> ## Documentation Index
> Fetch the complete documentation index at: https://docs.brik64.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Language

> BRIK64 PCD language guide.

PCD is the BRIK64 language for describing bounded logic as a circuit.

The public authoring profile is intentionally compact. It gives agents enough structure to produce inspectable logic without inventing a broad dialect.

The public standards repository for the PCD file and programming baseline is
[brik64/pcd-standard](https://github.com/brik64/pcd-standard).
The public `.brik` workspace standard is
[brik64/brik-standard](https://github.com/brik64/brik-standard).

## Core Shape

```pcd theme={null}
PC example {
    fn evaluate(input) {
        if (input <= 0) {
            return 0;
        }

        return 1;
    }
}
```

## Authoring Guidance

* Name the circuit with `PC`.
* Declare functions with explicit inputs.
* Use `if` branches with explicit returns.
* Use bounded loops when needed.
* Call monomers from the catalog.
* Return a defined value from every path.
* Explain external behavior before using extended monomers.

## Reading Path

1. [PCD Tutorial](/language/pcd-tutorial)
2. [PCD Syntax](/language/pcd-syntax)
3. [PCD File Standard](/language/pcd-file-standard)
4. [.brik Workspace](/language/brik-workspace)
5. [Examples](/language/examples)
6. [Errors](/language/errors)

## Agent Output

Every agent-authored PCD should be accompanied by:

```text theme={null}
Requirement:
Inputs:
Output:
Fail-closed behavior:
Monomers:
EVA structure:
Evidence status:
```