Hey team 👋 — running into what looks like a dashboard bug and wanted to flag it. Bug: When editing the System Prompt on an assistant that has a knowledgeBase attached, the dashboard automatically injects "model": "gemini-2.5-flash" into the knowledgeBase object on save. This then causes the publish to fail with the error: model.each value in knowledgeBase.property model should not exist So the dashboard is injecting a field that the API itself rejects — making it impossible to save any prompt changes through the UI. Steps to reproduce: Create an assistant with a knowledgeBase file attached Edit the System Prompt Click Publish Error appears: model.each value in knowledgeBase.property model should not exist Inspect the payload — "model": "gemini-2.5-flash" has been auto-injected into the knowledgeBase object Is this a known issue? Any timeline for a fix? Thanks!

Hey Azhar! Thanks for the detailed report, really helps. You've caught a genuine dashboard bug here. What's happening: when you publish an assistant that has a knowledge base attached, the dashboard is automatically injecting a

"model"

field into the

knowledgeBase

object. The API rejects that field because it's not part of the schema, which is why you're hitting

model should not exist

. I've flagged this to our engineering team as a dashboard-side bug. In the meantime, here's a workaround to update your system prompt without getting blocked: 1. Use the API directly to patch just the system prompt field:

PATCH https://api.vapi.ai/assistant/{your-assistant-id}

Authorization: Bearer <your-api-key>

Content-Type: application/json

{

"model": {

"messages": \[ { "role": "system", "content": "Your updated system prompt here" } \]

}

}

This bypasses the dashboard entirely and won't include the bad

knowledgeBase.model

injection, so it'll go through cleanly. I know it's an extra step, but it should unblock you while the fix is being worked on. Let me know if you run into any issues with the API call and I'll help you get it sorted. Regards, Chiranjeet Vapi Support