Borrowing it
Nothing to install: this file belongs to Krzysztof318/MailFathom. 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/Krzysztof318/MailFathom/main/.agents/skills/brandkit/SKILL.mdgit clone --depth 1 https://github.com/Krzysztof318/MailFathomWrote 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/skills/krzysztof318/mailfathom/brandkit)<a href="https://agentmods.dev/skills/krzysztof318/mailfathom/brandkit"><img src="https://agentmods.dev/badge/skills/krzysztof318/mailfathom/brandkit/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/skills/krzysztof318/mailfathom/brandkit"><img src="https://agentmods.dev/badge/skills/krzysztof318/mailfathom/brandkit.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 | $0.00089 | $0.03770 |
| Opus 5.5 | $0.00036 | $0.01508 |
| Sonnet 5.5 | $0.00018 | $0.00754 |
| Haiku 4.5 | $0.00009 | $0.00377 |
Grade A, and why
brandkit 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 15d 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.
The source is not reproduced here
Licensed AGPL-3.0
The repository is licensed AGPL-3.0, which this catalogue does not treat as permission to reproduce the file. Read it at the source.
What ships with it
1 file beside SKILL.md 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.
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.
- 15d ago First seen · 803 lines · 89 tokens per session scan A 45b465636715
brandkit is a skill published in the GitHub repository Krzysztof318/MailFathom (15 stars, last pushed 11d ago), licensed AGPL-3.0. It adds 89 tokens to every session and 3,770 once invoked, about $0.0004 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 2026-10-08.
Other skills, from other repositories
shadcn
Manages shadcn components and projects — adding, searching, fixing, debugging, styling, and composing UI. Provides project context, component docs, and usage examples. Applies when working with shadcn/ui, component registries, presets, --preset codes, or any project with a components.json file. Also triggers for…
backend-conventions
Backend convention reference (.NET 10 / C# 13). Auto-injected into backend-aware agents - not user-invocable.
polish-ui
Design-quality workflow that combines design taste, aesthetic direction, image-to-code, a Web Interface Guidelines audit, and real-browser verification. Use when building or polishing a UI surface, implementing a mockup/screenshot, or when asked to make a page "look great".
add-options-class
Add a typed options/configuration class with validation.
clean-architecture-dotnet
Use when domain logic leaks into API/Infrastructure, project references violate layer boundaries, or you need to decide between CQS (always), CQRS bus (complex domains), and DDD patterns (invariants and events).
creating-dotnet-mcp-servers
Use when building Model Context Protocol (MCP) servers in .NET, configuring tools, transports (SSE/stdio), JSON serialization for AOT, or testing MCP endpoints.