[DRAFT] docs(sdk): add docs for client SDK

[PetrBulanek]

Summary

• Rewrote the Client SDK overview to match current SDK entrypoints and workflows.
• Added new guides for A2A integration, error handling, message building, and message part rendering.
• Expanded extensions and client API docs.

Notes:

• Changes are limited to development docs. No stable mirror included yet.

Linked Issues

Closes: #1835

Documentation

• No Docs Needed:

If this PR adds new feature or changes existing. Make sure documentation is adjusted accordingly. If the docs is not needed, please explain why.

[gemini-code-assist]

Summary of Changes

Hello @PetrBulanek, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request significantly updates and expands the documentation for the AgentStack Client SDK. The primary goal is to provide developers with clearer, more detailed guidance on integrating the SDK, particularly concerning the Agent-to-Agent (A2A) protocol, managing extensions, handling API responses and errors, and constructing messages. The changes aim to streamline the developer experience by offering practical examples and structured explanations of core workflows.

Highlights

• Client SDK Overview Rewrite: The Client SDK overview has been rewritten to align with current SDK entrypoints and workflows, providing a clearer architectural understanding.
• New Comprehensive Guides: New detailed guides have been added covering A2A integration, robust error handling, structured message building, and effective message part rendering.
• Expanded Documentation for Extensions and API: The documentation for extensions and the client API has been significantly expanded and clarified, including new sections on response handling and error patterns.

🧠 New Feature in Public Preview: You can now enable Memory to help Gemini Code Assist learn from your team's feedback. This makes future code reviews more consistent and personalized to your project's style. Click here to enable Memory in your admin console.

Using Gemini Code Assist

The full guide for Gemini Code Assist can be found on our documentation page, here are some quick tips.

Invoking Gemini

You can request assistance from Gemini at any point by creating a comment using either /gemini <command> or @gemini-code-assist <command>. Below is a summary of the supported commands on the current page.

Feature	Command	Description
Code Review	/gemini review	Performs a code review for the current pull request in its current state.
Pull Request Summary	/gemini summary	Provides a summary of the current pull request in its current state.
Comment	@gemini-code-assist	Responds in comments when explicitly tagged, both in pull request comments and review comments.
Help	/gemini help	Displays a list of available commands.

Customization

To customize Gemini Code Assist for GitHub experience, repository maintainers can create a configuration file and/or provide a custom code review style guide (such as PEP-8 for Python) by creating and adding files to a .gemini/ folder in the base of the repository. Detailed instructions can be found here.

Limitations & Feedback

Gemini Code Assist may make mistakes. Please leave feedback on any instances where its feedback is incorrect or counter productive. You can react with 👍 and 👎 on @gemini-code-assist comments. If you're interested in giving your feedback about your experience with Gemini Code Assist for Github and other Google products, sign up here.

You can also get AI-powered code generation, chat, as well as code reviews directly in the IDE at no cost with the Gemini Code Assist IDE Extension.

Footnotes

1. Review the Privacy Notices, Generative AI Prohibited Use Policy, Terms of Service, and learn how to configure Gemini Code Assist in GitHub here. Gemini can make mistakes, so double check it and use code with caution. ↩

[gemini-code-assist]

Code Review

The pull request significantly enhances the client SDK documentation by providing a more structured overview, detailed guides for A2A integration, error handling, message building, and message part rendering. The new sections on core APIs, extensions, and error helpers are very valuable. However, many of the code examples within the documentation are not self-contained, as they rely on undeclared variables or types. For a better user experience, especially in quickstart and example sections, these snippets should be runnable independently or clearly indicate where the missing variables/types originate.