kastell-research

kastell-research is a skill for Claude Code from kastelldev/kastell. It costs 42 tokens per session (1,011 once invoked), scanned A, original, Apache-2.0.

A read-only guide for exploring the Kastell codebase, a software project for server security and infrastructure management.

In plain words
What is it for?
Use it to investigate bugs, find every use of a function, map features, or answer architecture questions without editing files.
Why use it?
It helps developers understand unfamiliar code and trace how commands, core logic, adapters, and providers connect before changing anything.

Skill for Claude Code

Written for Claude Code: allowed-tools in frontmatter. Also seen: agent in frontmatter.

Part of the kastell plugin — 4 skills, 1 agent, 4 hooks, 1 MCP server shipped together

Good fit Use it to investigate bugs, find every use of a function, map features, or answer architecture questions without editing files.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/kastelldev/kastell/kastell-research
Install

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.

Any agent
npx skills add kastelldev/kastell --skill kastell-research
Clone the repo
git clone --depth 1 https://github.com/kastelldev/kastell

Made for: Claude Code.

Or install kastell, the plugin that ships this one along with the rest of its 4 skills, 1 agent, 4 hooks, 1 MCP server.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for kastell-research

README.md
[![agentmods](https://agentmods.dev/badge/skills/kastelldev/kastell/kastell-research.svg)](https://agentmods.dev/skills/kastelldev/kastell/kastell-research)
Your own site
<a href="https://agentmods.dev/skills/kastelldev/kastell/kastell-research"><img src="https://agentmods.dev/badge/skills/kastelldev/kastell/kastell-research.svg" alt="Measured on agentmods" height="20"></a>
Per session 42 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,011 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe. Third-party audits
  • NVIDIA SkillSpector warn 7 Sept 2026
SkillSpector: 1 finding, up to medium

These are SkillSpector’s own severities. On a checked sample its high-severity flags on skills were ~96% false positives — a documented command, a public API, a “never do X” rule — so we show them as a caution to read, not a verdict. Why →

  • medium Agent Snooping · line 69
    Skill enumerates or reads other installed skills. Access to other skills' SKILL.md files or the skills directory reveals prompt instructions, capabilities, and secrets that should be invisible to peer skills.
    Fix: Remove all code or instructions that list or read other skills' files or directories. Skills should operate independently; cross-skill access is a privilege escalation.
How audits are shown
Origin original No closer match found in the catalogue.
Token cost

What 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.

ModelPer sessionOnce invoked
Fable 5.1 $0.00042 $0.01011
Opus 5 $0.00021 $0.00505
Sonnet 5 $0.00008 $0.00202
Haiku 4.5 $0.00004 $0.00101

Measured 8d ago against content hash ac577e2ee541, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-08, from the pricing page.

Security

Grade A, and why

kastell-research 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 8d ago.

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.

kastell-plugin/skills/kastell-research/SKILL.md · 91 lines

How it starts

The opening of the file, as written. The whole thing — 91 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Kastell Research

Purpose

Explore the Kastell codebase using read-only tools (Read, Grep, Glob). Runs in a forked Explore agent with Kastell architecture knowledge inlined.

When to Use

  • Bug investigation: Trace a bug from CLI command through core logic to adapters/providers. Start at the command file, follow imports to core, check utils and adapters.
  • Feature mapping: Map all callsites of a function, trace the import chain, understand how subsystems connect before making changes.
  • Architecture question: Understand how audit categories work, how the adapter dispatch flows, or how lock hardening steps are structured.

Live Codebase

Commands: !node -e "import('fs').then(f=>console.log(f.readdirSync('src/commands').filter(x=>x.endsWith('.ts')).map(x=>x.replace('.ts','')).join(', '))).catch(()=>console.log('commands dir not found'))" Provider registry: !node -e "import('fs').then(f=>{const c=f.readFileSync('src/constants.ts','utf8');const m=c.match(/PROVIDER_REGISTRY[\s\S]{0,200}/);console.log(m?m[0].split('\n').slice(0,4).join('\n'):'not found')}).catch(()=>console.log('constants.ts not found'))"

Architecture Map

src/
  commands/     # 31 thin CLI wrappers (parse args + delegate only)
  core/         # Business logic (ALL computation here)
    audit/      # Audit categories
    lock/       # Server hardening
  providers/    # Cloud API: hetzner, digitalocean, vultr, linode
  adapters/     # Platform abstraction: coolify, dokploy
    factory.ts  # getAdapter(platform) — entry point
  mcp/
    server.ts   # Tool registrations
    tools/      # Handler files
  utils/        # ssh, config, cloudInit, modeGuard
  types/        # ServerMode, ServerRecord, Platform
  constants.ts  # PROVIDER_REGISTRY

Layer Flow

Commands (parse args) --> Core (business logic) --> Providers (cloud API) / Adapters (platform ops). MCP tools also delegate to Core.

Research Workflows

Bug investigation:

  1. Find the command file (src/commands/<name>.ts)
  2. Follow the core import (src/core/<name>.ts)
  3. Check adapter/provider calls
  4. Check utils (ssh, config)

Read the full file on GitHub · 91 lines

Changes

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.

  1. 8d ago First seen · 91 lines · 42 tokens per session scan A ac577e2ee541

Subscribe to this mod's changes

kastell-research is a skill published in the GitHub repository kastelldev/kastell (60 stars, last pushed yesterday), licensed Apache-2.0. It adds 42 tokens to every session and 1,011 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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