stacklok / toolhive / 30825597926

70%

Build Type

push

github

Committed by web-flow

Commit Message

Opt Modern backends into log notifications via logLevel _meta (#6140)

The 2026-07-28 (Modern) MCP revision removed the logging/setLevel RPC;
the per-request io.modelcontextprotocol/logLevel _meta key replaces it.
modelcontextprotocol/go-sdk#1116 confirmed go-sdk's SetLoggingLevel is
wont-fix-by-design on Modern sessions, so a Modern backend never emits
notifications/message through vMCP.

When server->client forwarding is bound, modernCallTool now overlays
logLevel: debug onto the request _meta (the Modern analogue of the Legacy
enableBackendLogging) and relays interleaved notifications/message and
notifications/progress from the backend's SSE stream to the downstream
client. The logLevel key and listener are omitted when forwarding is
unbound, and every other Modern call site is unchanged.

Also export mcp.MetaKeyLogLevel for the overlay, and reframe the two
pin comments that attributed the -32020 rejection to a transient upstream
bug — it is the standing contract for a removed RPC.

Closes #6130

Coverage Stats

35 of 61 new or added lines in 3 files covered. (57.38%)

11 existing lines in 4 files now uncovered.

82736 of 118423 relevant lines covered (69.86%)

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