Use a reusable Plans.md rubric to make Codex produce a self-contained, milestone based implementation plan for a complex change. Alex plans a Python SDK from an existing TypeScript SDK before asking Codex to build it.
Source episode · 13:30
How I AI: 3 Advanced Codex Workflows for Faster, Smarter Development with OpenAI's Alex Embiricoswith Claire Vo
Alex copies OpenAI's planning guidance into Plans.md, asks Codex to plan a Python SDK from the TypeScript SDK, reads the resulting 120 line plan, and then invokes it in a new chat.
A self-contained implementation plan with architecture, milestones, file references, validation commands, and a progress record Codex can execute.
OpenAI's cloud-based AI software engineering agent that can execute code, run tests, and handle complex multi-file tasks autonomously.
Step by step
Follow the sequence once, then adapt the prompts, checks, and handoffs to your own setup.
4 steps
Add a Plans.md file at the repository root using the planning rubric your team wants Codex to follow. Require a self-contained document, milestones, concrete repository references, validation, decisions, and a progress section that stays current during execution.
Describe the complex goal and ask Codex to use Plans.md. Save the result to a named file in the repository so it can be inspected, revised, and invoked from a clean implementation session.
Using Plans.md, create a self-contained plan for building a Python SDK based on the TypeScript SDK in this repository. Identify the current API surface, naming and error conventions, package structure, tests, documentation, and release setup. Break the work into testable milestones and save the plan to sdk-plan.md.
Read the plan for repository specific evidence, architectural choices, milestone boundaries, and test commands. Ask for changes in the same planning chat so Codex retains the analysis that led to the first draft.
Revise sdk-plan.md so each milestone names the source TypeScript files, target Python modules, compatibility decisions, and commands that prove the milestone works. Add an explicit decisions section and unresolved questions. Keep the existing repository conventions.
Start a clean Codex implementation chat and point it to the saved plan. Have it work milestone by milestone, update the progress section, and run the validation commands recorded in the document.
Implement sdk-plan.md milestone by milestone. Keep its progress and decisions sections current as you work. Run the validation commands for each milestone before moving on, and finish with a summary of completed work and any unresolved items.
Turn an idea into a PRD, user stories, and a plan.
After the steps
How to recover when the loop fails and where human judgment helps.
Recover
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