# analysis_successful_prompt on PATCH /update-agent/{} stops working

Calls to PATCH /update-agent/{id}, body parameter analysis_successful_prompt on Retell AI API stopped working on June 15, 2026.

On June 15, 2026, Retell AI removed the body parameter analysis_successful_prompt from PATCH /update-agent/{id}. Calls that include this parameter fail since that date. The change took effect following the removal of legacy prompt fields from the API.

## What to use instead

Add a system preset item to post_call_analysis_data with type system-presets, name call_successful, and your prompt set as the description instead.

- API: Retell AI API (api.retellai.com)
- Kind: Parameter removal
- Takes effect: June 15, 2026
- Calls after that day: fail
- Calls it hits: `PATCH /update-agent/{id}`, `body parameter analysis_successful_prompt`
- Source: [Announcement](https://docs.retellai.com/deprecation-notice/2026/06-15_legacy_list_endpoints)
- Verified: November 6, 2026, against Retell AI API's own pages
- Page: https://www.okapi.bot/providers/retell-ai-api/breaking-changes/analysis-successful-prompt-on-patch-update-agent-stops-working/

## Retell AI API's words

> 1. The three prompt fields above will be removed from the API.

Okapi finds the calls this change hits in your repo and opens the pull request with the fix: https://github.com/apps/okapi-agent