Transport: Streamable HTTP with JSON responses

Relay MCP exposes read-only financial data through one public endpoint over Streamable HTTP. The server is stateless, so every request must be complete and carry its own headers. There are no server-side sessions, no Server-Sent Events, and no stream resumability.

Transport properties

Property	Value
Endpoint	`https://mcp.relayfi.com/mcp`
Public paths	`/mcp` and `/.well-known` only
Supported method	`POST /mcp`
Response format	JSON only
Capabilities	`tools` only
Supported JSON-RPC methods	`initialize`, `ping`, `tools/list`, `tools/call`
Sessions	None (stateless)
SSE streaming	Not supported
Resumability	Not supported

Disallowed methods

GET /mcp and DELETE /mcp return HTTP 405 Method Not Allowed with an Allow: POST header and this JSON-RPC error body:

{
  "jsonrpc": "2.0",
  "id": null,
  "error": {
    "code": -32000,
    "message": "Method not allowed."
  }
}

Stateless requests

The server retains nothing between requests. Even after a successful initialize, the negotiated parameters are not remembered. Every request must include its own Authorization header and full JSON-RPC envelope.

Common tool arguments

Every tool shares a small set of arguments:

Argument	Applies to	Description
`intent`	Every tool (required)	1 to 500 characters describing what the user asked for and why this call serves it.
`organizationId`	Every tool except `list_organizations` (required)	Stable organization ID from `list_organizations`. Never pass an organization name.
`cursor`	List tools (optional)	Opaque cursor from the previous page. See Pagination.
`pageSize`	List tools (optional)	Results per page, 1 to 100. Defaults to 50.

Writing a good `intent`

Describe the user’s request and how this specific call serves it, for example "User asked how much we spent on software in July; listing card debits for July." Calls without a valid intent are rejected, and the server’s initialize instructions remind agents to always supply it. Relay records intent with each tool call for auditing. Keep it short and factual, and never include credentials, full account or card numbers, or other sensitive personal data.

Example: tools/list

tools/list returns only the tools your token’s scopes allow. See Scopes and tool access.

Request

{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "tools/list"
}

Response

{
  "jsonrpc": "2.0",
  "id": 1,
  "result": {
    "tools": [
      {
        "name": "list_organizations",
        "description": "List organizations the token can access",
        "inputSchema": { ... },
        "outputSchema": { ... }
      }
    ]
  }
}

Example: tools/call

Request

{
  "jsonrpc": "2.0",
  "id": 2,
  "method": "tools/call",
  "params": {
    "name": "list_organizations",
    "arguments": {
      "intent": "User asked for their recent transactions; resolving which organization to query."
    }
  }
}

Response

{
  "jsonrpc": "2.0",
  "id": 2,
  "result": {
    "content": [
      {
        "type": "text",
        "text": "{\"object\":\"organization\",\"id\":\"org_1\",\"name\":\"Acme Inc\"}"
      }
    ],
    "structuredContent": {
      "object": "organization",
      "id": "org_1",
      "name": "Acme Inc"
    }
  }
}

Authentication

Learn how to obtain and send audience-bound OAuth tokens.

Result conventions

Understand dual-channel results, pagination, and money.

Get Started

Concepts

Transport: Streamable HTTP with JSON responses

Transport properties

Disallowed methods

Stateless requests

Common tool arguments

Writing a good `intent`

Example: tools/list

Example: tools/call

Authentication

Result conventions

​Transport properties

​Disallowed methods

​Stateless requests

​Common tool arguments

​Writing a good intent

​Example: tools/list

​Example: tools/call

Authentication

Result conventions

Transport properties

Disallowed methods

Stateless requests

Common tool arguments

Writing a good `intent`

Example: tools/list

Example: tools/call