[BUG]: "Operation cancelled by user" is re-injected as a user message after cancelling a turn

[jjoseph456]

Type rg --version### What happened?

When I cancel an in-progress turn (Esc / Ctrl-C), the line Operation cancelled by user is sent back to the model as if it were a new user message (it arrives with its own fresh timestamp). The agent then "replies" to it as though it were a real instruction/content, instead of the cancel simply aborting the current operation silently.

This produces phantom turns: every cancel results in the assistant responding to nothing.

Expected behavior

Cancelling a turn should abort the current operation and return to the prompt without injecting Operation cancelled by user into the conversation as a user turn. The model should not be prompted to respond to it.

Steps to reproduce

1. Send a prompt that triggers tool calls / a longer operation.
2. Cancel mid-operation (Esc / Ctrl-C).
3. Observe Operation cancelled by user appears as a user message with a new timestamp, and the assistant generates a reply addressed to it.

Notes

• Reported as a regression — a user observed this did not happen in earlier versions.
• Likely related to (but distinct from) the closed Stuck in "Cancelling" after operation cancelled by user #2502 "Stuck in "Cancelling" after operation cancelled by user".
• Behavior is client-side and version-dependent, not account- or repo-specific.

Version

1.0.63

OS

macOS (Darwin)