AI Agent Interoperability: Why AAIF, MCP, and A2A Are the Only Bet Worth Making

The Signal in the Noise

On December 9 2025, the Linux Foundation announced the launch of the Agentic AI Foundation (AAIF). The founding members Anthropic, Block, and OpenAI donated three projects to seed the effort: the Model Context Protocol (MCP), Goose, and AGENTS.md. The Platinum membership list includes AWS, Google, Microsoft, Bloomberg, Cloudflare, Anthropic, Block, and OpenAI.

This is not a research consortium or a policy talk shop. It is the largest infrastructure players placing coordinated bets on shared rails.

Most coverage treated this as a feel-good collaboration story. It is not. It signals the industry shifting into a new phase.

• Phase 1 (Discovery): “Can we make an agent that reasons?” Prototypes, demos, bespoke code.
• Phase 2 (Infrastructure): “How do we wire this into the global economy?” Standards, interoperability, reliability.

The release of MCP in 2024 was the spark. The A2A Protocol added fuel.
But, the formation of the AAIF in 2025 marks the beginning of Phase 2 in earnest.

Here is the maxim that will define the next five years: When infrastructure appears, standards wars follow. MCP was the opening shot. AAIF is the mobilization of the entire army.

To see what comes next, it helps to look backward.

The British Gauge Wars

In the 1840s, Britain experienced railway mania. Track mileage exploded. Capital poured in. But companies built incompatible systems. (Sound familiar?)

Two gauges emerged:

• Broad Gauge, promoted by Isambard Kingdom Brunel. Technically superior. Faster and more stable.
• Standard Gauge, promoted by George Stephenson. Narrower and less elegant, but far more widespread.

The collision point was a station called Gloucester.

At Gloucester, broad gauge from the Great Western Railway met standard gauge from the Midland Railway. Trains could not continue across the boundary.

Passengers disembarked and walked to another train. Freight was unloaded by hand and reloaded. Perishables spoiled. Fragile goods broke. Valuable goods disappeared.

The Gloucester Break did more than slow things down. It eliminated the network effect that made rail valuable in the first place.

The Gauge Wars ended only when Parliament intervened in 1846 and mandated standard gauge for new construction. Economic gravity defeated engineering purity. Commerce demanded a single rail.

The lesson still applies: Every time the rails don't match, someone is paying for it.

The Agent Economy: Our Own Gloucester Break

We are living through our own Gloucester Break.

Imagine a realistic near-future scenario. A Salesforce agent for sales qualification needs to coordinate with a Microsoft Copilot handling support tickets and a custom Python agent managing R&D prioritization. They need to share context, negotiate tasks, and hand off work.

Today they cannot. They run on different gauges: incompatible message formats, incompatible authentication, incompatible schemas.

Developers are writing the digital equivalent of "transloading" code:
normalizing payloads, rewrapping auth, retrying brittle calls, mapping capabilities by hand.

This glue code is the modern version of unloading freight wagon by wagon.

The economics are punishing. Teams routinely spend more time on wiring, adapters, schema normalization, and rewrapping auth headers than on agent logic. Integration dominates the budget. Every custom connector becomes a maintenance liability that must be updated any time an endpoint changes.

Enterprise adoption is not stalling because models are weak. It is stalling because the rails do not exist.

Why Standards Are Strategic Warfare, Not Charity

Why would direct competitors like Google, OpenAI, and Anthropic collaborate on AAIF?

It is not altruism. It is platform strategy.

Strategic Imperative A: Commoditize the Complement

Platform economics teaches a simple rule: commoditize your complement.

If you sell models and compute, you want connectivity, orchestration, and integration to be cheap or free.

By standardizing connectivity through MCP, A2A, and AGENTS.md, the hyperscalers shift value away from integration platforms and toward the model and cloud layers where they profit.

Strategic Imperative B: The Default Defaults

The standard defines more than the API. It defines the security baseline.

