Hey, thanks for the report. There are actually two separate things here, so I’ll cover both.
About Composer 1.5 in subagents: this is expected behavior. The built-in subagents (Explore, Browser, Bash) use faster models by default for efficiency. The idea is that the subagent does the “draft” work (search, navigation, parsing), then returns the result to the main agent, which runs on the model you selected (Opus 4.6). More details here: Subagents | Cursor Docs
If you want subagents to use a specific model too, you can create a custom subagent with model: opus-4.6-thinking in .cursor/agents/. The format docs are in the same place.
About the Browser MCP error: the screenshot shows “Browser MCP tools returned an error - possible configuration or permission issue”. That’s a separate issue. Can you share the Request ID from the chat where it happened? Also check in Cursor Settings > Tools & MCP that the Browser tool is enabled.
Let me know if anything’s still unclear.