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 v2.1.238 Home All releases olderv2.1.237 v2.1.239newer
Claude Code v2.1.238

MCP work aborts when the signed-in account changes mid-flight

Not switched on
Useful3 Signal4
MCP

Switching accounts would cancel in-flight MCP work instead of finishing it under the new identity, but it's dark.

Account-change aborts for tool calls, re-auth and reconnects depend on a counter that only advances with the MCP discovery cache on, and it is off.

Feature flag
tengu_mcp_discovery_cache_enable 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 v2.1.238: not a boolean we can read

Read once, for one account on one subscription tier, against v2.1.238. It isn't a statement about your account. What a flag value here can and cannot tell you

What

Claude Code now refuses to carry MCP tool calls, re-authentication, and reconnects across a switch of the signed-in account, so work started under one identity is never completed under another. A tool call that reaches a re-auth path is cancelled, pending re-auth started under the old account is refused rather than reused, and a reconnect that spans the switch fails and asks you to try again. The whole path depends on an account-change counter that only advances while the MCP discovery cache is on, and that cache is off in this build, so none of it can be observed on a default install.

Details
  • Aborted tool calls report "MCP tool call aborted: account changed before reauth" or the same message ending "during reauth".
  • A reconnect interrupted by a switch fails with error code IDENTITY_CHANGED and the message "Reconnect cancelled: the account changed while connecting. Choose Reconnect again."
  • Cancelled reconnects are recorded under the telemetry reason mcp_reconnect_identity_changed.
  • Purges of the MCP discovery cache on a 401 or 403 response are skipped when the account has already moved on, so stale-credential cleanup does not clobber the new identity.
  • A guard on disabled servers rides on the same counter and is likewise inert here.
  • Turn the path on by setting the MCP_DISCOVERY_CACHE environment variable to true, or by receiving a server value for the tengu_mcp_discovery_cache_enable flag; with neither, the strings ship but never appear.
Evidence

Reconnect cancelled: the account changed while connecting. Choose Reconnect again., mcp_reconnect_identity_changed

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

See this entry in the whole of v2.1.238 →