AWS Bedrock A2A – How AgentCore Enables Agent-to-Agent Communication

AWS Bedrock A2A gives development teams a standard way to let AI agents discover, communicate with, and delegate work to other agents.

Instead of building custom integration logic for every agent, organizations can use Amazon Bedrock AgentCore Runtime with the Agent-to-Agent protocol to create multi-agent systems that work across different frameworks and models.

Important distinction is that AWS Bedrock A2A support is delivered through Amazon Bedrock AgentCore Runtime.

AgentCore can host A2A servers while preserving the standard protocol behavior, including JSON-RPC communication and Agent Cards for agent discovery.

AWS adds production features such as authentication, session isolation, deployment management, and cloud infrastructure around that protocol.

For companies building customer service agents, operations assistants, research systems, workflow automation, or complex AI applications, A2A on AWS solves a growing problem: how do several specialized agents work together without becoming one tightly coupled application?

What Is AWS Bedrock A2A?

AWS Bedrock A2A is an implementation pattern for running Agent-to-Agent compatible AI agents through Amazon Bedrock AgentCore Runtime.

A2A protocol defines how one AI agent can discover another agent, understand its capabilities, send it work, and receive results in a standard format.

For example, imagine an ecommerce application with separate agents for:

• Customer support
• Inventory management
• Order processing
• Refund approval
• Shipping information

Customer support agent does not need to contain all five business functions.

It can identify the right specialized agent and delegate part of the request.

Amazon Bedrock AgentCore Runtime operates as a transparent layer around the A2A server.

JSON-RPC messages sent through the AgentCore Runtime invocation API are passed to the A2A container while the standard A2A interaction model remains intact.

This makes aws bedrock agentcore a2a useful when multiple independently developed AI agents must cooperate inside one business process.

How the AWS Bedrock A2A Protocol Works

AWS Bedrock A2A protocol flow starts with discovery, followed by a structured request between a client agent and a remote agent.

AgentCore Runtime expects an A2A server to use JSON-RPC 2.0 over HTTP.

A2A server must also publish an Agent Card at:

/.well-known/agent-card.json

Agent Card tells other agents what the agent does.

It can describe the agent name, skills, supported inputs, outputs, service endpoint, protocol version, and other capabilities.

A flow looks like this:

1. User makes a request

A user may ask:

“Check whether this order can be refunded and start the refund if it qualifies.”

2. Client agent evaluates the task

Customer service agent determines that another agent handles refunds.

3. Client discovers the remote agent

Client reads the remote agent Agent Card to understand its available skills.

4. Client sends an A2A request

Agents communicate using a JSON-RPC request such as message/send.

5. Remote agent performs the work

Refund agent evaluates the order and may use databases, API, or MCP tools.

6. Result returns to the client agent

Response can contain messages, tasks, or artifacts that the original agent can use to continue the workflow.

Result is cleaner separation between responsibilities without forcing every agent into the same application framework.

AWS Bedrock AgentCore A2A Architecture

AWS AgentCore Gateway architecture separates agent communication, agent execution, tool access, and security rather than placing everything inside one agent.

An architecture can contain:

Client or orchestrator agent → AgentCore Gateway → AgentCore Runtime A2A agent → business tools and services

Each part serves a different purpose.

Client Agent

Client agent receives the original goal and decides which specialist should handle a task.

AgentCore Runtime

AgentCore Runtime hosts the A2A server.

AWS requires AgentCore Runtime A2A containers to listen on 0.0.0.0, use port 9000, and expose the A2A service from the root path.

Agent Card

Agent Card provides standardized discovery information about the remote agent.

AgentCore Gateway

AWS Bedrock AgentCore Gateway provides a governed entry point for agents, tools, models, and HTTP services.

For A2A services, Gateway can use HTTP targets.

These requests are forwarded to the target without protocol translation or capability aggregation.

HTTP targets can include AgentCore Runtime agents and other A2A-compatible services.

This distinction matters. AgentCore Gateway A2A traffic is not converted into MCP.

A2A remains A2A.

Tools and Business Systems

Individual agents can still use API, Lambda functions, databases, SaaS applications, or MCP servers to complete their own tasks.

This creates a useful separation:

A2A connects agents to agents. MCP primarily connects agents to tools and resources.

A2A vs MCP on AWS

A2A and MCP solve different integration problems, and many production systems will use both.

MCP helps an agent access capabilities such as API, databases, search systems, and business functions.

A2A helps one independent agent communicate with another independent agent.

Consider an inventory agent.

Inventory agent might use MCP to query:

• Warehouse inventory
• Product information
• ERP records

It might then use A2A to tell a procurement agent:

“Stock for Product A will fall below the required level in three days.

Review suppliers and recommend a replenishment order.”

Procurement agent remains responsible for its own logic and tools.

This pattern prevents one agent from becoming responsible for every workflow in the company.

AWS Bedrock A2A Tutorial –  Implementation Flow

AWS Bedrock A2A tutorial involves creating an A2A project, testing it locally, deploying it to AgentCore Runtime, retrieving its Agent Card, and invoking it from another agent.

AWS provides AgentCore CLI support for creating A2A projects.

Step 1: Create the A2A Project

AgentCore CLI can scaffold an A2A application with:

agentcore create –protocol A2A

AWS documentation shows support for creating projects with frameworks including Strands Agents, LangChain/LangGraph, and Google ADK.

Agent contains its model, instructions, tools, and A2A server implementation.

Step 2: Run It Locally

Start the development server with:

agentcore dev

A2A server runs on port 9000.

You should then test both the main JSON-RPC endpoint and the Agent Card endpoint.

For example:

GET http://localhost:9000/.well-known/agent-card.json

Step 3: Configure Authentication

Production agents should not accept unrestricted requests.

