Reference · How-to · ~10 min
How to call a vision API
Last updated
Send an image + question in one request, then verify before any side effect.
Send an image + question in one request, then verify before any side effect.
#Prerequisites
- Vision-capable model ID
- Image you are allowed to upload (strip secrets from screenshots)
- Clear acceptance test (“list the three prices visible”)
#Steps
1. **Resize** large images; strip sensitive EXIF / metadata.
2. **Encode** as base64 or host behind a short-lived signed URL.
3. **Build** a user message with text + image parts (provider schema varies).
4. **Constrain** the answer: only visible evidence; mark unclear regions.
5. **Parse** the text response; never auto-execute tool calls from vision guesses.
6. **Verify** critical fields against the image yourself on a sample.
#Copy-paste prompt pattern
Only use what is visible in the image.
If text is unreadable, write [unclear] instead of guessing.
Return: bullet list of items + any prices exactly as printed.