I graded 36 popular MCP servers on agent usability. A third got a D or F

Tengli.dev's release of mcpgrade, a tool to measure MCP server usability, reveals that a third of 36 popular MCP servers received a D or F grade, highlighting significant usability issues for agents. This means that website owners who rely on MCP servers for agent interactions may be experiencing subpar performance, potentially leading to lost traffic or revenue. The fact that many servers are 100% spec-compliant yet still unusable by agents underscores the importance of going beyond mere compliance and focusing on real-world usability. To address these issues, website owners can take several actionable steps: first, use tools like mcpgrade to assess their MCP server's usability and identify areas for improvement; second, prioritize agent usability when selecting or configuring MCP servers; and third, regularly monitor AI bot traffic to detect potential issues related to server usability, and update their llms.txt files accordingly to ensure seamless interactions with agents.