Home / Field Notes / Anatomy of an AI Agent
UNDER THE HOOD · N°08

Anatomy of an AI Agent

Three layers: interface, orchestration, data. Most builders confuse the layers. The Forge does not. Here is why the architecture matters more than the model.

THE FORGE 7 MIN READ APR 22, 2026

The Layer Confusion

Most AI projects fail because they conflate the three layers of an agent into a single prompt. The prompt tries to handle how the user asks, how the work gets done, and where the data lives, all at once. The prompt becomes 4,000 tokens of instructions. The agent becomes unreliable. The project stalls.

The Forge architecture separates the three cleanly. The interface handles how a human asks. Orchestration handles how the work is actually done. The data layer is where the world is remembered. Each layer can be upgraded independently. Each layer has a clear owner.

Layer One · The Interface

The interface is surfaces: a voice line, a Slack DM, a web form, a phone call, an email. A single agent should be reachable through all of them, and the answer to "what is our Q3 pipeline" should not depend on which surface asked. The interface layer's only job is to normalize input and present output, it does not think.

The common mistake is building a different agent per surface. You do not. You build one orchestration and many thin interfaces. This is how the system stays coherent as you add channels.

The interface is the mouth. The orchestration is the mind. The ledger is the memory. Confuse them and nothing works.

Layer Two · Orchestration

The orchestration layer is where the work happens. It is deterministic code calling non-deterministic models, one structured step at a time. It decides which tools to use, which data to fetch, which path to walk. It is not a prompt. It is a state machine that sometimes asks a model for judgment.

This is where the industry is maturing fastest. The pattern now is: small models for classification, larger models for generation, deterministic code for everything in between. Orchestration discipline beats model size in nine out of ten production use cases.

[A single-prompt agent hallucinates the answer. An orchestrated agent hits the ledger, pulls the SKU list, joins the cost table, and cites.]

Layer Three · The Data Layer

No agent is better than the data it can reach. The data layer is the ledger we keep talking about, a single, queryable, versioned source of truth that every orchestration reads from and writes to. It is boring infrastructure. It is also the only thing that makes the agent trustworthy at scale.

Skip the data layer and every answer the agent gives is a plausible hallucination. Build the data layer first, and most of the orchestration becomes trivially easy. This is why The Forge's first install is always the ledger, even when the client asked us to "build an AI."

[The stack. One ledger, one orchestration, many interfaces. Never the other way around.]

Why It Matters

The architecture is not aesthetic. It is the difference between an agent that works in a demo and an agent that works in production for eighteen months without attention. It is the difference between a prompt you rewrite every month and a system you extend.

When a new model ships, you swap it into orchestration without touching the ledger or the interfaces. When a new channel opens, you add a thin interface without touching orchestration. The layers insulate you from change. That is the point.

Next step

From reading to installing.

Field Notes diagnose the friction. The Sprint and the Install eliminate it.