Agent-to-Agent Protocols

Standards and conventions by which agents discover, negotiate with and delegate to other agents — the interoperability layer of the agentic web.

Also known as: A2A, A2A (Agent-to-Agent), agent-to-agent, agent card, Handshake (A2A handshake), open agent protocol, protocols (externalized), two-agent collaboration, shared interfaces

How authors use it

Oldest first (extraction date when no publication date is known).

AuthorTheir termTheir meaning
Externalization in LLM Agents: A Unified Review of Memory, Skills, Protocols and Harness Engineering
Chenyu Zhou, Huacan Chai, Wenteng Chen, Zihan Guo, Rong Shan, Yuanyi Song, Tianyi Xu, Congming Zheng, Jiachen Zhu, Zeyu Zheng, Zhuosheng Zhang, Xingyu Lou, Zhihui Fu, Jianghao Lin, Weinan Zhang · 2026-04-09
protocols (externalized)Externalized interaction structure — rules and conventions governing how agents communicate and coordinate, stored outside weights
#3: How to Build an AI-Native Startup from Day One
Will Schenk (TheFocus.AI) and Ksenia Se (Turing Post) · 2026-04-11
shared interfacesEcosystem-level standards (skills, MCP, AGENTS.md) that replace costly one-off integrations and make agent systems interoperable
The Agentic P&L: Beyond the Empire of Headcount
Shreshta Shyamsundar and Anmol Jain · 2026-05
Handshake (A2A handshake)A unit of cognitive work in which one agent negotiates with another (often consulting a third enclave) to produce an economically meaningful outcome without a human in the critical path
The AI paradox: More automation, more humans, more work | Dan Shipper
Lenny Rachitsky (host); Dan Shipper (guest, CEO Every) · 2026-05
Two-agent collaborationThe pattern where the user's agent (Codex) talks to a product's agent on the user's behalf, carrying compressed context the user could never type — predicted to become the default integration pattern rather than custom in-app agents
This Week in AI: Rethinking the Agent Harness
Michelle Smith · 2026-05-22
open agent protocolBerryman's term for a not-yet-existing standard whereby an agent moving between environments (e.g., Obsidian to Wikipedia) is handed environment-specific skills by each environment.
The Production Gap: 5 Patterns for Building Long-Running AI Agents
Addy Osmani and Shubham Saboo (Google Cloud), published in Turing Post · 2026-05-22
Agent cardAn A2A-standardized self-description published at a well-known URL: capabilities, auth requirements, rate limits. 'Like OpenAPI for agent-to-agent.'
The Production Gap: 5 Patterns for Building Long-Running AI Agents
Addy Osmani and Shubham Saboo (Google Cloud), published in Turing Post · 2026-05-22
A2A (Agent-to-Agent)Open protocol standardizing how agents communicate with other agents, including cards and a discovery registry.
Article: Multi-Agent AI for Production Security Operations: An A2A and MCP Architecture in a 5G Core
Willem Berroubache · 2026-07-23
A2A (Agent-to-Agent protocol)An openly governed (Google-originated, now Linux Foundation), framework-agnostic coordination protocol for inter-agent task exchange, chosen specifically because its multi-year governance durability outlasts any single framework's convenience — agents written eighteen months apart can still interoperate if they share it.
Presentation: APIs for Agents: Rethinking API Programs in the MCP Era
Jim Gough, Andreea Niculcea · 2026-09-23
A2A (Agent-to-Agent)A protocol/paradigm where independent systems discover each other ('is anything capable of doing this particular task?'), then exchange messages that build on tasks — explicitly contrasted with MCP's model of one thing calling tools on another. Jim compares it informally to Akka-style actor coordination.

Documents (17)

Propositions touching this concept (9)

By publication month, oldest first (extraction month when no publication date is known).

2025-09

2026-04

2026-05

2026-06

2026-07

2026-09

Open gaps (53)