Add tool timeout support

pydantic_ai_slim/pydantic_ai/_tool_manager.py

@@ -7,6 +7,7 @@
 from dataclasses import dataclass, field, replace
 from typing import Any, Generic
 
+import anyio
 from opentelemetry.trace import Tracer
 from pydantic import ValidationError
 from typing_extensions import assert_never
@@ -35,6 +36,8 @@ class ToolManager(Generic[AgentDepsT]):
     """The cached tools for this run step."""
     failed_tools: set[str] = field(default_factory=set)
     """Names of tools that failed in this run step."""
+    default_timeout: float | None = None
+    """Default timeout in seconds for tool execution. None means no timeout."""
 
     @classmethod
     @contextmanager
@@ -62,6 +65,7 @@ async def for_run_step(self, ctx: RunContext[AgentDepsT]) -> ToolManager[AgentDe
             toolset=self.toolset,
             ctx=ctx,
             tools=await self.toolset.get_tools(ctx),
+            default_timeout=self.default_timeout,
         )
 
     @property
@@ -172,7 +176,23 @@ async def _call_tool(
                     call.args or {}, allow_partial=pyd_allow_partial, context=ctx.validation_context
                 )
 
-            result = await self.toolset.call_tool(name, args_dict, ctx, tool)
+            # Determine effective timeout: per-tool timeout takes precedence over default
+            effective_timeout = tool.timeout if tool.timeout is not None else self.default_timeout
+
+            if effective_timeout is not None:
+                try:
+                    with anyio.fail_after(effective_timeout):
+                        result = await self.toolset.call_tool(name, args_dict, ctx, tool)
+                except TimeoutError:
+                    m = _messages.RetryPromptPart(
+                        tool_name=name,
+                        content=f"Tool '{name}' timed out after {effective_timeout} seconds. Please try a different approach.",
+                        tool_call_id=call.tool_call_id,
+                    )
+                    self.failed_tools.add(name)
+                    raise ToolRetryError(m) from None
+            else:
+                result = await self.toolset.call_tool(name, args_dict, ctx, tool)
 
             return result
         except (ValidationError, ModelRetry) as e:

pydantic_ai_slim/pydantic_ai/agent/__init__.py

@@ -147,6 +147,7 @@ class Agent(AbstractAgent[AgentDepsT, OutputDataT]):
     _prepare_output_tools: ToolsPrepareFunc[AgentDepsT] | None = dataclasses.field(repr=False)
     _max_result_retries: int = dataclasses.field(repr=False)
     _max_tool_retries: int = dataclasses.field(repr=False)
+    _tool_timeout: float | None = dataclasses.field(repr=False)
     _validation_context: Any | Callable[[RunContext[AgentDepsT]], Any] = dataclasses.field(repr=False)
 
     _event_stream_handler: EventStreamHandler[AgentDepsT] | None = dataclasses.field(repr=False)
@@ -179,6 +180,7 @@ def __init__(
         instrument: InstrumentationSettings | bool | None = None,
         history_processors: Sequence[HistoryProcessor[AgentDepsT]] | None = None,
         event_stream_handler: EventStreamHandler[AgentDepsT] | None = None,
+        tool_timeout: float | None = None,
     ) -> None: ...
 
     @overload
@@ -206,6 +208,7 @@ def __init__(
         instrument: InstrumentationSettings | bool | None = None,
         history_processors: Sequence[HistoryProcessor[AgentDepsT]] | None = None,
         event_stream_handler: EventStreamHandler[AgentDepsT] | None = None,
+        tool_timeout: float | None = None,
     ) -> None: ...
 
