agents.WebSearchTool bug

[vincent507cpu]

Please read this first

• Have you read the docs?Agents SDK docs Yes
• Have you searched for related issues? Others may have faced similar issues. Yes

Describe the bug

Parameter type and format should be correct, but I still get this error.

---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
Cell In[3], line 1
----> 1 search_agent_res = await Runner.run(starting_agent=search_agent, input='Model Context Protocol MCP definition')
      2 search_agent_res.final_output

File /opt/homebrew/Caskroom/miniconda/base/envs/test/lib/python3.11/site-packages/agents/run.py:221, in Runner.run(cls, starting_agent, input, context, max_turns, hooks, run_config, previous_response_id)
    213 logger.debug(
    214     f"Running agent {current_agent.name} (turn {current_turn})",
    215 )
    217 if current_turn == 1:
    218     input_guardrail_results, turn_result = await asyncio.gather(
    219         cls._run_input_guardrails(
    220             starting_agent,
--> 221             starting_agent.input_guardrails
    222             + (run_config.input_guardrails or []),
    223             copy.deepcopy(input),
    224             context_wrapper,
    225         ),
    226         cls._run_single_turn(
    227             agent=current_agent,
    228             all_tools=all_tools,
    229             original_input=original_input,
    230             generated_items=generated_items,
    231             hooks=hooks,
    232             context_wrapper=context_wrapper,
    233             run_config=run_config,
    234             should_run_agent_start_hooks=should_run_agent_start_hooks,
    235             tool_use_tracker=tool_use_tracker,
    236             previous_response_id=previous_response_id,
    237         ),
    238     )
    239 else:
    240     turn_result = await cls._run_single_turn(
    241         agent=current_agent,
    242         all_tools=all_tools,
   (...)    250         previous_response_id=previous_response_id,
    251     )

TypeError: can only concatenate str (not "list") to str

Debug information

• Agents SDK version: (e.g. v0.0.3) 0.0.16
• Python version (e.g. Python 3.10) 3.12

Repro steps

Ideally provide a minimal python script that can be run to reproduce the bug.

from agents import WebSearchTool, Agent, Runner
from agents.model_settings import ModelSettings

INSTRUCTIONS = (
    "You are a research assistant. Given a search term, you search the web for that term and "
    "produce a concise summary of the results. The summary must 2-3 paragraphs and less than 300 "
    "words. Capture the main points. Write succinctly, no need to have complete sentences or good "
    "grammar. This will be consumed by someone synthesizing a report, so its vital you capture the "
    "essence and ignore any fluff. Do not include any additional commentary other than the summary "
    "itself."
)

search_agent = Agent(
    name='Search Agent',
    input_guardrails=INSTRUCTIONS,
    tools=[WebSearchTool()],
    model_settings=ModelSettings(tool_choice='required')
)

search_agent_res = await Runner.run(starting_agent=search_agent, input='Model Context Protocol MCP definition')

Expected behavior

A clear and concise description of what you expected to happen.

[robtinn]

I can repro this but input_guardrails needs to be list[InputGuardrail[TContext]]

e.g.

` @input_guardrail
async def my_guardrail(ctx: RunContextWrapper, agent: Agent, input: str) -> GuardrailFunctionOutput:
result = await Runner.run(guardrail_agent, input, context=ctx.context)
final_output = result.final_output

    return GuardrailFunctionOutput(
        output_info=final_output,
        tripwire_triggered=final_output.is_safe
    )

input_guardrails = [my_guardrail]`

I would recommend checking out - https://github.com/openai/openai-agents-python/blob/main/examples/agent_patterns/input_guardrails.py