feat(adapters): from_mcp + to_mcp behind the mcp feature (rmcp 1.8)
from_mcp (src/adapters/from_mcp/):
- tools/list discovery over streamable HTTP; per-tool
HandlerRegistration (Mutation, Once, FromMCP leaf, Internal;
ADR-015/022)
- structuredContent-preferred output, ContentBlock-union fallback,
isError -> MCP_TOOL_ERROR with content blocks as details (ADR-023)
- bearer token flows via capabilities key 'mcp' (ADR-014 no-env-vars)
- 19 unit tests + tests/from_mcp_integration.rs (5 tests vs a real
rmcp streamable-HTTP MCP server)
to_mcp (src/adapters/to_mcp.rs):
- 4 fixed gateway tools (search/schema/call/batch, ADR-041); Sub ops
excluded from search and uncallable (MCP is request/response)
- identity survives rmcp framing: bearer_auth_middleware stashes
Option<Identity> in http::request::Parts extensions, call_tool reads
it back from RequestContext extensions
- StreamableHttpService nested at /mcp in HttpAdapter's router,
bearer middleware around it (feature-gated)
Streamable HTTP only (ADR-037): rmcp default-features off, no stdio.
Default build compiles without rmcp (cargo tree: 0 hits).
Verified: cargo test (182 lib default / 218 all-features) + 5 MCP
integration + 10 WS, clippy -D warnings (both), fmt.
glm-5.3-flash
4ac337c3a5