claude-mythos-skills

claude-mythos-skills is a plugin for Claude Code from itallstartedwithaidea/agent-skills. Its manifest loads nothing; the 10 skills it bundles cost 309 tokens per session together, scanned A, original, MIT.

A collection of ten skills for Claude-based agents, covering prompt design, context management, tool use, verification, self-repair, security against hostile input, and portability between agent systems.

In plain words
What is it for?
It is for designing prompts, managing context, building verification loops, improving agent resilience, and adapting workflows between different agent setups.
Why use it?
It helps organize how an agent reasons, uses tools, checks its work, and recovers from mistakes across longer tasks.

Plugin for Claude Code

Written for Claude Code: a Claude Code plugin manifest.

Good fit It is for designing prompts, managing context, building verification loops, improving agent resilience, and adapting workflows between different agent setups.

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Install in Claude Code
/plugin marketplace add itallstartedwithaidea/agent-skills/plugin install claude-mythos-skills
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.

Clone the repo
git clone --depth 1 https://github.com/itallstartedwithaidea/agent-skills

Made for: Claude Code.

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 claude-mythos-skills

README.md
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Your own site
<a href="https://agentmods.dev/plugins/itallstartedwithaidea/agent-skills/claude-mythos-skills"><img src="https://agentmods.dev/badge/plugins/itallstartedwithaidea/agent-skills/claude-mythos-skills/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.

agentmods 80×15 button for claude-mythos-skills

Your own site · 80×15
<a href="https://agentmods.dev/plugins/itallstartedwithaidea/agent-skills/claude-mythos-skills"><img src="https://agentmods.dev/badge/plugins/itallstartedwithaidea/agent-skills/claude-mythos-skills.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session not measured What this adds to a session before it is invoked.
When invoked not measured The manifest loads nothing itself; its 10 skills cost 309 tokens a session between them.
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.
Security

Grade A, and why

claude-mythos-skills 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 5d 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.

.claude-plugin/marketplace.json#claude-mythos-skills · 18 lines

What it actually says

{
  "name": "claude-mythos-skills",
  "description": "10 Claude-specific skills: prompt architecture, context engineering, tool mastery, self-healing agents, verification loops, cognitive scaffolding",
  "source": "./",
  "strict": false,
  "skills": [
    "./skills/claude-mythos/prompt-architecture",
    "./skills/claude-mythos/context-engineering",
    "./skills/claude-mythos/anthropic-tool-mastery",
    "./skills/claude-mythos/cognitive-scaffolding",
    "./skills/claude-mythos/verification-loops",
    "./skills/claude-mythos/self-healing-agents",
    "./skills/claude-mythos/adversarial-resilience",
    "./skills/claude-mythos/agent-instinct-system",
    "./skills/claude-mythos/session-archaeology",
    "./skills/claude-mythos/multi-harness-portability"
  ]
}
Files

What ships with it

1 file beside marketplace.json#claude-mythos-skills 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.

  1. 5d ago First seen · 18 lines scan A 1fc871ab221c

Subscribe to this mod's changes

claude-mythos-skills is a plugin published in the GitHub repository itallstartedwithaidea/agent-skills (37 stars, last pushed 4mo ago), licensed MIT. Its token cost is not measured: this kind of file is read by the harness, not the model. 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 2026-09-03.