Reviewers start with the same unknowns the builder started with, plus one more: whether the builder accounted for the failure points an expert would probe. A good pitch doc kills both in one read.
Steps
Collect the artifacts: the spec or plan, the prototype or demo, the implementation notes, and the diff. Ask for a demo recording or screenshots if any user-facing behavior changed — lead with that.
Structure the document in reading order for a skeptic:
The demo — what it looks like working, first. A GIF or screenshot beats prose.
The problem and the bet — two paragraphs max: what this solves and the approach chosen over the alternatives.
What an expert would ask — the 3-5 hard questions a reviewer in this domain would raise (edge cases, scale, failure modes, migration), each answered honestly, including "not handled, here's why that's acceptable for now."
Deviations from plan — lifted straight from implementation-notes, because surprises found in review cost trust.
What's NOT in this change — scope fences, so the review doesn't sprawl.
Keep it one page. Link out to the spec, notes, and diff rather than inlining them.
Match the medium to the venue: a Slack-pasteable doc, a PR description, or a standalone HTML page — ask which if unclear.
Guardrails
Never oversell: a pitch that hides a known weakness converts one approval into a permanent credibility loss.
The "what an expert would ask" section is the heart. If it's easy to write, the questions aren't hard enough.