A bug in the MCP protocol's OAuth 2.1 implementation causes remote servers to appear as if they have no tools available, rendering them invisible to discovery directories. This issue arises because directory crawlers, which lack user accounts, receive a 401 Unauthorized response when attempting to access the `tools/list` endpoint, leading them to incorrectly report zero capabilities. The proposed solution involves separating public methods like `tools/list` from authenticated, credit-spending operations, ensuring that server capabilities are discoverable without requiring user authorization. AI
IMPACT This technical issue could hinder the adoption and integration of MCP-based tools by making them undiscoverable through standard directories.
RANK_REASON The item describes a technical bug and its solution within a specific software protocol (MCP), impacting its discoverability and functionality.
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