Rémi Kokabi | September 4, 2026 | 17 min read
Rémi Kokabi | September 4, 2026 | 17 min read
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Copywriting Refiner Claude Skill: Complete Guide to Auditing Outreach Copy in 2026
What the Copywriting Refiner Claude Skill does
The Copywriting Refiner is a Claude Skill that audits cold emails and LinkedIn messages against eight fixed quality checks, then rewrites whatever fails. Paste in a message, ask for an audit, and you get a pass/fail report plus a corrected version. Every time, no matter how you phrase the request.
A Claude Skill is a markdown file (.md) that gives Claude a specific, repeatable capability. Think of it as a playbook you hand to Claude before the conversation starts. Once it’s loaded, Claude follows those instructions instead of improvising, which matters when the task is “review my copy the same way every time.”
That consistency is the actual value here. Instead of vague feedback that shifts depending on how you word your prompt, you get the same eight checks and the same output format, whether it’s your first email this week or your fiftieth.
Eight quality checks the Copywriting Refiner runs on every message
So what exactly does the skill look for? Every message gets scored against the same eight checks, pass or fail, and each failure comes with the exact phrase that triggered it. That last part matters: you’re not left guessing what “too salesy” means in your specific email.
Six of the checks apply across formats:
- Em dashes and en dashes: Dashes make an email read like a brochure instead of a message from one person to another. Flagged instances get swapped for commas, periods, or parentheses.
- Rhetorical questions as openers: “Are you tired of X?” is one of the most overused hooks in cold outreach. If the question doesn’t genuinely need an answer from the prospect, it fails.
- Generic flattery: “Love what you’re building” fails on sight. A compliment needs to reference something verifiable, like a funding round or a specific post, or it reads as manipulation.
- Pompous jargon: Words like “synergies” and “best-in-class” have been used so often they’ve stopped meaning anything. These get replaced with a plain description of what the product actually does.
- “I” opener: Starting the body with “I” makes the message about the sender. The rewrite leads with the prospect’s context instead.
- Early meeting ask: Requesting a call in the first email, before the prospect has agreed the problem is worth solving, fails (unless you’ve told the skill you want that CTA).
The other two checks are more mechanical, but just as easy to get wrong. Message length has hard limits by format:
Format | Word limit |
|---|---|
Email 1 (first touch) | 120 words |
Email 2+ (follow-up) | 150 words |
LinkedIn Message 1 | 60 words |
LinkedIn Message 2 | 80 words |
Subject lines get their own rule: six words max, sentence case, no exclamation marks, and no filler like “Quick question.” It’s a small detail, but it’s often the difference between an email that gets opened and one that doesn’t.
How to install the Copywriting Refiner
Getting the skill running takes about two minutes, and there’s no code involved.
- Download the file. Go to lemlist’s Claude Skills page and download the SKILL.md file for the Copywriting Refiner.
- Load it into Claude. Open a Claude Project and upload the file to the project’s knowledge section. Every new conversation in that project will have the skill active from that point on.
- Verify it worked. Paste any cold email and type “audit this.” A correctly loaded skill responds with a structured pass/fail table and a rewrite underneath it. If you get a generic paragraph of suggestions instead, double check that the file is in project knowledge, not just pasted into the chat.
How to run your first outreach copy audit
Once the skill is loaded, the workflow itself is short.
Start by pasting your full cold email or LinkedIn message into Claude, subject line included if it’s an email. You can just paste and hit enter, or type something like “audit this cold email.” The skill detects the format automatically and applies the matching rules.
Claude then returns a table with all eight checks marked pass or fail, each failure quoting the exact phrase that caused it. A short summary underneath explains what’s dragging the copy down overall. This is where you actually learn something, since seeing your own phrase flagged tends to stick better than a general tip ever does.
Right below the audit sits a rewritten version with only the failing elements fixed. If your value prop was already clear, it stays untouched.
Tip: Read the original and rewritten versions side by side rather than just skimming the changelog. That comparison is what builds your instinct for what strong outreach copy sounds like, faster than reading rules ever will.
