Cloudflare Setup

This page covers only Cloudflare setup for a deployed relay. Local development commands live in the root and package README.md files. The hostnames and account-specific names below describe the project deployment; substitute the custom domains, Access team domain, policies, and account names chosen for another deployment.

Follow Get Started for the surrounding repository, bridge, and ChatGPT configuration steps.

Services

Mikoto uses these Cloudflare services:

• Workers for the relay Worker.
• Durable Objects for bridge/session coordination.
• Workers Custom Domains for production hostnames. In Wrangler config these are represented as routes entries with custom_domain: true.
• Cloudflare Access self-hosted applications, policies, and Managed OAuth.
• Cloudflare One Client in WARP mode for local computers that may connect to bridge-only endpoints.

Cloudflare Workers Builds are not used. Deployments are performed by GitHub Actions through Wrangler.

Hostnames

Production hostnames are configured as Wrangler custom-domain routes:

• mikoto.takuk.me: docs Worker.
• mcp.mikoto.takuk.me: relay Worker for ChatGPT-facing MCP traffic.
• bridge.mikoto.takuk.me: same relay Worker for local bridge and health traffic.

The relay production workers.dev route is disabled. The relay uses one Worker served through two custom domains so Cloudflare Access can keep ChatGPT Managed OAuth separate from WARP-restricted bridge authentication.

Access Applications

Create Cloudflare Access protection for the relay hostnames before using a deployed relay for real traffic.

The relay needs two different Access protections because the ChatGPT-facing MCP endpoint and the local bridge endpoint have different callers.

Use separate hostnames for the two protections. Sharing one hostname and only splitting by path couples applications with different callers, policies, and authentication flows. Separate hostnames preserve that security boundary, but do not work around the WARP-connected Managed OAuth limitation described below.

MCP Endpoint

Create a Cloudflare Access MCP server application for the ChatGPT-facing Streamable HTTP endpoint.

• Cloudflare service: Zero Trust Access AI controls MCP servers.
• Access application name: mikoto mcp.
• MCP server ID: mikoto.
• HTTP URL: https://mcp.mikoto.takuk.me/.
• Authentication: enable Managed OAuth for the MCP server application.
• Managed OAuth Dynamic Client Registration allowed redirect URIs:
  • https://chatgpt.com/connector/oauth/*
• Access policy: allow only the Cloudflare Access users or groups that may add the MCP server to ChatGPT. The current Cloudflare account uses the reusable mikoto mcp users policy, which allows risunosu.com email addresses and does not require Gateway/WARP.
• Application AUD tag: record the generated value for troubleshooting.

Use a hostname dedicated to the MCP server and serve the MCP endpoint at the hostname root. Cloudflare Access one-time-code verification URLs carry the target hostname but not the MCP path, so path-scoped MCP applications can fail after email submission with Unable to find your Access application!.

Do not require Cloudflare One Client, WARP, or Gateway for this application. After OAuth completes, ChatGPT is the caller of the MCP endpoint and cannot satisfy a local device/WARP policy.

The ChatGPT redirect URI wildcard is required for OpenAI’s ChatGPT Apps OAuth flow. When a user connects the custom app, ChatGPT dynamically registers an OAuth client with Cloudflare Access and supplies a callback URL under https://chatgpt.com/connector/oauth/. Cloudflare rejects the registration with invalid_client_metadata unless that callback is allowed in Managed OAuth’s Dynamic Client Registration settings.

ChatGPT App Setup

After the Cloudflare MCP application is ready, add Mikoto as a custom ChatGPT app:

1. Open ChatGPT.
2. Go to Apps.
3. Select Manage to open Settings > Apps.
4. Scroll to Advanced settings.
5. Select Create app.
6. Fill in:
   • Name: Mikoto
   • Description: Access Mikoto MCP tools through the Cloudflare-protected relay.
   • Connection: Server URL
   • Server URL: https://mcp.mikoto.takuk.me/
   • Authentication: OAuth
7. Open Advanced OAuth settings and confirm that Dynamic Client Registration is available. Cloudflare Managed OAuth should advertise:
   • Authorization URL: https://risu729.cloudflareaccess.com/cdn-cgi/access/oauth/authorization
   • Token URL: https://risu729.cloudflareaccess.com/cdn-cgi/access/oauth/token
   • Registration URL: https://risu729.cloudflareaccess.com/cdn-cgi/access/oauth/registration
   • Resource: https://mcp.mikoto.takuk.me/
8. Check I understand and want to continue.
9. Select Create.
10. Select Sign in with Mikoto and complete the Cloudflare Access login.

