Open Brain web gateway

OAuth-protected remote MCP gateway for Tony's Gemini Spark and Perplexity web clients. It forwards approved calls to the existing vanilla Open Brain and never creates another brain.

Boundaries

• Open Brain is operational memory, not Continuity, COTA, Current-State Tracker, or owner-acceptance authority.

• No automatic chat capture. Capture tools are for explicit requests only.

• The vanilla Open Brain repository and Edge Function remain unchanged.

• Browser clients receive short-lived OAuth tokens, never the long-lived Open Brain access key.

• OAuth tokens are validated and then terminated at this gateway; they are not passed to the upstream Open Brain.

Related MCP server: Brainbase MCP

Components

• open-brain-web-gateway: OAuth-protected Streamable HTTP MCP relay with client/user allowlists, exact and summary aliases, authoritative post-write receipts, and a server-enforced /readonly route that exposes only the seven bounded read tools.

• docs/: GitHub Pages email-link sign-in and OAuth consent UI, plus privacy and terms pages.

• open-brain-oauth-ui: deployable source retained as a fallback for a future custom Supabase domain; the default Supabase Functions domain intentionally rewrites HTML to plain text.

Required live configuration

1. Supabase OAuth 2.1 Server enabled with authorization path /oauth/consent.

2. Auth Site URL: https://derivedbetter.github.io/open-brain-oauth-ui.

3. Authorization path: /oauth/consent/ and redirect allowlist includes https://derivedbetter.github.io/open-brain-oauth-ui/**.

4. Pre-registered confidential clients for Gemini full access, Gemini Spark read-only access, Perplexity, and Claude.

5. Edge secrets:

   • OPEN_BRAIN_ALLOWED_EMAILS=<approved-email>

   • OPEN_BRAIN_OAUTH_CLIENT_IDS=<full-gemini-client-id>,<perplexity-client-id>,<claude-client-id>

   • OPEN_BRAIN_READ_ONLY_OAUTH_CLIENT_IDS=<read-only-gemini-client-id>

   • optional OPEN_BRAIN_OAUTH_AUDIENCES=authenticated,<gateway-url>

   • existing MCP_ACCESS_KEY remains server-side.

Dynamic client registration stays disabled for the pilot.

Validation

npm test
npx -y supabase@latest functions deploy open-brain-oauth-ui --project-ref zoptbgumxukgpkgbtnpz --no-verify-jwt
npx -y supabase@latest functions deploy open-brain-web-gateway --project-ref zoptbgumxukgpkgbtnpz --no-verify-jwt

Test discovery and unauthenticated failure before connecting a client:

• GET /functions/v1/open-brain-web-gateway/.well-known/oauth-protected-resource returns protected-resource metadata.

• GET /functions/v1/open-brain-web-gateway/readonly/.well-known/oauth-protected-resource returns distinct read-only protected-resource metadata.

• unauthenticated POST /functions/v1/open-brain-web-gateway returns 401 and an OAuth WWW-Authenticate challenge.

• authenticated tools/list on /functions/v1/open-brain-web-gateway/readonly omits every write/delete tool, and direct write calls fail closed.

• OAuth clients are endpoint-scoped: read-only client tokens are rejected by the full-access route, and full-access client tokens are rejected by the read-only route.

• invalid user, client, issuer, audience, and expired tokens fail closed without an upstream call.

Rollback

Revoke the affected OAuth client, disable the connector in Gemini or Perplexity, disable Supabase OAuth Server if no clients remain, and delete only the two gateway Edge Functions. Existing Open Brain data and the ChatGPT, Codex, and agy integrations remain unchanged.