OpenAI Codex API agent loop for implementation tasks

Objective

Use API calls to run a structured coding loop with explicit validation gates.

Loop design

Stage A: Plan

Prompt for:

• impacted modules
• implementation sequence
• test commands
• expected failure modes

Stage B: Implement

Apply only one logical change per pass:

• write patch
• run test command
• capture output

Stage C: Verify

Require the model to explain:

• what code path was exercised
• what remains unverified
• any assumptions still unresolved

Stage D: Summarize

Output machine-readable notes:

• files changed
• behavior changes
• evidence from test output

Why this works

• keeps code generation bounded
• makes failures visible early
• improves review quality for humans

Suggested safeguards

• fail closed on missing tests
• reject edits that exceed scope constraints
• persist run logs with timestamps