Borrowing it
Nothing to install: this file belongs to getskillseal/skillseal. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.
curl -O https://raw.githubusercontent.com/getskillseal/skillseal/main/AGENTS.mdgit clone --depth 1 https://github.com/getskillseal/skillsealWrote 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.
[](https://agentmods.dev/instructions/getskillseal/skillseal/agents-md)<a href="https://agentmods.dev/instructions/getskillseal/skillseal/agents-md"><img src="https://agentmods.dev/badge/instructions/getskillseal/skillseal/agents-md/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.
<a href="https://agentmods.dev/instructions/getskillseal/skillseal/agents-md"><img src="https://agentmods.dev/badge/instructions/getskillseal/skillseal/agents-md.svg" alt="Reviewed on agentmods" width="80" height="20"></a>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 | $0.00420 | $0.00420 |
| Opus 5.5 | $0.00168 | $0.00168 |
| Sonnet 5.5 | $0.00084 | $0.00084 |
| Haiku 4.5 | $0.00042 | $0.00042 |
Grade A, and why
skillseal AGENTS.md 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.
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.
What it actually says
Agents and SkillSeal
SkillSeal installs a skill as a plain Agent Skills
folder: a directory with a SKILL.md and optional scripts/, references/,
and assets/. Nothing about the format changes, so every agent that reads
Agent Skills reads a sealed skill with no plugin and no integration. The only
addition is the seal: one line that proves what the folder is before it lands.
How an agent gets a sealed skill
npx skillseal add sk1… # verify the line, then write the folder
skillseal add checks the line's checksum offline, verifies the publisher
signature and every file hash, and only then writes the folder into the skills
directory of each agent it finds. Discovery, activation, and execution then work
exactly as they do for any Agent Skill.
Where it installs
skillseal where lists the agents found on the machine. Out of the box it
writes to the skills folder of Claude Code and Claude Desktop, Hermes, goose,
Cursor, Codex, OpenCode, OpenHands, Letta, Amp, Gemini CLI, and GitHub Copilot.
Support for another agent is one line in skillseal/agents.mjs.
Backward compatibility
- A sealed skill is a normal Agent Skill folder. Remove SkillSeal and the folder still works.
- Name based installs keep working; the seal is additive.
- The install line is content addressed, so it resolves from any store and none has to be trusted.
Using a sealed skill as a tool
An agent can fetch, verify, and run a skill straight from storage with the same
verify then run path exposed as an MCP tool. See
demo/agent/skill-mcp.mjs and
docs/design/agent-uses-skill.md.
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 First seen · 41 lines · 420 tokens per session scan A bc380e26de2e
skillseal AGENTS.md is an instructions file published in the GitHub repository getskillseal/skillseal (2 stars, last pushed 2mo ago), licensed MIT. It adds 420 tokens to every session, about $0.0017 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.
Other instructions, from other repositories
vscode buildNext.instructions.md
Working notes and architecture documentation for the new esbuild-based build system in build/next. Use when making changes to the new build pipeline (transpile/bundle commands, NLS plugin, source-map handling, resource copying, or self-hosting watch tasks).
next.js AGENTS.md
AGENTS.md instructions for vercel/next.js, covering next.js development guide, codebase structure, monorepo overview, core package: packages/next and other important packages.
vscode oss-third-party-notices.instructions.md
Instructions for microsoft/vscode, covering vs code oss third-party-notices pipeline, architecture, pipeline flow in ci, cache eligibility and rollout and applying the notice (cutover).
langchain AGENTS.md
AGENTS.md instructions for langchain-ai/langchain, covering global development guidelines for the langchain monorepo, corridor security analysis, project architecture and context, monorepo structure and development tools & commands.
vscode copilot-instructions.md
Copilot instructions for microsoft/vscode, covering vs code copilot instructions, project overview, root folders, core architecture (src/ folder) and built-in extensions (extensions/ folder).
vscode model-prompts.instructions.md
Model-specific prompt authoring and registry guidelines.