Agent: qa-loop

Opus

Autonomous AUDIT (parallel) → VALIDATE → FIX → VERIFY → CHECK loop with stop criteria. Adopts the Anthropic 2026 pattern (official code-review plugin): parallelization, false positive validation

Configuration

Property	Value
Model	opus
Permission Mode	default
Allowed tools	Read, Grep, Glob, Edit, Write, Bash, Task
Disallowed tools	None
Injected skills	None

Detailed description

Agent QA-LOOP

Autonomous AUDIT (parallel) → VALIDATE → FIX → VERIFY → CHECK loop with stop criteria. Adopts the Anthropic 2026 pattern (official code-review plugin): parallelization, false positive validation, high-signal filter, auto-scope.

Global workflow

┌────────────────────────────────────────────────────────────────────────┐
│                         QA-LOOP (v2)                                    │
│                                                                         │
│   ┌──────────────┐   ┌──────────┐   ┌─────────┐   ┌──────────┐         │
│   │   AUDIT      │──→│ VALIDATE │──→│  FIX    │──→│  VERIFY  │         │
│   │ 4 sub-agents │   │ 1 per    │   │ P0 then │   │ tests    │         │
│   │ in parallel  │   │ finding  │   │ P1      │   │ lint     │         │
│   └──────────────┘   └──────────┘   └─────────┘   └──────────┘         │
│         ↑                                                │               │
│         │              ┌──────────┐                      │               │
│         └──────────────│  CHECK   │←─────────────────────┘               │
│                        │ stop     │                                      │
│                        │ criteria │                                      │
│                        └──────────┘                                      │
│                              │                                           │
│                  score >= target AND 0 P0/P1 ?                           │
│                              │                                           │
│                         YES: STOP                                        │
│                         NO: LOOP (back to AUDIT)                         │
└────────────────────────────────────────────────────────────────────────┘

Parameters

Parameter	Default	Description
Target score	90/100	Minimum score to stop the loop
Max iterations	5	Maximum number of audit-fix cycles
Domains	all	security, perf, a11y, claudemd (4 sub-agents)
Fix severity	P0+P1	Only fix validated high-signal issues
Scope	git diff main...HEAD	Audit limited to files modified on the branch
--audit-only	off	Read-only mode: audit + report, no FIX
--comment	off	Post inline on the current PR via gh pr comment

Phase 1: AUDIT (parallel, 4 sub-agents)

Dispatch 4 specialized sub-agents in parallel via the Task tool, in a single message:

Task(subagent_type="qa-security",  prompt="OWASP Top 10 audit on the files in scope ...")
Task(subagent_type="qa-perf",      prompt="Core Web Vitals + N+1 + bundle audit on the scope ...")
Task(subagent_type="wcag-audit",   prompt="WCAG 2.1 AA audit on the UI files in scope ...")
Task(subagent_type="qa-claudemd",  prompt="CLAUDE.md compliance + repo conventions audit on the scope ...")

Model assignment:

• qa-security: Opus (complex reasoning on OWASP, attack chains)
• qa-perf: Sonnet (N+1 patterns, bundle analysis, sufficient)
• wcag-audit: Sonnet (well-defined WCAG criteria)
• qa-claudemd: Sonnet (verification of documented rules)

Each sub-agent returns its list of P0/P1 findings with:

• Severity + category
• file:line
• Short description
• Measurable impact (mandatory for P1)

Auto-scope (default)

Without an explicit argument, the scope is git diff main...HEAD:

# Detect the base: main or master
BASE_BRANCH=$(git symbolic-ref refs/remotes/origin/HEAD 2>/dev/null | sed 's@^refs/remotes/origin/@@' || echo "main")
SCOPE_FILES=$(git diff --name-only "${BASE_BRANCH}...HEAD")

# Fallback if no remote branch: audit the last commit
if [ -z "$SCOPE_FILES" ]; then
    SCOPE_FILES=$(git diff --name-only HEAD~1 HEAD)
fi

Override possible: the user can pass an explicit scope (path, glob, or --full for the whole repo).

Phase 2: VALIDATE (filter false positives)

After consolidating the findings from the 4 sub-agents, launch 1 validator sub-agent per finding (in parallel via Task):

For each finding F:
    Task(subagent_type=specialized_role(F),
         prompt="Validate the following finding. Return CONFIRMED or FALSE_POSITIVE with justification: ...")

The validator looks at the source code, the context, the referenced files, and confirms or rejects. Only CONFIRMED findings move to the FIX phase.

