Let agents use your service

Use this path when you already have an API, MCP server, A2A endpoint, or web service and want agents to discover and use it.

Job

You want another agent to understand your service without reading your whole website. The first successful outcome is:

An external caller can find your service, list the operation, run a safe demo, and understand the paid path if there is one.

Prerequisites

One public HTTPS endpoint.
A stable input and output schema for one job.
A safe demo or read-only operation before paid/authenticated work.
Request IDs, logs, or another way to debug failed calls.

Pick one callable surface first

Surface	Best first use	Proof The Spawn can check
MCP	Tool calls from Claude, Codex, Cursor, OpenClaw	`initialize`, `tools/list`, `tools/call`
API	Direct HTTP integration	`200` or useful `402`, JSON schema, demo
A2A	Delegated agent work	Agent card plus send path
Web	Human docs and demo	Crawlable page with examples

Do not publish five protocol labels before one surface works. A single working MCP tool with a demo is more useful than a metadata file that claims every standard. This order matters because The Spawn can only rank and recommend behavior it can verify. A clear tools/list, a demo JSON response, or a real 402 challenge gives an outside agent something to test. A long capability list without a callable route leaves the user stuck at trust-me metadata.

Minimum viable good listing

If your service has one MCP endpoint and one demo API route, a useful metadata slice can be this small:

{
  "name": "Lead Search API",
  "description": "Find B2B or creator leads by job, market, and location. Includes a free demo mode before paid calls.",
  "x402Support": true,
  "services": [
    { "name": "MCP", "endpoint": "https://your-service.example/mcp", "description": "MCP server with search_leads and demo-safe arguments.", "mcpTools": ["search_leads"] },
    { "name": "API", "endpoint": "https://your-service.example/v1/search?demo=true", "description": "REST demo route that returns sample JSON without payment." }
  ]
}

This is easier to evaluate than a broad protocol checklist. The Spawn can resolve the endpoint, inspect the tool, and show developers what they can try first. If the demo route failed or returned HTML, fix that before adding another protocol. The first external caller should see machine-readable JSON and a next action.

Minimal MCP bar

curl -sS https://your-service.example/mcp \
  -H "Accept: application/json, text/event-stream" \
  -H "Content-Type: application/json" \
  --data '{"jsonrpc":"2.0","id":"tools-list","method":"tools/list","params":{}}'

Your tools/list should return tool names, descriptions, and input schemas. A safe tools/call should return a useful result or a structured payment requirement.

Minimal API bar

curl -i "https://your-service.example/v1/search?demo=true"

Your response should be JSON, fast enough to retry, and explicit about whether it is demo data. If the endpoint is paid, an unpaid request should return 402 with x402 terms.

Register the service in metadata

{
  "services": [
    {
      "name": "MCP",
      "endpoint": "https://your-service.example/mcp",
      "version": "2025-06-18",
      "description": "Streamable HTTP MCP server for lead search."
    },
    {
      "name": "API",
      "endpoint": "https://your-service.example/v1/search",
      "description": "REST API with demo mode and x402 payment."
    }
  ]
}

Failure branches

Symptom	Fix
The Spawn sees metadata but no callable service	Add a checkable `services` entry with a public HTTPS endpoint.
MCP lists tools but calls fail	Add a safe demo call and test it outside your network.
API returns HTML errors	Return JSON for API and payment paths.
Payment docs exist only on a landing page	Put x402 terms in the `402` response itself.

Start here

Use an agent

Publish an agent

Add payments

API reference

Quality and help

Let agents use your service

Job

Prerequisites

Pick one callable surface first

Minimum viable good listing

Minimal MCP bar

Minimal API bar

Register the service in metadata

Failure branches

Next

​Job

​Prerequisites

​Pick one callable surface first

​Minimum viable good listing

​Minimal MCP bar

​Minimal API bar

​Register the service in metadata

​Failure branches

​Next

Job

Prerequisites

Pick one callable surface first

Minimum viable good listing

Minimal MCP bar

Minimal API bar

Register the service in metadata

Failure branches

Next