A2A’s move into the Agentic AI Foundation clarifies a two-protocol architecture: MCP connects agents to tools; A2A coordinates agents across boundaries.
The Agent2Agent protocol was accepted in August as a Growth Stage project at the Agentic AI Foundation. The project describes its role clearly: MCP is the vertical integration layer connecting agents to tools and data, while A2A is the horizontal layer through which agents discover one another, delegate work and collaborate across frameworks and vendors.
That division is beginning to form a credible interoperability architecture for the agentic enterprise.
Why point-to-point integration will not scale
A large organisation will not have one agent platform. Different teams, vendors and acquired businesses will build agents with different frameworks. External suppliers may expose their own specialised agents. Some workloads will remain on private infrastructure while others use managed platforms.
Without a shared protocol, every handoff becomes custom code:
- how the agent is discovered;
- what capabilities it offers;
- how identity is represented;
- how a task is delegated;
- how progress is reported;
- how results and errors return;
- how long-running work is resumed.
The number of pairwise integrations grows quickly. Interoperability debt becomes the new API debt.
MCP and A2A solve different problems
An agent may use MCP to access an approved procurement capability. It may use A2A to delegate part of the work to a supplier-risk agent owned by another team or platform.
The distinction can be expressed simply:
- MCP: “Which tool can perform this operation, and how do I call it?”
- A2A: “Which agent can own this subtask, and how do we coordinate the work?”
A tool is usually a bounded capability. An agent has its own goals, state, reasoning and lifecycle.
Confusing them can produce overly intelligent tools or overly thin agents. Clear boundaries improve ownership and observability.
Agent cards become service contracts
A2A uses structured descriptions—agent cards—to advertise capabilities and interaction details. For enterprise adoption, the card should evolve into a governed service contract.
It should answer:
- who owns the agent;
- which tasks it accepts;
- which data classifications it can process;
- supported authentication and delegation;
- expected latency and availability;
- whether work can be cancelled;
- how results are signed or traced;
- which policies and regions apply;
- version and deprecation status.
Discovery should be permission-aware. An agent must not learn about or invoke every capability simply because it exists.
Delegation does not transfer accountability
When one agent delegates to another, responsibility can become ambiguous. The requesting agent may understand the user’s context; the receiving agent may control the domain action. A third platform may host the model.
The architecture needs an unbroken chain of authority:
user or business event → orchestrator → delegated agent → tools → result
Each transition should preserve purpose, identity, policy and correlation identifiers. The parent agent must know what it may delegate and what it must verify after return.
An external agent’s “success” should not automatically be treated as proof that the business outcome is correct.
Neutral governance matters
The A2A project says it is backed by more than 150 organisations and is moving under neutral foundation governance. Those are project-reported figures and will evolve. The significant point is the direction: enterprises are unlikely to accept agent-to-agent coordination that belongs exclusively to one vendor.
Open governance does not guarantee adoption or security. It does make it easier for platforms to implement a common contract without ceding the orchestration layer to a competitor.
What enterprises should standardise
Before creating an internal A2A mesh, define:
- approved agent registries;
- identity and delegated-authority patterns;
- capability and data-classification metadata;
- task lifecycle and cancellation;
- trace propagation;
- output verification;
- version compatibility;
- cross-border and third-party rules;
- incident isolation;
- human ownership for every delegated service.
The protocol removes some custom plumbing. It does not remove the need for architecture.
The Lexdatum view
A2A is emerging as the horizontal coordination layer for a multi-vendor agent estate.
The long-term opportunity is not a swarm of autonomous agents talking freely. It is a network of accountable services that can delegate bounded work while preserving identity, policy and evidence.
MCP makes enterprise capabilities callable. A2A makes delegated intelligence composable. Governance must connect both.
Sources
Research note: This analysis is based on public information available on 31 August 2026. Product capabilities, prices and regulatory interpretations can change. Vendor-reported metrics are identified as such. This is not legal, security or investment advice.