Propagate a Design Change

A PRD edit invalidates downstream work in proportion to how many artifacts referenced it. This skill enumerates that impact in one pass so nothing slips through.

Read-only — no file edits. The user runs follow-up skills (/architecture-decision, /design-system retrofit, /sprint-plan) to apply changes.

Purpose / When to Run

Run when:

• A PRD has just been edited (any section)
• A configurable value, formula, or interface in a PRD has changed
• A new edge case or acceptance criterion was added
• The user wants to know "if I change X, what breaks?"

Inputs

• Path to the changed PRD (required)
• Optional: a description of what changed (free text); skill is more accurate with this hint
• All ADRs in docs/architecture/
• docs/architecture/tr-registry.yaml if present
• All stories in production/epics/
• All other PRDs

Outputs

• A printed change-impact report

Phase 1: Identify the Change

If the user did not describe what changed, ask:

• Prompt: "What changed in this PRD?"
• Options:
  • New requirement added
  • Existing requirement modified
  • Configurable value changed (default or range)
  • Edge case added or modified
  • Acceptance criterion changed
  • Interface to another system changed (data shape / event)
  • Dependency added / removed
  • I don't know — scan and find out

If user picks "I don't know" or "interface changed", skip to Phase 2 and rely on full scan.

Phase 2: Identify Anchors

Build the list of "anchors" in the changed PRD that downstream work might reference:

• Every TR-ID in the PRD (TR-<system>-NNN)
• Every configurable value name (Section 6)
• Every interface / event / endpoint name (Section 3 / 5)
• The PRD's filename itself (some artifacts cite the path)
• Each entity name from the registry that this PRD owns (source: <this-prd>)

These anchors are the things downstream artifacts could cite.

Phase 3: Scan for Downstream References

For each anchor, grep the project:

• docs/architecture/ADR-*.md
• docs/architecture/tr-registry.yaml
• production/epics/*/EPIC.md
• production/epics/*/story-*.md
• Other design/prd/*.md
• design/ux/*.md
• tests/ (test names that reference TR-IDs)

Record every hit: file path + the anchor that matched.

Phase 4: Classify Impact

For each downstream artifact that has a hit, classify:

• STALE — REVIEW REQUIRED — the artifact references something whose definition just changed; must be re-read to confirm it still aligns.
• POTENTIALLY STALE — the artifact references the PRD generally but not a specific changed anchor; may not be affected.
• BLOCKED — for stories: a story Status: In Progress that references a changed TR-ID. Halt that work until the change is reconciled.

ADR-specific:

• Status Accepted and references a changed anchor → may need to be updated or superseded (/architecture-decision retrofit ...)
• Status Proposed and references a changed anchor → revise before accepting

Story-specific:

• Status Ready and references a changed TR-ID → re-read the story; may need to update Acceptance Criteria
• Status In Progress → BLOCKED — surface to the engineer immediately
• Status Complete → check if test evidence still passes against the new criteria; if not, file a regression task

PRD-specific (cross-PRD):

• Another PRD references a configurable value whose default just changed → that PRD's expectations may be wrong
• Another PRD references an interface whose shape just changed → must update

Phase 5: Produce the Impact Report

# Change Impact: <prd-path>

## What changed
<summary from Phase 1, or "scanned without explicit summary">

## Downstream impact

### ADRs (<N total, M stale)
- ADR-NNNN: <title> — Status: <Accepted | Proposed>
  References: TR-foo-001
  Action: re-read; if decision still valid, no change. If interface details have shifted, run `/architecture-decision retrofit docs/architecture/<adr>.md`.

### Stories (<N total, M stale, K blocked)
- production/epics/<epic>/story-NNN-<slug>.md — Status: <X>
  References: TR-foo-001 (changed), TR-foo-003 (unchanged)
  Action: <re-read | block | update acceptance criteria>

### Other PRDs (<N total, M stale)
- design/prd/<other>.md — references configurable `paywall_trigger_count` (default changed)
  Action: confirm the dependent PRD's expectations still hold.

### UX specs
- <list>

### Tests (regression risk)
- tests/integration/<...>_test.<ext> — Status: <pass | unknown>
  Action: re-run after changes propagate; failing tests indicate the change broke a verified behavior.

## Summary
- ADRs to revise: <N>
- Stories blocked: <N>
- Stories to re-validate: <N>
- PRDs to re-check: <N>

Phase 6: Walk Through Resolution

Use AskUserQuestion:

• Prompt: "Want to walk through these one by one?"
• Options:
  • Yes — start with the blocked stories
  • Yes — start with the stale ADRs
  • No — I'll handle them on my own

If yes: for each artifact in the chosen list, present:

• The file path
• The specific anchor reference
• The relevant section of the changed PRD
• A recommendation:
  • For stories: re-read; suggest acceptance criteria diff
  • For ADRs: suggest /architecture-decision retrofit ... or a supersession
  • For other PRDs: suggest /design-system retrofit ...
  • For tests: suggest re-running before merging

After each, capture user's intent (free text) — "skip", "fix later", "fix now". Tally these for a summary at the end.

Phase 7: Closing Summary

Print:

## Resolution log
- Acknowledged: <N>
- Action items captured: <N>
- Skipped: <N>

## Recommended sequence
1. Unblock in-progress stories first (talk to the engineer, update the story)
2. Update or supersede affected Accepted ADRs
3. Refresh other PRDs whose interface assumptions shifted
4. Re-run `/architecture-review` once stale ADRs are reconciled
5. Re-run `/consistency-check` once registry-affecting changes are pushed back to the registry

Edge Cases

• No downstream references found: print "No downstream artifacts reference this PRD's anchors. Change is isolated." Useful confirmation.
• The change involved deleting a TR-ID: surface this loudly — any artifact citing it has lost its anchor and should be rewritten or deleted.
• PRD path is ambiguous: ask which one.

Quality Gates

• Every downstream reference is named with file path + anchor
• Every CRITICAL / BLOCKED state surfaces an immediate action
• The skill never edits files itself
• The skill never silently deletes references — only reports

Examples

User edited design/prd/auth.md, changing the rate limit from 5 to 3 per minute.

• 2 ADRs reference the rate limit
• 1 story In Progress references it (BLOCKED — engineer needs the new value)
• 3 other PRDs reference the auth rate limit indirectly
• Tests in tests/integration/auth/ need to update their expected value
• Report walks through each, recommends /architecture-decision retrofit for ADR-0007, story update for the in-progress one