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quickstart-resources/weather-server-rust/README.md
olaservo ce055ae1fe Drop the hand-written list_tools now that rmcp emits cache hints 
`#[tool_handler]` generated `ttl_ms: None, cache_scope: None`, but both are
required on a paginated result at 2026-07-28, so a strict client rejected
tools/list before it could reach a tool call. The server worked around that by
hand-writing list_tools purely to set the two fields.

rust-sdk#1120 fixed the macro, released in rmcp 3.1.1: it now emits the fields
when the negotiated revision expects them and omits them otherwise. Both
lockfiles move to 3.1.2 and the override goes away, so the server is back to the
plain `#[tool_handler]` path the SDK documents.

Verified on the raw wire: after a 2026-07-28 handshake, tools/list carries
`ttlMs: 0` and `cacheScope: "public"` with no code setting them, and the smoke
test's strict client still validates both tools' structured content.
2026-08-09 17:52:24 -07:00

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A Simple MCP Weather Server written in Rust

See the Build an MCP server tutorial for more information.

Structured content

Both tools declare an output_schema and return structured_content. get_forecast returns an object; get_alerts returns a top-level JSON array, which protocol revision 2026-07-28 is the first to allow — see Structured Content in the spec.

Note that an array-rooted schema requires a 2026-07-28 client: rmcp sends it as written on every connection rather than projecting it down, so an older client rejects the tool list.