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 v2.1.228 Home All releases olderv2.1.227 v2.1.229newer
Claude Code v2.1.228

Bundled SDK ships a runtime for server-managed agent work

Not switched on
Useful2 Signal5
SDK Notable

The bundled SDK carries a worker that polls a server for agent work, unreachable from normal CLI use.

A full managed-agent worker runtime ships in every install but nothing in the CLI enters that flow.

What

The bundled Anthropic SDK gained a full worker runtime that polls a server for agent work and runs it locally. It is present in every install but only runs under managed-agents flows, which nothing in normal CLI use enters.

Details
  • Polls, acknowledges, heartbeats and stops against /v1/environments/{id}/work, every request sending the header anthropic-beta: managed-agents-2026-04-01
  • A session runner streams session events, executes tool calls, honours allow/deny confirmations from the user, and ends the turn after an idle status
  • Ships a default toolset of bash, read, write, edit, glob, grep, all confined to a working directory with checks that reject paths escaping it
  • None of these runtime pieces existed in 2.1.227
Evidence

Cannot iterate over a consumed SessionToolRunner

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

See this entry in the whole of v2.1.228 →