Bug – Async path in adapter can block event loop

• Where
  src/glean/agent_toolkit/adapters/openai.py::on_invoke_tool

• Issue
  The hook is async but calls the original tool synchronously. No detection of coroutine functions and no offloading for sync functions.

• Impact
  Can block the event loop under concurrency, reducing throughput and causing latency spikes.

• Proposal
  Detect if self.tool_spec.function is a coroutine function:
  If coroutine: await original_func(**params).
  Else: offload sync function via thread executor (anyio.to_thread.run_sync or asyncio.to_thread).
  Preserve error handling and return type consistency.

• Scope
  src/glean/agent_toolkit/adapters/openai.py : update on_invoke_tool

Async tools are awaited; sync tools do not block the event loop.

Suggested fix (with asyncio):

import inspect

async def on_invoke_tool(ctx: Any, input_str: str) -> Any:
    try:
        params = json.loads(input_str) if input_str else {}

        if inspect.iscoroutinefunction(original_func):
            return await original_func(**params)
        else:
            return await asyncio.to_thread(original_func, **params)

    except Exception as e:
        return f"Error executing tool: {str(e)}"

let me know if this sounds reasonable and we can try to come with a fix for this and will raise a PR on the same.

Read src/glean/agent_toolkit/adapters/openai.py and start at on_invoke_tool, reviewing its current parameter parsing and error handling. Validate the behavior with the existing test suite or focused checks: async tools are awaited, synchronous tools are offloaded without blocking the event loop, and errors and return types remain consistent.