fix: Preserve metadata in FastMCPProvider component wrappers

[NeelayS]

Description

When mounting FastMCP servers, component metadata (meta, title, icons) was not being forwarded through the provider wrapper classes. This caused MCP Apps to fail rendering in clients like Claude Desktop, since the meta["ui"] configuration was lost during composition.

The fix adds meta, title, and icons forwarding to all four FastMCPProvider* wrapper classes: Tool, Resource, Prompt, and ResourceTemplate.

Contributors Checklist

• My change closes MCP Apps metadata lost when mounting servers via FastMCPProvider #3056
• I have followed the repository's development workflow
• I have tested my changes manually and by adding relevant tests
• I have performed all required documentation updates

Review Checklist

• I have self-reviewed my changes
• My Pull Request is ready for review

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[coderabbitai]

Walkthrough

This change modifies src/fastmcp/server/providers/fastmcp_provider.py to propagate three optional fields—meta, title, and icons—through FastMCPProvider wrapper constructors for Tool, Resource, Prompt, and ResourceTemplate classes. The wrap() calls now forward these fields from wrapped objects into provider-wrapped instances as keyword arguments. No public API signatures were altered, and control flow remains unchanged; only additional parameters are passed during internal wrapping operations.

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly and concisely describes the main change: preserving metadata in FastMCPProvider wrapper classes, which is the core objective of the PR.
Description check	✅ Passed	The description is well-structured, addresses the problem, explains the fix, and includes all required checklist items properly marked as complete.
Linked Issues check	✅ Passed	The PR directly addresses issue #3056 by forwarding meta, title, and icons fields through all four FastMCPProvider wrapper classes, resolving the metadata loss during server composition.
Out of Scope Changes check	✅ Passed	All changes are scoped to the FastMCPProvider wrapper classes and focus exclusively on forwarding metadata fields without introducing unrelated modifications.
Docstring Coverage	✅ Passed	Docstring coverage is 100.00% which is sufficient. The required threshold is 80.00%.

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✨ Finishing touches

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🧪 Generate unit tests (beta)

• Create PR with unit tests
• Post copyable unit tests in a comment

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[jlowin]

Thanks!

[NeelayS]

Thanks for the quick merge, @jlowin! Just curious - do you guys have something like a release schedule? Would you be able to give me an estimate of when a version with this change would be available on PyPI? 🙂

[jlowin]

@NeelayS we are currently in the beta period for FastMCP 3, so releases are slower than usual. I expect 3.0 beta2 to land maybe end of this week or early next week. 3 will probably not be released fully until later this month, depending also on the release of the MCP SDK v2

[NeelayS]

@NeelayS we are currently in the beta period for FastMCP 3, so releases are slower than usual. I expect 3.0 beta2 to land maybe end of this week or early next week. 3 will probably not be released fully until later this month, depending also on the release of the MCP SDK v2

Gotcha, thanks!