Fly.io

Fly.io hosts the MCP server. You'll create an account, install the CLI, create an app, and set the runtime secrets it needs.

Install the CLI

1. Install flyctl: brew install flyctl (or see fly.io/docs/flyctl/install for other methods)
2. Log in: fly auth login

Create an app

1. Run fly apps create and choose a name (e.g. protocol-mcp) and region
2. Note the app name - you'll use it for secrets and GitHub Actions

Set runtime secrets

The MCP server reads environment variables at runtime. Set them on your Fly app:

fly secrets set \
  DATABASE_URL='your_db_url' \
  GOOGLE_CLIENT_ID='your_google_client_id' \
  GOOGLE_CLIENT_SECRET='your_google_client_secret' \
  MCP_SERVER_URL='https://<your-app-name>.fly.dev' \
  --app <your-app-name>

Machine configuration

fly.toml is pre-configured with min_machines_running = 1 and auto_stop_machines = 'suspend'. This keeps one machine always running so there are no cold starts - the Anthropic MCP proxy has a short connection timeout, and a suspended machine takes 5–8 seconds to wake up, causing 502 errors before the server is ready.

With a single shared-1x-512mb machine running 24/7, expect roughly $3-4/month. Use the Fly.io pricing calculator to estimate cost for your region and machine size.

Fly.io waives monthly bills under $5, so this setup is effectively free.

Create a deploy token

Generate a token for GitHub Actions to deploy on your behalf:

fly tokens create deploy --app <your-app-name>

Save this token - you'll add it as a GitHub Actions secret in the next section.

Update Google OAuth URIs

After creating the app, go back to your Google Cloud OAuth client and update (if needed):

• Authorized JavaScript origins: https://<your-app-name>.fly.dev
• Authorized redirect URIs: https://<your-app-name>.fly.dev/auth/callback

Keep localhost values too if you want to test it locally.

Outputs

After completing this step you should have the next values:

Key	Value	Where to get it	Purpose
FLY_API_TOKEN	Fly.io deploy token	fly tokens create deploy --app <your-app-name>	Github secret
FLY_APP_NAME	Fly.io app name	Chosen during fly apps create	Github secret