[BUG] Receiving session is interrupted when a cross-session message arrives, and afterwards has no knowledge of the message #86059

Preflight Checklist

• I have searched existing issues and this hasn't been reported yet
• This is a single bug report (please file separate reports for different bugs)
• I am using the latest version of Claude Code

What's Wrong?

[BUG] Receiving session is interrupted when a cross-session message arrives, and afterwards has no knowledge of the message

Version: 2.1.133 (Claude Code desktop, Windows 11 Pro 26200)
Regression: yes — worked correctly on the previous version, one day earlier.

What happens: When session B receives a message from session A (via mcp__ccd_session_mgmt__send_message), session B stops immediately mid-turn. When I then ask session B a new question, it has no knowledge of the message that was delivered — the content is not in its context.

Expected: the message is delivered into the receiving session's context and the session continues, or at minimum the message is available on the next turn.

Impact: cross-session coordination is unusable. The sending session believes the hand-off succeeded; the receiving session never saw it. Silent loss, no error on either side.

Frequency: roughly five times in one morning, across different session pairs.

Note: related but distinct from #78706 (approval friction on the same feature) and #35741 (random interrupts without messages, closed as duplicate).

What Should Happen?

Expected: the message is delivered into the receiving session's context and the session continues, or at minimum the message is available on the next turn.

Error Messages/Logs

Steps to Reproduce

1. Let a session perform a task
2. In the mean time, start another session and let it send a message to the first session
3. The first session reveives the message (according to the GUI), but stops processing and is unaware of the message.

Claude Model

Opus

Is this a regression?

Yes, this worked in a previous version

Last Working Version

No response

Claude Code Version

2.1.133 (Claude Code desktop, Windows 11 Pro 26200)

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

PowerShell

Additional Information

No response