Agent Skills: Code Review Standards

Code Review Standards

Purpose

This skill defines the structured checklist that the code-critic agent applies during Stage 4 of the code production pipeline. The checklist is severity-tagged so that PM and engineer both know exactly which findings block delivery and which are advisory. Engineers may load this skill for self-review before requesting a critic pass.

The checklist exists because unstructured code review in multi-agent systems produces inconsistent signal: one critic dispatch flags naming; another flags security; neither flags the same things. Severity tagging makes the review deterministic across dispatches.

The Severity-Tagged Checklist

CRITICAL (must fix, blocks delivery)

• [ ] No secrets, API keys, or credentials hardcoded
• [ ] No SQL injection vectors (parameterized queries only)
• [ ] No arbitrary code execution paths (no eval, exec, unrestricted pickle.loads)
• [ ] Authentication/authorization not bypassable
• [ ] No infinite loops without escape conditions

HIGH (must fix, blocks delivery)

• [ ] Type hints on all public functions and classes
• [ ] mypy --strict passes with zero errors
• [ ] pytest passes with zero failures
• [ ] Test coverage >= 90% on new code
• [ ] No bare except clauses
• [ ] No mutable default arguments
• [ ] No global mutable state
• [ ] No synchronous I/O inside async functions
• [ ] No N+1 query patterns
• [ ] Error cases handled explicitly (not silently swallowed)

MEDIUM (flag, note in report, proceed)

• [ ] Functions <= 20 lines (prefer <= 10)
• [ ] No nested loops where hash map would reduce complexity
• [ ] list.pop(0) replaced with deque.popleft() where relevant
• [ ] asyncio.gather uses return_exceptions=True where appropriate
• [ ] Async operations have explicit timeouts
• [ ] Docstrings on public methods (Google or NumPy style)
• [ ] No Any types in production code paths

Efficiency (see criteria-efficiency.md):

• [ ] No nested loops over two collections that should be a hash-map lookup (O(n*m) → O(n+m))
• [ ] No per-iteration I/O (queries/RPCs/fetches inside a loop) — batch outside the loop (HIGH on hot paths; see "No N+1 query patterns")
• [ ] Repeated deep property/selector resolution cached in a local (no greedy data access)
• [ ] String accumulation in loops uses list+join / StringBuilder, not +=
• [ ] No SELECT * / over-fetching in production query paths

Transferability (see criteria-transferability.md):

• [ ] No dead/unreachable code (statements after unconditional return/break/raise; uncalled private members)
• [ ] Long if/else if chains (3+ branches on one key) replaced by switch/match or dispatch map
• [ ] No nested switch/match — extract inner switch to a named function
• [ ] No actively misleading names (name contradicts the value it holds)

LOW (note only)

• [ ] PEP 8 compliance (black + isort handles this automatically)
• [ ] Variable naming is clear and descriptive
• [ ] No commented-out code left in
• [ ] Import ordering is clean
• [ ] Naming consistency across the change (same concept, same name; consistent casing)
• [ ] No file managing too many responsibilities (see 800-line file limit)

Verdict Format

Critic output MUST begin with the verdict on the first line, followed by the finding table, followed by a summary paragraph.

First line format:

VERDICT: APPROVE

or

VERDICT: WARN

or

VERDICT: BLOCK

Finding table format:

| Severity | File | Line | Issue | Required Fix | |----------|------|------|-------|--------------| | CRITICAL | auth.py | 47 | Hardcoded API key sk-... | Move to env var; add to .env.example | | HIGH | fetcher.py | 23 | requests.get() called inside async def | Replace with await httpx.AsyncClient().get() | | MEDIUM | parser.py | 88 | Function is 34 lines | Extract _parse_headers() helper |

Verdict definitions:

| Verdict | Condition | PM Action | |---------|-----------|-----------| | APPROVE | Zero CRITICAL, zero HIGH findings | Proceed to Stage 5 (Security) | | WARN | Zero CRITICAL, one or more HIGH findings | Proceed to Stage 5 with findings logged to docs handoff | | BLOCK | Any CRITICAL finding (one or more) | Halt pipeline; surface findings to user; await user direction |

APPROVE means the implementation is ready for security review. MEDIUM and LOW findings in an APPROVE review are passed to the Documentation agent as notes — they do not block delivery but are preserved for future reference.

WARN means the implementation has structural issues that should be fixed but do not represent exploitable defects or correctness failures. PM proceeds to security review and appends the WARN finding table to the documentation handoff message. PM also logs the findings (KB entry or todo) so they are not silently dropped.

BLOCK means the implementation has at least one defect that, if shipped, creates a security vulnerability, data loss risk, or silent failure mode. PM halts the pipeline immediately, presents the critic finding table verbatim to the user, and awaits explicit direction. PM MUST NOT auto-retry the engineer without user input.

80% Confidence Filter

A clean review is a valid review. Do not manufacture findings.

Only report issues with >80% confidence they are real problems. Do not flag:

• Style preferences as HIGH or CRITICAL
• "This could theoretically be an issue in an edge case" without specific evidence
• Patterns that look unusual but may be intentional and correct
• Missing features that were not in scope (check the Stage 1 spec)

When confidence is below 80%, note the concern as a question in the summary paragraph rather than as a finding in the table. Example: "The process_batch() function did not appear to handle empty input — verify whether the caller guarantees non-empty batches."

This filter prevents the critic from becoming a noise generator that trains PM to ignore findings. Each finding in the table should be actionable: engineer reads it, knows exactly what to fix, and can do so without asking for clarification.

Navigation

For detailed criteria with examples:

• CRITICAL Criteria: Detailed explanations and examples for each CRITICAL item
• HIGH Criteria: Detailed explanations and examples for each HIGH item
• MEDIUM Criteria: Detailed explanations and examples for each MEDIUM item
• LOW Criteria: Detailed explanations and examples for each LOW item
• Efficiency Criteria: Algorithmic/data-access patterns (nested loops, fetch-in-loop, greedy access, loop concatenation, over-fetching)
• Transferability Criteria: Maintainability patterns (dead code, long if/else-if chains, nested switch, naming hygiene)
• Verdict Protocol: Full PM behavior for each verdict, failure loop templates

The Efficiency and Transferability criteria are derived from CAST Highlight code quality indicators (https://doc.casthighlight.com/), paraphrased with original examples.