The shared internal foundation for the Capstone skills, containing their common rules, reference material, and scripts.

Use it indirectly as part of the Capstone suite, or run its help script when the core skill is invoked directly.

It allows the other Capstone skills to use the same instructions and supporting files; it is not intended as a standalone command.

core — Skill for Claude Code by GentBajko/capstone

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 GentBajko/capstone --skill core

Clone the repo

git clone --depth 1 https://github.com/GentBajko/capstone

Made for: Claude Code.

Or install capstone, the plugin that ships this one along with the rest of its 10 skills, 2 hooks.

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.

README.md

[![agentmods](https://agentmods.dev/badge/skills/gentbajko/capstone/core/github.svg)](https://agentmods.dev/skills/gentbajko/capstone/core)

Your own site

<a href="https://agentmods.dev/skills/gentbajko/capstone/core"><img src="https://agentmods.dev/badge/skills/gentbajko/capstone/core/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

Your own site · 80×15

<a href="https://agentmods.dev/skills/gentbajko/capstone/core"><img src="https://agentmods.dev/badge/skills/gentbajko/capstone/core.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 65 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.

When invoked 207 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.

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.

Model	Per session	Once invoked
Fable 5.1	$0.00065	$0.00207
Opus 5.5	$0.00026	$0.00083
Sonnet 5.5	$0.00013	$0.00041
Haiku 4.5	$0.00006	$0.00021

Measured 1mo ago against content hash 68c2b5e146ee, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

core 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 1mo ago.

The scan reads SKILL.md. This mod also ships 5 executable files (scripts/help-hook.sh, scripts/help.sh, scripts/init-config.sh, …), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

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.

skills/core/SKILL.md · 18 lines

What it actually says

Capstone: core (internal)

This folder is the capstone suite's shared brain: references/ (core rules, protocols, craft files) and scripts/ (help, config initializer, lint, and map-check.sh, the script half of map check that the CI gate runs). Every other capstone skill resolves it as ../core/ from its own base directory, so install the whole suite; a lone capstone skill without core cannot run.

Invoked directly, print the usage: run scripts/help.sh via bash from this skill's base directory and output its stdout verbatim; nothing else.

Files

What ships with it

34 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.

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.

1mo ago Changed · +1 lines 68c2b5e146ee
1mo ago First seen · 17 lines · 65 tokens per session scan A 1fed48250261

Subscribe to this mod's changes

core is a skill published in the GitHub repository GentBajko/capstone (5 stars, last pushed 29d ago), licensed Apache-2.0. It adds 65 tokens to every session and 207 once invoked, about $0.0003 per session on Opus 5.5. 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 2026-08-31.

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