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Sweep 27 Oct 2026 · 19:04Z Build v2.1.312 531 read Stable v2.1.308 Latest v2.1.312 Next v2.1.312 Feeds RSS JSON llms.txt llms-full.txt Unofficial
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Claude Code v2.1.311 ·

New internal names for streaming, MCP search and startup timing

Several new internal event and debug names appear, and one telemetry batching setting was renamed; none changes what you see on its own

Under the hood Internal Changes
JSON All of v2.1.311
Under the hoodTier: how much it should matter to you
1Useful: my rating, 1 to 5
2Signal: worth watching, 1 to 5
TelemetryArea: what it touches
Internal ChangesKind: in v2.1.311,
Internal ChangesSection of the release
What

Several new internal names appear in this build. They are labels Claude Code uses for its own reporting and debugging, not settings you can change:

  • headless_plain_delta_fast_path and mcp_search_redial, added to a list of event names
  • prompt.paint, added to a list of interfaces offered to programs that host Claude Code
  • tengu_startup_timing, a new event about startup that is sent with a site field
  • event_batch_upload, which replaces joint_upload in the settings for how usage reports are grouped before sending
Why

The names point to work on a faster path for streamed output when Claude Code runs without its interactive screen, on reconnecting MCP servers during a tool search, and on measuring how long startup takes. On their own they do not change anything you see.

See this entry in the whole of v2.1.311 →

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