     def __init__(
@@ -231,6 +234,7 @@ def __init__(
         instrument: InstrumentationSettings | bool | None = None,
         history_processors: Sequence[HistoryProcessor[AgentDepsT]] | None = None,
         event_stream_handler: EventStreamHandler[AgentDepsT] | None = None,
+        tool_timeout: float | None = None,
         **_deprecated_kwargs: Any,
     ):
         """Create an agent.
@@ -285,6 +289,9 @@ def __init__(
                 Each processor takes a list of messages and returns a modified list of messages.
                 Processors can be sync or async and are applied in sequence.
             event_stream_handler: Optional handler for events from the model's streaming response and the agent's execution of tools.
+            tool_timeout: Default timeout in seconds for tool execution. If a tool takes longer than this,
+                a retry prompt is returned to the model. Individual tools can override this with their own timeout.
+                Defaults to None (no timeout).
         """
         if model is None or defer_model_check:
             self._model = model
@@ -318,6 +325,7 @@ def __init__(
 
         self._max_result_retries = output_retries if output_retries is not None else retries
         self._max_tool_retries = retries
+        self._tool_timeout = tool_timeout
 
         self._validation_context = validation_context
 
@@ -569,7 +577,7 @@ async def main():
                 output_toolset.max_retries = self._max_result_retries
                 output_toolset.output_validators = output_validators
         toolset = self._get_toolset(output_toolset=output_toolset, additional_toolsets=toolsets)
-        tool_manager = ToolManager[AgentDepsT](toolset)
+        tool_manager = ToolManager[AgentDepsT](toolset, default_timeout=self._tool_timeout)
 
         # Build the graph
         graph = _agent_graph.build_agent_graph(self.name, self._deps_type, output_type_)
@@ -1031,6 +1039,7 @@ def tool(
         sequential: bool = False,
         requires_approval: bool = False,
         metadata: dict[str, Any] | None = None,
+        timeout: float | None = None,
     ) -> Callable[[ToolFuncContext[AgentDepsT, ToolParams]], ToolFuncContext[AgentDepsT, ToolParams]]: ...
 
     def tool(
@@ -1049,6 +1058,7 @@ def tool(
         sequential: bool = False,
         requires_approval: bool = False,
         metadata: dict[str, Any] | None = None,
+        timeout: float | None = None,
     ) -> Any:
         """Decorator to register a tool function which takes [`RunContext`][pydantic_ai.tools.RunContext] as its first argument.
 
@@ -1098,6 +1108,8 @@ async def spam(ctx: RunContext[str], y: float) -> float:
             requires_approval: Whether this tool requires human-in-the-loop approval. Defaults to False.
                 See the [tools documentation](../deferred-tools.md#human-in-the-loop-tool-approval) for more info.
             metadata: Optional metadata for the tool. This is not sent to the model but can be used for filtering and tool behavior customization.
+            timeout: Timeout in seconds for tool execution. If the tool takes longer, a retry prompt is returned to the model.
+                Defaults to None (no timeout). Overrides the agent-level `tool_timeout` if set.
         """
 
         def tool_decorator(
@@ -1118,6 +1130,7 @@ def tool_decorator(
                 sequential=sequential,
                 requires_approval=requires_approval,
                 metadata=metadata,
+                timeout=timeout,
             )
             return func_
 
@@ -1142,6 +1155,7 @@ def tool_plain(
         sequential: bool = False,
         requires_approval: bool = False,
         metadata: dict[str, Any] | None = None,
+        timeout: float | None = None,
     ) -> Callable[[ToolFuncPlain[ToolParams]], ToolFuncPlain[ToolParams]]: ...
 
     def tool_plain(
@@ -1160,6 +1174,7 @@ def tool_plain(
         sequential: bool = False,
         requires_approval: bool = False,
         metadata: dict[str, Any] | None = None,
+        timeout: float | None = None,
     ) -> Any:
         """Decorator to register a tool function which DOES NOT take `RunContext` as an argument.
 
