Model selection via /model does not apply to current conversation

Summary

When selecting a model via the /model command in Claude Code, the model change does not appear to take effect for the current conversation. The system metadata continues to report the previous model (e.g., claude-sonnet-4-6) even after /model confirms the switch to Opus 4.6.

Steps to Reproduce

1. Open Claude Code (configured with Opus 4.6 as default)
2. Start a conversation — the system metadata reports claude-sonnet-4-6
3. Run /model and confirm Opus 4.6 is selected
4. Ask the agent what model it is — it reports Sonnet 4.6 based on system metadata

Expected Behavior

When a user selects a model, the agent running in the current session should match that selection. The system metadata provided to the agent should reflect the user's chosen model.

Actual Behavior

The /model command confirms "Set model to Opus 4.6 (1M context) (default)" but the agent's system environment still says claude-sonnet-4-6. This creates confusion about which model is actually running and leads to incorrect attributions in commits and issues.

Environment

• Claude Code CLI
• Model selected: Opus 4.6 (1M context)
• Model reported by system: claude-sonnet-4-6
• OS: macOS (Darwin 25.3.0)