> ## 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.

# PCD File Standard

> Raw PCD source and the PCD file envelope.

PCD means Program Circuit Description. Raw `.pcd` source is the human-readable
circuit description.

The public standards repository is
[brik64/pcd-standard](https://github.com/brik64/pcd-standard). It publishes the
PCD File Standard v1.0, the PCD Programming Standard v1, and the schema files
derived from the current `brik64-prod` standards baseline.

For distributable or synchronized artifacts, BRIK64 can use a JSON envelope around exact source bytes.

```json theme={null}
{
  "schemaVersion": "brik64.pcd_file.v1",
  "pcd_source": "PC example {\\n  OUTPUT 1;\\n}\\n",
  "canonical": {
    "semantic_pcd_sha256": "sha256:<hash of exact pcd_source bytes>"
  },
  "metadata": {},
  "certification_refs": []
}
```

## Hash Boundary

The semantic hash is calculated from exact `pcd_source` bytes. Metadata and certificate references are operational context, not part of the semantic source.

## Metadata Boundary

Metadata can describe authorship, source authority and local workflow context. It must not contain secrets, tokens, raw private source snapshots or absolute local paths.

## Editing An Enveloped PCD

When editing an enveloped PCD:

1. Update `pcd_source` intentionally.
2. Recompute or request recomputation of `semantic_pcd_sha256`.
3. Preserve metadata only when it remains true.
4. Record the command that produced the new artifact.

## Public Boundary

The PCD standard defines file shape, metadata, canonical hash boundaries and
compiler-bound authoring rules. It is not itself a compiler release,
certificate, runtime artifact or evidence pack.