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Code ReviewMedium risk

Maker-Checker Loop

Use one agent to implement and another independent reviewer to check the result.

Updated 2026-07-14
First-hand site test
Maker-checker handoff rendered from this template

The handoff below was checked against the template boundaries: the checker stays read-only and a person keeps merge authority.

Practical evidence

Evidence handoff example

Maker output

Scoped diff, failing-before and passing-after test output, commands run, and a short residual-risk note.

Checker finding

The regression test passes, but the diff also changes an unrelated timeout default outside the approved scope.

Resolution

The maker removes the unrelated change, reruns the required checks, and returns a new evidence packet.

Human gate

A person reviews the final diff, checker result, and evidence before approving merge or deployment.

What this Loop Engineering template does

Implement a change with a maker agent, then have an independent checker verify it before a human merges.

The checker must be a separate, read-only process from the maker. Human approval is required before merge.

When to use it

Higher-risk changes
Cross-model review
Separation of duties

When not to use it

Trivial changes
Cases where no independent reviewer is available

Validation checks

validation
Maker output passes tests
Checker report is generated
Blocking issues are resolved or escalated

Boundaries & stop rule

!Checker must not be the same process that made the change
!Checker should be read-only unless explicitly authorized
!Human approval required before merge
Stop rule — Stop when the checker passes and a human approves, or escalate if blocking issues remain after 3 maker-checker rounds. If maker and checker disagree, summarize both positions and escalate to a human.

Copy the loop prompt

claude-goal.txt
/goal Implement a change with a maker agent, then have an independent checker verify it before a human merges.
 
Task type: Code Review
Target tool: Claude Code
 
Work toward this goal until all validation checks pass or the stop rule is reached.
 
Design hypothesis:
This maker-checker loop can produce a safer result if the scope stays narrow, validation is explicit, and a checker can reject shortcut work.
 
Smallest useful run:
Run one bounded pass on the newest relevant signal before expanding scope or adding a schedule.
 
Loop cycle:
1. Discovery — Read the latest signal for this template before acting: CI output, issue detail, review comment, dataset report, or content brief.
2. Handoff — Hand the work to one agent in an isolated branch, worktree, or clearly scoped session. Keep final approval with a human.
3. Verification — Use an independent review pass to confirm the result, inspect the diff or artifact, and reject shortcut work.
4. Persistence — Save a short run note with the signal reviewed, actions taken, validation result, and next recommended step.
5. Scheduling — Run manually until the loop is reliable; only then consider a scheduled or event-triggered run.
 
Context:
The checker must be a separate, read-only process from the maker. Human approval is required before merge.
 
Validation:
Maker output passes tests
Checker report is generated
Blocking issues are resolved or escalated
 
Validation evidence:
Record the original signal, checks run, final result, changed files or artifacts, and any checker rejection.
 
Independent checker:
Use an independent review pass to confirm the result, inspect the diff or artifact, and reject shortcut work.
 
Boundaries:
Checker must not be the same process that made the change
Checker should be read-only unless explicitly authorized
Human approval required before merge
 
Stop rule:
Stop when the checker passes and a human approves, or escalate if blocking issues remain after 3 maker-checker rounds.
Maximum iterations: 4
 
Budget:
Example only: stop before exceeding the agreed per-run token budget.
 
Human approval:
Required before merge, deploy, delete, purchase, or external communication.
 
Fallback:
If maker and checker disagree, summarize both positions and escalate to a human.
 
Loop Validation Log:
- Hypothesis: This maker-checker loop can produce a safer result if the scope stays narrow, validation is explicit, and a checker can reject shortcut work.
- Smallest useful run: Run one bounded pass on the newest relevant signal before expanding scope or adding a schedule.
- Expected evidence: Record the original signal, checks run, final result, changed files or artifacts, and any checker rejection.
- Actual evidence: [fill in after the run]
- Passed? [yes / no / partial]
- Feedback: After the run, note what the loop learned, what failed, and what should change before the next pass.
- Next step: [stop / adjust the loop / run the next pass]
 
Do not delete tests, bypass checks, or modify unrelated files just to satisfy the validation condition. If blocked, stop and summarize the blocker, attempted fixes, and recommended next action.

Failure modes to watch

Maker and checker share the same context
Checker gains write access and silently “fixes” issues
Endless maker-checker ping-pong
Merge without human approval
Worked scenario review · maintained by TianMingAI · 2026-07-21

Review receipt

This is a bounded review exercise for the template, not a claim about a production deployment.

Scenario

The maker claims a CI repair is complete after deleting the regression test that exposed the failure.

Baseline evidence

The checker receives the maker diff, before-and-after command output, original failing test name, declared boundaries, and merge authority separately from the maker's completion summary.

Validation result

Aggregate CI is green, but the checker returns Stop because required evidence disappeared; a corrected artifact restores the test, fixes the parser, and leaves merge to a person.

Shortcut rejected

Treating a green aggregate status as sufficient evidence is rejected when the exact regression test has been removed or weakened.

Human gate

A human reviews the independent checker findings and decides whether the corrected change may advance; neither maker nor checker can merge automatically.

Final decisionStop

Loop Engineering FAQ

A reviewer that shares the maker's context inherits its blind spots. Independence is what makes the check meaningful.