AgentCore Runtime supports OAuth 2.0 Bearer tokens and AWS SigV4 authentication for A2A workloads.

Authentication choice should reflect who calls the agent and whether requests originate from AWS identities, applications, users, or other agents.

Step 4: Deploy the Agent

Deployment can be performed with:

agentcore deploy

AWS packages the application, uploads deployment artifacts, creates the AgentCore Runtime, and deploys the agent.

Step 5: Retrieve the Agent Card

Retrieve the deployed Agent Card so the calling agent can identify the remote agent URL, capabilities, and supported behavior.

Step 6: Send the A2A Request

Client can then create an A2A message and send it to the remote agent.

That completes the basic AWS bedrock agent a2a communication loop.

AWS Bedrock A2A Example

AWS Bedrock A2A example is a customer service system where specialized agents share responsibility for resolving one customer request.

Suppose a customer says:

“My shipment is late. If it will not arrive tomorrow, cancel it and refund me.”

Instead of sending the entire problem to one massive agent, an orchestrator could work with three agents.

Shipping Agent

Checks carrier information and predicts whether the shipment will arrive.

Order Agent

Determines whether the order can still be cancelled.

Refund Agent

Checks refund policies and initiates the appropriate transaction.

Agent first sends the shipment information to the shipping agent through A2A.

If the shipping agent reports that delivery will be delayed, the orchestrator contacts the order agent.

If cancellation succeeds, it delegates the financial step to the refund agent.

Each agent remains focused on one business responsibility.

This structure makes individual agents easier to test, update, secure, and replace.

Where AWS Bedrock AgentCore Gateway Fits

AWS Bedrock AgentCore Gateway becomes valuable when organizations need centralized control over how agents reach other agents and services.

Gateway can provide one managed entry point rather than allowing every application to call individual runtimes directly.

AWS supports inbound authorization configurations including OAuth and IAM SigV4.

Gateway can also use several outbound authentication approaches when connecting to AgentCore Runtime targets.

Organizations can therefore place AWS Bedrock AgentCore Gateway between consuming applications and selected agent runtimes.

AWS also supports configurations where access to an AgentCore Runtime can be restricted so requests must come through the Gateway.

This allows organizations to apply centralized authorization, observability, interceptors, and governance controls before traffic reaches an agent.

For enterprise environments, this is preferable to exposing multiple agent endpoints independently.

When Should You Use A2A on AWS?

Use A2A when AI application contains independently useful agents that must cooperate rather than simply call tools.

Strong use cases include:

• IT incident management
• Customer service
• Supply chain coordination
• Financial operations
• Research workflows
• Sales operations
• Healthcare administration
• Insurance workflows
• Developer automation
• Multi-company agent integrations

A2A is less useful when the application has only one agent calling a few API.

In that case, direct tools or MCP may provide a simpler design.

Do not create ten agents simply because the architecture supports them.

Split agents when there is a clear separation in responsibility, security, ownership, domain knowledge, or deployment lifecycle.

Best Practices for AgentCore A2A

Production A2A systems need governance around agent identity, permissions, errors, and task boundaries.

Start by giving each agent a narrow responsibility.

An agent that is described as “handles everything related to customers” will be difficult to govern.

Keep Agent Cards accurate so orchestrators understand what an agent can perform.

Use OAuth or SigV4 authentication rather than exposing production agents publicly.

Design retries carefully.

AgentCore returns standard HTTP status codes alongside JSON-RPC error information for runtime failures, and AWS documents retry handling for certain session conflicts.

Finally, track the complete workflow rather than monitoring each agent independently.

Remote-agent call does not mean the original customer request was completed successfully.

FAQs About AWS Bedrock A2A

Does Amazon Bedrock support the A2A protocol?

Yes.

Amazon Bedrock AgentCore Runtime supports deploying A2A servers while preserving features such as Agent Cards, JSON-RPC communication, session isolation, and authentication.

What is the difference between AgentCore A2A and MCP?

A2A connects agents with other agents, while MCP mainly connects agents with tools and resources.

Production AI platform can use both protocols at the same time.

What does AgentCore Gateway do for A2A?

AgentCore Gateway can front A2A services as HTTP targets and provide an entry point for agent traffic.

It forwards HTTP traffic to A2A targets without converting the A2A protocol into MCP.

Does A2A require all agents to use the same AI model?

No.

One of the main reasons to use a protocol-based architecture is to reduce dependencies between agent implementations.

Different agents can use different models, frameworks, tools, and deployment environments as long as they correctly implement the required protocol.

Can an A2A agent call API and databases?

Yes.

An A2A agent can still use API, Lambda functions, MCP servers, databases, and other tools.

A2A defines how the agent communicates with other agents, not how every internal business operation must be implemented.

Is AWS Bedrock A2A suitable for enterprise applications?

Yes, when several agents must operate across defined security and responsibility boundaries.

AgentCore Runtime adds AWS authentication and session controls, while AgentCore Gateway can provide centralized access and governance for selected agent workloads.

Final Thoughts – AWS AgentCore Gateway Architecture

AWS Bedrock A2A is most valuable when organizations move beyond isolated AI assistants and start building systems where specialized agents must cooperate.

Amazon Bedrock AgentCore Runtime provides the execution environment for A2A servers, while the A2A protocol gives those agents communication model.

AgentCore Gateway can add another governance layer by controlling how applications and agents reach those runtimes.

Key architectural decision is not simply whether to “use A2A.”

It is deciding where one agent responsibility should end and another agent responsibility should begin.

For organizations planning agentcore a2a, AgentCore Gateway A2A, or a broader multi-agent AWS architecture, Qualix Solutions can help evaluate the use case, define agent boundaries, configure AWS infrastructure, and move the system from proof of concept to a production-ready implementation.

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