Summary
The current specification does not clearly define the expected Host behavior when a model executes multiple tool calls, each returning a UIResource.
Questions
-
Rendering multiple UIResources: If the model runs N tool calls, each with an associated UIResource, should the Host render N iframes? Or is it up to the Host to decide how and when to display these UIs?
-
Priority field behavior: The MCP spec includes a priority annotation (0.0 to 1.0), but it's unclear:
- What is the expected behavior when
priority is not set?
- What should Hosts do when all UIResources have the same priority (e.g., all
1.0)?
- How does
priority apply to UI rendering decisions specifically?
Understanding the intended behavior would help ensure consistent UX across different Host implementations.
Summary
The current specification does not clearly define the expected Host behavior when a model executes multiple tool calls, each returning a UIResource.
Questions
Rendering multiple UIResources: If the model runs N tool calls, each with an associated UIResource, should the Host render N iframes? Or is it up to the Host to decide how and when to display these UIs?
Priority field behavior: The MCP spec includes a
priorityannotation (0.0 to 1.0), but it's unclear:priorityis not set?1.0)?priorityapply to UI rendering decisions specifically?Understanding the intended behavior would help ensure consistent UX across different Host implementations.