Agent Tools

The discovery layer for the agent economy

One open, agent-readable directory for x402 paid APIs, MCP servers, and A2A agents — searchable by humans and callable by agents.

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Across the directory

/api/v1/stats /.well-known

Aggregated from public sources — x402scan, awesome-x402, Coinbase CDP Bazaar, the official MCP Registry, Smithery, PulseMCP, awesome-a2a — plus our own crawling and provider self-submissions. Everything is de-duplicated across sources, liveness-probed (health, JSON-RPC handshake, on-chain payment demand), statically safety-scanned for malware & prompt-injection patterns and filtered before listing, so the counts below are verified, not raw.

Total entries
27787
x402 · MCP · A2A combined
Healthy
16973
passed last liveness probe
x402 Services 10382

Paid HTTP APIs that settle micro-payments over the x402 protocol. Auto-verified, with payment + health metadata.

7817 healthy · on-chain demand-checked

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MCP Servers 16357

Model Context Protocol servers continuously aggregated and probed live for remote callability.

16357 remote-callable

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A2A Agents 1048

Agents that publish an A2A Agent Card. Discover skills, capabilities, and endpoints straight from /.well-known.

910 healthy

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Directory health & quality, at a glance

A synthesized read on what's actually usable right now — refreshed continuously (scores recomputed on every hourly liveness probe; leaderboards ranked live on each request).

Verified live
61%
16973 of 27787 passed the last liveness probe
Top-graded (A / B+)
4803
high availability + conformance + trust signals
Agent-payable (x402)
10915
settle per-call on-chain, no human signup
New this week
+914
freshly discovered MCP + A2A endpoints
The read: Of 27787 indexed entries, 61% answered their last liveness probe. Quality skews high on the MCP side (47% of healthy servers grade A/B+, conformance-verified via a real tools/list handshake), and on A2A (100% A/B+). The x402 side is graded on on-chain demand, so high grades are rarer and mean real paying traffic — the few A-grade services are the ones agents are actually paying. Roughly 12126 MCP servers are callable with no credentials at all; 4039 need a human to provision a key first. Scores recompute hourly; rankings are live.

Top MCP servers

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Top rated

# Tool Grade Score
1 Biosamples A 8.76
2 Ai Feeds A 8.75
3 Biostudies A 8.75
4 Opendota A 8.73
5 Complex Portal A 8.73

Top A2A agents

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Top rated

# Tool Grade Score
1 AgentRank A 9.55
2 GdayJames A 9.37
3 SolEnrich A 8.95
4 TESSA Marketing & Technology A 8.92
5 Handler A 8.80

Top x402 services

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Top rated

Built for agents, not just humans

Every page has a JSON counterpart. Ask for LLM-ranked recommendations, search by intent, or pull a single card — no scraping required. You can even scan any MCP server for malware & prompt-injection before connecting, via the scan_mcp_safety tool at /mcp-discovery or our A2A agent at /a2a.

POST /api/v1/ask /api/v1/search /api/v1/mcp/search /api/v1/a2a/search openapi.json