Step 1: Parse arguments

Extend an existing PRD with new requirements.

Step 1: Parse arguments

$ARGUMENTS contains: <prd-file> <requirement-description>

The first argument is the PRD file path (e.g., .plans/prd-user-auth.md). Everything after the first space-separated path is the requirement description.

Read the PRD file. If it doesn't exist, report the error and stop.

Extract the feature name from the filename: prd-<feature>.md -> <feature>.

Step 2: Read context

• Read AGENTS.md if it exists (for project conventions)
• Read .plans/tasks-<feature>.yml if it exists (to understand existing task structure)
• Read .plans/progress-<feature>.txt if it exists (to understand what's been done)

Step 3: Process references

If the requirement description contains file paths (e.g., ./docs/spec.md):

• Read those files and use as context

If the requirement description contains URLs (e.g., https://docs.stripe.com/api):

• Fetch those URLs and use as context

If references fail to load, ask the user about their intended content.

Step 4: Ask clarifying questions

Ask up to 3 clarifying questions about the new requirement, one at a time. Focus on:

• Scope of the new requirement relative to existing PRD
• Integration with existing requirements
• Edge cases specific to the addition

If the user says "done", stop asking and proceed.

Step 5: Update the PRD

Read the existing PRD and update it:

1. Requirements section: Add new requirements with sequential IDs

   • Find the highest existing REQ-F-XXX and REQ-NF-XXX numbers
   • Assign new IDs continuing from the highest number
   • Add under the appropriate subsection (Functional or Non-Functional)

2. Other sections: Update as needed:

   • Goals: Add new goals if the requirement introduces them
   • Technical Considerations: Add new technical concerns
   • Acceptance Criteria: Add new acceptance criteria
   • Open Questions: Add any unresolved questions

3. Write the updated PRD back to the same file.

Step 6: Update or create tasks

If .plans/tasks-<feature>.yml exists:

• Read it and find the highest existing task ID number
• Generate new tasks for the new requirements only
• New task IDs continue from the highest existing (e.g., if task-005 exists, new tasks start at task-006)
• Append new tasks to the existing tasks array
• Update updated_at timestamp
• Write the updated file

If no task file exists, tell the user:

PRD updated. Generate tasks with:
/hone:prd-to-tasks .plans/prd-<feature>.md

Step 7: Report results

Updated .plans/prd-<feature>.md with new requirements
Added <N> new requirements (REQ-F-XXX through REQ-F-YYY)

If tasks were updated:

Added <N> new tasks (task-XXX through task-YYY) to .plans/tasks-<feature>.yml