Source Intelligence

DisclaimerUnofficial, and not affiliated with Anthropic. Nearly all of this is read straight out of what ships: npm bundles, captured prompts, published docs. Anthropic's own notes go in verbatim, marked as theirs. The rest is my reading, and every entry carries the strings behind it. If one looks wrong, vote it down and say why.

All of v2.1.233 Home All releases olderv2.1.232 v2.1.234newer
Claude Code v2.1.233

MCP event subscriptions back off instead of reconnecting in a tight loop

You'll notice
Useful3 Signal2
MCP

A flaky MCP server that keeps dropping event streams now gets a pause instead of endless instant reconnects.

Feature flag
tengu_mcp_listen_reopen_park Not enough to say

Nothing here resolved what this flag was doing on this version, so nothing here should be read as on or off.

This account: no value returned · anonymous baseline: no value returned · compiled default in v2.1.233: off

These values were read against a different version of Claude Code, so treat them as the nearest reading available instead of one taken on this release.

tengu_mcp_listen_reopen_park_tuning Not enough to say

Nothing here resolved what this flag was doing on this version, so nothing here should be read as on or off.

This account: no value returned · anonymous baseline: no value returned · compiled default in v2.1.233: not a boolean we can read

These values were read against a different version of Claude Code, so treat them as the nearest reading available instead of one taken on this release.

Read once, for one account on one subscription tier, against v2.1.233. It isn't a statement about your account. What a flag value here can and cannot tell you

What

When an MCP server repeatedly kills a held event-subscription stream, the client now counts reopens in a trailing window and, past a threshold, pauses re-listening for a jittered delay rather than reconnecting immediately. This is on by default (tengu_mcp_listen_reopen_park, fallback true).

Details
  • The window size and pause length come from a separate tuning flag tengu_mcp_listen_reopen_park_tuning (fallback null), validated as windowMax 1-100 and parkDelayMinutes 1-1440; with no server value the built-in constants apply.
  • Each pause logs a tengu_mcp_listen_reopen event with outcome "parked".
Evidence

subscriptions/listen reopened ${i.length} times in the trailing window (the server keeps killing held streams); parking re-listen

Strings lifted out of the shipped bundle, so the claim above can be checked against them.

See this entry in the whole of v2.1.233 →