# "AI Model Not Found" error when running "/summarize"

**URL:** <https://forum.cursor.com/t/ai-model-not-found-error-when-running-summarize/176537>\
**Category:** Bug Reports\
**Tags:** context, anthropic\
**Created:** [October 28, 2026, 8:52pm UTC](https://forum.cursor.com/t/ai-model-not-found-error-when-running-summarize/176537 "2026-10-28T20:52:47Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![Syd\_Workman](https://avatars.discourse-cdn.com/v4/letter/s/3be4f8/32.png) [@Syd\_Workman](https://forum.cursor.com/u/Syd_Workman)\
**Post date:** [October 28, 2026, 8:52pm UTC](https://forum.cursor.com/t/ai-model-not-found-error-when-running-summarize/176537/1 "2026-10-28T20:52:47Z")

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### Where does the bug appear (feature/product)?

Cursor IDE

### Describe the Bug

When attempting to run “/summarize” command while using Claude Sonnet 5.5, I get the following error…

AI Model Not Found: Invalid parameters for registry model: “claude-sonnet-5-5”

Seems to be an issue with the way 5.5 is being handled / expected.

### Steps to Reproduce

- Start a chat with Claude Sonnet 5.5 model selected.
- Attempt to run `/summarize` to condense context window.

### Expected Behavior

Expect chat to summarize and context window to reduce. Only get an error. Works with Claude Opus.

### Operating System

MacOS

### Version Information

Version: 3.27.14  
VS Code Extension API: 1.128.0  
Commit: 69b724ebc67ec522c1b5d287a5025f7a7e81be90  
Date: 2026-10-23T21:46:59.851Z  
Layout: IDE  
Build Type: Stable  
Release Track: Default  
Electron: 42.11.16  
Chromium: 148.0.7778.280  
Node.js: 24.19.0  
V8: 14.8.178.38-electron.0  
xterm.js: 6.1.0-beta.291  
OS: Darwin arm64 27.0.0

### For AI issues: which model did you use?

Claude Sonnet 5.5

### Does this stop you from using Cursor

No - Cursor works, but with this issue

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<div class="post-metadata">

**Author:** ![Colin](https://sea3.discourse-cdn.com/cursor1/user_avatar/forum.cursor.com/colin/32/90452_2.png) [@Colin](https://forum.cursor.com/u/Colin)\
**Post date:** [October 29, 2026, 9:00am UTC](https://forum.cursor.com/t/ai-model-not-found-error-when-running-summarize/176537/11 "2026-10-29T09:00:24Z")

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Hi @Syd_Workman,

This is on our side, not your setup. Right now `/summarize` gets rejected when the chat uses Claude Sonnet 5.5 with the 1M context option, which is why it works on Opus. The team is aware of it.

In the meantime, either of these should get it through:

1. In the model picker, open the Claude Sonnet 5.5 options and switch Context from 1M to the smaller option, run `/summarize`, wait for “Chat context summarized”, then switch Context back to 1M.
2. Or switch the chat to Claude Opus just for the `/summarize`, then switch back to Sonnet 5.5.