GoogleProvider should expose enable_cimd parameter

[henrysouchien]

Problem

OAuthProxy.__init__ accepts an enable_cimd: bool = True parameter to control CIMD (Client ID Metadata Document) support, but GoogleProvider does not forward this parameter. There's no way to disable CIMD through the public API when using GoogleProvider.

Use Case

Claude Code's CIMD document (https://claude.ai/oauth/claude-code-client-metadata) lists redirect URIs without wildcard ports:

"redirect_uris": ["http://localhost/callback", "http://127.0.0.1/callback"]

But Claude Code uses dynamic ports for its OAuth callback (e.g., http://localhost:8080/callback). FastMCP's _match_port in redirect_validation.py treats no-port as port 80 exactly, so the redirect URI validation always fails for CIMD clients.

The workaround is to subclass GoogleProvider and null out _cimd_manager after super().__init__(), but this relies on a private attribute.

Suggested Fix

Forward enable_cimd through GoogleProvider.__init__ to the parent OAuthProxy:

class GoogleProvider(OAuthProxy):
    def __init__(
        self,
        *,
        # ... existing params ...
        enable_cimd: bool = True,  # <-- add this
    ):
        super().__init__(
            # ... existing args ...
            enable_cimd=enable_cimd,  # <-- forward it
        )

Environment

• fastmcp 3.1.0
• Python 3.13
• macOS / Linux

[marvin-context-protocol]

Found 1 possible duplicate issue:

1. Azure Provider could forward some parameters to OAuthProxy, eg to disable CIMD #3602: Azure Provider could forward some parameters to OAuthProxy, eg to disable CIMD

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[henrysouchien]

Already fixed in fastmcp 3.1.1 — GoogleProvider now accepts and forwards enable_cimd. Closing as resolved. Thanks!

[henrysouchien]

Reopening — the fix exists on main but hasn't been released yet (not in 3.1.1). We'll close once a release includes it.

[jlowin]

Issues are closed when the work is done, not when the release takes place - this will go out shortly.