OpenAI API 400 InvalidRequestError — 'messages must contain text or images'

What this error means

InvalidRequestError: 400 InvalidRequestError {'message': "Invalid type: 'None'. Expected one of ('string', 'list[string]', 'list[{\"type\": \"text\", \"text\": ...}\]') - 'content' from {'role': 'user'}.", 'type': 'invalid_request_error', 'param': 'messages', 'code': None} is a OpenAI API failure pattern reported for developers trying to fix openai chat completions api rejecting requests where user message content is null or empty — common in streaming/conversational uis after user cancels input. Based on the imported evidence, treat this as a tool-specific troubleshooting page rather than a generic API error.

Why this happens

Very common developer mistake: sending messages with null/empty content field after refactor or streaming cancellation. Not in covered list (which covers 401/429/model-not-found but NOT invalid request payload 400s). Strong commercial value as it breaks production chat apps.

Common causes

• Very common developer mistake: sending messages with null/empty content field after refactor or streaming cancellation. Not in covered list (which covers 401/429/model-not-found but NOT invalid request payload 400s). Strong commercial value as it breaks production chat apps.

Quick fixes

1. Confirm the exact error signature matches InvalidRequestError: 400 InvalidRequestError {'message': "Invalid type: 'None'. Expected one of ('string', 'list[string]', 'list[{\"type\": \"text\", \"text\": ...}\]') - 'content' from {'role': 'user'}.", 'type': 'invalid_request_error', 'param': 'messages', 'code': None}.
2. Check the OpenAI API account, local tool state, and provider configuration involved in the failing workflow.
3. Compare the failing environment with a known working setup, then change one configuration value at a time.

Platform/tool-specific checks

• Verify the command, editor, extension, or API client that produced the error.
• Compare local settings with CI, deployment, or editor-level settings when the error appears in only one environment.
• Avoid deleting credentials, local model data, or project settings until the failing scope is clear.

Step-by-step troubleshooting

1. Capture the exact error message and the command, editor action, or request that triggered it.
2. Check whether the failure is account/auth, quota/rate, model/provider, local runtime, or deployment configuration.
3. Review the source evidence below and compare it with your environment.
4. Apply one change at a time and rerun the smallest failing action.
5. Keep the working fix documented for the team or deployment environment.

How to prevent it

• Keep provider/tool configuration documented.
• Record non-secret diagnostics such as tool version, provider name, model name, and command path.
• Add a lightweight check before CI or production workflows depend on the tool.

Sources checked

• https://github.com/openai/openai-python/issues
• https://platform.openai.com/docs/guides/error-codes/api-errors

Evidence note: Very common developer mistake: sending messages with null/empty content field after refactor or streaming cancellation. Not in covered list (which covers 401/429/model-not-found but NOT invalid request payload 400s). Strong commercial value as it breaks production chat apps.

Related errors

• OpenAI API

FAQ

What should I check first?

Start with the exact InvalidRequestError: 400 InvalidRequestError {'message': "Invalid type: 'None'. Expected one of ('string', 'list[string]', 'list[{\"type\": \"text\", \"text\": ...}\]') - 'content' from {'role': 'user'}.", 'type': 'invalid_request_error', 'param': 'messages', 'code': None} text and the smallest action that reproduces it.

Can I ignore this error?

No. Treat it as a failed OpenAI API workflow until the root cause is understood.

Is this guaranteed to have one fix?

No. The imported evidence supports the troubleshooting path above, but tool behavior can vary by account, plan, version, provider, and local configuration.

How do I know the fix worked?

Rerun the same command, editor action, or request. The fix is working when that action completes without InvalidRequestError: 400 InvalidRequestError {'message': "Invalid type: 'None'. Expected one of ('string', 'list[string]', 'list[{\"type\": \"text\", \"text\": ...}\]') - 'content' from {'role': 'user'}.", 'type': 'invalid_request_error', 'param': 'messages', 'code': None}.