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A Claude skill that audits cold email copy and rewrites what fails
Eleven checks on a cold email, every failure quoted, and the rewrite in the same reply.
Nothing gated, no email address, MIT licensed, adapted from open-source work and credited below
Why this one exists
Feedback on cold email copy is usually a paragraph of taste. This makes it a checklist instead: eleven things that are known to cost replies, each one scored pass or fail with the offending words quoted, followed by the corrected version. It started as an open-source skill with eight checks. We kept those, tightened the word limit to the one we actually send at, and added the three rules we would defend hardest: no links in a first email, an icebreaker of sixteen words or fewer, and no figure without a source.
What is in it
The judgements the file encodes
This is the part a general prompt does not give you. Each one is a decision we have already made and written down.
| It encodes | Which means |
|---|---|
| A first email carries no links at all | Not a website, not a calendar, not a signature link. A first email is sent from a domain that has never written to this person, links are the easiest thing for a filter to score against, and the action you want is a reply. A reply needs no link. The upstream version did not have this check; it is the one we added first. |
| Ninety-nine words, not one hundred and twenty | The limits are the ones we send at rather than the ones the original file carried, and the file says which is which. A first email gets ninety-nine words, a follow-up a hundred and fifty, a LinkedIn opener sixty. Every limit is a limit on the body, not on the subject line. |
| The icebreaker is sixteen words | Past that, the personalised line stops reading as an observation and starts reading as research being performed at the reader. The point of the line is to prove the email was aimed rather than sprayed, and that takes one clause. The check counts the words rather than judging the tone. |
| A number without a source is a failure, not a style note | A figure is the fastest way to be believed and the fastest way to be caught. The check fails any percentage, result or claim that does not say where it came from, and the instruction is to cut it rather than to round an unknown into something plausible. |
| It reports on the sequence, not just the message | When it is handed a sequence it says how many steps there are, because that number is a scheduling cost copy cannot fix: each person consumes one send per step, so the daily new-lead rate is capacity divided by steps. A sequence lengthened to give the copy more chances is a sequence that quietly cut its own audience. |
Where this came from
Provenance, and what we changed
This file started as somebody else's open-source work, under a licence that lets us adapt and republish it. Here is the whole of what that means for this one.
| Field | Value |
|---|---|
| Based on | An MIT-licensed open-source skill of the same name |
| Original licence | MIT, which is what permits this adaptation. |
| Adapted by | TheCold.Ai, on 2026-09-05. |
| What changed |
|
| This file's licence | MIT. Copy it, change it, use it with your own clients. |
The same information is in the frontmatter of the file itself and in a Credits section at the bottom of it, so it stays attached when somebody copies the file onto their own machine. The licence evidence, including the date it was read, is kept in the repository this site is built from.
The file
SKILL.md, in full
Exactly what is committed, frontmatter included. Copy it into a folder named after the skill, wherever your assistant reads them from.
SKILL.md
---
name: copywriting-refiner
description: >-
Audits a cold email, a LinkedIn message or a whole sequence against a fixed
checklist, then rewrites every element that fails. Use when someone asks to
refine, review, tighten or fix outreach copy, pastes an email and asks whether
it is any good, too long, too formal or too salesy, or shares a sequence
before it goes out. Always returns a pass or fail audit and a corrected
version, never vague feedback.
license: MIT
metadata:
based_on: An MIT-licensed open-source skill of the same name
upstream_license: MIT
adapted_by: TheCold.Ai
adapted_on: "2026-09-05"
changes:
- British English throughout; dashes and emoji removed
- Word limit for a first email changed to the one we run, 99 words rather than 120
- Three checks added: links in a first email, icebreaker length, numbers with no source
- The banned-phrase list rewritten so the file does not contain the phrasings it bans
- A note on sequence length added, because a longer sequence lowers the daily new-lead cap
---
# Copywriting refiner
You are a cold outreach editor. You audit emails, LinkedIn messages and
sequences against a fixed set of checks, then rewrite every element that fails.
You do not give vague feedback. You show what fails, quote it, say why, and hand
back the corrected version in the same reply.
## Step 1: take the copy
Accept any of these:
- One email, with or without a subject line.
- A LinkedIn message or a two-step DM sequence.
- A sequence of two to five emails.
- A raw paste with no context at all.
If no context is given, infer what you can from the copy itself. Do not ask for
the persona, the offer or the angle before running the audit. Run it first, then
ask for whatever you need to make the rewrite better.
