How the Underpinning of AI Agents Relates, Differs, and Can Help Build Out Your Agentic Plans
AI Agents aren’t evolving in a vacuum. They are built on the same foundations of applications and data architecture that have long powered enterprises. As more businesses lean into agentic technologies, the jargon and complexity can feel overwhelming, especially for leaders responsible for balancing innovation and risk.
For security and IT leaders tasked with enabling the business while safeguarding it, understanding these foundations isn’t just academic. It’s practical, it’s urgent, and it’s the difference between slowing down innovation with friction or enabling it safely at scale.
It’s an uncomfortable tension: the business wants speed, but you carry the responsibility if something goes wrong. Understanding these building blocks is one way to reduce that tension without defaulting to ‘no.’
Three critical concepts matter most here: APIs (Application Programming Interfaces), MCPs (Model Context Protocols), and A2A (Agent-to-Agent communication). Each represents a layer in how systems share data, context, and intent - and together, they form the backbone of an enterprise-ready agentic strategy.
Why It Matters
The natural questions leaders ask are: Do I need to add more APIs? Do I replace APIs with MCPs? Do I choose between MCPs or A2A? And most importantly, what do these actually mean in practice?
The answer is that it’s not about choosing one over another. It’s about understanding how they work together. APIs and MCPs set the stage; A2A enables the play.
When combined, they reduce toil, accelerate decisions, and achieve that elusive state of productivity - without exposing the organisation to unmanaged risk.
This is the real unlock: visibility into how these elements interconnect gives you the tools to scale AI Agent use safely, while retaining oversight and governance.
So What’s What
APIs: Request-response interfaces that retrieve and share data based on predefined rules. They’re the documented pathways developers know and trust.
- Require predefined input/output formats
- Common in enterprise integrations
- Predictable and controlled
Security implementation concern: Secure by default, watch for excessive permissions, enforce least privilege, log and monitor agent-driven API calls separately from human calls.
MCPs: Standardised protocols that define and share meaning. They enable systems to not only exchange data but also align on intent and context.
- Focus on understanding, not just transfer
- Enable interoperability across intelligent systems
- Support dynamic negotiation and adaptation
Security implementation concern: Ensure schema governance like who defines context, how changes propagate, and what happens when definitions drift. Misaligned MCPs could lead to systemic risk.
A2A: The direct communication channel between autonomous agents. This is where systems start collaborating, reasoning, and adapting in real time.
- Decentralised, peer-to-peer
- Often asynchronous and event-driven
- Involves goals, strategies, and coordination
Security implementation concern: Introduce explicit oversight controls (e.g., audit trails and cross-system mitigations). Define acceptable agent autonomy levels per business domain.
How They Work Together
It’s tempting to look at APIs, MCPs, and A2A as competing approaches, but in practice they build on each other. APIs provide the basic connectivity between systems; MCPs introduce a shared context that makes those connections meaningful; and A2A allows autonomous agents to collaborate and adapt in real time.
This layering creates powerful opportunity, but it also changes the nature of the risks. APIs at scale can lead to sprawl if requests aren’t monitored. MCPs bring alignment, but any errors in context or schema can spread instantly across the agents that rely on them. A2A enables speed and flexibility, but with it comes emergent behaviour that’s difficult to predict or trace using traditional governance models.
Seeing these not as isolated tools but as an interconnected system is essential. APIs connect, MCPs align, and A2A adapts. Together, they can create systems that operate far beyond human capacity, which means visibility and oversight have to evolve in step.
A Simple Analogy
Imagine a large international dinner party. APIs are the menus and recipe cards - structured, reliable instructions for ordering and preparing food. MCPs are the shared cookbook and translator - ensuring “spice” means the same thing across cultures. A2A is the chefs in the kitchen collaborating directly, adjusting and negotiating as they cook.
Each layer has its role. Working together, they ensure the meal is delivered seamlessly, no matter how diverse the participants.
Final Thoughts
APIs, MCPs, and A2A aren’t competing technologies. They’re a progression from connectivity to comprehension to collaboration. For security and IT leaders, the opportunity lies in using them responsibly: maintaining visibility into interactions, enforcing governance of meaning and context, and having clear interventions when agent-to-agent behaviour takes an unexpected turn.
Organisations that approach these layers with clarity, as levers for safe innovation rather than abstract terminology, will be best positioned to scale agentic systems with confidence and resilience.
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