PlateSpinner: CTA-aware domain signal rendering (notification events + action buttons + correlation lifecycle)

[PolyphonyRequiem]

Context (revised 2026-05-28 — scope refinement)

Polyphony workflows are moving from blocking \human_gate\ nodes to a gate compression pattern: \ ype: notification\ + \script:\ poll-loop. The workflow fires a domain signal ('PR #N ready for review'), the user gets a toast, does the thing, and the workflow's poll script detects the resolution. PlateSpinner is the user-facing surface.

What PlateSpinner needs

P0 — Event parsing + CTA rendering

1. Parse \ ype: notification\ events from .events.jsonl. Extract the polyphony domain signal envelope (kind, severity, cta_url, cta_kind, correlation_id, expires_at, subject, work_item_id).
2. Render CTA buttons based on \cta_kind\ → button label/icon mapping. Clicking opens \cta_url\ in the default browser.
3. Severity-gated toast routing: \�ction_required\ → toast + badge + card. \warning\ → badge + inline. \info\ → inline only.

P1 — Correlation-based lifecycle

4. Auto-dismiss on resolution: When a signal with matching \correlation_id\ and severity \info\ arrives, clear/resolve the earlier \�ction_required\ card. Decrement tray badge.
5. Expiry enforcement: Clear signals whose \�xpires_at\ has passed. Prevent stale toasts.
6. Dedup: Same \correlation_id\ doesn't re-fire a toast (e.g., during poll retries).

P2 — Tray badge

7. 'N waiting on you' badge on the tray icon — count of unresolved \�ction_required\ signals across all active runs.

CTA kind → button mapping (proposed)

\cta_kind\	Button label	Behavior
\
eview_pr\	'Review PR'	Opens PR URL
\merge_pr\	'Merge PR'	Opens PR URL
\�pprove_plan\	'Review Plan'	Opens plan PR URL
\
esolve_conflict\	'Resolve'	Opens conflict artifact
\�iew_evidence\	'Review Evidence'	Opens evidence PR URL

Explicitly out of scope

• Two-way RPC back to conductor (NEVER)
• Hosting polling logic (that's a workflow \script:\ step)
• Replacing conductor dashboard for execution monitoring

Relationship

Part of Epic #521 (self-contained orchestration). Depends on:

• Conductor PR Closed-loop step 2: wire PlanObserver into state next-ready #213 (type: notification) shipping in dogfood fork
• Polyphony ADR \domain-signal-envelope.md\ being approved
• First domain signal prototype (likely in \github-pr.yaml)

Design Reference

.squad/decisions/inbox/bach-on-error-notifications-design-2026-05-28T155810-0700.md\ §2.1–2.4