openai/openai-python · error · ValueError

Expected a non-empty value for `thread_id` but received {thr

Error message

Expected a non-empty value for `thread_id` but received {thread_id!r}

What it means

The sync Runs.create() method requires a non-empty `thread_id`. The SDK raises ValueError before POSTing to /threads/{thread_id}/runs if the value is empty, None, or falsy.

Source

Thrown at src/openai/resources/beta/threads/runs/runs.py:574

        model: Union[str, ChatModel, None] | Omit = omit,
        parallel_tool_calls: bool | Omit = omit,
        reasoning_effort: Optional[ReasoningEffort] | Omit = omit,
        response_format: Optional[AssistantResponseFormatOptionParam] | Omit = omit,
        stream: Optional[Literal[False]] | Literal[True] | Omit = omit,
        temperature: Optional[float] | Omit = omit,
        tool_choice: Optional[AssistantToolChoiceOptionParam] | Omit = omit,
        tools: Optional[Iterable[AssistantToolParam]] | Omit = omit,
        top_p: Optional[float] | Omit = omit,
        truncation_strategy: Optional[run_create_params.TruncationStrategy] | Omit = omit,
        # Use the following arguments if you need to pass additional parameters to the API that aren't available via kwargs.
        # The extra values given here take precedence over values defined on the client or passed to this method.
        extra_headers: Headers | None = None,
        extra_query: Query | None = None,
        extra_body: Body | None = None,
        timeout: float | httpx2.Timeout | None | NotGiven = not_given,
    ) -> Run | Stream[AssistantStreamEvent]:
        if not thread_id:
            raise ValueError(f"Expected a non-empty value for `thread_id` but received {thread_id!r}")
        extra_headers = {"OpenAI-Beta": "assistants=v2", **(extra_headers or {})}
        return self._post(
            path_template("/threads/{thread_id}/runs", thread_id=thread_id),
            body=maybe_transform(
                {
                    "assistant_id": assistant_id,
                    "additional_instructions": additional_instructions,
                    "additional_messages": additional_messages,
                    "instructions": instructions,
                    "max_completion_tokens": max_completion_tokens,
                    "max_prompt_tokens": max_prompt_tokens,
                    "metadata": metadata,
                    "model": model,
                    "parallel_tool_calls": parallel_tool_calls,
                    "reasoning_effort": reasoning_effort,
                    "response_format": response_format,
                    "stream": stream,
                    "temperature": temperature,

View on GitHub (pinned to 9917c6e28e)

Solutions

Create the thread first and pass `thread.id` to the run
Validate `thread_id` is a non-empty string before creating the run
If the id arrives from user input or a queue, validate it at ingestion

Example fix

// before
run = client.beta.threads.runs.create(thread_id="", assistant_id=assistant_id)

// after
thread = client.beta.threads.create()
run = client.beta.threads.runs.create(thread_id=thread.id, assistant_id=assistant_id)

Defensive patterns

Strategy: validation

Validate before calling

if not thread_id:
    raise ValueError("thread_id is required to create a run")

Type guard

def is_valid_thread_id(thread_id: object) -> bool:
    return isinstance(thread_id, str) and bool(thread_id.strip())

Try / catch

try:
    run = client.beta.threads.runs.create(thread_id=thread_id, assistant_id=assistant_id)
except ValueError as e:
    logging.error("cannot start run: %s", e)
    raise

Prevention

Create the thread before the run in the same function
Pass ids explicitly between functions
Reject empty thread ids at input boundaries

When it happens

Trigger: Calling `client.beta.threads.runs.create(thread_id="", assistant_id="asst_...")`, or passing an undefined/None thread variable when starting a run.

Common situations: Running an assistant on a thread that was never created; thread id lost between functions or tasks; using an empty string as a placeholder in scaffolding code.

Understand the failure class

Background: Missing required parameter errors: what 'X is required' and 'the required X param is missing' mean, and how to fix them — this error's family across 27 libraries.

Related errors

AI-assisted analysis of openai/openai-python@9917c6e28e (2026-08-28). Data as JSON: /api/errors/fef3fdd3aecc47de. Report an issue: GitHub.