Claude-Skills cold-email

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git clone https://github.com/borghei/Claude-Skills
Claude Code · Install into ~/.claude/skills/
T=$(mktemp -d) && git clone --depth=1 https://github.com/borghei/Claude-Skills "$T" && mkdir -p ~/.claude/skills && cp -r "$T/marketing/cold-email" ~/.claude/skills/borghei-claude-skills-cold-email && rm -rf "$T"
manifest: marketing/cold-email/SKILL.md
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Cold Email Outreach

Production-grade B2B cold email that sounds like it came from a person, not a sequence tool.


Table of Contents


Keywords

cold email, cold outreach, prospecting email, SDR email, sales email, first-touch email, follow-up sequence, email prospecting, outbound email, sales development, sequence building, email personalization, email deliverability, CAN-SPAM, GDPR, B2B outreach, email compliance, subject lines, reply rates, breakup email


Quick Start

Write a First-Touch Email

  1. Define the ICP, specific problem, and outreach trigger
  2. Select voice calibration based on recipient seniority
  3. Write opener about their world (not yours)
  4. State relevance in 1-2 sentences with specific proof
  5. Close with a single, low-friction ask
  6. Generate 3 subject line variants
  7. Validate: under 150 words, no corporate speak, one CTA

Build a Full Sequence

  1. Write the first email (above)
  2. Plan 4-5 follow-ups, each with a different angle
  3. Set escalating gap cadence (Day 1, 4, 9, 16, 25, 35)
  4. Write each follow-up as a standalone (recipient does not remember earlier emails)
  5. End with a breakup email that closes the loop professionally
  6. Validate deliverability setup before sending

Core Workflows

Workflow 1: Single First-Touch Email

Step 1: Gather Context

Required information:

  • Sender context: Role, company, what they sell, key proof points
  • Prospect context: Job title, company type/size, likely problem, trigger for outreach
  • Goal: Book a call? Get a reply? Get a referral?

Step 2: Choose Framework

FrameworkBest WhenStructure
Problem-FirstProspect has a visible pain pointProblem observation > Relevance > Ask
Trigger-BasedThere is a specific event (funding, hiring, news)Trigger reference > Connection to problem > Ask
Mutual ConnectionReferral or shared networkName drop > Context > Ask
Value-FirstYou have something genuinely useful to shareInsight/resource > Brief context > Ask
Direct AskProspect is high-intent or very seniorBrief context > Direct question

Step 3: Draft the Email

Structure:

Subject: [2-4 words, looks like an internal email]

[Opener: 1 sentence about their world — trigger, observation, or question]

[Relevance: 1-2 sentences connecting their situation to what you do]

[Proof: 1 sentence of credible evidence — specific number, named customer, result]

[Ask: 1 sentence with a single, specific, low-friction CTA]

[Sign-off]

Step 4: Validate

  • Under 150 words total
  • Opener is about them, not you
  • No sentence starts with "I" or "We"
  • One CTA, not multiple
  • CTA is a question, not a statement
  • No jargon or corporate speak
  • Would a friend send this to another friend in business?

Workflow 2: Full Sequence Build

Step 1: Write Email 1 (Using Workflow 1)

Step 2: Plan Follow-Up Angles

Each follow-up needs a distinct angle. Plan before writing:

EmailDayAngleWhat is New
1Day 1Problem-firstInitial outreach
2Day 4New evidenceCase study, data point, or recent result
3Day 9Different pain pointAlternative angle on their world
4Day 16Industry insightSomething notable about their space
5Day 25Direct questionSimple, clear ask without context
6Day 35BreakupProfessional close, referral ask

Step 3: Write Each Follow-Up

Rules for every follow-up:

  • Standalone: does not require reading previous emails
  • New angle: brings something the previous email did not
  • Shorter than Email 1 (each subsequent email gets shorter)
  • Never says "just checking in" or "circling back"
  • Never references all previous emails ("As I mentioned in my last three emails...")

Step 4: Write the Breakup Email

The breakup email closes the loop. It signals this is the last one, which paradoxically increases reply rate.

Template:

Subject: closing the loop

[Name],

Last note from me. If [specific problem] becomes a priority,
reply here and I'll pick it up.

If there's someone else at [Company] better suited for this
conversation, a name would help.

Either way — [genuine well-wish related to something specific].

[Sign-off]

Workflow 3: Performance Iteration

Step 1: Diagnose the Problem

SymptomLikely CauseFix
Low open rate (< 25%)Subject linesTest new subject line patterns
Opens but no replies (< 2% reply rate)Email bodyRewrite with stronger relevance and lower-friction CTA
Replies but wrong outcomeCTA mismatchAdjust the ask
High bounce rate (> 5%)List qualityVerify email addresses before sending
Landing in spamDeliverabilityCheck SPF/DKIM/DMARC, reduce send volume, warm domain

Step 2: Rewrite the Underperforming Element

Focus on one element at a time. Do not rewrite the entire email when only the subject line is the problem.

