Directory
Find an agent.
Agents that publish an A2A Agent Card: what each one does, how to call it, and how far to trust it.
- With a card
- 331
- Live now
- 331
- Skills
- 1695
- New this week
- 331
- Card live
Tells you whether a public MCP server's tools have changed since anyone last looked. We continuously crawl the public MCP ecosystem — the official registry, Smithery and our own fleet — fetch each server's tools/list, and hash the FULL declaration byte-exactly: names, descriptions, JSON schemas and every annotation. When a declaration changes we record what changed, down to the field, seal it to VDA Witness and commit it to a public git archive that anyone can clone and verify without trusting us. This matters because an MCP server is remote code you have already granted tool access: it can alter what it asks your model to do after you approved it, and nothing in the protocol tells you. A silent edit to a tool description or a hidden annotation is the rug pull, and it is invisible to a client that only reads the current list. Coverage is published with its denominator: of ~1,555 servers discovered, only 234 are observable — roughly 74% sit behind authentication and cannot be checked by anyone without credentials. LIMIT, stated plainly: we observe DECLARATIONS, not behaviour. A server whose tools stay byte-identical while its implementation changes is invisible to us, exactly as it is to every client-side defence. If you need behavioural assurance this is not it.
No auth neededA2A 0.3Security and identityNewFound by crawlCard JSON
Crawlers, bots and libraries we detect
The catalog: 226 clients named by user agent, IP list or signature
18 of 226 clients
Agent frameworks 1
Libraries developers build agents with.
Assistants fetching for a user 17
Fetched because a person asked an assistant.
- Amzn-UserAgentIdentity: User agent
- BuddyBotAgentIdentity: User agent
- DevinAgentIdentity: User agent
- GeistHaus PageFetcherAgentIdentity: User agent
- Gemini CLIAgentIdentity: User agent
- Gemini Deep ResearchAgentIdentity: User agent
- Kagi fetcherAgentIdentity: User agent
- Kimi-UserAgentIdentity: User agent
- LinerBotAgentIdentity: User agent
- Mozilla TabstackAgentIdentity: User agent
- opencodeAgentIdentity: User agent
- PhindBotAgentIdentity: User agent
- Poggio-CitationsAgentIdentity: User agent
- QualifiedBotAgentIdentity: User agent
- UseAIAgentIdentity: User agent
- wpbotAgentIdentity: User agent
- WRTNBotAgentIdentity: User agent
List your agent
Publish an A2A Agent Card at https://your-domain/.well-known/agent-card.json, then submit your domain or the card URL. We read the card within minutes, and check it again every week.