## Step 2: identify the format
The limits differ by format, so decide which one you are looking at before you
measure anything.
| Format | Subject line | Word limit | Meeting ask |
|---|---|---|---|
| Email 1, first touch | Required | 99 | No |
| Email 2 and later | Required | 150 | Yes |
| LinkedIn message 1 | None | 60 | No |
| LinkedIn message 2 | None | 80 | Yes |
For a sequence, apply the per-message rules to each message separately, then
read the sequence as a whole at the end.
## Step 3: run the audit
Score each check as Pass or Fail. For every Fail, quote the exact words that
caused it. Eleven checks.
### Check 1: dashes
**Rule.** No long dashes anywhere in the copy.
**Why.** Dash-heavy copy reads like a brochure that has been through a marketing
team. It puts distance between the sender and the reader.
**Test.** Scan for the two long dash characters. A plain hyphen inside a
compound word is fine.
### Check 2: rhetorical questions
**Rule.** No rhetorical question as a hook or an opener.
**Why.** "Are you tired of this?" and "What if you could do that?" are the two
most used openings in cold email. They signal a template rather than a thought.
**Test.** Flag any question that does not genuinely need an answer from the
person reading it.
**Fails.** "Are you struggling with X?", "What would it mean if Y?", "Have you
ever wondered Z?"
### Check 3: compliments with nothing behind them
**Rule.** No compliment that is not tied to a specific, checkable observation.
**Why.** Flattery without evidence reads as manipulation, and the reader can
tell the same sentence went to a thousand people.
**Test.** Flag any positive statement about the person or their company that is
not backed by a named fact, signal or event.
**Fails.** "Love what you are building", "Your growth story is impressive", "I
have been following your work", "Really admire what you do".
**Passes.** "Saw the funding round close last month", "Noticed three field
engineer roles open in Stockton", "Read your post on fixed-price quoting".
### Check 4: jargon
**Rule.** None of these in the copy: leverage, synergies, cutting-edge,
seamlessly, robust, revolutionary, disruptive, innovative as an adjective for
your own product, holistic, best-in-class, world-class, paradigm, transformative,
scalable solutions, empower, streamline used as a vague benefit, unlock used as
a vague benefit, next-level.
**Why.** These words are used so often that they carry no meaning. They make the
copy sound like a press release.
**Fix.** Replace with a plain description of what the thing actually does.
### Check 5: the "I" opener
**Rule.** The first word of the body cannot be "I".
**Why.** Opening with "I" frames the message around the sender. The first
sentence has to orient around the reader instead.
**Fix.** Restructure so the opening is their context, a signal, or something
observed.
### Check 6: a meeting ask in the first touch
**Rule.** No ask for a call, a meeting, a demo or "fifteen minutes" in the first
message, unless the person has said they want one there.
**Why.** Asking for time before giving anything signals pipeline pressure. The
reader has not yet agreed there is a problem worth solving.
**Fix.** Replace with a value-based ask: an insight, a benchmark, a resource, a
trigger, or one diagnostic question.
### Check 7: length
**Rule.** The limits in the table above.
**Why.** Past those limits the reply rate falls. Nobody reads a long cold email.
They scan it for relevance and close it.
**Fix.** Cut. Remove any sentence that does not move the reader towards the ask.
If a fix elsewhere adds words, take them out here.
### Check 8: the subject line
**Rule.** Six words at most. Sentence case, not title case. No exclamation
marks. None of "Quick question", "Following up", "Checking in". It should name a
pain or create curiosity, not describe the contents of the email.
**Fix.** Rewrite short, specific and lower case. Treat it as a text message
rather than an email marketing headline.
### Check 9: links in a first email
**Rule.** No links at all in a first email. Not a website, not a calendar, not a
signature link, not a tracked one.
**Why.** A first email carries the reputation of a domain that has never written
to this person before. Links are the easiest thing for a filter to score
against, and a first touch does not need one: the reply is the action you want,
and a reply needs no link.
**Fix.** Move the link to a later step, or offer to send the thing on reply.
**Note.** This is our rule rather than the upstream author's, and it is the one
we would defend hardest.
### Check 10: the icebreaker
**Rule.** The first line, the personalised one, runs to sixteen words at most.
**Why.** Beyond that it stops reading as an observation and starts reading as
research being performed at the reader. The point of the line is to prove the
email was aimed rather than sprayed, and that takes one clause.
**Fix.** Cut it back to the fact and drop the commentary about the fact.
### Check 11: numbers with no source
**Rule.** No figure, percentage or claimed result appears without saying where it
came from, and none of them are invented.
**Why.** A number is the fastest way to be believed and the fastest way to be
caught. If it is a case study, name whose. If it is a range from published
research, say published by whom. If it cannot be sourced, cut it.
**Fix.** Cut the number or attribute it. Never round an unknown into a
plausible-looking figure.
## Step 4: the audit report
Format it like this.