Once you’re happy with the rewrite, copy it into your outbound tool. lemlist users can paste directly into a sequence step, and teams on lemlist MCP can push the updated copy into a live campaign from inside Claude without switching tabs.
Before and after examples of audited cold emails
Seeing the output tells you more than reading about it. Here’s one common pattern the skill catches.
Element | Before | After |
|---|---|---|
Subject line | “Quick Question About Your Growth” | “your SDR ramp time” |
Opening line | “I came across your company and love what you’re building.” | “Noticed you posted 2 SDR roles last week.” |
CTA | “Would you be open to a 15-min call?” | “Want the breakdown we used with [similar company]?” |
This one fails four checks at once: generic flattery, an “I” opener, an early meeting ask, and a Title Case subject line over six words. Notice the rewrite doesn’t change the angle, it just grounds each line in something the prospect can verify and swaps the meeting ask for a lower-friction offer.
How the Copywriting Refiner fits into your outbound workflow
Worth being clear about this: the Copywriting Refiner is a review step, not a drafting tool. It sits between writing a first draft and loading the message into your campaign.
- Draft: Write or generate the initial copy in Claude, a doc, or whatever you normally use.
- Audit: Run the Copywriting Refiner to flag weak spots.
- Fix: Accept the rewrite, or adjust it manually based on the audit.
- Launch: Push the final version into your sequence.
That loop is especially useful for multi-step sequences, since each follow-up gets checked against its own rules (longer limits, meeting asks allowed) rather than the Email 1 standard. The result is a sequence that builds on itself instead of repeating the same pitch four times with different subject lines.
Copywriting Refiner vs. generic AI copywriting prompts
You might be wondering why this beats just asking ChatGPT or Claude to “improve my cold email.” You can do that, sure, but the feedback changes depending on your prompt wording and, frankly, how the model happens to interpret “better” that day.
Generic AI prompt | Copywriting Refiner skill | |
|---|---|---|
Evaluation criteria | Undefined, changes each time | Fixed eight-check list |
Output format | Freeform paragraph | Pass/fail table plus rewrite |
Repeatability | Varies by prompt wording | Consistent across every audit |
Channel awareness | Treats email and LinkedIn the same | Adjusts limits per format |
Feedback specificity | “Consider shortening your email” | “FAIL, 147 words, limit is 120” |
The practical upside shows up at the team level. When every rep runs their copy through the same eight checks before sending, the floor for outreach quality rises across the whole team, not just for the person who happens to write good prompts.
Start auditing outreach copy before your next campaign
Every cold email that goes out unreviewed is a small bet that it doesn’t have an “I” opener, an early meeting ask, or a subject line that reads like a template. The Copywriting Refiner removes that bet before you hit send.
Download the skill from lemlist’s Claude Skills page, load it into Claude, and run it on your next message before it reaches an inbox. Looking to launch the campaigns themselves too? Start a 14-day free trial of lemlist, no credit card required.
Frequently asked questions about the Copywriting Refiner
Does the Copywriting Refiner work with LinkedIn messages, or only email?
Both. It detects the format automatically and adjusts the rules, applying different word limits for LinkedIn and skipping the subject line check entirely, since DMs don’t have one.
Both. It detects the format automatically and adjusts the rules, applying different word limits for LinkedIn and skipping the subject line check entirely, since DMs don’t have one.
Can I edit the checklist to match my team’s standards?
Yes. The skill is a plain markdown file, so opening it in any text editor lets you add checks, remove them, or update the banned jargon list. Claude follows whatever’s written into the file.
Yes. The skill is a plain markdown file, so opening it in any text editor lets you add checks, remove them, or update the banned jargon list. Claude follows whatever’s written into the file.
How is this different from lemlist’s sequence-writing skills?
Sequence-writing skills generate new campaign copy from a blank page. The Copywriting Refiner works in the opposite direction, taking copy you’ve already written and checking it against a fixed standard.
Sequence-writing skills generate new campaign copy from a blank page. The Copywriting Refiner works in the opposite direction, taking copy you’ve already written and checking it against a fixed standard.
