Implementation:Microsoft Agent framework AgentFactory Init

Knowledge Sources	Microsoft Agent Framework Agent Framework Declarative
Domains	Declarative_Systems, Agent_Architecture
Last Updated	2026-02-11 00:00 GMT

Overview

Concrete constructor for the AgentFactory class that initializes the factory with shared configuration for creating Agent instances from declarative YAML definitions.

Description

The AgentFactory.__init__ method stores the shared chat client, tool bindings, connection credentials, provider mappings, and safety settings that will be applied to every agent the factory creates. It merges any user-supplied additional_mappings with the built-in PROVIDER_TYPE_OBJECT_MAPPING table, sets the default provider key, and loads environment variables from an optional .env file via dotenv.

All parameters are keyword-only. When client is omitted, the factory will instantiate a chat client from the provider mapping at agent creation time based on the YAML model definition. When safe_mode is True (the default), PowerFx expressions in YAML definitions cannot access environment variables directly, enforcing credential management through constructor parameters.

Usage

Import AgentFactory from the declarative package and construct it with the desired shared configuration. Then call create_agent_from_yaml_path() or create_agent_from_yaml() to produce Agent instances.

Code Reference

Source Location

Repository: agent-framework
File: python/packages/declarative/agent_framework_declarative/_loader.py
Lines: L119-263

Signature

class AgentFactory:
    def __init__(
        self,
        *,
        client: SupportsChatGetResponse | None = None,
        bindings: Mapping[str, Any] | None = None,
        connections: Mapping[str, Any] | None = None,
        client_kwargs: Mapping[str, Any] | None = None,
        additional_mappings: Mapping[str, ProviderTypeMapping] | None = None,
        default_provider: str = "AzureAIClient",
        safe_mode: bool = True,
        env_file_path: str | None = None,
        env_file_encoding: str | None = None,
    ) -> None:

Import

from agent_framework.declarative import AgentFactory

I/O Contract

Inputs

Name	Type	Required	Description
client	SupportsChatGetResponse or None	No	Shared chat client instance passed to every created Agent. When omitted, the factory instantiates a client from the YAML model definition's provider field.
bindings	Mapping[str, Any] or None	No	Dictionary mapping tool names (strings) to Python callables. Allows YAML definitions to reference tools by name.
connections	Mapping[str, Any] or None	No	Dictionary of connection objects used to resolve ReferenceConnection entries in YAML definitions.
client_kwargs	Mapping[str, Any] or None	No	Additional keyword arguments forwarded to the chat client constructor when the factory instantiates a client from a provider mapping.
additional_mappings	Mapping[str, ProviderTypeMapping] or None	No	Dictionary extending the built-in provider registry. Each entry maps a provider key (e.g., `"CustomProvider.Chat"`) to a ProviderTypeMapping with `package`, `name`, and `model_id_field`.
default_provider	str	No (default: "AzureAIClient")	Provider key used when the YAML model definition does not specify a `provider` field.
safe_mode	bool	No (default: True)	When True, blocks environment variable access in PowerFx expressions within YAML definitions. Set to False only when the YAML source is trusted.
env_file_path	str or None	No	Path to a `.env` file from which to load environment variables via `dotenv`.
env_file_encoding	str or None	No	Character encoding of the `.env` file (defaults to utf-8).

Outputs

Name	Type	Description
instance	AgentFactory	Initialized factory instance ready to create Agent objects from YAML definitions via `create_agent_from_yaml_path()` or `create_agent_from_yaml()`.

Instance Attributes Set

Attribute	Type	Description
self.client	SupportsChatGetResponse or None	The shared chat client, or None if per-agent client creation is deferred to YAML resolution.
self.bindings	Mapping[str, Any] or None	The tool bindings dictionary as provided.
self.connections	Mapping[str, Any] or None	The connection credentials dictionary as provided.
self.client_kwargs	Mapping[str, Any]	Keyword arguments for client construction (defaults to empty dict).
self.additional_mappings	Mapping[str, ProviderTypeMapping]	Extended provider mappings (defaults to empty dict).
self.default_provider	str	The default provider key string.
self.safe_mode	bool	Whether safe mode is enabled.

Usage Examples

Basic Initialization With Shared Client

from agent_framework.declarative import AgentFactory
from agent_framework.azure import AzureOpenAIResponsesClient
from azure.identity import AzureCliCredential

factory = AgentFactory(
    client=AzureOpenAIResponsesClient(credential=AzureCliCredential()),
    bindings={"get_weather": get_weather},
)

agent = factory.create_agent_from_yaml_path("weather_agent.yaml")

Minimal Initialization

from agent_framework.declarative import AgentFactory

# Let YAML definitions specify their own provider and model
factory = AgentFactory()
agent = factory.create_agent_from_yaml_path("agent.yaml")

With Custom Provider Mappings

from agent_framework.declarative import AgentFactory

factory = AgentFactory(
    additional_mappings={
        "CustomProvider.Chat": {
            "package": "my_package.clients",
            "name": "CustomChatClient",
            "model_id_field": "model_name",
        },
    },
    default_provider="CustomProvider.Chat",
)

With Environment File and Explicit Connections

from agent_framework.declarative import AgentFactory

factory = AgentFactory(
    env_file_path=".env",
    env_file_encoding="utf-8",
    connections={"my_api": api_connection},
    safe_mode=False,  # trust the YAML source
)

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