Stop sending log messages to MCP clients - #522
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The MCP logging feature is deprecated in the 2026-07-28 revision, and stderr logging is its sanctioned replacement, which this server already has. Remove the broadcast registry, the per-era registration with its onclose chaining, and the logging capability. Logging to stderr and MCP_LOG_LEVEL are unchanged. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
The logging-absent check also passed when no capabilities arrived at all; asserting the tools capability first makes it prove the surface it inspects exists. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
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Removes the MCP logging feature: the server no longer sends
notifications/messageto connected clients and no longer advertises theloggingcapability. The 2026-07-28 revision deprecates the feature (SEP-2577), naming stderr logging as the migration target — which this server already has. Stderr logging andMCP_LOG_LEVELare unchanged.This deletes the broadcast registry in
src/runtime/logger.ts, the per-era registration with itsonclosechaining insrc/server.ts, and the now-unusedreqCtxparameter ofcreateServer.To decide: clients on pre-2026 revisions stop receiving log notifications during the deprecation window rather than at its end. They keep working otherwise; with the capability no longer advertised, a legacy
logging/setLevelnow answers method-not-found, which is the spec-correct consequence.Verified: full suite (1,720 tests), plus a test asserting the
loggingcapability is no longer advertised, written first and confirmed failing against the previous code. Smoke-tested the built dist on both transports: a real stdio client sees nologgingcapability and stderr keeps its JSON lines, and a raw legacyinitializeover HTTP answers capabilities withoutlogging.🤖 Generated with Claude Code