Desktop app broadcasts single prompt to multiple sessions simultaneously

Bug Description

When sending a single prompt in the Claude Code desktop app (macOS), the prompt is duplicated and sent to multiple other sessions simultaneously — sessions that were not active and did not receive any user input.

Steps to Reproduce

1. Have multiple sessions visible in the left sidebar (desktop app, Code mode)
2. Open one session and type a prompt
3. Press Enter / send the prompt once
4. Observe: the same prompt appears in 3-4 other sessions in the sidebar, each generating independent responses

Observed Behavior

• One prompt sent → four sessions received it (see screenshots below)
• Three of the four responses were identically the same, one was functionally equivalent
• The user did NOT open, click on, or interact with the other three sessions
• The sessions were on completely different topics (pipeline config, workstream tracker, pipeline adaptations, commercialization planning)
• Each session generated independent responses, consuming tokens and creating conflicting work

Expected Behavior

A prompt sent in one session should only appear in that session. Other sessions should remain untouched.

Impact

• Significant user confusion — appears as if sessions are "intermingling"
• Wasted compute — 4x token consumption for one prompt
• Conflicting work — multiple sessions acting on the same instruction against different contexts
• Lost productivity — user spent substantial time debugging which session was "real" and trying to untangle the mess

Environment

• App: Claude Code desktop app (macOS, Code mode — not CLI)
• Model: Opus 4.6
• Date: February 21, 2026
• macOS: Apple Silicon Mac

Evidence

Four screenshots showing four different sessions, each with different topics listed in the sidebar, all displaying the same user prompt and generating responses to it. The prompt was only sent once by the user.

(Screenshots available — unable to attach from CLI but can be provided on request)

Possibly Related

• GitHub Issue #18619 (session management / data loss bugs previously reported by same user)

Workaround

Keeping only one session open/visible at a time may prevent the broadcast behavior, but this defeats the purpose of multi-session support.