A2A on AMP

Overview

CrewAI AMP extends the open-source A2A protocol implementation with production infrastructure for deploying distributed agents at scale. AMP supports A2A protocol versions 0.2 and 0.3. When you deploy a crew or agent with A2A server configuration to AMP, the platform automatically provisions distributed state management, authentication, multi-transport endpoints, and lifecycle management.

Usage

Add A2AServerConfig to any agent in your crew and deploy to AMP. The platform detects agents with server configuration and automatically registers A2A endpoints, generates agent cards, and provisions the infrastructure described below.

from crewai import Agent, Crew, Task
from crewai.a2a import A2AServerConfig
from crewai.a2a.auth import EnterpriseTokenAuth

agent = Agent(
    role="Data Analyst",
    goal="Analyze datasets and provide insights",
    backstory="Expert data scientist with statistical analysis skills",
    llm="gpt-4o",
    a2a=A2AServerConfig(
        auth=EnterpriseTokenAuth()
    )
)

task = Task(
    description="Analyze the provided dataset",
    expected_output="Statistical summary with key insights",
    agent=agent
)

crew = Crew(agents=[agent], tasks=[task])

After deploying to AMP, the platform registers two levels of A2A endpoints:

• Crew-level: an aggregate agent card at /.well-known/agent-card.json where each agent with A2AServerConfig is listed as a skill, with a JSON-RPC endpoint at /a2a
• Per-agent: isolated agent cards and JSON-RPC endpoints mounted at /a2a/agents/{role}/, each with its own tenancy

Clients can interact with the crew as a whole or target a specific agent directly. To route a request to a specific agent through the crew-level endpoint, include "target_agent" in the message metadata with the agent's slugified role name (e.g., "data-analyst" for an agent with role "Data Analyst"). If no target_agent is provided, the request is handled by the first agent in the crew.

See A2A Agent Delegation for the full list of A2AServerConfig options.

File Inputs and Structured Output

A2A on AMP supports passing files and requesting structured output in both directions. Clients can send files as FileParts and request structured responses by embedding a JSON schema in the message. Server agents receive files as input_files on the task, and return structured data as DataParts when a schema is provided. See File Inputs and Structured Output for details.

What AMP Adds

Distributed State Management

In the open-source implementation, task and context state lives in memory on a single process. AMP replaces this with persistent, distributed stores.

Storage Layers

Multiple A2A deployments are automatically isolated from each other, preventing data collisions when sharing infrastructure.

Enterprise Authentication

AMP supports six authentication schemes for incoming A2A requests, configurable per deployment. Authentication works across both HTTP and gRPC transports.

The configured auth scheme automatically populates the agent card's securitySchemes and security fields. Clients discover authentication requirements by fetching the agent card before making requests.

Extended Agent Cards

AMP supports role-based skill visibility through extended agent cards. Unauthenticated users see the standard agent card with public skills. Authenticated users receive an extended card with additional capabilities.

This enables patterns like:

• Public agents that expose basic skills to anyone, with advanced skills available to authenticated clients
• Internal agents that advertise different capabilities based on the caller's identity

gRPC Transport

If enabled, AMP provides full gRPC support alongside the default JSON-RPC transport.

• TLS termination with configurable certificate and key paths
• gRPC reflection for debugging with tools like grpcurl
• Authentication using the same schemes available for HTTP
• Extension validation ensuring clients support required protocol extensions
• Version negotiation across A2A protocol versions 0.2 and 0.3

For deployments exposing multiple agents, AMP automatically allocates per-agent gRPC ports and coordinates TLS, startup, and shutdown across all servers.

Context Lifecycle Management

AMP tracks the lifecycle of A2A conversation contexts and automatically manages cleanup.

Lifecycle States

A background cleanup task runs hourly to scan for idle and expired contexts. All state transitions emit CrewAI events that integrate with the platform's observability features.

Signed Push Notifications

When an A2A agent sends push notifications to a client webhook, AMP signs each request with HMAC-SHA256 to ensure integrity and prevent tampering.

Signature Headers

Security Properties

• Integrity: payload cannot be modified without invalidating the signature
• Replay protection: signatures are timestamp-bound with a configurable tolerance window
• Retry with backoff: failed deliveries retry with exponential backoff

Distributed Event Streaming

In the open-source implementation, SSE streaming works within a single process. AMP propagates SSE events across instances so that clients receive updates even when the instance holding the streaming connection differs from the instance executing the task.

Multi-Transport Endpoints

AMP serves REST and JSON-RPC by default. gRPC is available as an additional transport if enabled.

All active transports share the same authentication, version negotiation, and extension validation. Agent cards are generated from agent and crew metadata — roles, goals, and tools become skills and descriptions — and automatically include interfaces for each active transport. They can also be manually configured via A2AServerConfig.

Version and Extension Negotiation

AMP validates A2A protocol versions and extensions at the transport layer.

Version Negotiation

• Clients send the A2A-Version header with their preferred version
• AMP validates against supported versions (0.2, 0.3) and falls back to 0.3 if unspecified
• The negotiated version is returned in the response headers

Extension Validation

• Clients declare supported extensions via the X-A2A-Extensions header
• AMP validates that clients support all extensions the agent requires
• Requests from clients missing required extensions receive an UnsupportedExtensionError

Next Steps

• A2A Agent Delegation — A2A protocol fundamentals and configuration
• A2UI — Interactive UI rendering over A2A
• Deploy to AMP — General deployment guide
• Webhook Streaming — Event streaming for deployed automations