{"uid":"cap_qAiKxzOjfVSeFJ2yquFNf","slug":"agentindex-x402-mcp-discovery-cd2270b3","name":"AgentIndex x402 MCP Discovery","description":"Find MCP servers matching a need, ranked by semantic similarity over a curated snapshot of 10101 MCP servers. Returns name, endpoint, description, source registry and a 0-1 relevance per match. Paid POST: up to 25 matches. Try GET /discover/sample.","url":"https://x402.agentindex.world/discover?utm_source=zero.xyz","method":"GET","headers":{},"bodySchema":{"type":"object","properties":{"q":{"type":"string","description":"The need to match, in plain language - e.g. \"read a PDF and give me markdown\" or \"persistent knowledge graph\". Matched against a curated snapshot of MCP servers (official registry + carnet) by semantic similarity."},"max_results":{"type":"integer","maximum":25,"minimum":1,"description":"Maximum number of servers to return (default 5)."},"min_similarity":{"type":"number","maximum":1,"minimum":0,"description":"Minimum cosine similarity to include a result (default 0.30). Raise it for fewer, closer matches."}}},"responseSchema":{"type":"json","example":{"q":"read a PDF and give me markdown","matches":3,"results":[{"url":"https://example.org/mcp/","name":"PDF Extract MCP","registry":"registre-mcp","relevance":0.7211,"description":"Extract a public PDF into clean markdown text, plus metadata and a real token count.","observed_at":"2026-09-02T19:07:49.374328Z"},{"url":null,"name":"Docling Server","registry":"annuaire","relevance":0.6487,"description":"Document conversion to markdown and structured text for LLM agents.","observed_at":"2026-09-10T12:00:00Z"},{"url":"https://example.com/mcp/","name":"Srclight","registry":"registre-mcp","relevance":0.4102,"description":"Deep code indexing for AI agents. FTS5 + embeddings + call graphs. Fully local.","observed_at":"2026-09-15T08:30:00Z"}],"snapshot_date":"2026-09-18","snapshot_rows":10101,"min_similarity":0.3}},"example":null,"exampleRequest":null,"tags":["x402"],"displayCostAmount":"0.001","displayCostAsset":"USDC","priceDynamic":false,"priceHint":null,"priceStatus":"priced","priceSource":"probe","requiresHandshake":false,"reviewCount":0,"rating":{"score":"0.00","successRate":"0.00","reviews":0,"stars":null,"state":"unrated"},"availabilityStatus":"unknown","priceObserved":null,"sessionDeposit":null,"pricing":{"kind":"static","summary":"$0.001/call","primary":{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.001","per":"call","confidence":"exact"},"accepted":[{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.001","per":"call","confidence":"exact"}]},"paymentMethods":[{"uid":"pm_ePvi8eo8OXd0Y6hw7cR3u","protocol":"x402","methodType":"crypto","chain":"base","mode":"charge","costAmount":"0.001","costPer":"request","priority":0,"asset":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","unit":"request","depositMicros":null,"planRef":null}],"brandName":null,"brandSlug":null,"brandBaseUrl":null,"brandDocsUrl":null,"whatItDoes":"Semantically searches a snapshot of 10,000+ MCP servers to find the best-matching server for a plain-language capability need","exampleAgentPrompt":"Search the MCP registry for servers that can read a PDF and return clean markdown — show me the top 3 results with at least 0.4 similarity.","exampleUseCases":[{"title":"Find PDF extraction MCP server","prompt":"I need an MCP server that can extract text from a PDF and convert it to markdown — find me the top 5 matches from the registry, with a minimum similarity of 0.35."},{"title":"Discover knowledge graph tooling","prompt":"Search the MCP server registry for something that does persistent knowledge graphs or graph databases — return up to 3 results."},{"title":"Locate browser automation agent tool","prompt":"Find me the best MCP servers for browser automation or web scraping — top 4 results, minimum similarity 0.40."}],"resultDescription":"Returns a JSON object containing the matched query string, the number of servers above the similarity threshold, and an ordered list of the top matching MCP servers — each with name, description, registry source, endpoint URL (if known), and cosine relevance score — plus snapshot metadata (date taken, total rows in snapshot).","failureModes":["Query string too vague — returns low-relevance or zero results below the min_similarity threshold","min_similarity set too high — filters out all candidates and returns an empty results array","Snapshot may be days old — newly published MCP servers may not appear","Truncated description in crawled schema may cause unexpected input validation errors","Payment failure via x402/USDC on Base blocks the call entirely"],"whenToPreferThis":"Choose this endpoint when an AI agent needs to programmatically discover which MCP server best fits a particular capability need, rather than maintaining a hardcoded list of tools. It is especially useful for meta-agent architectures that dynamically select tools at runtime, or for agent builders exploring what MCP tooling exists for a given domain. Prefer it over manual registry browsing or hardcoded tool lists when the capability requirement is expressed in natural language.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-10-02T04:39:55.041Z","isFirstParty":false,"canonicalSlug":"agentindex-x402-mcp-discovery-cd2270b3"}