Hi,
What you're seeing is largely expected behavior with Copilot Studio generative orchestration today. When a tool throws a hard failure (like HTTP 400), the orchestrator often escalates it to the OnError system topic, and there currently isn't a built-in “silently recover and continue” setting.
The most reliable workarounds right now are:
Option 1 — Handle errors inside the Power Automate flow (Recommended)
Instead of allowing the HTTP 400 to bubble back to Copilot Studio:
- Use Configure run after on the failing actions
- Catch the failure inside the flow
- Return a valid structured response back to Copilot Studio such as:
- "Tool failed"
- "Invalid parameters"
- "Retry with corrected input"
This prevents the orchestrator from treating it as a fatal tool error, so the OnError topic may never trigger.
Option 2 — Modify the OnError topic
Inside the OnError system topic:
- Remove End all topics
- Avoid terminating the full conversation
- Redirect to a recovery topic or orchestration entry point
- Optionally set a variable like ErrorOccurred = true
This can sometimes allow the orchestrator to continue, although behavior is not always fully deterministic with generative orchestration.
Option 3 — Improve tool instructions and validation
Add guidance in your agent instructions such as:
> “If a tool call fails or returns invalid parameters, retry with corrected parameters instead of ending the conversation.”
Also consider validating parameters before calling the tool to reduce HTTP 400 responses entirely.
Option 4 — Use softer recovery messaging
Instead of displaying a hard error message in OnError:
- Replace it with something neutral like:
- “Let me try that another way.”
- Use End topic instead of End all topics
In some cases this may allow orchestration to resume more naturally.
References:
Vishnu WR
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