What Claude plan does this require?
The skill itself works on any Claude plan. That said, Claude Pro or Team (which support Projects) makes life easier, since you can keep the skill loaded across conversations instead of re-uploading it each time.
What the Copywriting Refiner Claude Skill does
The Copywriting Refiner is a Claude Skill built by lemlist that audits cold emails and LinkedIn messages against eight specific quality checks, then rewrites every failing element on the spot. You can trigger it by saying “refine this email,” “clean up my copy,” “check this email,” or “fix my cold email” (Claude Code Skills Directory - 100+ AI Agent Skills | ColdIQ), and it always produces a pass/fail audit plus a corrected version of the copy. (Claude Code Skills Directory - 100+ AI Agent Skills | ColdIQ)
A Claude Skill is a reusable markdown (.md) instruction file you load into Claude that gives it a specific, repeatable capability. When you load a skill into a Claude conversation, it’s like handing an expert playbook to your AI. Claude reads the instructions and follows them precisely, producing higher-quality, more consistent outputs than a generic prompt ever could. (How to Use lemlist Claude Skills (.md Files) in Claude | Step-by-Step Guide)
So instead of typing “make my cold email better” and getting different feedback every time, the Copywriting Refiner runs a fixed checklist. Same criteria, same output format, same rigor, whether you’re reviewing your first email or your fiftieth. It also works when you paste an email and ask if it’s good, too long, too formal, or “too salesy.” (Claude Code Skills Directory - 100+ AI Agent Skills | ColdIQ)
Eight quality checks the Copywriting Refiner runs on every message
The skill evaluates every message against the same eight checks, scored as pass or fail. For each failure, it quotes the exact offending phrase so you see precisely what went wrong. Here’s what gets checked:
Em dashes and en dashes
Dashes (both — and –) make cold email copy read like a polished brochure rather than a one-to-one message. The skill flags every instance and rewrites the sentence using commas, periods, or parentheses instead.
Rhetorical questions as openers
Openings like “Are you tired of X?” or “What if you could Y?” are the most overused hooks in cold email. The skill flags any question that doesn’t genuinely require an answer from the prospect, because those signal template, not thought.
Generic flattery
“Love what you’re building” and “Really admire your work” fail this check instantly. To pass, a compliment has to reference a specific, verifiable fact: a recent funding round, a job posting, a LinkedIn post. If it can’t be fact-checked, it reads as manipulation.
Pompous jargon
The skill maintains a banned word list that includes terms like “synergies,” “game-changer,” “best-in-class,” and “holistic.” These words are used so often they carry zero meaning. Every instance gets replaced with a plain-language description of what the product actually does.
“I” opener
If the first word of the email body is “I,” the check fails. Starting with “I” frames the message as being about the sender. The rewrite restructures the opening to lead with the prospect’s context or a relevant observation.
Meeting ask in the first touchpoint
Asking for a call, demo, or “30 minutes” in Email 1 or LinkedIn Message 1 fails this check (unless you explicitly told the skill you want a meeting CTA). Before a prospect agrees that the problem is worth solving, a meeting ask signals pipeline pressure. The rewrite replaces it with a value-based CTA: an insight, benchmark, or diagnostic question.
Message length
Each format has a hard word limit:
Format | Word limit |
|---|---|
Email 1 (first touch) | 120 words |
Email 2+ (follow-up) | 150 words |
LinkedIn Message 1 | 60 words |
LinkedIn Message 2 | 80 words |
Anything over the limit gets flagged, and the rewrite cuts aggressively. Every sentence that doesn’t move the reader toward the CTA gets removed.
Subject line (email only)
Subject lines are capped at six words, written in sentence case (not Title Case), with no exclamation marks and no generic openers like “Quick question” or “Following up.” The subject line treats the inbox like a text thread, not an email marketing campaign.
