What does not documented mean?

Not documented means the cited page does not state the fact. The line names that page and the day it was read. It is not a claim that the fact is false.

What does omitted mean?

Omitted means this note has no checked source for that dimension. The dimension was left out rather than filled in.

Does the index rank these products?

No. The table can be sorted by name, by dimension status, or by checked date. Sort order is not a score.

Where is the machine readable file?

GET /data/gaps.json. The file includes every note, the cited sources, and the read dates.

Gap note

A2A gaps

A2A is a gap note assembled on 2026-10-22. It quotes primary pages for settlement asset, spend controls, revocation, protocol composition, license, governance body, and cross-company use. A line that says not documented uses the day that page was read. The note does not rank the listing.

Last verified 2026-10-21

Sources

A2A listing · Protocol compatibility · Gaps JSON

Dimension status for A2A
Dimension	Status
Settlement asset	Not documented
Spend controls	Omitted
Revocation	Omitted
Protocol composition	Documented
License	Documented
Governance body	Documented
Cross-company use	Documented

Settlement asset

Not documented

Not documented as of 2026-10-21. The project site read on 2026-10-21 does not name a settlement asset.
A2A protocol site · Read 2026-10-21

Spend controls

No checked source for this dimension in this note.

Revocation

No checked source for this dimension in this note.

Protocol composition

Documented

The project site says MCP connects an agent to tools and A2A connects agents to other agents, and that the two are meant to be used together.
A2A protocol site · Read 2026-10-21
AP2's site says the protocol is available as an extension for A2A and for the Universal Commerce Protocol.
AP2 protocol documentation · Read 2026-10-21
The UCP specification defines an A2A transport whose endpoint is an Agent Card URL.
Universal Commerce Protocol specification · Read 2026-10-21
The A2A x402 extension v0.2 spec defines on-chain payments for A2A, including an embedded flow that nests x402 data inside an AP2 mandate.
A2A x402 payments extension v0.2 · Read 2026-10-21
The PACT overview says the protocol sits on A2A 1.0.
PACT protocol overview · Read 2026-10-16
ERC-8004 names A2A as an agent communication protocol and allows a registration file to list an A2A endpoint.
ERC-8004 Trustless Agents · Read 2026-10-21

License

Documented

Apache-2.0. The same page states the Apache License 2.0. The GitHub license API also reported Apache-2.0 for a2aproject/A2A on 2026-10-21.
A2A protocol site · Read 2026-10-21

Governance body

Documented

The project site says A2A was developed by Google, donated to the Linux Foundation, and is maintained by a Technical Steering Committee.
A2A protocol site · Read 2026-10-21

Cross-company use

Documented

The project site says A2A was developed by Google, donated to the Linux Foundation, and is maintained by a Technical Steering Committee.
A2A protocol site · Read 2026-10-21

Questions

What does not documented mean?: Not documented means the cited page does not state the fact. The line names that page and the day it was read. It is not a claim that the fact is false.
What does omitted mean?: Omitted means this note has no checked source for that dimension. The dimension was left out rather than filled in.
Does the index rank these products?: No. The table can be sorted by name, by dimension status, or by checked date. Sort order is not a score.
Where is the machine readable file?: GET /data/gaps.json. The file includes every note, the cited sources, and the read dates.