Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
npx skills add j4flmao/agent-skills --skill transactional-emailgit clone --depth 1 https://github.com/j4flmao/agent-skillsWrote 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/j4flmao/agent-skills/transactional-email)<a href="https://agentmods.dev/skills/j4flmao/agent-skills/transactional-email"><img src="https://agentmods.dev/badge/skills/j4flmao/agent-skills/transactional-email/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/j4flmao/agent-skills/transactional-email"><img src="https://agentmods.dev/badge/skills/j4flmao/agent-skills/transactional-email.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector pass
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 | $0.00066 | $0.04796 |
| Opus 5 | $0.00033 | $0.02398 |
| Sonnet 5 | $0.00013 | $0.00959 |
| Haiku 4.5 | $0.00007 | $0.00480 |
Grade A, and why
backend-transactional-email 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 12d 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 — 529 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Transactional Email Skill
Purpose
Build reliable, deliverable, and compliant transactional email systems using proven provider integrations, responsive MJML templates, and deliverability best practices.
Architecture Decision Trees
Provider Selection
| Criterion | Amazon SES | SendGrid | Resend | Postmark | SMTP (self) |
|---|---|---|---|---|---|
| Volume pricing | $0.10/1K (62K free) | $19.95/50K | Free tier: 3K/mo | $10/10K | Infrastructure cost |
| Deliverability | Good (reputation shared) | Good | Excellent (dedicated IP) | Excellent | Depends on setup |
| Template engine | Custom HTML | Dynamic templates | React Email / MJML | Custom HTML | Any |
| Webhooks | SNS + SQS | Event Webhook | Webhooks (built-in) | Webhooks | Custom |
| Open/click tracking | SES Config Set | Built-in | Built-in | Built-in | Custom |
| Dedicated IP | Yes (paid) | Yes (paid) | Yes | Yes | Yes |
| API style | AWS SDK / SMTP | REST / SMTP | REST (simple) | REST / SMTP | SMTP |
| Best for | High volume, AWS shops | Mid-volume marketing | Modern DX, dev teams | Transactional only | Full control |
Decision: Resend for modern apps with great DX. SES for cost-sensitive high volume. Postmark for transactional-only where deliverability is critical.
Template Rendering Strategy
| Strategy | Pros | Cons | Best For |
|---|---|---|---|
| MJML → HTML (build-time) | Fast, no runtime dep | Rebuild to change templates | Static templates |
| MJML → HTML (runtime) | Dynamic per-user | CPU cost per send | Personalized templates |
| React Email (JSX) | Component reuse, type-safe | Node.js only, build step | React codebases |
| Handlebars + HTML | Universal, simple | No responsive guarantees | Mixed stacks |
| Provider templates (SendGrid, SES) | No rendering code | Vendor lock-in, less flexible | Simple notifications |
Decision: MJML compiled at build-time with runtime variable injection via Handlebars. React Email for all-React codebases.
What ships with it
8 files 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.
- references/deliverability.md 18 KB
- references/delivery-setup.md 13 KB
- references/email-analytics.md 8.2 KB
- references/email-compliance.md 9.2 KB
- references/email-testing.md 17 KB
- references/mjml-templates.md 19 KB
- references/transactional-email-advanced.md 12 KB
- references/transactional-email-fundamentals.md 11 KB
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.
- 12d ago First seen · 529 lines · 66 tokens per session scan A 3b2ef093fb5d
backend-transactional-email is a skill published in the GitHub repository j4flmao/agent-skills (23 stars, last pushed 5d ago), licensed MIT. It adds 66 tokens to every session and 4,796 once invoked, about $0.0003 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 2026-08-30.
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