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Subagent

Mark

Designs and stewards visual identities — logo usage rules, brand guidelines, asset libraries, and visual identity systems that stay consistent across contexts. Use when creating brand guidelines or auditing existing brand assets. Trigger with \"write brand guidelines\", \"audit our brand assets\".

Type
Subagent
GitHub stars
2.8k
License
MIT
Repo last updated
Sep 27, 2026
Model
sonnet
Version
1.0.0
Author
Jeremy Longshore <[email protected]>

What Mark is

Mark is a subagent published in the jeremylongshore/tons-of-skills-marketplace repository on GitHub, which has about 2.8k stars. The repository describes itself as: “Model-agnostic agent-skills platform with a harness-free canonical layer, verified adapters, and the ccpi package manager. Explore at tonsofskills.com.”

A subagent is a specialist assistant that Claude can hand part of a task to. It is a markdown file whose frontmatter sets a name, a description that tells Claude when to delegate, and optionally the tools and model it may use; the body becomes the subagent's own system prompt.

Because a subagent works in its own context, it keeps the main conversation focused: Claude can send a narrow job, such as a review or a specialised analysis, to Mark and get back a compact result.

How to install Mark

Claude Code

  1. Download mark.md from the repository.
  2. Save it to ~/.claude/agents/ to use it in every project, or to .claude/agents/ inside one project to share it through version control.
  3. Claude Code watches these folders, so the subagent is usually available right away. Ask Claude to use it by name, or @-mention it to make sure it runs.

Claude Cowork

  1. Cowork loads subagents through plugins. If the repository is packaged as a plugin marketplace, add it under Customize → Plugins → Add marketplace and install the plugin that contains this subagent.
  2. Otherwise, bundle the file into your own plugin's agents/ folder and upload it from Customize → Plugins.

New to extending Cowork? Our plugins guide and Customize guide explain how skills, plugins, and connectors fit together.

Inside the source file

An excerpt from plugins/ai-agency/tonone/agents/mark.md, shared under the repository's MIT license. Read the full file on GitHub.

You are Mark — Brand Designer on the Design Team. Designs and stewards visual identities — from logo usage rules to the full brand guidelines that keep everything consistent.

Think in design systems, not one-off decisions. Every design choice should be derivable from a principle or a token — not made fresh each time. Always frame output as: what the system is, why it works, and how to implement it.

Communication

Respond terse. All design substance stays — only filler dies. Follow output-kit protocol: compressed prose, no filler, fragments OK. Documents: normal prose. See docs/output-kit.md for CLI skeleton, severity indicators, 40-line rule.

Operating Principle

A brand is a promise, repeated consistently. Brand guidelines exist to prevent entropy — every person who touches the brand introduces variability, and guidelines are the correction mechanism. The best brand systems are opinionated enough to be consistent but flexible enough to work across contexts.

What you skip: Product UI design — that's Form and Draft territory. Mark handles the brand layer that sits above the product.

What you never skip: Never approve a logo use on a busy background without testing. Never allow the logo below its minimum size. Never let the brand voice be set by whoever writes copy that day — document it.

Scope

Owns: Logo usage, brand guidelines, visual identity, asset library management

Skills

  • Mark Brand: Write brand guidelines — logo usage, color, typography, voice, and visual principles.
  • Mark Asset: Design an asset library structure — naming conventions, formats, and delivery specs.
  • Mark Recon: Audit existing brand assets and usage — find inconsistencies, off-brand applications, and gaps.

Key Rules

  • Logo rules: clearspace (= x-height of the logo), minimum size, color variations, forbidden uses
  • Brand voice: 3-5 adjectives with examples of in/out language
  • Asset library: named, versioned, accessible to all stakeholders
  • Primary, secondary, and lockup logo variants for different contexts
  • Co-brand guidelines prevent partners from destroying the brand

Process Disciplines

When performing Mark work, follow these superpowers process skills:

Iron rule: No completion claims without fresh verification.

Before you install

  • Read the whole file first. Skills, commands, and subagents are instructions Claude will follow, so make sure they match what you want.
  • Check which tools, scripts, or MCP servers it uses. Local servers and scripts run with your permissions.
  • Try it in a test project or a copy of your files before pointing it at real work.
  • Pin the version you tested, and review changes before updating.
  • Watch for instructions that fetch web content or run shell commands; those are where prompt injection risks start. See our prompt injection guide.

FAQ

What is Mark?

Mark is a subagent for Claude Code and Claude Cowork from the jeremylongshore/tons-of-skills-marketplace repository on GitHub. Designs and stewards visual identities — logo usage rules, brand guidelines, asset libraries, and visual identity systems that stay consistent across contexts. Use when creating brand guidelines or auditing existing brand assets. Trigger with \"write brand guidelines\", \"audit our brand assets\".

How do I install Mark in Claude Code?

Download mark.md from the repository. Save it to ~/.claude/agents/ to use it in every project, or to .claude/agents/ inside one project to share it through version control. Claude Code watches these folders, so the subagent is usually available right away. Ask Claude to use it by name, or @-mention it to make sure it runs.

Can I use Mark in Claude Cowork?

Cowork loads subagents through plugins. If the repository is packaged as a plugin marketplace, add it under Customize → Plugins → Add marketplace and install the plugin that contains this subagent. Otherwise, bundle the file into your own plugin's agents/ folder and upload it from Customize → Plugins.

Is Mark safe to install?

It is a third-party community resource, not reviewed by Anthropic or this site. Read the source file first, check which tools and connectors it uses, and install only from sources you trust.

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Listing data comes from the public GitHub repository and was last checked in September 2026. Excerpts are © their authors and shared under MIT. This directory is independent and not affiliated with Anthropic or the resource's authors.