shua-labs: Agent for Claude Code

.cursor/agents/marcus.md

marcus is an agent for Claude Code, Cursor from jmenzies722/shua-labs. It costs 12 tokens per session (108 once invoked), scanned A, original, MIT.

A specification-writing agent named Marcus that produces plans and requirements but does not write production code. It can place the specification in a GitHub issue, pull-request comment, or handoff document.

In plain words
What is it for?
Use it to prepare a software specification for another developer or agent, while leaving application code and deployment unchanged.
Why use it?
It separates deciding what to build from implementing it, reducing the risk that requirements and code are mixed together.

Agent for Claude CodeCursor

Written for Cursor and Claude Code: installed under .cursor/, but also a Claude Code subagent (agents/*.md).

This is jmenzies722/shua-labs's own configuration. It tells Claude Code and Cursor how to work on shua-labs itself, so it is not a mod to install elsewhere. Copy it as a starting point and replace the rules that are about this project. Everything shua-labs configures →

Reuse

Borrowing it

Nothing to install: this file belongs to jmenzies722/shua-labs. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file
curl -O https://raw.githubusercontent.com/jmenzies722/shua-labs/master/.cursor/agents/marcus.md
Clone the repo
git clone --depth 1 https://github.com/jmenzies722/shua-labs

Made for: Claude Code, Cursor.

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 marcus

README.md
[![agentmods](https://agentmods.dev/badge/agents/jmenzies722/shua-labs/marcus/github.svg)](https://agentmods.dev/agents/jmenzies722/shua-labs/marcus)
Your own site
<a href="https://agentmods.dev/agents/jmenzies722/shua-labs/marcus"><img src="https://agentmods.dev/badge/agents/jmenzies722/shua-labs/marcus/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 marcus

Your own site · 80×15
<a href="https://agentmods.dev/agents/jmenzies722/shua-labs/marcus"><img src="https://agentmods.dev/badge/agents/jmenzies722/shua-labs/marcus.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 12 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 108 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.

ModelPer sessionOnce invoked
Fable 5.1 $0.00012 $0.00108
Opus 5 $0.00006 $0.00054
Sonnet 5 $0.00002 $0.00022
Haiku 4.5 $0.00001 $0.00011

Measured 9d ago against content hash 289a6b2c77bb, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-09, from the pricing page.

Security

Grade A, and why

marcus 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 9d 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.

.cursor/agents/marcus.md · 11 lines

What it actually says

You are Marcus. You write specs only.

Put the spec on GitHub (issue or PR comment) and, if needed, in HANDOFF.md / a spec doc. Do not write production code. Do not edit app/, components/, data/, or any product UI.

Do not implement. Do not deploy. Do not merge. Do not create a Vercel project. Hand the spec to Devon.

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. 9d ago First seen · 11 lines · 12 tokens per session scan A 289a6b2c77bb

Subscribe to this mod's changes

marcus is an agent published in the GitHub repository jmenzies722/shua-labs (2 stars, last pushed 5d ago), licensed MIT. It adds 12 tokens to every session and 108 once invoked, about $0.0001 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 2026-08-31.

Related

Other agents, from other repositories