MCP search returns results for nonsense queries
Error: Search returns unrelated hits instead of nothing
What causes it
Most docs and search servers we tested (Exa, Microsoft Learn, AWS Knowledge, Astro, and every Mintlify-hosted docs server) always return their nearest matches. Only a few return a clean empty result: OpenAI Docs, Retool Docs, LiveKit Docs, grep.app, CoinGecko, and Cohere Docs, which refuses off-topic questions. A nonsense query gave unrelated pages in our runs, so an agent cannot tell "nothing found" from a weak match.
How to fix it
- Check relevance yourself (title or URL contains your key term) before trusting a result.
- Ask the agent to verify a hit with a fetch before citing it.
Where we hit it
- Langfuse Docs MCP test report (tested Oct 16, 2026). Setup: Claude, Claude Code, Cursor, VS Code, ChatGPT
- GitMCP for Next.js MCP test report (tested Oct 16, 2026). Setup: Claude, Claude Code, Cursor, VS Code, ChatGPT
- Astro Docs MCP test report (tested Oct 16, 2026). Setup: Claude, Claude Code, Cursor, VS Code, ChatGPT
- CrewAI Docs MCP test report (tested Oct 16, 2026). Setup: Claude, Claude Code, Cursor, VS Code, ChatGPT
- Trigger.dev Docs MCP test report (tested Oct 16, 2026). Setup: Claude, Claude Code, Cursor, VS Code, ChatGPT
- Turso Docs MCP test report (tested Oct 16, 2026). Setup: Claude, Claude Code, Cursor, VS Code, ChatGPT
- Windsurf Docs MCP test report (tested Oct 16, 2026). Setup: Claude, Claude Code, Cursor, VS Code, ChatGPT
- Perplexity Docs MCP test report (tested Oct 16, 2026). Setup: Claude, Claude Code, Cursor, VS Code, ChatGPT
- Resend Docs MCP test report (tested Oct 16, 2026). Setup: Claude, Claude Code, Cursor, VS Code, ChatGPT
- Firecrawl Docs MCP test report (tested Oct 16, 2026). Setup: Claude, Claude Code, Cursor, VS Code, ChatGPT
- Model Context Protocol Docs MCP test report (tested Oct 16, 2026). Setup: Claude, Claude Code, Cursor, VS Code, ChatGPT
- Pinecone Docs MCP test report (tested Oct 16, 2026). Setup: Claude, Claude Code, Cursor, VS Code, ChatGPT
- LangChain Docs MCP test report (tested Oct 16, 2026). Setup: Claude, Claude Code, Cursor, VS Code, ChatGPT
- AWS Knowledge MCP test report (tested Oct 16, 2026). Setup: Claude, Claude Code, Cursor, VS Code, ChatGPT
- Exa MCP test report (tested Oct 16, 2026). Setup: Claude, Claude Code, Cursor, VS Code, ChatGPT
- Microsoft Learn MCP test report (tested Oct 16, 2026). Setup: Claude, Claude Code, Cursor, VS Code, ChatGPT
Related fixes
- MCP tool results too large: context window blown by one call
- MCP tool call times out on slow servers
- MCP server accepts calls missing a required field
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