BaseTool.run / StructuredTool raise 'asyncio.run() cannot be called from a running event loop' when a tool returns a coroutine

[Shailendra005]

Description

Executing a tool whose _run (or wrapped func) returns a coroutine raises RuntimeError: asyncio.run() cannot be called from a running event loop whenever the call happens inside an already-running event loop — e.g. a FastAPI request handler, a Jupyter cell, or any async def. Synchronous scripts are unaffected, which is why this slips through basic testing but breaks every async-server deployment.

Location

• lib/crewai/src/crewai/tools/base_tool.py:342 — BaseTool.run does result = asyncio.run(result)
• lib/crewai/src/crewai/tools/base_tool.py:553 — Tool.run (the @tool decorator class), same pattern
• lib/crewai/src/crewai/tools/structured_tool.py:441 and :446 — CrewStructuredTool.invoke, same pattern

result = self._run(*args, **kwargs)
if asyncio.iscoroutine(result):
    result = asyncio.run(result)   # <-- raises under a running loop

In-repo precedent (this is a known pattern here)

The codebase already solves exactly this elsewhere and the tool paths simply don't use it:

• lib/crewai/src/crewai/tasks/llm_guardrail.py:24 — _run_coroutine_sync: try: asyncio.get_running_loop() and, if a loop is running, run the coroutine in a ThreadPoolExecutor(max_workers=1) via pool.submit(ctx.run, asyncio.run, coro).result(), else asyncio.run(coro).
• Same guard in tools/mcp_native_tool.py:86, a2a/utils/agent_card.py, a2a/utils/delegation.py, mcp/tool_resolver.py, project/wrappers.py, project/annotations.py.

Reproduction

import asyncio
from crewai.tools import tool

@tool("echo")
async def echo(value: str) -> str:
    """Echo the value."""
    await asyncio.sleep(0.01)
    return f"echo: {value}"

async def handler():          # simulates a FastAPI route / Jupyter cell
    return echo.run(value="hi")

asyncio.run(handler())
# RuntimeError: asyncio.run() cannot be called from a running event loop

The same failure occurs with a BaseTool subclass whose _run returns a coroutine and with CrewStructuredTool.from_function(func=<async fn>).invoke(...).

Expected

run() / invoke() return the coroutine's result regardless of whether an event loop is already running, consistent with llm_guardrail._run_coroutine_sync.

Environment

crewai main (v1.15.15 snapshot), Python 3.13.