@@ -1209,6 +1224,8 @@ async def spam(ctx: RunContext[str]) -> float:
             requires_approval: Whether this tool requires human-in-the-loop approval. Defaults to False.
                 See the [tools documentation](../deferred-tools.md#human-in-the-loop-tool-approval) for more info.
             metadata: Optional metadata for the tool. This is not sent to the model but can be used for filtering and tool behavior customization.
+            timeout: Timeout in seconds for tool execution. If the tool takes longer, a retry prompt is returned to the model.
+                Defaults to None (no timeout). Overrides the agent-level `tool_timeout` if set.
         """
 
         def tool_decorator(func_: ToolFuncPlain[ToolParams]) -> ToolFuncPlain[ToolParams]:
@@ -1227,6 +1244,7 @@ def tool_decorator(func_: ToolFuncPlain[ToolParams]) -> ToolFuncPlain[ToolParams
                 sequential=sequential,
                 requires_approval=requires_approval,
                 metadata=metadata,
+                timeout=timeout,
             )
             return func_
 

pydantic_ai_slim/pydantic_ai/tools.py

@@ -262,6 +262,7 @@ class Tool(Generic[ToolAgentDepsT]):
     sequential: bool
     requires_approval: bool
     metadata: dict[str, Any] | None
+    timeout: float | None
     function_schema: _function_schema.FunctionSchema
     """
     The base JSON schema for the tool's parameters.
@@ -285,6 +286,7 @@ def __init__(
         sequential: bool = False,
         requires_approval: bool = False,
         metadata: dict[str, Any] | None = None,
+        timeout: float | None = None,
         function_schema: _function_schema.FunctionSchema | None = None,
     ):
         """Create a new tool instance.
@@ -341,6 +343,8 @@ async def prep_my_tool(
             requires_approval: Whether this tool requires human-in-the-loop approval. Defaults to False.
                 See the [tools documentation](../deferred-tools.md#human-in-the-loop-tool-approval) for more info.
             metadata: Optional metadata for the tool. This is not sent to the model but can be used for filtering and tool behavior customization.
+            timeout: Timeout in seconds for tool execution. If the tool takes longer, a retry prompt is returned to the model.
+                Defaults to None (no timeout). Overrides the agent-level `tool_timeout` if set.
             function_schema: The function schema to use for the tool. If not provided, it will be generated.
         """
         self.function = function
@@ -362,6 +366,7 @@ async def prep_my_tool(
         self.sequential = sequential
         self.requires_approval = requires_approval
         self.metadata = metadata
+        self.timeout = timeout
 
     @classmethod
     def from_schema(
@@ -417,6 +422,7 @@ def tool_def(self):
             strict=self.strict,
             sequential=self.sequential,
             metadata=self.metadata,
+            timeout=self.timeout,
             kind='unapproved' if self.requires_approval else 'function',
         )
 
@@ -503,6 +509,13 @@ class ToolDefinition:
     For MCP tools, this contains the `meta`, `annotations`, and `output_schema` fields from the tool definition.
     """
 
+    timeout: float | None = None
+    """Timeout in seconds for tool execution.
+
+    If the tool takes longer than this, a retry prompt is returned to the model.
+    Defaults to None (no timeout). Overrides the agent-level `tool_timeout` if set.
+    """
+
     @property
     def defer(self) -> bool:
         """Whether calls to this tool will be deferred.

pydantic_ai_slim/pydantic_ai/toolsets/abstract.py

@@ -57,6 +57,12 @@ class ToolsetTool(Generic[AgentDepsT]):
 
     For example, a [`pydantic.TypeAdapter(...).validator`](https://docs.pydantic.dev/latest/concepts/type_adapter/) or [`pydantic_core.SchemaValidator`](https://docs.pydantic.dev/latest/api/pydantic_core/#pydantic_core.SchemaValidator).
     """
+    timeout: float | None = None
+    """Timeout in seconds for tool execution.
+
+    If the tool takes longer than this, a retry prompt is returned to the model.
+    Defaults to None (no timeout). Overrides the agent-level `tool_timeout` if set.
+    """
 
 
 class AbstractToolset(ABC, Generic[AgentDepsT]):

pydantic_ai_slim/pydantic_ai/toolsets/combined.py

@@ -80,6 +80,7 @@ async def get_tools(self, ctx: RunContext[AgentDepsT]) -> dict[str, ToolsetTool[
                     args_validator=tool.args_validator,
                     source_toolset=toolset,
                     source_tool=tool,
+                    timeout=tool.timeout,
                 )
         return all_tools
 

pydantic_ai_slim/pydantic_ai/toolsets/function.py

@@ -119,6 +119,7 @@ def tool(
         sequential: bool | None = None,
         requires_approval: bool | None = None,
         metadata: dict[str, Any] | None = None,
+        timeout: float | None = None,
     ) -> Callable[[ToolFuncEither[AgentDepsT, ToolParams]], ToolFuncEither[AgentDepsT, ToolParams]]: ...
 
