docs: update agent examples to use middleware for dynamic behavior

[christian-bromann]

Updates agent documentation examples to reflect the current API where createAgent accepts a string-based model parameter and uses middleware for dynamic behavior.

Changes

1. Dynamic Model Selection Pattern (agents.mdx)

Before: Used a function passed to the llm parameter that returned a chat model instance with tools bound
After: Uses middleware with wrapModelCall to dynamically select models based on state

2. Dynamic System Prompts (context.mdx)

Python:

• Replaced create_react_agent with prompt parameter
• Now uses create_agent with @dynamic_prompt decorator middleware

JavaScript:

• Replaced createReactAgent with stateModifier parameter
• Now uses createAgent with createMiddleware and wrapModelCall

3. Parameter Naming Consistency

Updated createAgent calls across multiple files to use model instead of deprecated llm:

• mcp.mdx
• multi-agent.mdx
• short-term-memory.mdx
• test.mdx
• tools.mdx
• stagehand.mdx

4. Import Consolidation

Simplified imports in test.mdx to use the unified langchain package

[Copilot]

Pull Request Overview

This PR updates agent documentation examples to reflect the current LangChain API where createAgent accepts a string-based model parameter. The changes introduce middleware patterns for dynamic behavior that was previously handled through function parameters.

Key changes:

• Replaces deprecated llm parameter with model parameter across agent examples
• Updates dynamic model selection to use createMiddleware with wrapModelCall instead of passing functions
• Migrates dynamic prompt patterns to use middleware decorators and createMiddleware

Reviewed Changes

Copilot reviewed 8 out of 8 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
agents.mdx	Refactors dynamic model selection from function-based approach to middleware pattern
context.mdx	Updates dynamic prompt examples for both Python and JavaScript to use middleware
mcp.mdx	Updates model parameter name and changes to string-based model identifier
multi-agent.mdx	Simplifies model parameter usage
short-term-memory.mdx	Simplifies model parameter usage
test.mdx	Updates model parameter and consolidates imports to unified package
tools.mdx	Updates model parameter while maintaining ChatOpenAI instance
stagehand.mdx	Updates import path and model parameter

[github-actions]

Preview ID generated: preview-cbjsfi-1760438879-96087af

[Copilot]

Pull Request Overview

Copilot reviewed 8 out of 8 changed files in this pull request and generated no new comments.

[github-actions]

Preview ID generated: preview-cbjsfi-1760439024-2f68a66