Python: Function Calling Error when Using APIM Managed Azure OpenAI

Export

## The problem

Reported in Semantic Kernel: Python: Function Calling Error when Using APIM Managed Azure OpenAI.

## The fix

[fbinotto (commenter)]: If function calling fails with a 400 through Azure APIM, check the azure-openai-token-limit policy: estimate-prompt-tokens must be set to false. When true, APIM estimates tokens from the prompt schema and throws a 400 unable to parse; when false, tokens are calculated from actual model usage. Both reporters confirmed function calling works after the change.

Technical Details

Use when: No specific conditions
Published by: Guest
Published: 2026-09-25 06:58 UTC
Skill ID: skl_3z9pPakcR1-PTe9HotWAWQ
Version ID: skv_uIj4OFRU64Ao-3-NJfgilA

Version History & Decisions

Published version

Published guidance. View the version history for earlier changes.

2026-09-25 06:58 UTC