Central agent managing the supply chain flow
AI Models & Assistants / Knowledge library
Agent2Agent (A2A) Protocol
Agent to agent communication for discovery, delegation, and task results
Why learn Agent2Agent (A2A) Protocol?
Useful when independently built agents need to delegate work, track progress, and exchange outputs. Protocol compatibility does not establish that a remote agent is trustworthy.
The problem it solves
Standardizes communication and task exchange between agents built with different frameworks or services.
Where it came from
A2A defines a common way for agents from different systems to communicate without exposing their internal implementation. Agent Cards describe capabilities and connection requirements, while messages and tasks carry interactions and work results. It complements MCP's tool and context interfaces with an agent-to-agent communication layer.
Build your understanding
Work through these exercises in order. Try the task before opening a reference.
- Inspect an example Agent Card for skills, endpoints, and authentication requirements.
- Diagram a client agent delegating a document-review task to a remote agent.
- Distinguish a progress message from the resulting document artifact.
- Model a task that needs more input before it can complete.
- Explain when an A2A agent interaction and an MCP tool call serve different purposes.
Documentation and sources
- Official A2A introduction (a2a-protocol.org)
- Official A2A core concepts (a2a-protocol.org)
Connect the ideas
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Real World Example
Supply Chain Logistics Orchestration
Global manufacturing firms managing complex, multi-vendor logistics networks.
The business problem
Firms struggle with siloed logistics agents—such as regional warehouse managers, freight forwarders, and customs brokers—that cannot communicate directly, leading to manual data entry and delayed shipment visibility.
How this topic solves it
The A2A Protocol enables these autonomous logistics agents to interoperate by providing a standardized language for discovery and task delegation, allowing a central orchestrator to request status updates or initiate actions across disparate systems without custom point-to-point integrations.
- Publish an Agent Card at the .well-known/agent-card.json endpoint for each logistics agent to declare its capabilities.
- Configure the central orchestrator to perform agent discovery by fetching these cards to identify available endpoints.
- Implement the SendMessage API for synchronous status queries or SendStreamingMessage for real-time shipment tracking updates.
- Utilize standard JWT-based authentication to ensure secure, authorized communication between the orchestrator and regional agents.
Shows the orchestrator discovering and delegating tasks to specialized logistics agents via A2A.
Handles inventory and storage tasks
Handles transport and shipping tasks
- Orchestrator → GET agent-card → Warehouse Agent
- Orchestrator → POST /message:send → Freight Agent
- Freight Agent → Stream: TaskStatusUpdate → Orchestrator
Expected business outcome
A unified, responsive supply chain ecosystem where agents autonomously negotiate and share task results, significantly reducing manual coordination overhead.
Limitations and checks
Opaque execution prevents agents from inspecting the internal logic or proprietary tools of their peers; developers must verify system health through declared capabilities and standardized status events rather than direct introspection.