Follow Discord
Sweep 10 Nov 2026 · 02:18Z Build v2.1.322 539 read Stable v2.1.311 Latest v2.1.322 Next v2.1.322 Feeds RSS JSON llms.txt llms-full.txt Unofficial
HomeReleasesv2.1.281entry #775

Claude Code v2.1.281 ·

Session start gains takeClaimSessionStartHooks / sdkMcpServersPending / noteSdkEntryWait hooks

SDK and print sessions can now hold back SessionStart hooks and wait for SDK MCP servers that are still starting

Under the hood Internal Changes
JSON All of v2.1.281
Under the hoodTier: how much it should matter to you
1Useful: my rating, 1 to 5
2Signal: worth watching, 1 to 5
SDKArea: what it touches
Internal ChangesKind: in v2.1.281,
Internal ChangesSection of the release

Unclear The finding does not say how long the session waits or exactly when the held-back hooks run.

What

When another program runs Claude Code through the SDK (the kit for driving Claude Code from code), or in print mode (a single request that prints the answer and exits), the session runner gains new steps at startup. These steps are active:

  • takeClaimSessionStartHooks: holds back SessionStart hooks, the scripts you configure to run when a session begins or resumes.
  • sdkMcpServersPending: waits for MCP servers supplied through the SDK that are not ready yet. An MCP server is an add-on that gives Claude extra tools.
  • noteSdkEntryWait: records that the session waited at startup.
Why

If you run Claude Code from the SDK with your own MCP servers or SessionStart hooks, startup now waits for those servers and runs the hooks later. Your hooks may therefore fire at a slightly different moment than before.

How sure we are
Something disagreesSomething we can check disagrees with this entry, or the writer said they could not settle it.
The writer flagged doubtThe finding does not say how long the session waits or exactly when the held-back hooks run.

See this entry in the whole of v2.1.281 →

Feedback