Bad request ... input should be image/jpeg ...

[FlominatorTM]

Description

Bad Request: messages.2.content.0.tool_result.content.1.image.source.base64.media_type: Input should be 'image/jpeg', 'image/png', 'image/gif' or 'image/webp'

Plugins

No response

OpenCode version

1.14.21
1.14.22

Steps to reproduce

1. Ask to update something in the spec of a custom image format
2. the spec file is read
3. message Bad Request: messages.2.content.0.tool_result.content.1.image.source.base64.media_type: Input should be 'image/jpeg', 'image/png', 'image/gif' or 'image/webp'appears using Claude Sonnet 4.6 (but similar error messages also come with Gemini/ChatGPT, while Big Pickle seems to work)

I've updated to the latest version and I've added explicitly to agents.md not to send, retrieve ety. any images

Screenshot and/or share link

Error Slaude Sonnet 4.6:

Error ChatGPT:

Operating System

Win11 25H2

Terminal

Windows Terminal

[github-actions]

This issue might be a duplicate of existing issues. Please check:

• Support AVIF images or auto-convert to supported format before sending to API #17772: Same exact error message (Input should be 'image/jpeg', 'image/png', 'image/gif' or 'image/webp') when OpenCode reads an unsupported image format (AVIF/custom format) and forwards it to the API — the root cause and symptoms appear identical.
• Read: invalid image payload from file attachment poisons subsequent turns #15264: Related issue where invalid/unrecognized image payloads from file attachments cause provider errors and poison subsequent turns.

Please review those issues and, if they cover your case, consider adding a comment there instead.

[FlominatorTM]

Maybe also related to #23983

[FlominatorTM]

Problem persists with 1.14.22. Explicitly telling OpenCode to avoid the spec file works (except when wanting it to be updated)