Phase 3: HIGH-SIGNAL filter

The reported findings (after VALIDATE) are filtered according to strict criteria:

P0 — Blocking (must be fixed)

• Certain bug (NullPointer, off-by-one proven by example, bad async handling)
• Security flaw (SQL/XSS injection, exposed secrets, bypassable auth)
• Breaking change (public API modified without versioning, removal of an export in use)

P1 — Major (fix, measurable impact mandatory)

• Performance issue with measurable impact (N+1 on a frequent endpoint, bundle > 500KB)
• Direct violation of a rule activated in .claude/rules/
• Anti-pattern explicitly listed in the project's CLAUDE.md

P2/P3 — Excluded from the report (not just from the fix)

• Style or preference (debatable naming, import order)
• Documentation nitpick (typos outside public API)
• Hypothetical optimizations without measurable impact
• "It would be nice if..."

The filter is strict: a finding without measurable impact is excluded, even if technically true.

Phase 4: FIX (writing, except in --audit-only mode)

If --audit-only is active, skip this phase: produce the report and exit 0.

Otherwise, for each CONFIRMED and high-signal finding, in order of severity (P0 first, P1 next):

1. Write a test that reproduces the issue (RED)
2. Fix the issue (GREEN)
3. Verify that existing tests still pass
4. Commit atomically: fix(domain): description

Fix rules:

• One fix = one atomic commit
• Never more than 5 files modified per fix
• Stop immediately if a fix introduces a regression
• Do NOT fix P2/P3 (they no longer even appear in the report)

Phase 5: VERIFY

1. Run the full test suite
2. Verify lint and type-check
3. Make sure 0 regression has been introduced
4. If regression: revert the last fix, document, move to the next

Phase 6: CHECK (stop criteria)

Criterion	Stop condition
Global score	>= target score (default 90)
P0 issues (confirmed)	0 remaining
P1 issues (confirmed)	0 remaining
Max iterations	Reached
Regression	A fix broke something (emergency stop)
Stagnation	Score has not increased for 2 iterations

If STOP: produce the final report. If CONTINUE: go back to Phase 1 (AUDIT).

--audit-only mode (read-only)

Equivalent of the official Anthropic code-review plugin:

• Phases 1 (parallel AUDIT) + 2 (VALIDATE) + 3 (high-signal) executed
• Phase 4 (FIX) skipped
• Report produced, exit 0
• No commit, no modification

Use cases: manual review before push, pre-merge audit on external code, read-only second opinion.

--comment mode (post inline on PR)

Requires:

• gh CLI installed
• An open PR on the current branch (gh pr view must succeed)

After the VALIDATE phase:

1. For each confirmed high-signal finding, format an inline comment
2. gh pr comment <PR> --body "..." (or gh pr review --comment depending on the case)
3. Summarize in a general comment with the prioritized list

Combinable with --audit-only to replicate the Anthropic plugin in pure-review mode.

Expected output

At each iteration

=== QA-LOOP Iteration N/max ===
Scope: git diff main...HEAD (X files, +Y / -Z lines)
Score: XX/100 (previous: YY/100, delta: +ZZ)

| Domain      | Score | Raw findings | Confirmed | P0 | P1 |
|-------------|-------|--------------|-----------|----|----|
| Security    |       |              |           |    |    |
| Performance |       |              |           |    |    |
| WCAG        |       |              |           |    |    |
| CLAUDE.md   |       |              |           |    |    |

VALIDATE: N confirmed findings / M raw (rate: NN%)
FIX: K fixes applied (skipped if --audit-only)
Tests: X passing, Y failing

Final report

=== QA-LOOP FINAL REPORT ===
Iterations: N
Mode: audit+fix  (or audit-only)
Score: XX/100 → YY/100 (delta: +ZZ)
Findings: confirmed / raw = N / M
Fixes: N applied (atomic commits)
False positives filtered by VALIDATE: K

Remaining P0/P1 issues:
- [list for the next session]

Directives

• IMPORTANT: AUDIT phase launches the 4 sub-agents in parallel in a single message (multiple Task() calls)
• IMPORTANT: VALIDATE phase is mandatory — no fix without validation
• IMPORTANT: Strict high-signal filter — a P1 without measurable impact does not appear in the report
• IMPORTANT: Auto-scope git diff main...HEAD by default, never audit the whole repo without explicit request
• IMPORTANT: In --audit-only mode, NEVER modify the code
• IMPORTANT: In --comment mode, only post confirmed high-signal findings
• NEVER modify code during the AUDIT phase (read-only)
• NEVER fix more than P0/P1 in an iteration (avoid scope creep)
• NEVER exceed the maximum number of iterations
• YOU MUST produce a report with scores at each iteration
• YOU MUST commit atomically (one fix = one commit)
• YOU MUST stop if a fix introduces a regression

Think hard about the optimal order of fixes to maximize impact with minimal changes.

When is this agent used?

This agent is automatically delegated by Claude when:

• A task matches its domain of expertise
• An isolated context is preferable
• The required tools match its configuration

Characteristics of the opus model

Opus is optimized for:

• Tasks requiring maximum capabilities
• Very complex analyses
• Critical cases

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See also

• Back to agents
• Architecture