fix(mcp): FastMCP-compatible redirect-URI patterns for DCR allow-list#34
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hunzlahmalik wants to merge 1 commit into
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fix(mcp): FastMCP-compatible redirect-URI patterns for DCR allow-list#34hunzlahmalik wants to merge 1 commit into
hunzlahmalik wants to merge 1 commit into
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MCP_ALLOWED_CLIENT_REDIRECT_URIS is one value shared across the stack, written in FastMCP's pattern syntax (http://localhost:*, https://claude.ai/*). The origin-equality matcher merged in #33 can't satisfy a port wildcard: http://localhost:* has no port in its prefix, so its origin resolves to http://localhost and never equals http://localhost:6274 — every MCP Inspector / loopback DCR registration fails with "redirect_uri is not allowed by this server". Port FastMCP's component-wise matcher: scheme compared exactly, host with *.example.com subdomain wildcards (apex excluded), port with a "*" wildcard plus RFC 8252 loopback any-port semantics, path as a glob. URIs carrying userinfo are rejected outright, so http://localhost@evil.com can never satisfy a localhost pattern and a host can never be extended past a too-broad entry. Verified against the sandbox allow-list (20 cases): Inspector loopback callbacks and claude.ai / claude.com callbacks match; evil-host, userinfo and scheme-swap variants do not. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
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What
Fixes the DCR redirect-URI allow-list matcher so the shared
MCP_ALLOWED_CLIENT_REDIRECT_URISvalue parses the same way in the Penpot MCP gate as it does forsurfsense-mcp/plane-mcp. Follow-up to #33.Problem
MCP_ALLOWED_CLIENT_REDIRECT_URISis one value shared across all three MCP servers, written in FastMCP's pattern syntax (http://localhost:*,https://claude.ai/*). The origin-equality matcher merged in #33 can't satisfy a port wildcard:http://localhost:*has no port in its prefix, sonew URL("http://localhost:").originresolves tohttp://localhostand never equalshttp://localhost:6274.Result on the sandbox: every MCP Inspector / loopback DCR registration fails with
Fix
Port FastMCP's component-wise matcher (
fastmcp/server/auth/redirect_validation.py):*.example.comsubdomain wildcards (apex excluded)*wildcard, plus RFC 8252 loopback any-port semantics (http://localhost:*/http://127.0.0.1:*match any port)/auth/*)http://localhost@evil.comcan never satisfy a localhost pattern and a host can't be extended past a too-broad entryVerified
Tested against the exact sandbox allow-list — 20 cases:
http://localhost:6274/oauth/callback,/oauth/callback/debug,http://127.0.0.1:*https://claude.ai/*,https://claude.com/*,https://sandbox.askii.ai/*and the other askii subdomainshttp://localhost@evil.com/...,https://claude.ai.evil.com/...,https://sandbox.askii.ai.evil.com/..., scheme swaps, unparseable valuestsc --noEmitclean.Note
A no-redeploy env stopgap exists for the currently-deployed image (give the loopback entries explicit ports:
http://localhost:6274/*,http://127.0.0.1:6274/*). This PR is the real fix — once merged and deployed, the allow-list can return to the FastMCP:*form for proper any-port loopback support, identical to the other MCP servers.🤖 Generated with Claude Code