Claude Code Loop Engineering for Production AI Agents

Example workflow

• Write a loop contract with the goal, done definition, stop condition, and required evidence before the agent edits files.
• Persist run state in Markdown or JSON so another agent or human can resume the current cycle without reconstructing context from chat history.
• Limit each cycle to one scoped edit, one scoped investigation, or one verification pass, then update the state file.
• Run a reviewer gate that checks scope, unrelated changes, tests, assumptions, and evidence before the loop proceeds.
• End each cycle with a concrete next action: continue, revise, escalate, or stop.

Stack recommendations

• Claude Code for long-context coding and local repo work.
• Git worktrees or isolated branches for safe execution lanes.
• A checked-in run log such as .agent/runs or docs/agent-runs.
• Lint, typecheck, tests, build output, screenshots, or route checks as proof artifacts.
• Optional paired review with Codex or another model family for adversarial pressure.

Failure modes

• The agent claims completion without evidence.
• A long prompt tries to replace durable state.
• The loop edits outside the agreed scope.
• Reviewer feedback is accepted as prose but never converted into a new action.
• Stop conditions are vague enough that the run keeps spending tokens after it needs a human decision.

Verification checklist

• State file contains the current cycle, next action, blockers, and evidence list.
• Git status shows only intended changes.
• The reviewer gate records pass/fail and required fixes.
• All declared proof commands have command output or a documented blocker.
• The final handoff includes changed files, test results, and unresolved risks.

Use when

• The coding task has multiple steps and can benefit from resumable execution.
• You need proof before merge, not just an agent summary.
• The repo has reliable checks the agent can run after each slice.

Avoid when

• The task is a one-line answer or a single mechanical edit.
• The next action requires credentials or product decisions the agent cannot infer.
• The repository has no meaningful verification path yet.

Alternatives

• Use a human-run checklist for small changes.
• Use Codex as the primary worker when you want a second implementation lane.
• Use a CI-only gate when the workflow is already deterministic and does not need agent review.

Tradeoffs

• Loop engineering adds ceremony, but it makes long agent runs resumable.
• Reviewer gates slow the happy path, but they catch scope drift and missing proof.
• State files need upkeep, but they are cheaper than reconstructing context from a long transcript.