Prepare docs for v3.0 beta release

[jlowin]

Updates documentation for the v3.0.0b1 release:

• Upgrade guide: Reorganized to be concise and actionable—breaking changes, behavior changes, and deprecations are clearly separated. Reduced from ~550 lines to ~200.

• Updates page: Added v3.0.0b1 announcement entry.

• Installation page: Added "Upgrading" section with links to upgrade guide for 2.x users.

• Navigation: Moved upgrade guide higher in the sidebar for better visibility during beta.

[coderabbitai]

Caution

Review failed

The pull request is closed.

Note

Other AI code review bot(s) detected

CodeRabbit has detected other AI code review bot(s) in this pull request and will avoid duplicating their findings in the review comments. This may lead to a less comprehensive review.

Walkthrough

Rewrites and reorganizes v3 documentation: replaces a verbose multi-version migration guide with a concise v3.0.0 upgrade guide focused on breaking changes and updated examples. Key topics consolidated under a single "Breaking Changes" section (transport, auth loading, provider/tool transform APIs, proxy API swap, mount/visibility/server-level changes, prompt/message serialization, async context/state API, metadata namespace rename). Installation and tasks docs updated to recommend pinning the 3.0.0b1 prerelease. Navigation moved: the upgrade guide was added to v3 "Get Started" and removed from v3 "Development". A new release/update entry for 3.0.0b1 was added.

Possibly related PRs

• Add missing v3 features to tracking docs #2888: Documents the deprecation of FastMCP.as_proxy() and its replacement with create_proxy()—directly overlaps the upgrade-guide proxy changes.
• Add session-scoped state persistence #2873: Implements session-scoped async context state methods (get_state, set_state, delete_state) that the guide lists as breaking changes.
• Add transform system for modifying components in provider chains #2836: Introduces the new transform system and ToolTransform APIs referenced by the upgrade guide as replacements for prior transformation APIs.

🚥 Pre-merge checks | ✅ 2 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Description check	⚠️ Warning	The PR description addresses most key aspects of the changes but lacks required contributor and review checklist items from the repository template.	Add the Contributors Checklist and Review Checklist sections with appropriate checkboxes as specified in the repository's description template.

✅ Passed checks (2 passed)

Check name	Status	Explanation
Title check	✅ Passed	The PR title clearly and concisely summarizes the main change: preparing documentation for the v3.0 beta release, which aligns with all file modifications.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.

_{✏️ Tip: You can configure your own custom pre-merge checks in the settings.}

---

Thanks for using CodeRabbit! It's free for OSS, and your support helps us grow. If you like it, consider giving us a shout-out.

❤️ Share

• X
• Mastodon
• Reddit
• LinkedIn

_{Comment @coderabbitai help to get the list of available commands and usage tips.}

[chatgpt-codex-connector]

💡 Codex Review

Here are some automated review suggestions for this pull request.

Reviewed commit: 958653f398

ℹ️ About Codex in GitHub

Your team has set up Codex to review pull requests in this repo. Reviews are triggered when you

• Open a pull request for review
• Mark a draft as ready
• Comment "@codex review".

If Codex has suggestions, it will comment; otherwise it will react with 👍.

Codex can also answer questions or update the PR. Try commenting "@codex address that feedback".

[chatgpt-codex-connector]

Note include_fastmcp_meta removal in metadata section

The sentence says this change “only affects code that reads component metadata,” but v3 removes the include_fastmcp_meta parameter entirely (it’s absent from FastMCP.__init__ and Tool.to_mcp_tool()), so any code that still passes that argument will now fail with TypeError even if it never reads metadata. Please call out the parameter removal/metadata-always-included behavior here so upgrades don’t miss a breaking change.

Useful? React with 👍 / 👎.