Refine Product Requirement Document

Update it_{current_iteration}_product-requirement-document.md in place based on user feedback. The file must already exist; this skill does not create it from scratch.

Do NOT start implementing. Only update the document.

Two modes available — the agent asks at the start:

• Editor mode — apply specific changes requested by the user.
• Challenger mode — act as an independent critical reviewer: challenge assumptions, question scope, find gaps, and propose improvements. The user accepts or rejects each suggestion before anything is written.

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The Job

1. Check if .agents/state.json exists. If it does, read it to obtain requirement_definition.file (e.g. it_000001_product-requirement-document.md). If it does not exist, ask the user to provide the required information:
   • A. Enter the path to the existing PRD file (e.g. it_000037_product-requirement-document.md)
2. Read the current document from .agents/flow/{file}.
3. Open by asking: "Would you like me to challenge the existing document as an independent reviewer, or would you prefer to tell me what to change?"
   • Answer → challenge: run Challenger Mode (see below).
   • Answer → edit: run Editor Mode (see Questions Flow).
4. Apply changes to the document following the same Output Structure as define-requirement.
5. Re-enforce MVP constraint: remove any user stories not explicitly listed by the user; do not add new ones without confirmation.
6. Write the updated file back to the same path.
7. Do not update state.json — requirement_definition.status stays "in_progress".

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Challenger Mode

Act as a second agent reviewing the document with fresh eyes. Do not apply any change without explicit user approval.

Challenge areas — examine each (in order):

1. Assumptions — List implicit assumptions in the goals or stories. Ask: are these validated? what if they are wrong?
2. Scope creep — Flag any user story that is not strictly MVP-necessary. Propose removal and ask for confirmation.
3. Vague acceptance criteria — Highlight criteria that are not concretely verifiable. Suggest a specific rewrite.
4. Missing non-goals — Identify things the document is silent on that could be misread as in-scope. Propose additions to Non-Goals.
5. Missing edge cases — Point out failure paths or user states not covered by any acceptance criterion.
6. Conflicting requirements — Flag any FR-N that contradicts another or contradicts an acceptance criterion.

Challenger output format — one observation at a time:

CRITICAL: Present findings one at a time. After delivering one finding, stop and wait for the user to respond before moving on. Do not queue or batch findings.

For each finding, format it as:

Challenge [N/total]: <area name>

Finding: <what the issue is>
Suggestion: <proposed change>

Accept / Reject / Discuss?

• After the user responds, acknowledge their decision and immediately present the next finding.
• If the user types Discuss, engage in a short back-and-forth until they give a final Accept or Reject, then move on.
• Once all findings have been reviewed, summarise the accepted changes and apply them to the file in a single write.
• Do not write anything to the file until all findings have received a response.

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Editor Mode (Questions Flow)

Ask only what is needed to understand the requested change.

1. What would you like to change or add?
   A. Replace or rewrite a user story
   B. Add a new user story (must be MVP-justified)
   C. Remove a user story
   D. Tighten acceptance criteria
   E. Update goals or non-goals
   F. Other: [describe]

2. If adding a user story — is it strictly necessary for the MVP?
   [Open answer — skip if not adding stories]

3. Anything else to update in this pass?
   [Open answer — skip if none]

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Refinement Rules

• MVP constraint holds: do not add user stories unless the user explicitly requests them and confirms they are MVP-necessary.
• Preserve numbering: renumber US-NNN and FR-N entries only if a story is removed; otherwise keep existing IDs stable.
• Verifiable criteria: any new or edited acceptance criterion must be concrete and testable (same standard as define-requirement).
• UI stories: if a new or edited story touches the UI, "visually verified in browser" must be an acceptance criterion.

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Checklist

Before saving:

• User's requested changes applied
• No new user stories added without explicit MVP justification
• All acceptance criteria remain verifiable
• US-NNN and FR-N numbering is consistent
• File written back to .agents/flow/it_{current_iteration}_product-requirement-document.md
• state.json not modified (status stays "in_progress")