Step 3: Test and Measure

  • A/B test subject lines with minimum 100 sends per variant
  • Test one variable at a time
  • Wait for 3-5 days of data before drawing conclusions
  • Document every test and result for future reference

Writing Principles

1. Write Like a Peer, Not a Vendor

The moment your email sounds like marketing copy, it is deleted.

Test: Would you send this to a smart colleague at another company? If not, rewrite.

2. Every Sentence Earns Its Place

Each sentence must do one of these jobs:

  • Create curiosity
  • Establish relevance
  • Build credibility
  • Drive to the ask

If a sentence does none of these, cut it.

3. Personalization Must Connect to the Problem

Generic personalization is worse than none.

  • Bad: "I saw you went to Stanford" followed by a pitch unrelated to Stanford
  • Good: "I saw you're hiring three SDRs — usually a signal that you're scaling cold outreach. That's exactly the challenge we help with."

The personalization must bridge to the reason for reaching out.

4. Lead with Their World, Not Yours

The opener should be about their situation, problem, or context. Not about you or your product.

5. One Ask Per Email

Do not ask them to book a call, watch a demo, read a case study, AND reply with their timeline. Pick one.


Voice Calibration by Audience

AudienceLengthToneSubject StyleWhat Works
C-suite (CEO, CRO, CMO)3-4 sentencesUltra-brief, peer-level, strategicShort, vague, internal-lookingBig problem > relevant proof > one question
VP / Director5-7 sentencesDirect, metrics-consciousSlightly more specificSpecific observation + clear business angle
Manager7-10 sentencesPractical, shows homeworkCan be descriptiveSpecific problem + practical value + easy CTA
Technical (Engineer, Architect)7-10 sentencesPrecise, no fluffTechnical specificityExact problem > precise solution > low-friction ask
Founder / Solo5-7 sentencesEmpathetic, peer-to-peerCasual, humanShared experience + relevant proof + conversational ask

Rule: The higher up the org chart, the shorter your email needs to be.


Subject Line Framework

Principles

The goal of a subject line is to get the email opened. Not to convey value, not to be clever. Just opened.

The best cold email subject lines look like internal emails: short, slightly vague, enough curiosity to click.

Patterns That Work

PatternExampleWhy It Works
Two or three words"quick question"Looks like a real email from a colleague
Specific trigger + question"your TechCrunch piece"Specific enough to not look like spam
Shared context"re: Series B"Feels like a follow-up, not cold
Observation"your ATS setup"Relevant, not salesy
Referral hook"[mutual name] suggested I reach out"Social proof front-loaded
Role-specific"SDR team scaling"Shows you know who they are

Patterns That Kill Opens

  • ALL CAPS anything
  • Emojis in subject lines
  • Fake Re: or Fwd: (damages trust before the first word)
  • Question format ("Are you struggling with X?") — sounds like an ad
  • Company name mention ("Acme Corp: helping you achieve...")
  • Blog headline format ("5 ways to improve your...")
  • Exclamation marks

Follow-Up Strategy

Cadence

EmailSend DayGapNotes
Email 1Day 1First touch
Email 2Day 4+3 daysNew evidence angle
Email 3Day 9+5 daysDifferent pain point
Email 4Day 16+7 daysIndustry insight
Email 5Day 25+9 daysDirect question
BreakupDay 35+10 daysClose the loop

Gaps increase over time. Persistent but not annoying.

Follow-Up Angle Rotation

Angle TypeDescriptionExample
New evidenceCase study, data point, recent result"Since my last note, we helped [Company] reduce [metric] by [%]"
Different painAlternative problem in their world"Setting aside [topic A] — are you dealing with [topic B]?"
Industry insightSomething notable about their space"Saw [industry trend]. Most teams are responding by [approach]"
Direct questionSimple ask without buildup"[Name], quick one: who handles [function] at [Company]?"
Reverse askRequest for referral"If this isn't your area, who would you point me to?"
Social proofRelevant peer doing it"[Similar company] just went through this — here's what worked"

Personalization Framework

Three Tiers of Personalization

Tier 1: Segment-Level (Minimum)

  • Industry-specific pain points
  • Company size-specific challenges
  • Role-specific language and priorities

Tier 2: Company-Level (Standard)

  • Recent company news (funding, hiring, product launch)
  • Tech stack signals (what tools they use)
  • Growth signals (job postings, office expansion)

Tier 3: Individual-Level (Premium)

  • Content they have published (posts, articles, talks)
  • Career moves (new role, promotion)
  • Shared connections or experiences
  • Specific project or initiative they are leading

Personalization Sources

SourceWhat You FindHow to Use
LinkedIn profileRole, tenure, content they shareRole-specific opener, reference their posts
Company blogPriorities, culture, technology choicesConnect your solution to their stated priorities
Job postingsGrowth areas, pain points, tech stack"You're hiring for X, which usually means..."
Press/newsFunding, partnerships, launchesTrigger-based openers
GitHub/tech blogsTechnical decisions, stack choicesTechnical relevance and credibility
Podcast/talksOpinions, expertise areas"Your point about X in [talk] resonated..."

