Saxon Fletcher b04e26872b feat(ui-library): add MCP server block (#49573) ...

## I have read the
[CONTRIBUTING.md](https://github.com/supabase/supabase/blob/master/CONTRIBUTING.md)
file.

YES

## What kind of change does this PR introduce?

Feature — a new UI Library block. Bottom of a two-PR stack; #49579
builds on it.

## What is the new behavior?

Adds an `mcp-server` block: a Supabase Edge Function that exposes MCP
tools scoped to the signed-in user. It is backend-only, so every file
has an explicit target and no `components.json` is needed.

- `withSupabase({ auth: 'user' })` verifies the access token and gives
each tool an RLS-scoped client. Both product session tokens and OAuth
tokens work; only the latter carry `client_id`.
- `withOAuthProtectedResource` serves RFC 9728 metadata and adds a
`WWW-Authenticate` challenge to `401`s, so external MCP clients can
discover the authorization server.
- Tools are composed in `tools/index.ts`. One is included, `whoami`,
which shows the caller's identity and OAuth client.

Docs at `/library/docs/headless/mcp-server`, under a new MCP group in
the sidebar. `BlockItem` gained a `showOpenInV0` flag (v0 cannot take
Deno functions), and the file-tree viewer now picks a language per file
instead of always TypeScript.

## To test

1. `npx shadcn@latest add
http://localhost:3004/library/r/mcp-server.json` into a Supabase project
or empty directory.
2. Add `[functions.mcp-server] verify_jwt = false` to
`supabase/config.toml`, then:
   ```bash
   supabase start
supabase functions serve mcp-server --env-file supabase/functions/.env
   ```
3. **Unauthenticated:** `curl -i
localhost:54321/functions/v1/mcp-server` returns `401` with a
`WWW-Authenticate` header, and
`/functions/v1/mcp-server/oauth-protected-resource` returns the metadata
document.
4. **Product session:** sign up a user, then call the endpoint with
`Authorization: Bearer <their access token>`. `tools/list` shows
`whoami`; calling it returns that user's id and `client_id: null`.
5. **External client:** enable `[auth.oauth_server]` with
`allow_dynamic_registration = true`, install the OAuth Consent block,
point an MCP client (Claude Code, Codex) at the function URL, approve
the consent screen, and call `whoami` again. `client_id` is now
populated.
6. Confirm RLS holds: add a table with a user-scoped policy and a tool
that reads it, then check a second user cannot see the first user's
rows.
7. Docs page renders at `/library/docs/headless/mcp-server`, and
`deno.json` / `.env.example` in the folder tree highlight as JSON and
bash rather than TypeScript.

<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
## Summary by CodeRabbit

- **New Features**
- Added an installable Supabase MCP Server block with user-scoped
authentication and a read-only identity tool.
  - Added MCP Blocks to documentation navigation and setup guidance.
- Code blocks now automatically detect syntax highlighting from file
names.
  - Added an option to hide the “Open in v0” button.

- **Documentation**
- Expanded MCP Server guidance covering installation, configuration,
validation, deployment, OAuth, and security.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

---------

Co-authored-by: Cursor Agent <cursoragent@cursor.com>
Co-authored-by: Saxon Fletcher <SaxonF@users.noreply.github.com>

2026-09-02 14:53:38 +10:00

..

docs

feat(ui-library): add MCP server block (#49573)

2026-09-02 14:53:38 +10:00