How to install the Copywriting Refiner
Getting the skill running takes about two minutes, and you don’t write any code. Here’s the process:
1. Download the .md skill file
Go to lemlist’s Claude Skills page and click the download button. Pick the skill that matches what you’re trying to accomplish and click the download button to grab the .md file. (How to Use lemlist Claude Skills (.md Files) in Claude | Step-by-Step Guide) The file you’re downloading is called
SKILL.md.2. Load the skill into Claude
Open a Claude Project and upload the .md file to the project’s knowledge section. Once it’s there, every new conversation inside that project will have the Copywriting Refiner active. Each skill is a self-contained markdown file that gives Claude deep domain knowledge. Drop one into your project and invoke it with a slash command. (GitHub - boraoztunc/skills: Claude Code skills for copywriting, SEO, design, and more · GitHub)
3. Verify the skill is active
Paste any cold email into the conversation and type “audit this.” If Claude responds with a structured pass/fail table and a rewritten version beneath it, the skill loaded correctly. If you get a generic paragraph of suggestions instead, double-check that the .md file is in the project knowledge, not just pasted into a chat.
How to run your first outreach copy audit
Once the skill is loaded, the actual workflow is four steps.
1. Paste your cold email or LinkedIn message
Drop the full message into Claude, subject line included if it’s an email. You can type “audit this cold email” or just paste and hit enter. The skill detects the format automatically (Email 1, follow-up, LinkedIn DM) and applies the matching rules.
2. Read the pass/fail audit report
Claude returns a table with all eight checks, each marked pass or fail. Every failure includes a direct quote of the offending phrase so you can see what triggered the flag. At the bottom, a one-to-two sentence summary explains what’s dragging the copy down overall.
3. Review the rewritten version
Right below the audit, the skill delivers a corrected version with every failing element fixed. It only changes what failed. If your value prop was clear and your length was fine, those stay untouched. Below the rewrite, you’ll see a changelog showing the original phrase and what replaced it.
Tip: Compare the original and rewritten versions side by side. The changelog tells you what changed, but reading both versions back-to-back builds intuition for what strong outreach copy actually sounds like.
4. Apply changes to your campaign
Copy the rewritten message into your outbound tool. If you’re using lemlist, you can paste directly into a sequence step. Teams using lemlist MCP can go further: push the updated copy into a live campaign from Claude without switching tabs, since your agent can search and enrich leads, launch campaigns, monitor performance, and update sequences. 40+ tools at its fingertips. (lemlist MCP | Connect AI Agents to Sales Outreach & Lead Data)
Before and after examples of audited cold emails
Seeing the output is more useful than reading about it. Here are two common patterns the Copywriting Refiner catches and fixes.
Cold email with a weak subject line and a meeting ask
Element | Before | After |
|---|---|---|
Subject line | “Quick Question About Your Growth” | “your SDR ramp time” |
Opening line | “I came across your company and love what you’re building.” | “Noticed you posted 2 SDR roles last week.” |
CTA | “Would you be open to a 15-min call?” | “Want the breakdown we used with [similar company]?” |
The original fails four checks: generic flattery (“love what you’re building”), an “I” opener, a meeting ask on the first touch, and a Title Case subject over six words. The rewrite keeps the same angle but grounds every sentence in something verifiable and swaps the meeting ask for a value offer.
LinkedIn connection request with surface-level personalization
Element | Before | After |
|---|---|---|
Opening | “Hi Sarah, I really admire what you’re doing at Acme.” | “Hi Sarah, saw your post on ramping SDRs without a playbook.” |
Body | “We help companies like yours streamline their outbound with our innovative platform.” | “We helped a 12-person sales team at a similar-stage SaaS co cut ramp time from 6 weeks to 3.” |
Length | 94 words | 58 words |
The original triggers generic flattery, pompous jargon (“streamline,” “innovative”), and exceeds the 60-word limit for LinkedIn Message 1. The rewrite replaces vague claims with a specific result and trims 36 words.
