Add _meta field to resource, content, and result classes#310
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koic wants to merge 1 commit intomodelcontextprotocol:mainfrom
Open
Add _meta field to resource, content, and result classes#310koic wants to merge 1 commit intomodelcontextprotocol:mainfrom
_meta field to resource, content, and result classes#310koic wants to merge 1 commit intomodelcontextprotocol:mainfrom
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## Motivation and Context MCP 2025-11-25 spec defines a `_meta` general field on many types, but the Ruby SDK only exposed it on `Tool` and `Prompt`. To attach metadata (e.g. MCP Apps CSP hints on resource contents), consumers had to subclass existing classes and override `to_h`. Add a `meta:` keyword argument and `_meta` serialization to: - `Resource::Contents`, `Resource::TextContents`, `Resource::BlobContents` - `Resource`, `ResourceTemplate` - `Content::Text`, `Content::Image`, `Content::Audio`, `Content::EmbeddedResource` - `Tool::Response` (`CallToolResult`) - `Prompt::Result` (`GetPromptResult`) This aligns the Ruby SDK with the Python and TypeScript SDKs, which both expose `_meta` on these types. Resolves modelcontextprotocol#308. ## How Has This Been Tested? Added unit tests for each updated class covering two patterns: `_meta` present (asserts the value is reflected in `to_h[:_meta]`) and `_meta` omitted (asserts no `:_meta` key in `to_h`, i.e., `.compact` behavior). All existing tests continue to pass, and `rake rubocop` is clean. ## Breaking Changes None. All new `meta:` parameters are optional keyword arguments defaulting to `nil`. The `to_h` output stays backward-compatible because `nil` values are removed by the existing `.compact` call, so existing callers require no changes.
atesgoral
approved these changes
Apr 11, 2026
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Motivation and Context
MCP 2025-11-25 spec defines a
_metageneral field on many types, but the Ruby SDK only exposed it onToolandPrompt. To attach metadata (e.g. MCP Apps CSP hints on resource contents), consumers had to subclass existing classes and overrideto_h.Add a
meta:keyword argument and_metaserialization to:Resource::Contents,Resource::TextContents,Resource::BlobContentsResource,ResourceTemplateContent::Text,Content::Image,Content::Audio,Content::EmbeddedResourceTool::Response(CallToolResult)Prompt::Result(GetPromptResult)This aligns the Ruby SDK with the Python and TypeScript SDKs, which both expose
_metaon these types.Resolves #308.
How Has This Been Tested?
Added unit tests for each updated class covering two patterns:
_metapresent (asserts the value is reflected into_h[:_meta]) and_metaomitted (asserts no:_metakey into_h, i.e.,.compactbehavior). All existing tests continue to pass, andrake rubocopis clean.Breaking Changes
None. All new
meta:parameters are optional keyword arguments defaulting tonil. Theto_houtput stays backward-compatible becausenilvalues are removed by the existing.compactcall, so existing callers require no changes.Types of changes
Checklist