cold-email

cold-email is a skill for Claude Code, Codex from AgentlyLabs/founder-skills. It costs 236 tokens per session (1,913 once invoked), scanned A, original, MIT.

A guide for writing and checking targeted business-to-business outreach emails sent to people who do not already know the sender. It covers email delivery, regional legal requirements, and the wording used to seek a reply.

In plain words
What is it for?
Use it to check SPF, DKIM, DMARC, sender rules, and regional requirements, then write or improve low-volume personalized outreach.
Why use it?
It helps identify whether messages are failing because they cannot reach the inbox or do not meet legal requirements, instead of focusing only on the copy.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

Good fit Use it to check SPF, DKIM, DMARC, sender rules, and regional requirements, then write or improve low-volume personalized outreach.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/agentlylabs/founder-skills/cold-email
Install

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.

Any agent
npx skills add AgentlyLabs/founder-skills --skill cold-email
Clone the repo
git clone --depth 1 https://github.com/AgentlyLabs/founder-skills

Made for: Claude Code, Codex.

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 cold-email

README.md
[![agentmods](https://agentmods.dev/badge/skills/agentlylabs/founder-skills/cold-email/github.svg)](https://agentmods.dev/skills/agentlylabs/founder-skills/cold-email)
Your own site
<a href="https://agentmods.dev/skills/agentlylabs/founder-skills/cold-email"><img src="https://agentmods.dev/badge/skills/agentlylabs/founder-skills/cold-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.

agentmods 80×15 button for cold-email

Your own site · 80×15
<a href="https://agentmods.dev/skills/agentlylabs/founder-skills/cold-email"><img src="https://agentmods.dev/badge/skills/agentlylabs/founder-skills/cold-email.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 236 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,913 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 $0.00236 $0.01913
Opus 5 $0.00118 $0.00957
Sonnet 5 $0.00047 $0.00383
Haiku 4.5 $0.00024 $0.00191

Measured 12d ago against content hash c6a018660c22, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-12, from the pricing page.

Security

Grade A, and why

cold-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.

The scan reads SKILL.md. This mod also ships 2 executable files (scripts/check_domain.py, scripts/score_email.py), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

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.

skills/cold-email/SKILL.md · 153 lines

How it starts

The opening of the file, as written. The whole thing — 153 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Cold Outbound That Reaches and Gets Replies

What decides the outcome

Three independent systems have to succeed, in this order:

  1. Delivery. An unauthenticated message never gets read, however good it is. This is deterministic, checkable, and the most common silent failure.
  2. Legality. What you must include, and whether you may send at all, depends on where the recipient is. The US, EU/UK, and Canada have materially different regimes.
  3. The reply. Copy craft, which is where nearly all published advice lives and where the least of it is verifiable.

Most outbound fails at (1) while the sender rewrites (3). So diagnose in order, and never skip Step 1 because the copy looks like the interesting problem.

The discipline in this skill: every recommendation names its mechanism, and metrics that cannot be measured are called out rather than reported. Open rates in particular are close to meaningless now — see references/deliverability.md.

Scope

This is for targeted outreach at low volume: a researched list where you can state, per recipient, why you emailed that person. That is both the legally defensible posture and the one that actually works — reply rate collapses as list size grows, because the specific reason for the email is what earns the reply.

If the user wants high-volume untargeted blasting, say plainly that it will burn the sending domain, and that the domain reputation damage is slow to reverse. Then help them do the targeted version.

Step 1 — Audit the sending domain before writing anything

Run this first, every time, even if the user only asked for copy help:

python3 scripts/check_domain.py example.com

It resolves SPF, DKIM (probing common selectors), DMARC, MX, MTA-STS and TLS-RPT, then reports each as PASS / WARN / FAIL with the specific fix. Add --json for machine output, --selectors s1,s2 to probe custom DKIM selectors.

Interpret the result against references/deliverability.md, which has the actual provider requirements — including the distinction almost everyone gets wrong: Google requires SPF or DKIM from all senders, but SPF and DKIM and DMARC with alignment from bulk senders (5,000+ messages/day to Gmail). Know which set applies before you tell the user what is mandatory.

Read the full file on GitHub · 153 lines

Files

What ships with it

7 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.

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. 12d ago First seen · 153 lines · 0 tokens per session scan A c6a018660c22

Subscribe to this mod's changes

cold-email is a skill published in the GitHub repository AgentlyLabs/founder-skills (2 stars, last pushed 15d ago), licensed MIT. It adds 236 tokens to every session and 1,913 once invoked, about $0.0012 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.

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