4 
404.directory
404.directory provides agent discovery and trust infrastructure for AI agents, including official-docs search, tool discovery, website verification, webpage understanding, and controlled read-only invocation of curated remote MCP tools. It publishes both MCP and REST interfaces plus machine-readable discovery metadata on its website.
404.directory exposes two public developer integration surfaces on its own domain: a Streamable HTTP MCP server at `/mcp` and a REST API described by an OpenAPI document at `/openapi.json`; the MCP surface is explicitly unauthenticated, while the REST API is mostly public/read-only with some registry-write operations documented as bearer-protected in OpenAPI.
discovered 6d ago
MCP servers1
- 404.directory MCP serverdetected
REST · OpenAPI1
- 404.directory REST APIdetected
conventions · 5/8 published
- integrations.json✓https://404.directory/.well-known/integrations.json
- llms.txt✓https://404.directory/llms.txt
- API catalog✓https://404.directory/.well-known/api-catalog
- OpenAPI document✓https://404.directory/openapi.json
- MCP server card✓https://404.directory/mcp
- OAuth protected resource✗
/.well-known/oauth-protected-resource - Agent card✗
/.well-known/agent-card.json - Agent skills✗
/.well-known/agent-skills/index.json
Publish these signals → /publishing