If ChatGPT reports Dynamic client registration failed with redirect_uri is not allowed by the account configuration, re-open the mikoto mcp Access application in Cloudflare, go to Advanced settings > Managed OAuth, and verify that https://chatgpt.com/connector/oauth/* is present in Allowed redirect URIs.

If Cloudflare Access reports Unable to find your Access application! after sending the login code, verify that the MCP application uses the hostname root and not a path-scoped URL such as /mcp.

If an existing Cloudflare Protected MCP server record was created with https://mcp.mikoto.takuk.me/mcp, Cloudflare may show the HTTP URL as read-only. In that case, replace the Protected MCP server record with one that uses https://mcp.mikoto.takuk.me/, then reconnect the ChatGPT app using the root server URL.

WARP-Connected OAuth Login

Cloudflare Access Managed OAuth login currently does not work for this deployment when the browser completing the login is connected through Cloudflare One Client in WARP/Gateway mode. Access may classify the authorization as a private-application flow even when:

• the MCP and bridge applications use separate hostnames;
• Authenticate with Cloudflare One Client is disabled for the MCP application (allow_authenticate_via_warp is false);
• the MCP application is served at the hostname root.

After the one-time code is submitted, the verification page then reports Unable to find your Access application!. This behavior is tracked in issue #123.

As a workaround, disconnect WARP before selecting Sign in with Mikoto, complete the Cloudflare Access OAuth login, and then reconnect WARP. The bridge remains WARP-restricted and requires WARP after the OAuth login is complete. Do not permanently exclude the Access team domain, such as risu729.cloudflareaccess.com, with Split Tunnels: Cloudflare One Client also uses that domain for its own authentication and session handling.

Bridge And Health Endpoints

Create a separate Cloudflare Access self-hosted application for the local bridge WebSocket endpoint and health check.

• Cloudflare service: Zero Trust Access Applications.
• Access application name: mikoto bridge.
• Public hostname: bridge.mikoto.takuk.me.
• Protected paths:
  • /bridge*
  • /health*
• Access policy: allow only intended local operators and require the local computer to be connected through Cloudflare One Client in WARP mode. The current Cloudflare account uses the reusable default policy for this, backed by the default rule group that allows risunosu.com email addresses and requires Gateway/WARP.
• Managed OAuth: leave disabled for this application. The bridge is not an MCP OAuth client.

Keep bridge traffic on bridge.mikoto.takuk.me, separate from the ChatGPT-facing mcp.mikoto.takuk.me hostname. ChatGPT should authenticate to https://mcp.mikoto.takuk.me/ through Access Managed OAuth, while bridge connections should use wss://bridge.mikoto.takuk.me/bridge and be limited to trusted local computers.

Each hostname is DNS-public when the Worker route exists. Until both Access applications and policies exist, treat deployed relay paths as internet-reachable.

Official References

• Secure MCP servers with Cloudflare Access
• Managed OAuth for self-hosted applications
• OpenAI Apps SDK authentication
• Access policies
• Access application tokens

GitHub Actions Inputs

GitHub Actions needs:

• Repository variable CLOUDFLARE_ACCOUNT_ID.
• Repository secret CLOUDFLARE_API_TOKEN.

Minimum Cloudflare API token permissions for the current docs and relay deployments:

• Account risu: Workers Scripts: Edit.
• Zone takuk.me: Workers Routes: Read.

Wrangler reads the zone’s Worker routes before publishing each configured route to detect assignments to another Worker. That preflight requires Workers Routes: Read even though the current routes are Workers Custom Domains (custom_domain: true). Custom Domains create their own DNS records and certificates, so they do not require DNS: Edit.

If an ordinary route is added later, replace Workers Routes: Read with Workers Routes: Edit for its zone. Such a route also needs a separately configured proxied DNS record; grant DNS: Edit only if the workflow will create or change that record. Account Settings: Read and User Details: Read are not required for deployment.

The relay Worker does not currently require runtime Worker secrets or GitHub environment variables beyond CLOUDFLARE_ACCOUNT_ID.

Do not store Cloudflare API tokens in repository files or local config.