docs: update Ask Fern backend models and remove model selection config (#4925)

Co-authored-by: fern-support <support@buildwithfern.com>
Co-authored-by: bot_apk <apk@cognition.ai>
Co-authored-by: fern-api[bot] <115122769+fern-api[bot]@users.noreply.github.com>
Co-authored-by: Devin Logan <devinannlogan@gmail.com>

Author: 5 people

fern/products/docs/pages/ask-fern/what-is-ask-fern.mdx

@@ -4,7 +4,7 @@ description: Ask Fern is an AI search feature that indexes your documentation an
 ---
 
 
-Ask Fern is Fern's AI Search feature, powered by **Claude 4.6 Sonnet** and **Retrieval Augmented Generation (RAG)**, that indexes your documentation and provides an interface for your end users to ask questions and get answers. Responses include citations that link directly to source pages.
+Ask Fern is Fern's AI Search feature, powered by [Claude 4.6 Sonnet](https://www.anthropic.com/news/claude-sonnet-4-6) and [Claude 4.5 Haiku](https://www.anthropic.com/news/claude-haiku-4-5) with Retrieval Augmented Generation (RAG). Ask Fern indexes your documentation and provides an interface for your end users to ask questions and get answers. Responses include citations that link directly to source pages.
 
 <Frame caption="Ask Fern appears as a side panel that works with all Fern Docs layouts and stays open as users navigate between pages. Responses are filtered by version, product, and role.">
   <video

fern/products/docs/pages/changelog/2026-04-14.mdx

@@ -0,0 +1,9 @@
+---
+tags: ["ai-features"]
+---
+
+## AI search model update
+
+Ask Fern now uses [Claude 4.6 Sonnet](https://www.anthropic.com/news/claude-sonnet-4-6) and [Claude 4.5 Haiku](https://www.anthropic.com/news/claude-haiku-4-5).
+
+<Button intent="none" outlined rightIcon="arrow-right" href="/learn/docs/ai-features/ask-fern/overview">Read the docs</Button>

fern/snippets/ask-fern-config.mdx

@@ -30,11 +30,3 @@ ai-search:
   See Anthropic's [prompting guide](https://docs.anthropic.com/en/docs/build-with-claude/prompt-engineering/overview) for ideas and examples.
 </ParamField>
 
-<ParamField path="ai-search.model" type="string" required={false} toc={true}>
-  The AI model to use for Ask Fern responses. Options:
-  - `claude-4.6` - Claude 4.6 Sonnet (default)
-  - `claude-4.5` - Claude 4.5 Sonnet
-  - `claude-4.5-haiku` - Claude 4.5 Haiku
-  - `claude-4` - Claude 4 Sonnet
-  - `claude-3.7` - Claude 3.7 Sonnet
-</ParamField>