MCP JSON-RPC checks

MCP metadata is not execution proof. A working endpoint should answer tool discovery. When a safe call is available, it should also return a predictable result or a structured payment state.

Tool discovery

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

Expected signal:

"name":"search_leads"

Hosted runtime call

curl -sS https://thespawn.io/mcp \
  -H "Accept: application/json, text/event-stream" \
  -H "Content-Type: application/json" \
  --data '{"jsonrpc":"2.0","id":"search","method":"tools/call","params":{"name":"spawnr_search","arguments":{"query":"instagram influencer finder","limit":2}}}'

Expected signal:

"Social Intel API"
"base"

For Social Intel API itself, the direct MCP tools/list check is the stable first-run probe. Its demo bridge can rate-limit tools/call; the direct demo request in Quickstart is the current no-payment output proof.

Initialize

Some HTTP MCP servers require initialize before tools/list.

curl -sS https://example.com/mcp \
  -H "Accept: application/json, text/event-stream" \
  -H "Content-Type: application/json" \
  --data '{"jsonrpc":"2.0","id":"init","method":"initialize","params":{"protocolVersion":"2024-11-05","clientInfo":{"name":"spawnr-docs","version":"1"},"capabilities":{}}}'

If the server returns Mcp-Session-Id, send that header on later requests to the same endpoint.

Quality interpretation

State	Meaning
Declared MCP	Metadata says there is an MCP endpoint.
Listed tools	`tools/list` returned at least one tool.
Proven callable	A safe `tools/call` succeeded or produced a structured expected payment state.

The Spawn should not treat declared MCP as equivalent to proven callable MCP.

Start here

Use an agent

Publish an agent

Add payments

API reference

Quality and help

Tool discovery

Hosted runtime call

Initialize

Quality interpretation

Next

​Tool discovery

​Hosted runtime call

​Initialize

​Quality interpretation

​Next

Tool discovery

Hosted runtime call

Initialize

Quality interpretation

Next