> ## Documentation Index > Fetch the complete documentation index at: https://docs.agentwire.io/llms.txt > Use this file to discover all available pages before exploring further. # Types > Documentation for the core types used in the Agent User Interaction Protocol Python SDK # Core Types The Agent User Interaction Protocol Python SDK is built on a set of core types that represent the fundamental structures used throughout the system. This page documents these types and their properties. ## RunAgentInput `from ag_ui.core import RunAgentInput` Input parameters for running an agent. In the HTTP API, this is the body of the `POST` request. ```python theme={null} class RunAgentInput(ConfiguredBaseModel): thread_id: str run_id: str state: Any messages: List[Message] tools: List[Tool] context: List[Context] forwarded_props: Any ``` | Property | Type | Description | | ----------------- | --------------- | --------------------------------------------- | | `thread_id` | `str` | ID of the conversation thread | | `run_id` | `str` | ID of the current run | | `state` | `Any` | Current state of the agent | | `messages` | `List[Message]` | List of messages in the conversation | | `tools` | `List[Tool]` | List of tools available to the agent | | `context` | `List[Context]` | List of context objects provided to the agent | | `forwarded_props` | `Any` | Additional properties forwarded to the agent | ## Message Types The SDK includes several message types that represent different kinds of messages in the system. ### Role `from ag_ui.core import Role` Represents the possible roles a message sender can have. ```python theme={null} Role = Literal["developer", "system", "assistant", "user", "tool"] ``` ### DeveloperMessage `from ag_ui.core import DeveloperMessage` Represents a message from a developer. ```python theme={null} class DeveloperMessage(BaseMessage): role: Literal["developer"] content: str ``` | Property | Type | Description | | --------- | ---------------------- | ------------------------------------------------ | | `id` | `str` | Unique identifier for the message | | `role` | `Literal["developer"]` | Role of the message sender, fixed as "developer" | | `content` | `str` | Text content of the message (required) | | `name` | `Optional[str]` | Optional name of the sender | ### SystemMessage `from ag_ui.core import SystemMessage` Represents a system message. ```python theme={null} class SystemMessage(BaseMessage): role: Literal["system"] content: str ``` | Property | Type | Description | | --------- | ------------------- | --------------------------------------------- | | `id` | `str` | Unique identifier for the message | | `role` | `Literal["system"]` | Role of the message sender, fixed as "system" | | `content` | `str` | Text content of the message (required) | | `name` | `Optional[str]` | Optional name of the sender | ### AssistantMessage `from ag_ui.core import AssistantMessage` Represents a message from an assistant. ```python theme={null} class AssistantMessage(BaseMessage): role: Literal["assistant"] content: Optional[str] = None tool_calls: Optional[List[ToolCall]] = None ``` | Property | Type | Description | | ------------ | -------------------------- | ------------------------------------------------ | | `id` | `str` | Unique identifier for the message | | `role` | `Literal["assistant"]` | Role of the message sender, fixed as "assistant" | | `content` | `Optional[str]` | Text content of the message | | `name` | `Optional[str]` | Name of the sender | | `tool_calls` | `Optional[List[ToolCall]]` | Tool calls made in this message | ### UserMessage `from ag_ui.core import UserMessage` Represents a message from a user. ```python theme={null} class UserMessage(BaseMessage): role: Literal["user"] content: str ``` | Property | Type | Description | | --------- | ----------------- | ------------------------------------------- | | `id` | `str` | Unique identifier for the message | | `role` | `Literal["user"]` | Role of the message sender, fixed as "user" | | `content` | `str` | Text content of the message (required) | | `name` | `Optional[str]` | Optional name of the sender | ### ToolMessage `from ag_ui.core import ToolMessage` Represents a message from a tool. ```python theme={null} class ToolMessage(ConfiguredBaseModel): id: str role: Literal["tool"] content: str tool_call_id: str ``` | Property | Type | Description | | -------------- | ----------------- | -------------------------------------------- | | `id` | `str` | Unique identifier for the message | | `content` | `str` | Text content of the message | | `role` | `Literal["tool"]` | Role of the message sender, fixed as "tool" | | `tool_call_id` | `str` | ID of the tool call this message responds to | ### Message `from ag_ui.core import Message` A union type representing any type of message in the system. ```python theme={null} Message = Annotated[ Union[DeveloperMessage, SystemMessage, AssistantMessage, UserMessage, ToolMessage], Field(discriminator="role") ] ``` ### ToolCall `from ag_ui.core import ToolCall` Represents a tool call made by an agent. ```python theme={null} class ToolCall(ConfiguredBaseModel): id: str type: Literal["function"] function: FunctionCall ``` | Property | Type | Description | | ---------- | --------------------- | ---------------------------------------- | | `id` | `str` | Unique identifier for the tool call | | `type` | `Literal["function"]` | Type of the tool call, always "function" | | `function` | `FunctionCall` | Details about the function being called | #### FunctionCall `from ag_ui.core import FunctionCall` Represents function name and arguments in a tool call. ```python theme={null} class FunctionCall(ConfiguredBaseModel): name: str arguments: str ``` | Property | Type | Description | | ----------- | ----- | ------------------------------------------------ | | `name` | `str` | Name of the function to call | | `arguments` | `str` | JSON-encoded string of arguments to the function | ## Context `from ag_ui.core import Context` Represents a piece of contextual information provided to an agent. ```python theme={null} class Context(ConfiguredBaseModel): description: str value: str ``` | Property | Type | Description | | ------------- | ----- | ------------------------------------------- | | `description` | `str` | Description of what this context represents | | `value` | `str` | The actual context value | ## Tool `from ag_ui.core import Tool` Defines a tool that can be called by an agent. ```python theme={null} class Tool(ConfiguredBaseModel): name: str description: str parameters: Any # JSON Schema ``` | Property | Type | Description | | ------------- | ----- | ------------------------------------------------ | | `name` | `str` | Name of the tool | | `description` | `str` | Description of what the tool does | | `parameters` | `Any` | JSON Schema defining the parameters for the tool | ## State `from ag_ui.core import State` Represents the state of an agent during execution. ```python theme={null} State = Any ``` The state type is flexible and can hold any data structure needed by the agent implementation.