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# [A2A ProtocolA2A Project · agent-communication](https://www.agentlist.io/systems/a2a)vs[AGNTCYAGNTCY · agent-communication](https://www.agentlist.io/systems/agntcy)

Two Linux-Foundation-era agent protocols. A2A standardizes task exchange and Agent Cards between agents; AGNTCY (Cisco-originated) aims at the whole 'Internet of Agents' stack — directory, SLIM messaging, identity, observability.

agentlist.io · spec diff · verified 2026-09-25 — list prices only, not benchmarks

SEC.01

## Spec diff

A2A ProtocolAGNTCY

vendorA2A ProjectAGNTCY

categoryagent-communicationagent-communication

interfacesapiapi

hostinglocal · cloudlocal · cloud

pricingOpen protocol (free)Free (OSS, Apache-2.0)

statusactively maintainedactively maintained

also known asAgent2Agent, A2AInternet of Agents

SEC.02

## Pick which

pick A2A Protocol if

You want the protocol with the widest vendor adoption signal (Google, IBM, Microsoft, Salesforce ecosystems) and a narrow, implementable scope.

pick AGNTCY if

You need the fuller stack — discovery directory and messaging fabric, not just a task-exchange schema.

watch out

The two overlap and both are young — expect convergence rather than a clean winner; avoid baking assumptions deep into application code.

SEC.03

## Feature notes

-   A2A Protocol
-   01Agent Cards for capability discovery
-   02Task lifecycle and artifacts
-   03Streaming updates
-   04Vendor-neutral governance (Linux Foundation)
-   05Composes with MCP

-   AGNTCY
-   01Agent directory
-   02SLIM messaging fabric
-   03Identity and badges
-   04Observability SDKs
-   05Linux Foundation project

FAQ

## Frequently asked

### A2A Protocol or AGNTCY — which should I pick?

Two Linux-Foundation-era agent protocols. A2A standardizes task exchange and Agent Cards between agents; AGNTCY (Cisco-originated) aims at the whole 'Internet of Agents' stack — directory, SLIM messaging, identity, observability. Pick A2A Protocol if: You want the protocol with the widest vendor adoption signal (Google, IBM, Microsoft, Salesforce ecosystems) and a narrow, implementable scope. Pick AGNTCY if: You need the fuller stack — discovery directory and messaging fabric, not just a task-exchange schema.

### Is A2A Protocol or AGNTCY cheaper?

A2A Protocol: Open protocol (free). AGNTCY: Free (OSS, Apache-2.0). List prices as of 2026-09-25; usage pools and seat terms change the real cost.

### Does A2A Protocol or AGNTCY run locally?

A2A Protocol hosting: local, cloud. AGNTCY hosting: local, cloud. Interfaces differ too: A2A Protocol exposes api, AGNTCY exposes api.

### Are A2A Protocol and AGNTCY still maintained?

A2A Protocol: actively maintained. AGNTCY: actively maintained. Statuses are re-verified each catalog refresh (2026-09-25); see the changelog for the full history.

ALT

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A

## A2A Protocol

A2A (Agent2Agent) is the open protocol for cross-vendor agent communication — Google-originated, now governed at the Linux Foundation — standardizing Agent Cards for capability discovery plus task-based messaging between agents.

[full spec sheet →](https://www.agentlist.io/systems/a2a)

-   [↗ github.com/a2aproject/A2A](https://github.com/a2aproject/A2A)
-   [↗ a2a-protocol.org](https://a2a-protocol.org/)

B

## AGNTCY

AGNTCY is the Cisco-originated 'Internet of Agents' collective — an open-source stack for agent discovery (directory), secure messaging (SLIM), identity, and observability across vendors.

[full spec sheet →](https://www.agentlist.io/systems/agntcy)

-   [↗ agntcy.org](https://agntcy.org/)
-   [↗ github.com/agntcy](https://github.com/agntcy)

SRC

## Data

Fields come from the seed catalog, re-verified 2026-09-25. This page compares recorded specs — it does not rank performance. See the [changelog](https://www.agentlist.io/changelog) or the [JSON feed](https://www.agentlist.io/api/v1/systems).

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