Can I delete or modify an existing message in a thread?

Below is what the API currently supports regarding your questions:

Deleting an Existing Message

• API Support:
  There is no documented endpoint for deleting an existing message. The API documentation only shows endpoints for creating or modifying messages within a thread.

• Implication:
  If you want to avoid interference from previous responses, you’ll need to consider alternative strategies—such as starting a new thread or ensuring that your application logic ignores past messages—rather than relying on a deletion capability from the API.

Modifying the Content of an Existing Message

• API Support for Modifications:
  The documented endpoints (both the current beta version and the legacy version) allow you to modify a message, but they only support changing the associated metadata. This is done via a POST request to:

  BASHCopied
  https://api.openai.com/v1/threads/{thread_id}/messages/{message_id}

  with a JSON body that can include a metadata map.

• Modification Limitations:
  The request body in the modify message endpoints does not include a field for changing the message's text content or other main attributes. It solely allows for modifying structured metadata (e.g., flags or supplementary information).

• Implication:
  You cannot change the actual content of an existing message—instead, you can only update its metadata. If you need to rerun a similar message with changed content, you would need to create a new message rather than modifying an existing one.

Summary

• Deleting a Message: Not supported.
• Modifying Message Content: Not supported; you can only update metadata.
• Recommended Approach: If you want to send a new message that won't be affected by previous responses, consider generating a new message rather than trying to delete or modify an existing one.

This should help you plan your agent's design when considering how to handle message interference and content updates.