singularity-forge/mintlify-docs/guides/skills.mdx

---
title: "Skills"
description: "Specialized instruction sets that provide domain-specific guidance to the LLM."
---

Skills are specialized instruction sets that SF loads when the task matches. They provide domain-specific guidance — coding patterns, framework idioms, testing strategies, and tool usage.

## Bundled skills

SF ships with these skills, installed to `~/.sf/agent/skills/`:

| Skill | Trigger | Description |
|-------|---------|-------------|
| `frontend-design` | Web UI work | Production-grade frontend with high design quality |
| `swiftui` | macOS/iOS apps | Full lifecycle from creation to shipping |
| `debug-like-expert` | Complex debugging | Methodical investigation with evidence gathering |
| `rust-core` | Rust code | Idiomatic, safe, performant Rust patterns |
| `axum-web-framework` | Axum web apps | Complete Axum development guide |
| `tauri` | Tauri v2 desktop apps | Cross-platform desktop development |
| `github-workflows` | GitHub Actions | CI/CD, workflow debugging |
| `security-audit` | Security auditing | Dependency scanning, OWASP |
| `review` | Code review | Diff-aware quality analysis |
| `test` | Test generation | Auto-detects frameworks |
| `lint` | Linting and formatting | ESLint, Biome, Prettier |

## Skill discovery

The `skill_discovery` preference controls how SF finds skills:

| Mode | Behavior |
|------|----------|
| `auto` | Skills found and applied automatically |
| `suggest` | Skills identified but require confirmation (default) |
| `off` | No skill discovery |

## Skill preferences

```yaml
always_use_skills:
  - debug-like-expert
prefer_skills:
  - frontend-design
avoid_skills:
  - security-docker
skill_rules:
  - when: task involves Clerk authentication
    use: [clerk]
  - when: frontend styling work
    prefer: [frontend-design]
```

### Resolution order

1. **Bare name** — e.g., `frontend-design` → scans `~/.sf/agent/skills/` and project skills
2. **Absolute path** — e.g., `/Users/you/.sf/agent/skills/my-skill/SKILL.md`
3. **Directory path** — looks for `SKILL.md` inside

User skills take precedence over project skills.

## Custom skills

Create a directory with a `SKILL.md` file:

```
~/.sf/agent/skills/my-skill/
  SKILL.md           — instructions for the LLM
  references/        — optional reference files
```

### Project-local skills

```
.sf/agent/skills/my-project-skill/
  SKILL.md
```

## Skill health dashboard

```
/sf skill-health              # overview table
/sf skill-health rust-core    # detailed view
/sf skill-health --stale 30   # unused for 30+ days
/sf skill-health --declining  # falling success rates
```

The dashboard flags:
- Success rate below 70% over the last 10 uses
- Token usage rising 20%+
- Skills unused beyond the staleness threshold

### Staleness detection

```yaml
skill_staleness_days: 60    # default: 60, set 0 to disable
```

Stale skills are excluded from automatic matching but remain invokable explicitly.