Borrowing it
Nothing to install: this file belongs to haabe/mycelium. 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/haabe/mycelium/main/AGENTS.mdgit clone --depth 1 https://github.com/haabe/myceliumWrote 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/haabe/mycelium/agents-md)<a href="https://agentmods.dev/instructions/haabe/mycelium/agents-md"><img src="https://agentmods.dev/badge/instructions/haabe/mycelium/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/haabe/mycelium/agents-md"><img src="https://agentmods.dev/badge/instructions/haabe/mycelium/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 | $0.02378 | $0.02378 |
| Opus 5.5 | $0.00951 | $0.00951 |
| Sonnet 5.5 | $0.00476 | $0.00476 |
| Haiku 4.5 | $0.00238 | $0.00238 |
Grade A, and why
mycelium 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.
How it starts
The opening of the file, as written. The whole thing — 100 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Agents
This repository uses Mycelium, a theory-guided harness for AI-assisted product development. See README.md for what it is and why.
If you are operating in this repo
Claude Code agents (plugin install — recommended as of v0.20.0):
/plugin marketplace add haabe/mycelium
/plugin install mycelium@haabe-mycelium
After install, run /mycelium:start (the recommended first-run command — composes setup + 10-minute discovery interview into one invocation). Skills are namespaced as /mycelium:<name> (e.g., /mycelium:interview, /mycelium:diamond-assess). Hooks (PreToolUse / PostToolUse / Stop / SessionStart / PostToolUseFailure) auto-fire. Plugin lives in ~/.claude/plugins/cache/... — your project root stays user-owned.
Invoking namespaced skills. Anthropic's plugin convention requires /<plugin>:<skill>. Two ergonomics make the prefix tax cheap:
- Tab completion in Claude Code:
/myc<Tab>expands to/mycelium:, then a few letters +<Tab>finishes the skill name. - Natural-language invocation: prose like "run mycelium start" or "have mycelium assess where we are" routes to the right skill. Use whichever form is faster for you.
Claude Code agents (legacy npx degit install — pre-v0.20.0): your operating manual is CLAUDE.md. Read it first. Skills invoke as /<name> without namespace. Mycelium's full enforcement layer (hooks, gates, reflexion loops, framework-guard, secret detection) is Claude-Code-specific. Both install paths supported during transition; plugin form is the recommended path.
Other agents (Codex, Cursor, Aider, Copilot, etc.): active enforcement is not yet portable. You can still read and contribute to the canvas — see "Minimal path" below. The portable surface is canvas reading + writing + decision logging; Claude-Code-specific is everything that fires automatically (PreToolUse hooks, PostToolUseFailure reflexion, secret-detection, framework-guard). For non-Claude-Code agents, the canonical instructions surface is THIS file (AGENTS.md) — Codex / Cursor / Aider / Copilot read it natively. Claude Code falls back to AGENTS.md when no CLAUDE.md exists. The framework canonical content lives at plugins/mycelium/ in the upstream haabe/mycelium repo (skill SKILL.md files are pure markdown — readable by any agent).
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 · 100 lines · 2,378 tokens per session scan A 472d8d029670
mycelium AGENTS.md is an instructions file published in the GitHub repository haabe/mycelium (47 stars, last pushed yesterday), licensed MIT. It adds 2,378 tokens to every session, about $0.0095 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 2026-08-30.
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.
deepseek-harness AGENTS.md
AGENTS.md instructions for deepseek-ai/deepseek-harness, covering agents.md, pre-stable apis and released session data, repository layout, commands and host sandbox failures.
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).