oobabooga/textgen · error · InvalidRequestError

messages: missing content

Error message

messages: missing content

What it means

Every message must have non-null 'content', except assistant messages that carry 'tool_calls' (OpenAI permits content:null there; the server coerces those to empty string). Any other message whose content is None (or absent) raises InvalidRequestError (400, param='messages').

Source

Thrown at modules/api/completions.py:509

    tool_choice = body.get('tool_choice', None)
    if tool_choice == "none":
        tools = None  # Disable tool detection entirely

    messages = body['messages']
    for m in messages:
        if 'role' not in m:
            raise InvalidRequestError(message="messages: missing role", param='messages')
        elif m['role'] == 'function':
            raise InvalidRequestError(message="role: function is not supported.", param='messages')

        # Handle multimodal content validation
        content = m.get('content')
        if content is None:
            # OpenAI allows content: null on assistant messages when tool_calls is present
            if m['role'] == 'assistant' and m.get('tool_calls'):
                m['content'] = ''
            else:
                raise InvalidRequestError(message="messages: missing content", param='messages')

        # Validate multimodal content structure
        if isinstance(content, list):
            for item in content:
                if not isinstance(item, dict) or 'type' not in item:
                    raise InvalidRequestError(message="messages: invalid content item format", param='messages')
                if item['type'] not in ['text', 'image_url']:
                    raise InvalidRequestError(message="messages: unsupported content type", param='messages')
                if item['type'] == 'text' and 'text' not in item:
                    raise InvalidRequestError(message="messages: missing text in content item", param='messages')
                if item['type'] == 'image_url' and ('image_url' not in item or 'url' not in item['image_url']):
                    raise InvalidRequestError(message="messages: missing image_url in content item", param='messages')

    # Chat Completions
    object_type = 'chat.completion' if not stream else 'chat.completion.chunk'
    created_time = int(time.time())
    cmpl_id = "chatcmpl-%d" % (int(time.time() * 1000000000))
    resp_list = 'data' if is_legacy else 'choices'

View on GitHub (pinned to ed888c71f2)

Solutions

  1. Set content to a string (empty "" is acceptable) for every non-tool-call message.
  2. For assistant tool-call messages, include a non-empty 'tool_calls' array if content is null, or just set content to ''.
  3. Guard client-side: replace None content with '' before sending.

Example fix

# before
messages.append({"role": "user", "content": None if not q else q})

# after
messages.append({"role": "user", "content": q or ""})
Defensive patterns

Strategy: validation

Validate before calling

def ensure_content(messages):
    for m in messages:
        if m.get('content') is None:
            if m.get('role') == 'assistant' and m.get('tool_calls'):
                m['content'] = ''
            else:
                m['content'] = ''  # or raise your own error before the API call
    return messages

Type guard

def message_has_content(m) -> bool:
    return m.get('content') is not None or (m.get('role') == 'assistant' and bool(m.get('tool_calls')))

Try / catch

try:
    resp = client.chat.completions.create(model=m, messages=msgs)
except openai.BadRequestError as e:
    if 'missing content' in str(e):
        msgs = ensure_content(msgs)
        resp = client.chat.completions.create(model=m, messages=msgs)
    else:
        raise

Prevention

When it happens

Trigger: POST /v1/chat/completions with {"role": "user", "content": null}, a message dict that omits 'content', or an assistant tool-call message where content is null but 'tool_calls' is also missing/empty.

Common situations: Client code doing messages.append({"role": "user", "content": user_input}) with user_input=None; multimodal pipelines that null out content; sending an assistant message with tool_calls=[] (falsy) plus content:null, which fails the exception branch.

Related errors

AI-assisted analysis of oobabooga/textgen@ed888c71f2 (2026-08-15). Data as JSON: /api/errors/6e17ff0005013f51. Report an issue: GitHub.