedupe across versions, S-first layering) and surface dspack-gen representability refusals in turn attempts/failures.
• Update Checks UI to sort by severity, collapse fidelity notes, and add an expander for full raw evidence; add Worker callModel() with a single retry on unusable provider output plus tests.

Reviewed changes

Copilot reviewed 11 out of 11 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
packages/composer-core/src/index.ts	Re-export catalogGateFindings and related types for shared use.
packages/composer-core/src/findings.ts	Add evidence to findings and implement catalogGateFindings() (per-instance + capped message).
packages/composer-core/src/diagnostics.test.ts	Add fail-first tests for catalog-gate findings and build-failure layering/dedup/representability surfacing.
packages/composer-core/src/build.ts	Deduplicate A-gate reasons, collapse A-gate walls when S-gates explain failure, and surface representability refusal.
apps/composer/worker/propose.test.mjs	Add tests for bounded retry behavior on unusable provider output (and no retry on provider failures).
apps/composer/worker/propose.mjs	Implement runModel (timer cleanup) + callModel with one retry on parse-only failures; export helper for tests.
apps/composer/app/views/validate-view.tsx	Sort findings by severity, collapse fidelity notes, and add evidence expander rendering.
apps/composer/app/views/build-view.tsx	Display representability failures and annotate repair details accordingly.
apps/composer/app/validation.ts	Use catalogGateFindings() for browser emit gate reporting.
apps/agent/src/record-fixture.ts	Use catalogGateFindings() to print per-instance gate diagnostics in fixture recording.
apps/agent/src/project.ts	Use catalogGateFindings() for agent emit gate reporting.

Suppressed comments (2)

packages/composer-core/src/findings.ts:155

• gate.errors is treated as string[], but the input is a loose CatalogGateLike coming from external reports. If errors is unexpectedly not an array, this path will attach a non-array value as evidence and break cappedMessage/UI consumers. Guard with Array.isArray.

    });
  }
  const evidence = gate.errors ?? [];
  return [withEvidence(finding(gateId, code, "error", fallbackTarget, cappedMessage(evidence, code || "gate failed")), evidence)];
}

apps/composer/app/views/validate-view.tsx:52

• data-testid for the evidence block only uses gate + code, which can collide across multiple findings (especially with per-instance A-gate findings). Include target (or another stable discriminator) so each evidence expander is uniquely addressable.

            </summary>
            <pre
              data-testid={`finding-evidence-${f.gate}-${f.code}`}
              style={{ fontFamily: "var(--mono)", fontSize: 11, whiteSpace: "pre-wrap", maxHeight: 200, overflow: "auto", color: "var(--fg-dim)", margin: "4px 0 0" }}
            >

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