ACP
A REST-native alternative to A2A for teams that want inter-agent messaging over plain HTTP with minimal new machinery.
- name
- ACP
- full_name
- Agent Communication Protocol
- layer
- interop
- creator
- IBM / AGNTCY
- status
- emerging
- year
- 2025
- one_liner
- A REST-native alternative to A2A for teams that want inter-agent messaging over plain HTTP with minimal new machinery.
- spec_url
- https://agentcommunicationprotocol.dev
- snippet
POST /agents/{id}/runs { "input": [ ... ] } // ordinary REST, no special transport- abbreviation
- ACP
- also_known_as
Agent Communication Protocol- canonical_spec_url
- https://agentcommunicationprotocol.dev
- entity_uri
- https://agentcommunicationprotocol.dev
- taxonomy_layer
- interop
- sub_layer
- agent-to-agent
- protocol_type
- transport
- central_problem
- Provides inter-agent messaging over ordinary REST/HTTP so teams can connect agents without adopting a new transport or RPC layer.
- maintainer
- IBM / AGNTCY community (Linux Foundation AGNTCY initiative)
- governance_body
- AGNTCY / Linux Foundation verify-against-primary-at-build ↗ https://agentcommunicationprotocol.dev
- license
- Apache-2.0 verify-against-primary-at-build ↗ https://agentcommunicationprotocol.dev
- maturity_tag
- emerging
- current_spec_version
- — verify-against-primary-at-build ↗ https://agentcommunicationprotocol.dev
- spec_date
- — verify-against-primary-at-build ↗ https://agentcommunicationprotocol.dev
- launch_date
- 2025 verify-against-primary-at-build ↗ https://agentcommunicationprotocol.dev
- last_verified
- 2026-06-15
- transport
- REST over HTTP
- core_mechanism
- Agents expose REST endpoints (e.g. POST /agents/{id}/runs) and exchange runs/messages as ordinary JSON over HTTP, deliberately avoiding a bespoke transport so existing web infrastructure applies.
- discovery_endpoint
- REST agent endpoints (implementation-defined; e.g. /agents/{id})
- settlement_type
- —
- adoption_metric
- — verify-against-primary-at-build ↗ https://agentcommunicationprotocol.dev
- notable_adopters
{"value":"IBM","source":"https://agentcommunicationprotocol.dev"}- relationships
{"predicate":"competes_with","target":"a2a","note":"ACP is positioned as a REST-native alternative to A2A for inter-agent messaging."}- ideal_use_case
- Teams that want agent-to-agent messaging using plain REST conventions and existing HTTP tooling.
- when_to_use
- When you prefer a low-ceremony REST interface for agent messaging over A2A's richer agent-card + task model.
- when_not_to_use
- When you need the broad ecosystem, Agent Cards, and governance of A2A, or cross-vendor production interop today.
- code_example
- POST /agents/researcher/runs HTTP/1.1 Content-Type: application/json { "input": [{ "role": "user", "content": "Summarize the agentic web" }] }
- source
- Spec home: https://agentcommunicationprotocol.dev . Maintainer (IBM/AGNTCY): research §2 (AGNTCY listed among protocols to add).
- agent_readiness_link
- agent-readiness/a2a
- layer_legacy
- agent