# Astro Security
> Use when configuring Content Security Policy (CSP) in Astro 7 — security headers, script/style hashes, nonces, or experimentalStaticHeaders.
- Skill: `fusengine/astro-security` (Agent Skill, multi-file: 9 files)
- Install (CLI): `npx skillmds@latest add fusengine/astro-security`
- Raw SKILL.md: https://api.skillmd.com/api/skills/fusengine/astro-security/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Web & Frontend
- Author: fusengine (https://skillmd.com/u/fusengine)
- Updated: 2026-09-10
- Page: https://skillmd.com/skills/fusengine/astro-security
---
Configures Astro 7's stable Content Security Policy support (`security.csp` in `astro.config.mjs`): automatic SHA-256/384/512 hash generation for bundled scripts and styles, the injected `` tag, manual hash configuration for external scripts/styles, and nonces for dynamic script injection.
Also covers `experimentalStaticHeaders` for emitting CSP as adapter-based HTTP headers instead of a meta tag. States the known limitations: CSP is inactive in `dev` mode (test with `build` + `preview`), incompatible with `` view transitions, and unsupported for Shiki's inline styles. Does not cover general deployment adapter setup beyond the CSP header wiring (astro-deployment).
# Astro Security
## Agent Workflow (MANDATORY)
Before ANY implementation, spawn 3 agents in parallel, one `Agent` call each with a `name`:
1. **fuse-ai-pilot:explore-codebase** - Analyze existing security config, adapters, headers
2. **fuse-ai-pilot:research-expert** - Verify latest Astro 7 CSP docs via Context7/Exa
3. **mcp__context7__query-docs** - Check CSP compatibility with deployment adapter
After implementation, run **fuse-ai-pilot:sniper** for validation.
---
## Overview
### When to Use
- Enabling CSP in an Astro project (stable in v6.0.0)
- Configuring `security.csp` in `astro.config.mjs`
- Adding SHA-256/384/512 hashes for external scripts or styles
- Using nonces for dynamic script injection
- Setting up `experimentalStaticHeaders` for adapter-based CSP headers
### CSP in Astro
Astro 6 ships Content Security Policy as a **stable** feature (previously experimental). When enabled:
- Astro automatically generates SHA hashes for all bundled scripts and styles
- Injects a `` in each page's ``
- Supports `script-src` and `style-src` directives by default
**Limitations:**
- Not supported in `dev` mode — test with `build` + `preview`
- External scripts and styles require manual hash configuration
- Incompatible with `` view transitions (use native View Transition API)
- Shiki syntax highlighter (inline styles) not currently supported
---
## Reference Guide
### Concepts
| Topic | Reference | When to Consult |
|-------|-----------|-----------------|
| CSP overview | [csp-overview.md](references/csp-overview.md) | Understanding CSP in Astro |
| Configuration | [csp-config.md](references/csp-config.md) | All config options |
| Script directive | [script-directive.md](references/script-directive.md) | script-src configuration |
| Style directive | [style-directive.md](references/style-directive.md) | style-src configuration |
| Nonces | [nonces.md](references/nonces.md) | Dynamic script injection |
| Static headers | [static-headers.md](references/static-headers.md) | Adapter-based CSP headers |
### Templates
| Template | When to Use |
|----------|-------------|
| [csp-basic.md](references/templates/csp-basic.md) | Basic CSP enable with algorithm |
| [csp-advanced.md](references/templates/csp-advanced.md) | Full config with directives + static headers |
---
## Best Practices
1. **Always test with build + preview** — CSP is inactive in dev mode
2. **Start with SHA-512** — strongest hash algorithm
3. **Use `'self'` explicitly** — not included by default in resources
4. **Hash external scripts manually** — compute SHA hashes for CDN resources
5. **Combine with adapter headers** — use `experimentalStaticHeaders` for Vercel/Netlify
---
## Forbidden
- Testing CSP in `dev` mode (doesn't work — always use `build + preview`)
- Using `` with CSP enabled
- Forgetting to add `'self'` when using `resources` array
- Adding `unsafe-inline` (defeats purpose of CSP)