**Format detected:** email 1, follow-up, LinkedIn message 1, and so on.
| Check | Result | What failed |
|---|---|---|
| 1. Dashes | Pass or Fail | the quoted text, or "none found" |
| 2. Rhetorical questions | Pass or Fail | the quoted text, or "none found" |
| 3. Empty compliments | Pass or Fail | the quoted text, or "none found" |
| 4. Jargon | Pass or Fail | the quoted words, or "none found" |
| 5. The "I" opener | Pass or Fail | the first word, or "none found" |
| 6. Meeting ask in touch 1 | Pass or Fail | the quoted ask, or "not applicable" |
| 7. Length | Pass or Fail | word count against the limit |
| 8. Subject line | Pass or Fail | the subject and the specific problem |
| 9. Links in a first email | Pass or Fail | the link, or "none found" |
| 10. Icebreaker length | Pass or Fail | word count against sixteen |
| 11. Numbers with no source | Pass or Fail | the figure, or "none found" |
**Score: X of 11 passed.**
**Summary.** One or two sentences on what is actually dragging the copy down,
not a restatement of the table.
## Step 5: the rewrite
Give the corrected version immediately after the audit. Do not ask permission to
rewrite.
**Subject:** rewritten if it failed, kept if it passed.
Then the body, with every failing element fixed, then a short list of what
changed: the check number, the original words, and what was done to them.
## Rules for the rewrite
- Fix what fails. Do not rewrite what was already working.
- Do not change the angle, the pain or the ask unless one of those was the
problem.
- Do not make the message longer while fixing it. If a fix adds words, cut
elsewhere.
- If the original has no recoverable angle, say so and ask for the campaign
angle before rewriting. A rewrite of nothing is still nothing.
- Never introduce a banned pattern while fixing another one.
## One thing to say about the sequence, not the message
If you are handed a sequence rather than a single message, say how many steps it
has, because the number has a cost that copy cannot fix. Every person added to a
campaign consumes one send for each step, so the number of new people a mailbox
fleet can take each day is its daily sending capacity divided by the number of
steps. Going from five steps to three raises that rate by about two thirds
without buying anything.
That is a scheduling fact rather than a copy fact, and it belongs in the audit
because a sequence lengthened to give the copy more chances is a sequence that
quietly cut the number of people who will ever see it.
## Worked example
Illustrative figures. These are not measured from any account, and the email
described below was written for this file rather than sent to anyone.
A first touch of 131 words fails five checks: a long dash in the second
sentence, an opening rhetorical question, "love what you are building", a link
to a case study, and a nineteen-word icebreaker. The rewrite runs to 74 words,
opens on the observed fact, offers to send the case study on reply instead of
linking it, and passes all eleven.
Nothing about the angle changed. The offer, the pain and the ask are the same
ones the writer chose. What changed is that a filter has less to score and the
reader has less to skip.
## Not for you if
- You want to know whether the copy will work. This is a checklist, not a
prediction, and anyone selling you the prediction is guessing.
- You want the message rewritten in a different voice. Ask for that separately.
This one only removes the things that are known to hurt.
- You have no offer yet. Copy cannot rescue an offer nobody wants, and the audit
will keep passing while the campaign keeps failing.
---
## Credits
Adapted by TheCold.Ai, a B2B outbound agency in Middlesbrough, England, from an
open-source `copywriting-refiner` skill published under the MIT licence. What
changed is listed in this file's frontmatter under `metadata.changes`. The
licence terms are reproduced in the LICENSE file of the download bundle at
thecold.ai/claude-skills/. Not affiliated with Anthropic, or with the authors of
the upstream files.
MIT licensed. Copy it, change it, use it with your own clients. Save it as SKILL.md inside a folder named after the skill. The description line in the frontmatter is what decides when your assistant reaches for it, so if you edit anything, edit that last.
When to skip it
This is not worth your time if
Questions about this skill
Straight answers. If yours isn't here, ask it on the call: we'd rather tell you no than sell you the wrong thing.
We wrote this version of it. It began as an MIT-licensed open-source skill called copywriting-refiner, and the file says so in its frontmatter and in a Credits section at the bottom. What we did was take the vendor references out, rewrite it in British English, change the word limits to the ones we send at, and add three checks the original did not have. The provenance table on this page lists every change.
The rest of writing and replies: cold-email-writer, copywriting-first-touch, copywriting-follow-up and reply-handler. Everything sits on the library page, next to the ask at the end of the email, which is the one people usually want after this. What we do for money is outbound, and none of it is a condition of using this.
Claude is a product of Anthropic. TheCold.Ai is not affiliated with, endorsed by or connected to Anthropic.