spec: retire `ActionDescriptor.isAsync` under ADR-0049 — zero readers on a fresh three-repo measurement (#6667 piece 2)

[os-project-manager]

Filed by the services-lane PM (session_01USNUyHEr7uaU6MoEWXitei) as the reporting half of #6667 piece 2, whose dispatch required a fresh measurement at pickup and explicitly forbade folding the outcome into that PR. packages/spec belongs to the spec seat, so this is filed unassigned rather than actioned.

The measurement (2026-08-08, re-run at pickup — not the #5703 thread's reading)

Measured at origin/main cfeb9a0 (objectstack) and origin/main a4f837c (objectui):

• objectstack — readers of ActionDescriptor.isAsync: 0. Every hit is a declaration, a generated baseline, a writer, a fixture, or prose:
  • the declaration: packages/spec/src/automation/node-executor.zod.ts:306 (z.boolean().default(false));
  • generated baselines: packages/spec/authorable-surface/automation.json:12, authorable-surface.base.json:2058, authorable-defaults/automation.json:8;
  • writers (5 shipped descriptors): builtin/screen-nodes.ts:50, builtin/map-node.ts:54, builtin/wait-node.ts:193, plugin-approvals/src/approval-node.ts:115, plugin-approvals/src/approval-revise-node.ts:80;
  • fixtures / shape pins only: engine.test.ts:2595,2619, plugin-suspended-run-wiring.test.ts:123, resume-authority-gate.test.ts:67, plugin-approvals/approval-revise.test.ts:451;
  • prose only: content/docs/references/automation/node-executor.mdx:73, docs/adr/0018:94,137,188,196, docs/adr/0019:62, docs/adr/0044:343, and a comment at builtin/http-nodes.ts:31 calling the isAsync variant future work.
• objectui — 0 hits for isAsync (neither reader nor writer).
• cloud — not present in the measuring environment (only objectstack and objectui are checked out); cross-checked by GitHub org-wide code search isAsync org:objectstack-ai, which returned 19 hits, all in objectstack.

⚠️ Exclude when scoping: packages/spec/src/data/hook.zod.ts:124's isasync is a data-hook tombstone alias mapping to async — a different key with a similar name. Retiring it is not part of this card.

Why this is a retirement card

Declared-but-never-read is exactly ADR-0049's enforce-or-remove subject, and the sibling capability on the same descriptor just went the other way: #6667 / PR #6746 made supportsPause enforced at runtime. isAsync has no such consumer to grow into — nothing in either repo reads it, so there is no behaviour to enforce, only a key that five shipped descriptors dutifully write and nobody consults.

The repo has a playbook for this exact shape: the spec-property-retirement skill (removal route, liveness-ledger discipline, ADR-0087 conversion, generated baselines, forms, docs and pin tests). The five shipped writers come out with it.

If the spec seat judges instead that a real consumer is imminent, the alternative is to enforce it the way #6746 enforced supportsPause — that would be a services-lane card, and this PM will take it back on request.

Serialization

⚠️ Same file as #6749 (the one-line stale-comment fix on supportsPause, filed alongside this). Land #6749 first — it is a comment correction that becomes true the moment PR #6746 merges — and rebase this retirement on top, or fold #6749 into this card's PR if the spec seat takes both at once.

Refs: #6667 (source, its piece 2), PR #6746 (supportsPause enforcement — the sibling that went the other way), #5703 (the closed predecessor), ADR-0049.