Evidence record / claude-code
A dated record of one change, kept so the writing that cites it can be checked. Compiled from the sources listed below by the research run, not written for reading. The judgment lives in the issues that cite it, below.
2026-08-10-claude-code-claude-code-sessions-can-now-message-each-other-and-mentions-another
Claude Code sessions can now message each other, and @ mentions another session by name.
v2.1.224 added cross-session SendMessage: "Claude Code sessions can now message each other, on any of your machines, with ListAgents to discover them (macOS and Linux)." The digest is precise about the payload boundary -- "A message is text Claude writes for the other session, never your conversation history or files." v2.1.232 made it usable: typing @ in the prompt mentions another session by name, SendMessage delivers to a bare name that exactly matches one live session instead of demanding a ref, and sessions on one machine are forced to unique names (a collision gets a name-word-word variant). The governance surface arrived with the feature rather than after it: v2.1.224 added crossSessionInbound and dialogExpiry settings, where "cross-session messages sent to a session running with bypassed permissions are held for your approval", and v2.1.222 put the classifier in front of the send -- "messages sent to other agent sessions via SendMessage are now evaluated by the permission classifier before dispatch." v2.1.232 exposed both as /config rows.
Channel: tagged-release. Ancestry: Closed source; npm publish record is the release proof. registry time[] gives 2.1.224 = 2026-08-07T01:36:32Z and 2.1.232 = 2026-08-13T21:30:53Z, both plain semver under dist-tag latest. The feature is documented on its own docs page, https://code.claude.com/docs/en/cross-session-messaging (HTTP 200), and the Week 32 digest pins it to v2.1.224 with the line "Requires v2.1.224 or later" -- a version pin, so this is a code channel and not a marketing surface.
Operator consequence: Try it if you run several long-lived sessions on one machine, but decide the inbound policy deliberately rather than inheriting it. The interesting property for anyone building on Claude Code is that a message is now an untrusted input channel between agents: text one session's model wrote lands in another session's context. Set crossSessionInbound to hold or refuse on any session you start with bypassed permissions -- the default already holds there, and that default is the tell that Anthropic considers the channel a privilege boundary. macOS and Linux only; Windows operators can ignore this entirely for now.
Receipt
Finding metadata
Run: 2026-08-10-weekly-digest-2026-08-03_2026-08-10-frontier-v0
Finding ID: 2026-08-10-claude-code-claude-code-sessions-can-now-message-each-other-and-mentions-another
Source links
Primary links, including exact changelog lines when available.
Versioned source: run artifact