> ## 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.

# Core And Extended Monomers

> How to read BRIK64 core and extended monomer ranges.

BRIK64 uses two public monomer ranges.

| Range           | Meaning                                                            |
| --------------- | ------------------------------------------------------------------ |
| `MC_00..MC_63`  | Core operation vocabulary.                                         |
| `MC_64..MC_127` | Extended operation vocabulary for specialized or external domains. |

## Core Monomers

Core monomers should be the first choice for ordinary arithmetic, logic, memory, control, I/O, string, crypto and system-shaped operations.

## Extended Monomers

Extended monomers are useful when the behavior crosses into specialized domains such as float math, network, graphics, audio, filesystem extensions, concurrency or interop.

## Selection Guidance

When extended monomers appear in a PCD, document why a core monomer was insufficient.

```text theme={null}
Extended monomer:
Reason:
External boundary:
Evidence status:
```