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
HomeReleasesv2.1.259entry #21

Claude Code v2.1.259 ·

Headless SDK sessions expose a bindable $.tool.register API for MCP servers

Headless SDK sessions expose a session object for MCP servers with addMcpServer, removeMcpServer, toast, status and refreshContext.

Use it now New Features
JSON All of v2.1.259
Use it nowTier: how much it should matter to you
5Useful: my rating, 1 to 5
3Signal: worth watching, 1 to 5
SDKArea: what it touches
New FeaturesKind: in v2.1.259,
What probably matters to youSection of the release

Headless SDK sessions now expose a $.tool.register-style session object with addMcpServer, removeMcpServer, toast, status, and refreshContext hooks for MCP servers. In a headless session, calls to toast and status are logged rather than displayed, since there is no notification bar or status row to show them in.

Read from
Names in the bundleaddMcpServerremoveMcpServerrefreshContext
What the documentation says
Documented inapi/agents-and-tools/mcp-connector
Since it was published

The entry above is what we published on the day. These lines were added later, as Anthropic's own pages caught up, and they sit beside the original rather than replacing it.

Confirmed since Anthropic's documentation has since written up addMcpServer, on permission-policies. .addMcpServer( managed-agents/permission-policies see the edit
How sure we are
One source agreesOne thing we can check says the same as this entry.
Anthropic's documentation agreesAnthropic's documentation has since written up addMcpServer, on permission-policies.

See this entry in the whole of v2.1.259 →

Feedback