pydantic_ai.ag_ui
Provides an AG-UI protocol adapter for the Pydantic AI agent.
This package provides seamless integration between pydantic-ai agents and ag-ui for building interactive AI applications with streaming event-based communication.
SSE_CONTENT_TYPE
module-attribute
SSE_CONTENT_TYPE = 'text/event-stream'
Content type header value for Server-Sent Events (SSE).
OnCompleteFunc
module-attribute
OnCompleteFunc: TypeAlias = (
Callable[[AgentRunResult[Any]], None]
| Callable[[AgentRunResult[Any]], Awaitable[None]]
| Callable[[AgentRunResult[Any]], AsyncIterator[EventT]]
)
Callback function type that receives the AgentRunResult of the completed run. Can be sync, async, or an async generator of protocol-specific events.
StateDeps
dataclass
Bases: Generic[StateT]
Dependency type that holds state.
This class is used to manage the state of an agent run. It allows setting
the state of the agent run with a specific type of state model, which must
be a subclass of BaseModel.
The state is set using the state setter by the Adapter when the run starts.
Implements the StateHandler protocol.
Source code in pydantic_ai_slim/pydantic_ai/ui/_adapter.py
86 87 88 89 90 91 92 93 94 95 96 97 98 99 | |
StateHandler
Bases: Protocol
Protocol for state handlers in agent runs. Requires the class to be a dataclass with a state field.
Source code in pydantic_ai_slim/pydantic_ai/ui/_adapter.py
60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 | |
AGUIApp
Bases: Generic[AgentDepsT, OutputDataT], Starlette
ASGI application for running Pydantic AI agents with AG-UI protocol support.
Source code in pydantic_ai_slim/pydantic_ai/ui/ag_ui/app.py
38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 | |
__init__
__init__(
agent: AbstractAgent[AgentDepsT, OutputDataT],
*,
output_type: OutputSpec[Any] | None = None,
message_history: Sequence[ModelMessage] | None = None,
deferred_tool_results: (
DeferredToolResults | None
) = None,
model: Model | KnownModelName | str | None = None,
deps: AgentDepsT = None,
model_settings: ModelSettings | None = None,
usage_limits: UsageLimits | None = None,
usage: RunUsage | None = None,
infer_name: bool = True,
toolsets: (
Sequence[AbstractToolset[AgentDepsT]] | None
) = None,
builtin_tools: (
Sequence[AbstractBuiltinTool] | None
) = None,
on_complete: OnCompleteFunc[Any] | None = None,
debug: bool = False,
routes: Sequence[BaseRoute] | None = None,
middleware: Sequence[Middleware] | None = None,
exception_handlers: (
Mapping[Any, ExceptionHandler] | None
) = None,
on_startup: Sequence[Callable[[], Any]] | None = None,
on_shutdown: Sequence[Callable[[], Any]] | None = None,
lifespan: Lifespan[Self] | None = None
) -> None
An ASGI application that handles every request by running the agent and streaming the response.
Note that the deps will be the same for each request, with the exception of the frontend state that's
injected into the state field of a deps object that implements the StateHandler protocol.
To provide different deps for each request (e.g. based on the authenticated user),
use AGUIAdapter.run_stream() or
AGUIAdapter.dispatch_request() instead.
Parameters:
| Name | Type | Description | Default |
|---|---|---|---|
agent
|
AbstractAgent[AgentDepsT, OutputDataT]
|
The agent to run. |
required |
output_type
|
OutputSpec[Any] | None
|
Custom output type to use for this run, |
None
|
message_history
|
Sequence[ModelMessage] | None
|
History of the conversation so far. |
None
|
deferred_tool_results
|
DeferredToolResults | None
|
Optional results for deferred tool calls in the message history. |
None
|
model
|
Model | KnownModelName | str | None
|
Optional model to use for this run, required if |
None
|
deps
|
AgentDepsT
|
Optional dependencies to use for this run. |
None
|
model_settings
|
ModelSettings | None
|
Optional settings to use for this model's request. |
None
|
usage_limits
|
UsageLimits | None
|
Optional limits on model request count or token usage. |
None
|
usage
|
RunUsage | None
|
Optional usage to start with, useful for resuming a conversation or agents used in tools. |
None
|
infer_name
|
bool
|
Whether to try to infer the agent name from the call frame if it's not set. |
True
|
toolsets
|
Sequence[AbstractToolset[AgentDepsT]] | None
|
Optional additional toolsets for this run. |
None
|
builtin_tools
|
Sequence[AbstractBuiltinTool] | None
|
Optional additional builtin tools for this run. |
None
|
on_complete
|
OnCompleteFunc[Any] | None
|
Optional callback function called when the agent run completes successfully.
The callback receives the completed |
None
|
debug
|
bool
|
Boolean indicating if debug tracebacks should be returned on errors. |
False
|
routes
|
Sequence[BaseRoute] | None
|
A list of routes to serve incoming HTTP and WebSocket requests. |
None
|
middleware
|
Sequence[Middleware] | None
|
A list of middleware to run for every request. A starlette application will always
automatically include two middleware classes. |
None
|
exception_handlers
|
Mapping[Any, ExceptionHandler] | None
|
A mapping of either integer status codes, or exception class types onto
callables which handle the exceptions. Exception handler callables should be of the form
|
None
|
on_startup
|
Sequence[Callable[[], Any]] | None
|
A list of callables to run on application startup. Startup handler callables do not take any arguments, and may be either standard functions, or async functions. |
None
|
on_shutdown
|
Sequence[Callable[[], Any]] | None
|
A list of callables to run on application shutdown. Shutdown handler callables do not take any arguments, and may be either standard functions, or async functions. |
None
|
lifespan
|
Lifespan[Self] | None
|
A lifespan context function, which can be used to perform startup and shutdown tasks.
