workflow-fix: code-reviewer must FAIL on missing smoke-architecture-check marker

Overview / Motivation

Auto-filed by the workflow-fix-on-bug protocol from a workflow-fix candidate raised on task #811 (emitting agent: orchestrator, /issue 811 session).

Goal

Add a mechanical check to the code-reviewer's contract checks (Step 0.5/0.6 family) that FAILs an experiment-task review round when no epm:smoke-architecture-check marker exists for the current implementer round.

Workflow gap

• Bug observed: On task #811 the implementer wrote its PASS_UNIFIED smoke/sweep-parity self-assessment into the dispatcher header ("PASS_UNIFIED — see the epm:smoke-architecture-check marker") but never posted the marker across 5 implementation rounds; both the Claude and Codex code-reviewers PASSed rounds without flagging the missing marker, and the gap surfaced only at the orchestrator's Step 6d.0 pre-dispatch gate — after all review rounds were spent (in general, after Step 6a-6c pod provisioning has already run).
• Why it is a workflow gap: experiment-implementer.md ("Before writing code" item 5) mandates the marker "before code-review-PASS", and SKILL.md Step 6d.0 refuses dispatch without it — but no reviewer-side mechanical check enforces it at review time, so the omission survives all rounds and costs a post-review bounce (or an orchestrator transcription) at the most expensive point in the pipeline.
• Confidence (emitter): medium

Proposed change (candidate diff sketch — refine in planning)

.claude/agents/code-reviewer.md (Step 0.5/0.6 mechanical-contract block):
+ - For `kind: experiment` tasks: verify an `epm:smoke-architecture-check v<n>`
+   marker exists for the CURRENT implementer round (verdict PASS_UNIFIED or
+   PASS_CANARY with a named canary cell). Missing -> FAIL with blocker tag
+   `marker-shape` (mechanical-contract class; orchestrator Step 5c-bis strip
+   applies when the marker is in fact present + conforming).

Consider also whether the orchestrator's Step 5c-bis mechanical set and/or the Step 4b implementer brief template (SKILL.md) should name the marker explicitly so round-1 briefs surface the duty; the spawned session's planner decides scope.

Scope / surfaces

• Primary target: .claude/agents/code-reviewer.md
• Grep the workflow surface for the pattern before editing (grep -rln 'smoke-architecture-check' .claude/agents .claude/skills .claude/workflow.yaml CLAUDE.md) and update every hit needing consistency; list them in the plan. Known enforcement sites today: .claude/agents/experiment-implementer.md (mandate), .claude/skills/issue/SKILL.md Step 6d.0 (late gate), .claude/workflow.yaml (marker schema), .claude/skills/issue/markers.md.

Constraints / invariants

• Workflow-surface only — never experiment code, configs/, or tasks/.
• scripts/workflow_lint.py --check-asks passes; ruff on touched files passes; if workflow.yaml or CLAUDE.md change, they stay consistent with the rule file.
• This session runs under EPM_WORKFLOW_FIX_SESSION=1 and carries a workflow_fix_target: Provenance line — it MUST NOT auto-route any of its own subagents' workflow-fix candidates (recursion guard).

Provenance

• workflow_fix_target: .claude/agents/code-reviewer.md
• fingerprint: 734d58e6ad57

target_file: .claude/agents/code-reviewer.md bug_observed: issue 811 implementer wrote PASS_UNIFIED self-assessment into the dispatcher header but never posted epm:smoke-architecture-check across 5 rounds; both Claude and Codex code-reviewers PASSed without flagging it; the gap surfaced only at Step 6d.0 pre-dispatch why_workflow_gap: the marker is mandated pre-code-review-PASS by experiment-implementer.md and gated by SKILL.md Step 6d.0, but no reviewer-side mechanical check enforces its presence at review time proposed_change: code-reviewer mechanical checks must FAIL an experiment-task round whose current implementer round has no epm:smoke-architecture-check marker diff_sketch: |

• Step 0.6-adjacent mechanical check (kind: experiment only): an
• epm:smoke-architecture-check v marker exists for the current round
• (PASS_UNIFIED | PASS_CANARY canary_cell=); missing -> FAIL,
• blocker tag marker-shape. confidence: medium related_task: #811