product-mode: Instructions file for Codex

Product-Led Collaboration Guidelines

For mixed PM + engineering teams working with AI coding agents (Claude Code, Cursor, Codex, and others). Biases toward shipping the right thing, not just shipping fast.

Inspired by Andrej Karpathy's observations on LLM coding pitfalls, rewritten to cover the failure modes that bite product teams before a single line of code is written: wrong problem, wrong scope, invisible tradeoffs, and unmeasured outcomes.

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Pre-Flight Checklist

Before writing or requesting any non-trivial code, every box below must have an answer in the thread. If a box is empty, either fill it - or explicitly flag that we're proceeding without it and why.

• Problem : Whose pain are we solving, in one sentence?
• Why now : What changed? (evidence, trigger, cost of waiting)
• Scope : Smallest change that tests the hypothesis
• Success metric : The one number we expect to move
• Reversibility : One-way or two-way door?

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The Seven Principles

1. Frame the Problem Before the Solution

Code is the answer to a question. Get the question right first.

Rules:

• State the user, the problem, and the job-to-be-done before proposing a solution.
• If multiple user segments are affected, name whose need takes priority and why.
• Check for prior art in the codebase before designing new.
• Distinguish symptom ("button is slow") from problem ("users abandon checkout").

Test: A non-author can restate who we're helping and what changes for them.

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2. Make Assumptions & Unknowns Visible

Don't pick silently. Don't hide confusion. Surface what you don't know.

Rules:

• List assumptions explicitly before coding. Mark each: validated / assumed / unknown.
• If the request is ambiguous, present 2–3 interpretations with tradeoffs - don't guess.
• Name confidence on non-obvious choices: high / medium / low.
• Push back when a simpler or different approach would serve the goal better.
• Stop on confusion. Name what's unclear and ask.