Choose Product, then Profile. Select the Foundation Models template. Record on a device or simulator that runs iOS 27 or macOS 27. Exercise one user task, then stop.
Session 243 shows lanes for instructions and model inference, plus a tree of sessions, requests, inferences, prompts, responses, and tool calls. Use that tree when you ask "did the model call a tool" or "how long was inference."
The instrument supports Dynamic Instructions and more than one session or profile. If a Dynamic Profile never switches, you will see one instruction set stay active. That is a real bug when the UI thought it changed mode.
Prompt and response logging is for the recording. Treat the trace as sensitive. Do not keep customer traces in a shared folder.
Clocks from this template pair with Stream tokens and measure speed. Quality of the path belongs in Test AI behavior before you ship.
Next, add those spans.
Key concepts
- Record one user task with the Foundation Models template on iOS 27 or macOS 27.
- The tree shows sessions, requests, inferences, prompts, responses, and tool calls.
- It supports Dynamic Instructions and multiple sessions or profiles.
- Prompt and response logging is for recording only.
Takeaways
- Use Instruments for Apple's hops. Use your spans for context pack and guardrail.
- One instruction set staying active when the UI thought the mode changed is a real bug.
- Do not keep customer traces in shared folders.