Add SDK Guide for Critic Feature (Experimental)

[xingyaoww]

Summary

This PR adds comprehensive documentation for the new experimental Critic feature in the OpenHands SDK.

What's Added

A new guide at sdk/guides/critic.mdx that covers:

Core Concepts

• What is a Critic? - Explanation of the LLM-based evaluation system
• When to Use Critics - Use cases for quality monitoring, early intervention, and performance analysis
• Evaluation Modes - Two modes: finish_and_message (default) and all_actions

Implementation Guide

• Setting Up APIBasedCritic - Complete example with configuration
• Configuration Options - All parameters explained (server_url, api_key, model_name, mode)
• Understanding Results - How to interpret CriticResult scores and feedback
• Visualizing Results - Color-coded output in the conversation visualizer
• Programmatic Access - How to access critic results in callbacks

Technical Details

• How It Works - Step-by-step evaluation flow
• Chat Template Format - Qwen3-4B-Instruct-2507 template explanation
• Security - API key handling with SecretStr
• Performance Considerations - Latency, cost, and parallelization details

Advanced Usage

• Custom Critic Implementations - Extending CriticBase with custom logic
• Built-in Critics - PassCritic, AgentFinishedCritic, EmptyPatchCritic
• Troubleshooting - Common issues and solutions

Example Code

Includes the full example from examples/01_standalone_sdk/34_critic_model_example.py with:

• Auto-configuration for All-Hands LLM proxy
• Manual configuration fallback
• Running instructions

⚠️ Experimental Status

The guide includes prominent warnings that this feature is:

• Highly experimental and subject to change
• Not recommended for production without thorough testing
• Subject to API and behavior changes based on feedback

Related PR

This documentation corresponds to OpenHands/software-agent-sdk#1269 which implements the Critic feature.

Preview

The guide follows the same structure and style as existing SDK guides, including:

• Clear warnings about experimental status
• Code examples with syntax highlighting
• Step-by-step instructions
• Troubleshooting section
• Links to related guides

Checklist

• Added comprehensive guide for Critic feature
• Included clear experimental warnings
• Provided complete code examples
• Added troubleshooting section
• Documented all configuration options
• Linked to example code in repository
• Followed existing documentation style and format

[openhands-ai]

Looks like there are a few issues preventing this PR from being merged!

• GitHub Actions are failing:
  • .github/workflows/sync-docs-code-blocks.yml
  • .github/workflows/sync-agent-sdk-openapi.yml

If you'd like me to help, just leave a comment, like

@OpenHands please fix the failing actions on PR #263 at branch `xw/critic-model`

Feel free to include any additional details that might help me get this PR into a better state.

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