Deliverability Setup

Infrastructure Requirements

ComponentWhatWhy
Dedicated sending domainmail.yourdomain.com or outreach.yourdomain.comProtects primary domain reputation
SPF recordDNS TXT record authorizing sending serversProves you are authorized to send
DKIM signingCryptographic signature on emailsProves emails were not modified in transit
DMARC policyDNS record specifying SPF/DKIM enforcementTells receiving servers how to handle failures
Domain warmup4-6 weeks of gradually increasing volumeBuilds sender reputation with ISPs

Warmup Schedule

WeekDaily VolumeNotes
110-20Send to engaged contacts only
220-40Mix of warm and cold contacts
340-70Begin cold outreach at low volume
470-100Monitor bounce rates closely
5-6100-150Increase if bounce rate < 3%
7+150-200 maxSteady state for cold outreach

Deliverability Monitoring

  • Bounce rate: Keep under 3% (above 5% damages reputation)
  • Spam complaint rate: Keep under 0.1%
  • Verify email addresses before sending (use verification services)
  • Monitor blacklists monthly (MXToolbox, Google Postmaster)
  • Use mail-tester.com to check deliverability score before campaigns

Email Format Rules

  • Plain text or minimal HTML (no logos, images, or heavy formatting)
  • No tracking pixels if possible (they trigger spam filters)
  • Limit links to 1-2 maximum
  • Avoid spam trigger words: "free," "guarantee," "act now," "limited time"
  • Keep emails under 200 words
  • Include a physical address (CAN-SPAM requirement)
  • Include an unsubscribe mechanism

Compliance Requirements

CAN-SPAM (United States)

Required for all commercial email to US recipients:

  • Sender identity is clear and not misleading
  • Subject line is not deceptive
  • Physical postal address included
  • Opt-out mechanism present and functional
  • Opt-out requests honored within 10 business days
  • Message identified as an advertisement (if applicable)

GDPR (European Union)

Required for email to EU/EEA residents:

  • Legitimate interest basis documented for B2B outreach
  • Prospect data collected from lawful sources
  • Privacy notice accessible
  • Data processing records maintained
  • Right to erasure honored promptly
  • Data minimization: only collect what you need
  • No consent required for B2B if legitimate interest applies, but this must be documented and defensible

CASL (Canada)

Required for commercial electronic messages to Canadian recipients:

  • Express or implied consent documented
  • Sender identification clear
  • Unsubscribe mechanism functional
  • Implied consent valid for 2 years from last transaction or 6 months from inquiry

Best Practice Regardless of Jurisdiction

  • Always include an easy unsubscribe option
  • Honor opt-outs immediately (do not wait the legal maximum)
  • Do not buy email lists (poor quality, compliance risk)
  • Document your legal basis for outreach
  • Keep records of consent and opt-out requests

Anti-Patterns

PatternWhy It Fails
"I hope this email finds you well"Instant signal that this is templated mass outreach
"I wanted to reach out because..."Three words of nothing before saying anything
Opening with "My name is X and I work at Y"They can see your name. Start with something useful.
Feature dump in email 1Nobody cares about features when they do not trust you yet
HTML templates with logos and colorsLooks like marketing, gets spam-filtered
Fake Re:/Fwd: subject linesDeceptive, destroys trust
"Just checking in" follow-upsAdds no value, removes credibility
Social proof without context"We work with 500 companies" means nothing without relevance
Long-form case study in email 1Save it for follow-up
Passive CTAs ("Let me know if you're interested")Weak. Ask a direct question or propose a specific step.
Multiple CTAs in one emailCreates decision paralysis. One ask per email.
Sending from your primary domainRisks your entire domain reputation

Best Practices

  1. Send from a real person, not a company alias — "sarah@mail.acme.com" outperforms "sales@acme.com" every time.

  2. Read the email aloud before sending — If you hear yourself droning, cut. If it sounds like a brochure, rewrite.

  3. Time your sends — Tuesday through Thursday, 8-10 AM in the prospect's timezone, produces the highest open rates for B2B.

  4. Verify emails before campaigns — A 5% bounce rate damages your domain reputation. Verify every address.

  5. Track reply rate, not open rate — Open tracking is unreliable (privacy features block tracking pixels). Reply rate is the metric that matters.

  6. Build sequences, not individual emails — Most replies come from follow-ups, not the first email. Plan the full sequence before writing.

