---
title: "MGS1048: a layers entry magus cannot honor"
description: Fires when a magus.project "layers" entry names a directory that does not exist, a glob that matches no directory, a path outside the workspace, or a malformed layer name. The workspace load stops.
tags: [MGS1048, magusfile, layers, knowledge graph, figures]
---

# MGS1048: a layers entry magus cannot honor

`layers` on `magus\project({...})` maps a workspace-relative directory, or a glob
of directories, to a layer name. The knowledge graph stamps that name on each
directory, `magus query "layer=<name>"` filters by it, and `magus\layer(name)`
returns every directory in it.

This code fires when an entry cannot be honored:

- the directory does not exist, or the glob matches no directory;
- the path escapes the workspace;
- the layer name is blank or not a lowercase slug (`^[a-z][a-z0-9-]*$`);
- one directory is declared under two layer names.

## Why

A layer that silently covers nothing reads as a boundary the tree keeps when
nothing checks it. The load stops so the declaration and the tree agree.

## Resolution

The message names the entry and the cause.

- **A moved or deleted directory.** Point the entry at the directory's new
  path, or delete the entry.
- **A glob that matches nothing.** Check the pattern against `magus ls` and
  the tree; a glob matches directories, not files.
- **A malformed name.** Use a lowercase slug such as `handler` or `transport`.
- **Two names for one directory.** Keep one; a directory sits in one layer.