fix: support nested MCP header property paths - #1111
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nolankhoingo wants to merge 1 commit into
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DaleSeo
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Aug 3, 2026
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| fn contains_annotation(value: &Value) -> bool { | ||
| match value { | ||
| Value::Object(object) => { | ||
| object.contains_key("x-mcp-header") || object.values().any(contains_annotation) | ||
| } | ||
| Value::Array(values) => values.iter().any(contains_annotation), | ||
| _ => false, |
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How could this distinguish subschemas from ordinary JSON values so that something like default: {"x-mcp-header":"literal"} does not cause a valid tool to be rejected?
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Summary
Why
MCP 2026-07-28 permits statically reachable primitive annotations under plain properties chains. The current top-level-only cache rejects otherwise valid tools.
Specification: https://modelcontextprotocol.io/specification/2026-07-28/basic/transports/streamable-http
Validation
cargo test -p rmcp --lib --features client,transport-streamable-http-client,server-side-http transport::common::mcp_headers::tests
All 36 focused header tests pass.