Proposal: "isLongRunning" property for Tool interface

[contextablemark]

Some Agent platforms (e.g., ADK) make an explicit distinction at invocation time between long running (e.g., HITL) and non long-running tools. When defining tools dynamically (i.e., based purely on the contents of the "tools" element in a new run), there is no established means to indicate to the backend whether or not a frontend tool is long-running.

It would therefore be useful if the Tool interface had a top-level "isLongRunning" property to allow the backend to make this determination at runtime, rather than playing games with the tool name (e..g, appending "long_running" to the end of the tool name) or adding fake parameters (e.g., adding an "is_long_running" parameter and documenting it as a pseudo-property that is ignored at invocation time).

[contextablemark]

See discussion here.