     def tool(
@@ -137,6 +138,7 @@ def tool(
         sequential: bool | None = None,
         requires_approval: bool | None = None,
         metadata: dict[str, Any] | None = None,
+        timeout: float | None = None,
     ) -> Any:
         """Decorator to register a tool function which takes [`RunContext`][pydantic_ai.tools.RunContext] as its first argument.
 
@@ -193,6 +195,8 @@ async def spam(ctx: RunContext[str], y: float) -> float:
                 If `None`, the default value is determined by the toolset.
             metadata: Optional metadata for the tool. This is not sent to the model but can be used for filtering and tool behavior customization.
                 If `None`, the default value is determined by the toolset. If provided, it will be merged with the toolset's metadata.
+            timeout: Timeout in seconds for tool execution. If the tool takes longer, a retry prompt is returned to the model.
+                Defaults to None (no timeout). Overrides the agent-level `tool_timeout` if set.
         """
 
         def tool_decorator(
@@ -213,6 +217,7 @@ def tool_decorator(
                 sequential=sequential,
                 requires_approval=requires_approval,
                 metadata=metadata,
+                timeout=timeout,
             )
             return func_
 
@@ -233,6 +238,7 @@ def add_function(
         sequential: bool | None = None,
         requires_approval: bool | None = None,
         metadata: dict[str, Any] | None = None,
+        timeout: float | None = None,
     ) -> None:
         """Add a function as a tool to the toolset.
 
@@ -267,6 +273,8 @@ def add_function(
                 If `None`, the default value is determined by the toolset.
             metadata: Optional metadata for the tool. This is not sent to the model but can be used for filtering and tool behavior customization.
                 If `None`, the default value is determined by the toolset. If provided, it will be merged with the toolset's metadata.
+            timeout: Timeout in seconds for tool execution. If the tool takes longer, a retry prompt is returned to the model.
+                Defaults to None (no timeout). Overrides the agent-level `tool_timeout` if set.
         """
         if docstring_format is None:
             docstring_format = self.docstring_format
@@ -295,6 +303,7 @@ def add_function(
             sequential=sequential,
             requires_approval=requires_approval,
             metadata=metadata,
+            timeout=timeout,
         )
         self.add_tool(tool)
 
@@ -340,6 +349,7 @@ async def get_tools(self, ctx: RunContext[AgentDepsT]) -> dict[str, ToolsetTool[
                 args_validator=tool.function_schema.validator,
                 call_func=tool.function_schema.call,
                 is_async=tool.function_schema.is_async,
+                timeout=tool_def.timeout,
             )
         return tools
 

tests/models/test_model_request_parameters.py

@@ -68,6 +68,7 @@ def test_model_request_parameters_are_serializable():
                     'sequential': False,
                     'kind': 'function',
                     'metadata': None,
+                    'timeout': None,
                 }
             ],
             'builtin_tools': [
@@ -131,6 +132,7 @@ def test_model_request_parameters_are_serializable():
                     'sequential': False,
                     'kind': 'function',
                     'metadata': None,
+                    'timeout': None,
                 }
             ],
             'prompted_output_template': None,

tests/test_logfire.py

@@ -547,6 +547,7 @@ async def my_ret(x: int) -> str:
                                 'sequential': False,
                                 'kind': 'function',
                                 'metadata': None,
+                                'timeout': None,
                             }
                         ],
                         'builtin_tools': [],
@@ -994,6 +995,7 @@ class MyOutput:
                                 'sequential': False,
                                 'kind': 'output',
                                 'metadata': None,
+                                'timeout': None,
                             }
                         ],
                         'prompted_output_template': None,