Borrowing it
Nothing to install: this file belongs to mtnyilmaz/agents. 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/mtnyilmaz/agents/main/.agents/skills/email-developer/SKILL.mdgit clone --depth 1 https://github.com/mtnyilmaz/agentsWrote 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/mtnyilmaz/agents/email-developer)<a href="https://agentmods.dev/skills/mtnyilmaz/agents/email-developer"><img src="https://agentmods.dev/badge/skills/mtnyilmaz/agents/email-developer/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/mtnyilmaz/agents/email-developer"><img src="https://agentmods.dev/badge/skills/mtnyilmaz/agents/email-developer.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 | $0.00061 | $0.02652 |
| Opus 5.5 | $0.00024 | $0.01061 |
| Sonnet 5.5 | $0.00012 | $0.00530 |
| Haiku 4.5 | $0.00006 | $0.00265 |
Grade A, and why
email-developer 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 — 357 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Email Developer
Expert in building cross-client compatible, deliverable HTML email templates. Supports all three major email template frameworks: React Email, MJML, and Maizzle.
How to Choose a Framework
| Situation | Use |
|---|---|
| TypeScript/React codebase, transactional emails | React Email |
| Standalone email repo, TypeScript team, strong component model | React Email |
| Complex marketing/newsletter campaigns, HTML-first team | MJML |
| Design-system driven, Tailwind already in use, large template library | Maizzle |
| Non-technical team edits templates | MJML or Maizzle (no JSX) |
Detect from package.json:
@react-email/components→ React Email projectmjml→ MJML project@maizzle/framework→ Maizzle project
Reference Rules
Load these rules for the relevant context:
.agents/layers/concern/email/fundamentals.md— shared HTML email rules (inline styles, 600px, compliance — applies to all frameworks).agents/layers/framework/email/react/patterns.md— React Email components and patterns.agents/layers/framework/email/mjml/patterns.md— MJML XML syntax, partials, build pipeline.agents/layers/framework/email/maizzle/patterns.md— Maizzle Tailwind + Handlebars patterns.agents/layers/concern/email/deliverability.md— deliverability, compliance, infrastructure.agents/layers/universal/security-baseline.md— security requirements
Tech Stack (2026)
| Tool | Use case |
|---|---|
| React Email | Transactional emails in TypeScript codebase |
| MJML | Marketing / newsletter templates (XML → HTML) |
| Maizzle | Tailwind-based template system (Handlebars + Vite) |
| Resend | Primary sending provider (best DX, React Email native) |
| Postmark | Transactional-only (high deliverability) |
| SendGrid / Brevo | High-volume bulk / marketing campaigns |
| Email on Acid | Cross-client visual regression testing |
| mail-tester.com | Spam score testing |
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.
- 1mo ago First seen · 357 lines · 61 tokens per session scan A 36c71275cc89
email-developer is a skill published in the GitHub repository mtnyilmaz/agents (6 stars, last pushed 5mo ago), licensed MIT. It adds 61 tokens to every session and 2,652 once invoked, about $0.0002 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.
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