Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
npx agentmods add skills/managedcode/dotnet-skills/astro-developernpx skills add managedcode/dotnet-skills --skill astro-developergit clone --depth 1 https://github.com/managedcode/dotnet-skillsWhat it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5 | $0.00044 | $0.01244 |
| Opus 5 | $0.00022 | $0.00622 |
| Sonnet 5 | $0.00009 | $0.00249 |
| Haiku 4.5 | $0.00004 | $0.00124 |
Grade A, and why
astro-developer scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured yesterday.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
How it starts
The opening of the file, as written. The whole thing — 133 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Astro Developer Skill
Context-loading skill for AI agents and developers working in the Astro monorepo. Loads relevant documentation based on your task.
Quick Decision Matrix
What are you doing? → Read these files:
| Task | Primary Docs | Supporting Docs |
|---|---|---|
| Adding a core feature | architecture.md, constraints.md | testing.md |
| Fixing a bug | debugging.md | architecture.md |
| Writing/fixing tests | testing.md | constraints.md |
| Creating an integration | Explore packages/integrations/ for examples |
testing.md |
| Understanding architecture | architecture.md | - |
| Dealing with errors | debugging.md, constraints.md | testing.md |
| Understanding constraints | constraints.md | architecture.md |
Critical Warnings
Before you start, be aware of these common pitfalls:
- Prefer Unit Tests: Write unit-testable code by default. Use integration tests only when necessary → testing.md
- Node.js API Restrictions: Cannot use Node.js APIs in
runtime/code → constraints.md - Test Isolation: Must set unique
outDirfor each integration test → testing.md - Runtime Boundaries: Core vs Vite vs Browser execution contexts → architecture.md
- Prerelease Mode: Changesets target
origin/nextbranch (check.changeset/config.json)
What ships with it
6 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- yesterday First seen · 133 lines · 44 tokens per session scan A 3361e07e0dd7
astro-developer is a skill published in the GitHub repository managedcode/dotnet-skills (477 stars, last pushed 2d ago), licensed MIT. It adds 44 tokens to every session and 1,244 once invoked, about $0.0002 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.
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