# A2A Compliance · Agenstry

## The funnel

11,135

Candidates discovered

From 9 public sources

4,292

HTTP 200

Server returned something

8,640

Valid AgentCard

Schema-validated A2A v1.0

1,064

Live JSON-RPC

Actually operational

## Real agents, but un-probeable by us

143 of the 11,135 candidates returned 401/403 on the agent-card URL. Some of these are stale URLs in our discovery feed that happen to point at credentialed endpoints (CDN paths, admin pages, etc.); others are real agents whose card requires authentication. Both count as "agent exists," but we can't anonymously probe them.

Auth-gated (401/403)
**87**
0.8%

Real agent — but the card requires credentials we don't have. Counts as 'agent exists' but un-anonymously-probeable.

Auth-gated (401/403)
**56**
0.5%

Real agent — but the card requires credentials we don't have. Counts as 'agent exists' but un-anonymously-probeable.

## Why most candidates didn't return a valid agent card

6,700 of the 11,135 candidates failed at the card-fetch step (404, server error, network failure, or returned 200 but with invalid card body). Almost none of this is our bug; it's stale URLs in upstream discovery feeds.

HTTP 404
**3,892**
35.0%

URL has no agent card. These are mostly repos/sites that talk about A2A but don't actually serve /.well-known/agent-card.json.

Network failure
**2,447**
22.0%

DNS failed, connect refused, hard timeout, or blocked by safety policy. The host is dead or our crawler couldn't reach it.

HTTP 410
**78**
0.7%

Non-2xx response on the agent-card URL.

Server error (503)
**74**
0.7%

Their server is currently broken. Could recover; we re-probe in cold tier.

HTTP 402
**69**
0.6%

Non-2xx response on the agent-card URL.

Server error (530)
**38**
0.3%

Their server is currently broken. Could recover; we re-probe in cold tier.

Server error (502)
**27**
0.2%

Their server is currently broken. Could recover; we re-probe in cold tier.

HTTP 400
**21**
0.2%

Non-2xx response on the agent-card URL.

Rate-limited (429)
**12**
0.1%

Provider throttled our crawler — we'll back off and retry.

HTTP 405
**11**
0.1%

Non-2xx response on the agent-card URL.

Server error (500)
**9**
0.1%

Their server is currently broken. Could recover; we re-probe in cold tier.

Server error (525)
**6**
0.1%

Their server is currently broken. Could recover; we re-probe in cold tier.

Server error (522)
**4**
0.0%

Their server is currently broken. Could recover; we re-probe in cold tier.

Server error (526)
**2**
0.0%

Their server is currently broken. Could recover; we re-probe in cold tier.

Server error (521)
**2**
0.0%

Their server is currently broken. Could recover; we re-probe in cold tier.

Server error (520)
**2**
0.0%

Their server is currently broken. Could recover; we re-probe in cold tier.

Server error (504)
**2**
0.0%

Their server is currently broken. Could recover; we re-probe in cold tier.

HTTP 204
**2**
0.0%

Non-2xx response on the agent-card URL.

Server error (523)
**1**
0.0%

Their server is currently broken. Could recover; we re-probe in cold tier.

HTTP 441
**1**
0.0%

Non-2xx response on the agent-card URL.

## Of the 8,640 valid cards: who actually responds?

2,765
32.0%

2,101
24.3%

1,064
12.3%

1,044
12.1%

908
10.5%

423
4.9%

214
2.5%

99
1.1%

22
0.3%

**Not yet probed:**
2765 cards · 32.0%: Indexed but live-probe hasn't run yet (e.g. recently added).

Not yet probed
**2,765**
32.0%

Indexed but live-probe hasn't run yet (e.g. recently added).

Examples

- [E2B](/agents/e2b.dev) · e2b.dev
- [ScreenshotOne](/agents/screenshotone.com) · screenshotone.com
- [Demand Factory Base x402 Courier](/agents/api-v2.appdeploy.ai) · api-v2.appdeploy.ai
- [Parallel](/agents/parallel.ai) · parallel.ai
- [domain.hugen.tokyo](/agents/domain.hugen.tokyo) · domain.hugen.tokyo

Not yet probed
**2,101**
24.3%

Indexed but live-probe hasn't run yet (e.g. recently added).

Examples

- [HexNest Machine Reasoning Network](/agents/hex-nest.com) · HexNest
- [HexNest Machine Reasoning Network](/agents/hexnest-mvp-roomboard.onrender.com) · HexNest
- [Graph Advocate](/agents/graph-advocate-production.up.railway.app) · PaulieB14
- [Torify — Japanese Locale APIs for AI Agents](/agents/torify.dev) · Torify (operated by Hiroki Sonoda)
- [Viseon AI Router](/agents/viseoncrawltest.uk) · Differentia Consulting

Responds to JSON-RPC
**1,064**
12.3%

Agent endpoint accepts message/send and returns a valid A2A response.

