microsoft/semantic-kernel · error · AgentInitializationException

Missing required 'client' in OpenAIResponsesAgent._from_dict

Error message

Missing required 'client' in OpenAIResponsesAgent._from_dict()

What it means

Raised by OpenAIResponsesAgent._from_dict() when the kwargs passed in do not contain a 'client' key (or it is None). The declarative-spec deserialization path requires a pre-built AsyncOpenAI client because the spec YAML describes the agent, not its credentials; the client must be supplied externally.

Source

Thrown at python/semantic_kernel/agents/open_ai/openai_responses_agent.py:542

        *,
        kernel: Kernel,
        prompt_template_config: "PromptTemplateConfig | None" = None,
        **kwargs,
    ) -> _T:
        """Create an Assistant Agent from the provided dictionary.

        Args:
            data: The dictionary containing the agent data.
            kernel: The kernel to use for the agent.
            prompt_template_config: The prompt template configuration.
            kwargs: Additional keyword arguments. Note: unsupported keys may raise validation errors.

        Returns:
            AzureAIAgent: The OpenAI Assistant Agent instance.
        """
        client: AsyncOpenAI = kwargs.pop("client", None)
        if client is None:
            raise AgentInitializationException("Missing required 'client' in OpenAIResponsesAgent._from_dict()")

        spec = AgentSpec.model_validate(data)

        if "settings" in kwargs:
            kwargs.pop("settings")

        args = data.pop("arguments", None)
        arguments = None
        if args:
            arguments = KernelArguments(**args)

        # Handle arguments from kwargs, merging with any arguments from data
        if "arguments" in kwargs and kwargs["arguments"] is not None:
            incoming_args = kwargs["arguments"]
            arguments = arguments | incoming_args if arguments is not None else incoming_args

        if not (spec.model and spec.model.id):
            raise AgentInitializationException("model.id required when creating a new OpenAI Responses Agent.")

View on GitHub (pinned to c028a0c7dc)

Solutions

1. Build the client first (create_client()) and pass it: agent = OpenAIResponsesAgent.from_dict(data, kernel=kernel, client=client).
2. Ensure the kwargs key is exactly 'client' (not 'openai_client' or 'async_client').
3. If loading many agents from spec, create the client once and reuse it across from_dict calls.

Example fix

// before
agent = OpenAIResponsesAgent.from_dict(spec, kernel=kernel)

// after
client = OpenAIResponsesAgent.create_client()
agent = OpenAIResponsesAgent.from_dict(spec, kernel=kernel, client=client)

client = kwargs.get('client')
if client is None:
    client = OpenAIResponsesAgent.create_client()
agent = OpenAIResponsesAgent.from_dict(data, kernel=kernel, client=client)

from openai import AsyncOpenAI
def has_valid_client(kwargs) -> bool:
    return isinstance(kwargs.get('client'), AsyncOpenAI)

from semantic_kernel.exceptions.agent_exceptions import AgentInitializationException
try:
    agent = OpenAIResponsesAgent.from_dict(data, kernel=kernel, client=client)
except AgentInitializationException as e:
    if 'client' in str(e):
        client = OpenAIResponsesAgent.create_client()
        agent = OpenAIResponsesAgent.from_dict(data, kernel=kernel, client=client)
    raise

When it happens

Trigger: Calling OpenAIResponsesAgent.from_dict(data, kernel=..., client=...) without providing client, or passing client=None. The method does not construct a client from settings — it expects one already instantiated.

Common situations: Loading an agent from a declarative YAML/JSON file and forgetting to thread the client through, or assuming from_dict() will read env vars like the constructor does. Common when wiring agents dynamically from config.

Related errors

• Missing required 'client' in AzureAIAgent._from_dict()
• Expected AzureOpenAISettings, got {type(settings).__name__}
• Expected AzureOpenAISettings, got {type(settings).__name__}
• Missing required 'client' in OpenAIAssistantAgent._from_dict
• model.id required when creating a new OpenAI Responses Agent

AI-assisted analysis of microsoft/semantic-kernel@c028a0c7dc (2026-08-13). Data as JSON: /api/errors/aa28b2f15e0bf9dd. Report an issue: GitHub.