[dgesteves]

Roadmap item: X2-22-signoff-ui (support tiers and a 4-week integration freeze, the signoff-ui part).

What was wrong

The docs had the "Works with" matrix (tested in CI vs. should work, #167), but nothing said what the two columns mean for support: what a break in each gets, or where something the docs name but the matrix leaves out (Pydantic AI in ag-ui.md, a real ACP agent) stands. CONTRIBUTING.md had no rule on new integrations, while chat kits, protocol adapters and agent SDKs (assistant-ui #57, ACP #59) are the surface that grows fastest and that one maintainer has to keep working.

What changed

• examples/playground/content/docs/limits.md: a Support tiers section, before "What's next". It does not add a second table: it links Works with and maps its columns to the tiers.
  • Tier 1: tested in CI. Names the nine ci.yml jobs that run on every pull request, by the names the checks show (Lint, typecheck, test, build; AI SDK 6; React 18; Next.js quickstart; assistant-ui binding; CopilotKit example; Coding agent reference app; WebKit; Firefox). A break there is a bug and comes first.
  • Tier 2: documented, not verified. The untested column (AI Elements, Mastra, Cloudflare Agents, Vercel Eve, LangGraph, Next.js 14 and 15, ...), plus anything the docs name that the matrix doesn't list, such as Pydantic AI, and each real ACP agent, since CI runs the ACP adapter on scripted turns. Fixed as time allows; an entry moves to Tier 1 once a CI job runs it.
  • The intro line now says the page also covers what is tested.
• CONTRIBUTING.md: a New integrations section. Until Thursday 2026-11-19, four weeks after the 2026-10-22 launch, no new chat kit, protocol adapter or agent SDK (package entry, registry item, example or docs page), unless someone who needs it asks in an issue. It says how to ask (the feature request form, with what you're building and what it runs on), what happens after the four weeks, and links the tiers. It gives no date, so it reads correctly before and after the launch.
• packages/signoff-ui/test/support-tiers.test.ts (new): checks that the tiers section exists, links the matrix and calls its columns by their real headers, adds no table of its own, and that the Tier 1 job list equals the set of ci.yml jobs whose if runs them on pull requests (so a job added or renamed fails the test). It also checks that each Tier 2 name is in the matrix's untested column and not the tested one, and that the CONTRIBUTING section names the three kinds, links the feature request form (whose description mentions integrations) and /docs/limits#support-tiers, and has no year or month in it.

No changeset: docs and a test only.

How it was tested

• On main (doc changes stashed), pnpm exec vitest run test/support-tiers.test.ts: 8 failed of 8. With this branch: 8 passed.
• pnpm install --frozen-lockfile --prefer-offline, pnpm format:check, pnpm lint, pnpm lint:registry, pnpm build:lib, pnpm size, pnpm typecheck: all pass.
• pnpm test: 85 files, 1486 tests passed.
• pnpm test:site: 82 passed, 0 failed.
• No registry items touched, so no pnpm registry:check.

Follow-ups (outside this PR's files)

• The Works with matrix (getting-started.md and the README, owned by other PRs this wave) has no "last checked" date. Tier 1 needs none, since CI runs it on every pull request, but a Tier 2 entry checked by hand could carry one.
• The matrix's "AG-UI framework" row lists LangGraph, CrewAI and Mastra, but ag-ui.md also names Pydantic AI. And no row covers ACP agents: the ACP adapter is tested on scripted turns, and acp.md describes Claude Code's ExitPlanMode options. The tiers text covers both as Tier 2 for now; the matrix could list them.
• The README's Works with section could link the tiers too.
• The limits page's description in examples/playground/lib/docs.ts doesn't mention the tiers.