  7. Document your playbook — Every winning email, subject line, and angle should be documented for the team. Build institutional knowledge.

  8. Respect opt-outs immediately — Not just legally required, but professionally essential. Process within 24 hours.

  9. Rotate sending domains — Use 2-3 sending domains to distribute volume and protect reputation.

  10. Segment relentlessly — A generic template sent to 1,000 people will underperform a personalized email sent to 50 who match your ideal profile.


Integration Points

  • Copywriting — Use for landing page copy and marketing page copy. Cold email follows different constraints (shorter, personal tone, no visual design).
  • Content Strategy — Use to create content assets (case studies, guides) referenced in follow-up emails.
  • Marketing Context — Use for ICP definition and positioning. If you do not know who you are targeting and why, cold email is the wrong tool.
  • Marketing Psychology — Apply psychological principles (reciprocity, social proof, scarcity) to strengthen email messaging.
  • Campaign Analytics — Use to track sequence performance and optimize based on data.

Troubleshooting

SymptomLikely CauseFix
Open rate below 15%Subject lines too long, spammy, or genericTest 2-4 word internal-email-style subjects. Run
subject_line_scorer.py
.
Opens but reply rate below 1%Email body lacks relevance or CTA is too high-frictionRewrite opener about their world. Use a question CTA, not a statement.
Emails landing in spam (2026)Missing SPF/DKIM/DMARC or RFC 8058 one-click unsubscribeGmail/Yahoo/Microsoft now reject non-compliant bulk mail. Run
deliverability_checker.py
.
Bounce rate above 3%Unverified email list or role-based addressesVerify every address before sending. Remove catch-alls and role accounts.
Spam complaint rate above 0.10%Irrelevant targeting or too-frequent sendsGmail enforces 0.10% threshold as of 2026. Improve targeting and reduce volume per domain.
Replies but wrong outcomeCTA mismatch with funnel stageAlign CTA friction to prospect readiness. C-suite wants a question; managers accept a demo link.
Domain blacklistedSending from primary domain or too-high volumeUse dedicated sending subdomains. Warm new domains 4-6 weeks. Max 100 emails/day/address.

Success Criteria

  • Open rate consistently above 35% across sequence (benchmark: 25-40% for cold B2B)
  • Reply rate above 3% (benchmark: 2-5% for well-targeted cold outreach)
  • Bounce rate below 2% on every campaign (Gmail/Microsoft 2026 threshold)
  • Spam complaint rate below 0.10% (2026 Gmail/Yahoo hard enforcement line)
  • Deliverability rate above 95% with SPF/DKIM/DMARC/RFC 8058 fully configured
  • Sequence produces replies from emails 2-5, not just email 1 (follow-ups carry 60%+ of replies)
  • Every email under 150 words with one CTA and zero corporate speak

Scope & Limitations

In Scope:

  • B2B cold email outreach strategy and copy
  • Multi-email sequence design and optimization
  • Subject line and body copy frameworks
  • Deliverability infrastructure setup (SPF, DKIM, DMARC, domain warming)
  • CAN-SPAM, GDPR, CASL compliance guidance
  • Performance diagnosis and iteration methodology

Out of Scope:

  • Email HTML template design (use email-template-builder)
  • Marketing automation platform configuration (Outreach, Salesloft, Apollo)
  • Email list building or scraping (compliance risk)
  • Warm/inbound email sequences (use email-sequence)
  • Phone call scripts or LinkedIn outreach sequences
  • Legal advice on compliance (consult legal counsel for jurisdiction-specific requirements)

Limitations:

  • Scripts use heuristic analysis, not live inbox testing (use mail-tester.com for production validation)
  • Deliverability checker cannot perform live DNS lookups (verify SPF/DKIM/DMARC records separately)
  • Benchmarks are B2B SaaS-focused; adjust thresholds for other industries

Python Automation Tools

1. Subject Line Scorer (
scripts/subject_line_scorer.py
)

Scores cold email subject lines on deliverability, spam risk, and open-rate potential using deterministic heuristics.

python scripts/subject_line_scorer.py "quick question"
python scripts/subject_line_scorer.py --file subjects.txt --json

2. Deliverability Checker (
scripts/deliverability_checker.py
)

Audits email content for spam triggers, HTML complexity, link density, and compliance against 2025-2026 Gmail/Yahoo/Microsoft requirements.

python scripts/deliverability_checker.py email.txt
python scripts/deliverability_checker.py email.txt --domain yourdomain.com --json

3. Sequence Optimizer (
scripts/sequence_optimizer.py
)

Analyzes cold email sequence performance data against industry benchmarks. Diagnoses open rate, reply rate, bounce rate, and cadence issues.

python scripts/sequence_optimizer.py sequence_data.json
python scripts/sequence_optimizer.py --sample --json