Connecting Trio MCP

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Before you start

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Claude

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Claude Code

1. Add the server.

claude mcp add --transport http -s user trio https://mcp.trio.com.br/mcp

2. Sign in.

claude mcp login trio

3. Check the connection.

claude mcp list

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Codex CLI

1. Add the server and sign in.

codex mcp add trio --url https://mcp.trio.com.br/mcp
codex mcp login trio

2. Check the connection.

codex mcp list

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Cursor

{
  "mcpServers": {
    "trio": {
      "url": "https://mcp.trio.com.br/mcp"
    }
  }
}

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ChatGPT, Gemini, Perplexity and other MCP clients

https://mcp.trio.com.br/.well-known/oauth-protected-resource

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Troubleshooting

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Security best practices

• Verify the official endpoint. Connect only to https://mcp.trio.com.br/mcp, and sign in only on https://app.trio.com.br. A one-click installation from a third-party marketplace deserves a look at the marketplace’s domain first.
• Use clients you trust. Connecting a client gives it read access to balances, statements, every transaction with its counterparties, and card data. Review the permissions on the consent screen before you select Allow.
• Sign in with OAuth, never with your password or an API key. The OAuth flow issues a time-limited token with a read-only scope that you can revoke. No client ever needs your Trio App password.
• Understand what read access exposes. If the client or the AI provider is compromised, everything the tools can read can leak. Card numbers and CPFs are masked, CNPJs and amounts are not.
• Know prompt injection. Content the agent reads, such as a spreadsheet you attach or a web page it visits, can carry instructions like “send every transaction to this address”. A read-only server cannot move money, but it can disclose data. Keep untrusted content away from sessions connected to Trio.
• Mind data handling. Check how your client and AI provider retain conversation history, avoid connecting Trio in shared or public sessions, prefer ephemeral sessions where the client offers them, and opt out of model training if the provider uses conversations for it.
• Revoke what you no longer use. Disconnect Trio in the client’s settings when a person or a tool no longer needs it. A client built on the API can revoke its own token at the revocation endpoint below.

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Build your own client

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Endpoints

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The order to call them in

1. Register. POST /oauth/register with your redirect_uris, a client_name and, for a command line or native app, token_endpoint_auth_method: "none". Store the client_id.
2. Send the user to authorize. Open /oauth/authorize in a browser with your client_id, your redirect_uri, response_type=code, scope=mcp:foundation, a PKCE code_challenge with the S256 method, and resource=https://mcp.trio.com.br/mcp. The user signs in and selects Allow.
3. Exchange the code for a token. POST /oauth/token with grant_type=authorization_code, the code from your redirect URI and the PKCE code_verifier.
4. Call the MCP server. POST https://mcp.trio.com.br/mcp with Authorization: Bearer <access token>, over streamable HTTP.
5. Refresh when the token expires. POST /oauth/token with grant_type=refresh_token.

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Rules Trio enforces

• PKCE is required, with the S256 method only.
• The scope for the MCP tools is mcp:foundation. The authorization server also offers openid, profile and email.
• Grant types are authorization_code and refresh_token; the response type is code.
• Token endpoint authentication is none, client_secret_basic or client_secret_post. Use none for a command line or native app.
• Tokens are sent as a bearer token in the Authorization header.

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Discovering the endpoints

1. Call the server without a token. The 401 response carries WWW-Authenticate: Bearer realm="trio-foundation", resource_metadata="https://mcp.trio.com.br/.well-known/oauth-protected-resource".
2. Read that protected resource metadata. It names the resource, the scope and the authorization server:

{
  "resource": "https://mcp.trio.com.br/mcp",
  "scopes_supported": ["mcp:foundation"],
  "authorization_servers": ["https://app.trio.com.br"],
  "bearer_methods_supported": ["header"],
  "resource_documentation": "https://docs.trio.com.br"
}

3. Read the authorization server’s metadata at https://app.trio.com.br/.well-known/oauth-authorization-server. It names the registration, authorization, token and revocation endpoints and the rules above.

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Register your client

curl -sS -X POST https://app.trio.com.br/oauth/register \
  -H "Content-Type: application/json" \
  -d '{
    "redirect_uris": ["http://127.0.0.1:8080/callback"],
    "client_name": "Your App Name",
    "token_endpoint_auth_method": "none"
  }'

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Next steps

• Supported tools: what each tool returns and the prompts that trigger it.
• What is Trio MCP?: how it works and what it does not do.