This is a newer style that replaces the |
None
|
Source code in pydantic_ai_slim/pydantic_ai/ui/ag_ui/app.py
41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 | |
handle_ag_ui_request
async
handle_ag_ui_request(
agent: AbstractAgent[AgentDepsT, Any],
request: Request,
*,
output_type: OutputSpec[Any] | None = None,
message_history: Sequence[ModelMessage] | None = None,
deferred_tool_results: (
DeferredToolResults | None
) = None,
model: Model | KnownModelName | str | None = None,
deps: AgentDepsT = None,
model_settings: ModelSettings | None = None,
usage_limits: UsageLimits | None = None,
usage: RunUsage | None = None,
infer_name: bool = True,
toolsets: (
Sequence[AbstractToolset[AgentDepsT]] | None
) = None,
on_complete: OnCompleteFunc[BaseEvent] | None = None
) -> Response
Handle an AG-UI request by running the agent and returning a streaming response.
Parameters:
| Name | Type | Description | Default |
|---|---|---|---|
agent
|
AbstractAgent[AgentDepsT, Any]
|
The agent to run. |
required |
request
|
Request
|
The Starlette request (e.g. from FastAPI) containing the AG-UI run input. |
required |
output_type
|
OutputSpec[Any] | None
|
Custom output type to use for this run, |
None
|
message_history
|
Sequence[ModelMessage] | None
|
History of the conversation so far. |
None
|
deferred_tool_results
|
DeferredToolResults | None
|
Optional results for deferred tool calls in the message history. |
None
|
model
|
Model | KnownModelName | str | None
|
Optional model to use for this run, required if |
None
|
deps
|
AgentDepsT
|
Optional dependencies to use for this run. |
None
|
model_settings
|
ModelSettings | None
|
Optional settings to use for this model's request. |
None
|
usage_limits
|
UsageLimits | None
|
Optional limits on model request count or token usage. |
None
|
usage
|
RunUsage | None
|
Optional usage to start with, useful for resuming a conversation or agents used in tools. |
None
|
infer_name
|
bool
|
Whether to try to infer the agent name from the call frame if it's not set. |
True
|
toolsets
|
Sequence[AbstractToolset[AgentDepsT]] | None
|
Optional additional toolsets for this run. |
None
|
on_complete
|
OnCompleteFunc[BaseEvent] | None
|
Optional callback function called when the agent run completes successfully.
The callback receives the completed |
None
|
Returns:
| Type | Description |
|---|---|
Response
|
A streaming Starlette response with AG-UI protocol events. |
Source code in pydantic_ai_slim/pydantic_ai/ag_ui.py
51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 | |
run_ag_ui
run_ag_ui(
agent: AbstractAgent[AgentDepsT, Any],
run_input: RunAgentInput,
accept: str = SSE_CONTENT_TYPE,
*,
output_type: OutputSpec[Any] | None = None,
message_history: Sequence[ModelMessage] | None = None,
deferred_tool_results: (
DeferredToolResults | None
) = None,
model: Model | KnownModelName | str | None = None,
deps: AgentDepsT = None,
model_settings: ModelSettings | None = None,
usage_limits: UsageLimits | None = None,
usage: RunUsage | None = None,
infer_name: bool = True,
toolsets: (
Sequence[AbstractToolset[AgentDepsT]] | None
) = None,
on_complete: OnCompleteFunc[BaseEvent] | None = None
) -> AsyncIterator[str]
Run the agent with the AG-UI run input and stream AG-UI protocol events.
Parameters:
| Name | Type | Description | Default |
|---|---|---|---|
agent
|
AbstractAgent[AgentDepsT, Any]
|
The agent to run. |
required |
run_input
|
RunAgentInput
|
The AG-UI run input containing thread_id, run_id, messages, etc. |
required |
accept
|
str
|
The accept header value for the run. |
SSE_CONTENT_TYPE
|
output_type
|
OutputSpec[Any] | None
|
Custom output type to use for this run, |
None
|
message_history
|
Sequence[ModelMessage] | None
|
History of the conversation so far. |
None
|
deferred_tool_results
|
DeferredToolResults | None
|
Optional results for deferred tool calls in the message history. |
None
|
model
|
Model | KnownModelName | str | None
|
Optional model to use for this run, required if |
None
|
deps
|
AgentDepsT
|
Optional dependencies to use for this run. |
None
|
model_settings
|
ModelSettings | None
|
Optional settings to use for this model's request. |
None
|
usage_limits
|
UsageLimits | None
|
Optional limits on model request count or token usage. |
None
|
usage
|
RunUsage | None
|
Optional usage to start with, useful for resuming a conversation or agents used in tools. |
None
|
infer_name
|
bool
|
Whether to try to infer the agent name from the call frame if it's not set. |
True
|
toolsets
|
Sequence[AbstractToolset[AgentDepsT]] | None
|
Optional additional toolsets for this run. |
None
|
on_complete
|
OnCompleteFunc[BaseEvent] | None
|
Optional callback function called when the agent run completes successfully.
The callback receives the completed |
None
|
Yields:
| Type | Description |
|---|---|
AsyncIterator[str]
|
Streaming event chunks encoded as strings according to the accept header value. |
Source code in pydantic_ai_slim/pydantic_ai/ag_ui.py
107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 | |