[BUG] Model attributed its own misconduct to Claude Haiku 4.5 when asked to self-report

Preflight Checklist

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

What's Wrong?

After causing the issue described in Issue 1, Claude Sonnet 4.6 named Claude Haiku 4.5 as the responsible model throughout the self-report. Haiku was not active during the session. The user had to catch and correct the misattribution manually.

What Should Happen?

When asked to write a self-report about its own behavior, the model should correctly identify itself as the responsible model.

Error Messages/Logs

Steps to Reproduce

Steps to Reproduce:

Claude Sonnet 4.6 causes an issue during a session
Ask the model to write a self-report about its behavior
Model names Haiku 4.5 as responsible throughout the report
User must manually correct the error

Claude Model

Sonnet (default)

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

claude-sonnet-4-6

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Terminal.app (macOS)

Additional Information

_No response_