How the Copywriting Refiner fits into your outbound workflow
The Copywriting Refiner is a review step, not a drafting tool. It sits between writing your first draft and loading the message into your campaign. Here’s where it typically fits:
- Draft: Write or generate your initial copy in Claude, a doc, or whatever you use
- Audit: Run the Copywriting Refiner to flag weak elements
- Fix: Accept the rewrite or manually adjust based on the audit
- Launch: Push final copy into your sequence
That loop works once, but it’s especially useful as a recurring check. When you write follow-up emails for the same sequence, the skill enforces consistency across all steps. Each follow-up gets audited against its own format rules (longer word limits, meeting asks allowed), so the sequence holds together rather than repeating the same pitch four times.
For teams on lemlist, the loop tightens further. You can use lemlist MCP to pull campaign analytics from inside Claude, identify underperforming emails, run the Copywriting Refiner on the weak steps, and push the corrected copy back into the live campaign. The drafting, review, and deployment stay in one place.
Copywriting Refiner vs. generic AI copywriting prompts
You might be thinking: “Can’t I just ask ChatGPT or Claude to improve my cold email?” You can. But the feedback you get varies based on how you phrase the prompt, what mood the model is in, and whether it decides to rewrite aggressively or politely suggest tweaks.
The Copywriting Refiner solves that inconsistency. Here’s how the two approaches compare:
Generic AI prompt | Copywriting Refiner skill | |
|---|---|---|
Evaluation criteria | Undefined, changes each time | Fixed eight-check quality checklist |
Output format | Freeform paragraph of suggestions | Structured pass/fail table plus rewrite |
Repeatability | Varies by prompt wording | Consistent across every audit |
Channel awareness | No distinction between email and LinkedIn | Adjusts word limits and rules per format |
Feedback specificity | “Consider shortening your email” | “❌ FAIL — 147 words, limit is 120” |
The practical difference is that teams can use the Copywriting Refiner as a shared quality bar. When every rep runs outreach through the same eight checks before launch, the floor rises across the whole team.
Start auditing outreach copy before your next campaign
Every cold email or LinkedIn message that goes out unreviewed is a small bet that the copy doesn’t have an “I” opener, a meeting ask that’s too early, or a subject line that screams template. The Copywriting Refiner removes that bet.
Download the skill from lemlist’s Claude Skills page, load it into Claude, and audit your next outreach message before it hits an inbox. If you’re also looking for a platform to run those campaigns at scale, with multichannel sequences, deliverability monitoring, and a 650M+ lead database, start a 14-day free trial of lemlist. No credit card required.
Frequently asked questions about the Copywriting Refiner
Does the Copywriting Refiner work with LinkedIn messages or only cold emails?
Yes, the skill audits both. It automatically detects the format you paste in and adjusts the rules. LinkedIn messages get different word limits (60 words for Message 1, 80 for Message 2) and skip the subject line check since LinkedIn DMs don’t have subject lines.
Can I modify the quality checklist to match my team’s outreach guidelines?
The skill is a plain markdown file, so you can open it in any text editor and change whatever you want. You can add new checks, remove existing ones, adjust word limits, or update the banned jargon list to reflect your brand’s standards. Claude will follow whatever rules are in the file.
How is the Copywriting Refiner different from lemlist’s sequence-writing skills?
Skills are organized by category, including lead research, email copywriting, data enrichment, campaign analysis, ICP building, and more. (How to Use lemlist Claude Skills (.md Files) in Claude | Step-by-Step Guide) The sequence-writing skills generate new outreach copy from scratch, usually a full multi-email campaign. The Copywriting Refiner works in the opposite direction: it takes existing copy and reviews it against a fixed checklist. One creates, the other quality-checks.
What Claude plan do I need to use the Copywriting Refiner?
You can use the free plan or any paid plan. Skills work with all Claude versions. (How to Use lemlist Claude Skills (.md Files) in Claude | Step-by-Step Guide) You’ll want a Claude plan that supports Projects (Claude Pro or Team) for the best experience, since Projects let you keep the skill loaded across multiple conversations without re-uploading each time.
Hi there, I’m Rémi, co-founder of the GTM Club powered by lemlist & Claap. If you believe Go-To-Market is the new moat in this AI-era, you should apply: https://www.thegtmclub.com/
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