What is easy becomes normal.

If the reference implementation ships with unauthenticated HTTP examples because they are simpler in a tutorial, that becomes the ecosystem norm. Developers copy them. Security teams inherit them.

If the reference implementation ships with mTLS and signed agent identities as the default template, the industry baseline rises instead.

Whoever sets these defaults determines the compliance floor for the next decade.

AAIF matters because the decisions made now about authentication, capability negotiation, and trust delegation will shape what enterprise architecture looks like long after the working groups are forgotten.

The Stakes: Who Loses the War?

Every standards war produces winners and casualties.

The likely losers include:

• Integration platforms that still charge per connector. Once connectivity is free, translation loses value.
• Proprietary agent ecosystems where agents only talk to agents from the same vendor. These resemble Broad Gauge: technically strong but economically isolated.
• Internal platforms built on custom protocols that will become stranded when convergence arrives.

There is a reasonable concern that AAIF could fragment into yet another standard. That risk exists. But given the alignment of Google, Microsoft, AWS, OpenAI, Anthropic, Cloudflare, and Bloomberg, betting against convergence is the riskier choice.

When this much capital aligns, gravity follows.

The Missing Layer: Identity in a Standardized World

Assume AAIF succeeds.

MCP becomes the standard for reading context and invoking tools.
A2A becomes the standard for agent-to-agent negotiation.

The rails are connected.

There is still a critical gap.

• MCP solves syntax: how to parse a tool call.
• A2A solves coordination: how agents exchange messages and negotiate.
• Neither provides a verifiable global identity layer. They define how agents talk, not who is actually talking across organizational boundaries.

These protocols often run over secure transports. That is not enough. Enterprise agents need identity that spans domains, vendors, and networks. Without that, standardized communication simply makes spoofing and impersonation easier.

Once every agent speaks MCP, attackers know how to craft a valid-looking request.
Once every agent uses A2A, the handshake pattern is public.

The perimeter does not shrink. It disappears.

This is one of the critical gaps CapiscIO fills.

CapiscIO is a registry and trust network for agents using AAIF-aligned protocols. It verifies who the agent is, what it is allowed to do, and signs the traffic it sends.

Operationally:

• Passport Control: domain-verified agent identities, signed agent cards, revocation when compromised.
• Switching Signals: policy evaluation and allow or deny decisions for agent-to-agent calls.

AAIF defines the rails. Vendors implement them. We make those rails safe for enterprise traffic.

The Emerging Stack

The industry is converging on a three-layer architecture:

Context Layer: MCP for how agents read data and invoke tools.

Coordination Layer: A2A for how agents negotiate and collaborate.

Trust Layer: identity verification, integrity signing, and policy enforcement.

This stack mirrors how governance bodies and technical groups are describing the evolution of agent systems. Protocols and orchestration sit at the bottom. Trust and policy sit at the top.

The implication is clear. Stop building connectors. Build on rails.

What To Do Now

The rails are being joined. The trains are about to move faster. Here is how to position yourself.

For Builders

Stop inventing new gauges. Build against MCP and A2A.

Assume a trust layer will be required. Do not hardcode credentials or embed auth.

Watch the reference implementations. Defaults in sample code will become defaults in production.

For Leaders

Audit your current agent pilots. Count the number of custom authentication schemes. That number is your exposure.

Shift attention from model selection to identity architecture.

Ask this question in your next review: If an unknown MCP-speaking agent calls us tomorrow, what happens? If the answer is “it depends on the glue code,” you do not have an identity model.

The Closing Question

The Gauge Wars ended when Parliament imposed a single standard. The economics left no alternative.

AAIF is the market’s equivalent of that intervention. The rails are being standardized. The question of whether agents can communicate is being solved.

The real question now is: Do you know who is on the line?

CapiscIO builds the identity and trust layer for the agent economy. We help enterprises verify who their agents are talking to before the conversation starts.