Examples

- [Perkoon — Agent Data Layer](/agents/perkoon.com) · Perkoon
- [Bot Hub](/agents/baconhollow.com)
- [GitDealFlow Signal Agent](/agents/signals.gitdealflow.com) · GitDealFlow
- [Silas](/agents/silas.sylex.ai) · Sylex Commons
- [TESSA Marketing & Technology](/agents/tessa.tech) · TESSA Marketing & Technology

No URL declared
**1,044**
12.1%

Agent card is valid but has no .url field — can't be called directly.

Examples

- [APIMesh](/agents/apimesh.xyz) · APIMesh
- [microsandbox](/agents/docs.microsandbox.dev) · microsandbox
- [Model Context Protocol](/agents/modelcontextprotocol.io) · Model Context Protocol
- [Atla](/agents/docs.atla-ai.com) · Atla
- [CoinGecko API](/agents/docs.coingecko.com) · CoinGecko API

Non-compliant response
**908**
10.5%

Endpoint returned HTTP 200 but the body isn't a valid JSON-RPC 2.0 A2A response.

Examples

- [Hive Civilization](/agents/thehiveryiq.com) · Hive Civilization
- [Merchant-0](/agents/merchant-0.com) · Merchant-0
- [CyMetica AI](/agents/cymetica.com) · Cymetica
- [NEXUS Intelligence](/agents/nexus-agent-xa12.onrender.com) · NEXUS Intelligence
- [BuyWhere](/agents/buywhere.ai) · BuyWhere

Endpoint missing
**423**
4.9%

Card declares a URL, but that URL returns HTTP 404. Card claim mismatch.

Examples

- [ThinkNEO Control Plane (MCP Bridge)](/agents/mcp.thinkneo.ai) · ThinkNEO
- [machins-marketplace](/agents/machins.co) · machins
- [Weftly](/agents/api.weftly.ai) · Woven Record Media
- [Validate Agent](/agents/validate-agent.fly.dev) · Validate Agent
- [BlockRun](/agents/blockrun.ai) · BlockRun, Inc.

Auth required
**214**
2.5%

Agent exists and responds, but requires credentials (401/403). Real but non-anonymous.

Examples

- [The Houstonian Hotel, Club & Spa – Reservations](/agents/d65d5b82-da29-4f57-811e-03840e03b91f.agents.inhotel.io) · inHotel
- [The Grand Hotel in Salem – Reservations](/agents/5d629123-fd38-46cd-8db6-59b4d3ba02b9.agents.inhotel.io) · inHotel
- [Phoenix Inn – Reservations](/agents/4c11ab75-217f-47fc-b47c-0288efb8d67d.agents.inhotel.io) · inHotel
- [AlgoVoi Payment Agent](/agents/api1.ilovechicken.co.uk) · AlgoVoi
- [The Hotel Salem – Reservations](/agents/87fd546d-b3b5-4502-8ee4-d256783c2654.agents.inhotel.io) · inHotel

Unreachable
**99**
1.1%

DNS failed, connection refused, or hard timeout — host might be down.

Examples

- [Korean Public Data Agent](/agents/publicdata-agent.songt50.us) · sapjilcoding
- [AI Dev Jobs](/agents/aidevboard.com)
- [Trade It](/agents/thetradeagent.ai) · Trade It, Inc.
- [BoldSign](/agents/boldsign.com)
- [CeloFX](/agents/celofx.vercel.app) · CeloFX

Server error
**22**
0.3%

Endpoint exists but currently returns 5xx errors — likely unhealthy.

Examples

- [Research Agent](/agents/prassanna-ravishankar--research-agent-research-agent-app.modal.run)
- [The Data Collector — Web Scraping API](/agents/frog03-20494.wykr.es) · AI Hustler
- [Code Agent](/agents/prassanna-ravishankar--code-agent-code-agent-app.modal.run)
- [AI Truism](/agents/ai-truism.vercel.app) · AI Truism
- [Data Transformation Agent](/agents/prassanna-ravishankar--data-agent-data-agent-app.modal.run)

## Are there really this few agents?

These counts cover agents we can discover and check publicly. Private,
authenticated and unadvertised deployments are outside this funnel.

Each stage separates a discovered listing from a responding agent.
See [source coverage](/coverage) for collection dates and limits.