Active account

TOOL add_watch

MCP tool that watches a UDI-DI or SRN. The first read is a baseline. A repeat subject returns the existing watch.

Active account. Argument subject is required. Same rules as POST /v1/watches. The first successful read is a baseline and does not create an event. Watching the same subject again does not reset that baseline.

{"jsonrpc":"2.0","id":4,"method":"tools/call","params":{"name":"add_watch","arguments":{"subject":"AT-MF-000000252"}}}

Text payload: {"watch":{…},"error":null}. On failure watch is null and error is set, so isError is true. The call itself is POST /mcp.