claude-code - 💡(How to fix) Fix Thinking summaries missing on Opus 4.7 — harness doesn't set display: "summarized" [6 comments, 6 participants]

Switched to Opus 4.7 on v2.1.111 and noticed thinking summaries stopped showing up. Took a bit to track down — writing it up in case it's useful.

The extended-thinking API docs note that Opus 4.7 changed the default for the display parameter to "omitted" (Opus 4.6 and earlier defaulted to "summarized"). The reason given is faster time-to-first-token on streaming responses.

The result is the API returns thinking blocks with empty thinking fields by default, so the UI has nothing to render. Setting "showThinkingSummaries": true in settings.json doesn't help — that controls rendering of what the API sends back, not what the API decides to send.

Repro

1. Run v2.1.111 with "showThinkingSummaries": true set
2. /model claude-opus-4-7
3. Ask something that triggers extended thinking
4. No summaries appear in the UI

Switching to claude-opus-4-6 or claude-sonnet-4-6 brings them back since those still default to "summarized".

Suggested fix When the selected model defaults to display: "omitted" (currently Opus 4.7 and Mythos Preview per the docs) and the user has showThinkingSummaries enabled, the harness should pass display: "summarized" explicitly in the API request.

Environment

• Claude Code 2.1.111
• Model: claude-opus-4-7 (1M context variant)
• macOS 15.3 (Darwin 25.3.0)