Add structured content to the Ruby weather server and client - #184
Draft
olaservo wants to merge 3 commits into
Draft
Add structured content to the Ruby weather server and client#184olaservo wants to merge 3 commits into
olaservo wants to merge 3 commits into
Conversation
The mcp gem 1.1.0 (2026-08-01) is the first to negotiate 2026-07-28, so the Ruby examples can finally show the same thing the other four do: get_alerts declares an array-rooted output_schema and returns a bare top-level JSON array, get_forecast returns an object. Declaring `type:` at the root is what suppresses the SDK object-root default. Failure paths return an error result rather than a bare text one, because a tool declaring an output_schema MUST return conforming structured content. No alerts is an empty array, not an error. The client compiles each declared schema at connect time and validates every non-error result. The SDK client does not do this itself, so the spec client-side SHOULD costs real code here, as it does in Go and Rust. NOT READY TO SHIP. The gem never emits the `resultType` field that the 2026-07-28 schema marks mandatory, and no user-level knob sets it, so a spec-strict client rejects every response including tools/list. Verified end-to-end against the Ruby client, which does not check the field; blocked against the TypeScript SDK client. See the server README. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
The gem's default_capabilities advertises tools, prompts, resources and
logging. This server has only tools; logging is additionally deprecated as of
2026-07-28 (SEP-2577).
Passing capabilities: { tools: {} } makes server/discover honest. No
listChanged flag, because change notifications at this revision are delivered
over subscriptions/listen and this server does not serve it.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
The spec never uses the phrase "structured output". It defines two separate things under Tool Result: "Structured Content" (the `structuredContent` field) and "Output Schema" (the `outputSchema` field). Collapsing them into "structured output" conflates the two. It is also actively confusing here. In LLM tooling "structured output" means constrained decoding — making the *model* emit conforming JSON. These clients call a model API, so a reader could reasonably take the phrase to mean the tool constrains the model's response, which is the opposite of what is going on: the tool describes the shape of its own result. Headings and prose now say "structured content". References to real identifiers are left alone: the Python SDK's own docs page is called Structured Output and lives at docs/servers/structured-output.md, and its decorator parameter is `structured_output`. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
1 participant
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
Completes the set with #164 (Python), #165 (TypeScript), #166 (Go), #167 (Rust): both tools declare an
output_schemaand return matchingstructured_content, and the client validates results against the declared schema.Draft — blocked on an
mcpgem release. 1.1.0 negotiates2026-07-28but its server never stamps theresultTypefield the revision makes mandatory, so a spec-strict client rejects every response. The fix is on ruby-sdkmainand unreleased; 1.1.0 is still the newest gem. The version floor here should name that release rather than 1.1.0 once it ships.Until then the Ruby weather server cannot be added to the smoke tests (see #183, which covers the Ruby client only), so nothing in this diff is exercised by CI.