---
title: "Configuration"
description: "Choose the Skillset configuration layer that owns a project-level authoring decision."
---

> Documentation Index
> Fetch the complete documentation index at: https://nimbus.focal.host/llms.txt
> Use this file to discover all available pages before exploring further.

# Configuration

<a id="configuration"></a>

Skillset configuration is layered. Start with the narrowest layer that expresses the intent, then use a provider override only when the shared form cannot carry the same meaning.

| If you need to... | Start here |
| --- | --- |
| Select providers or configure project-wide compilation | [Project configuration](/skillset/configuration/project-configuration/) |
| Add metadata to a skill, agent, or rule | [Frontmatter](/skillset/configuration/frontmatter/) |
| Change one provider's output or behavior | [Target overrides](/skillset/configuration/target-overrides/) |
| Express portable or [provider-native](/skillset/glossary/#provider-native) tool intent | [Tools policy](/skillset/configuration/tools-policy/) |

## How the Layers Relate

A Skillset [workspace](/skillset/glossary/#workspace) supplies project-wide settings. Defaults then flow through a [cascade](/skillset/glossary/#cascade): workspace defaults, plugin defaults, [source-unit](/skillset/glossary/#source-unit) fields, and finally provider-specific fields. A more specific layer should refine the shared intent rather than define a second copy of it.

For the files behind those layers, see the [workspace layout](/skillset/reference/source/workspace-layout/), [rule source](/skillset/reference/source/rules/), and [preprocessing reference](/skillset/reference/source/preprocessing/).

## Exact Contracts and Inspection

The [generated schemas and examples](/skillset/reference/schemas/) are the exhaustive field reference. Use [`skillset check`](/skillset/reference/cli/check/) to validate source, [`skillset lookup`](/skillset/reference/cli/lookup/) to inspect schema and compatibility facts, and [`skillset explain`](/skillset/reference/cli/explain/) to trace how a source unit resolves for each provider.

Source: https://nimbus.focal.host/skillset/configuration/index.mdx