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Sweep 22 Sep 2026 · 17:19Z Build v2.1.280 501 read Stable v2.1.267 Latest v2.1.280 Next v2.1.280 Feeds RSS JSON llms.txt Unofficial
Claude Code v2.1.271 ·

New backoff/coalescing helper for MCP list_changed refetches

MCP tool-list refetches now use a debounced, backed-off scheduler instead of firing on every change notification

TierUnder the hoodhow much it should matter to you
Useful2my rating, 1 to 5
Signal1worth watching, 1 to 5
AreaMCPwhat it touches
KindInternal Changesin v2.1.271,
Under the hood

MCP tool-list refetches now use a debounced, backed-off scheduler instead of firing on every change notification

What

When an MCP (Model Context Protocol) server sends repeated list_changed notifications that its tool list has changed, a new scheduler now coalesces rapid successive notifications into a single refetch instead of triggering one refetch per notification. If a refetch fails, the wait before the next attempt doubles, up to a capped maximum.

Why

This avoids hammering an MCP server with repeated refetch calls when it sends a burst of change notifications, and backs off automatically if refetching keeps failing.

How sure we are
One source agreesOne thing we can check says the same as this entry.
Anthropic's release notes agreeFixed sustained high CPU usage and repeated tool-list requests when an MCP server sends list_changed notifications in a tight loop

See this entry in the whole of v2.1.271 →

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