From GTM Skills
Finds verified work email addresses for B2B contacts using multi-provider waterfall discovery. Activates on email find, lookup, enrichment requests.
How this skill is triggered — by the user, by Claude, or both
Slash command
/gtm-skills:email-findingThe summary Claude sees in its skill listing — used to decide when to auto-load this skill
Finding verified work emails is the highest-stakes step in B2B prospecting.
Finding verified work emails is the highest-stakes step in B2B prospecting. Unverified emails damage sender reputation within a week. A single batch of bounces can require months of domain warmup to recover from.
This skill walks through email discovery using a multi-provider waterfall — starting with the highest-accuracy source first, falling back only when that source returns empty. Every email found must be verified before entering any outbound sequence.
Do NOT use for:
Email finding follows waterfall enrichment principles from DAMA-DMBOK data-quality dimensions (waterfall waterfall: Apollo → ZoomInfo → PDL → Claygent → Claude normalization) and Ziellab's 3-waterfall architecture (separate company, email, and phone waterfalls run independently).
The core insight: no single provider covers more than 60-75% of B2B contacts. Chaining 3-5 providers in sequence routinely pushes coverage to 85-92%.
Ask the user for:
Order providers by cost-per-hit for the user's specific ICP segment:
| Provider | Best For | Match Rate Est. | Cost Profile |
|---|---|---|---|
| LeadMagic Email Finder | US B2B, all segments | 60-75% | Pay-per-result |
| Apollo | SMB, mid-market, US | 60-75% | Subscription-based |
| ZoomInfo | Enterprise, Fortune 5000 | 30-40% incremental | High, annual contract |
| People Data Labs | Technical roles, EU, early-stage | 10-18% incremental | Moderate, API credits |
| Hunter.io | Domain-pattern matching | 15-25% | Low, per-request |
| EU-compliant email provider | GDPR-compliant, EU | 10-20% | Moderate |
| Claygent (Clay) | Founders, execs, web-visible | 5-15% incremental | Credits per search |
Build the waterfall from cheapest + highest-coverage first, falling back to more expensive providers only when earlier steps miss.
For each contact:
Primary provider — Run the highest-accuracy, lowest-cost provider first. For most US B2B: LeadMagic Email Finder (returns verified results) or Apollo.
Fallback 1 — If primary returns empty, run secondary provider. ZoomInfo for enterprise, Hunter for domain-based lookup.
Fallback 2 — If still empty, run tertiary. People Data Labs or regional compliance provider depending on region.
AI-assisted (Claygent) — For remaining 10-15%, use Claygent with an explicit prompt: "Find the work email for [name] at [company]. Return the email address AND the source URL. Do NOT guess or construct emails from patterns. If no verified source found, return empty."
Normalization — Consolidate results. Use COALESCE logic: prefer results from earlier waterfall steps. Prefer verified over pattern-matched.
Every found email must be verified before use. Run verification as a separate step — never skip it. See contact-verification skill.
Acceptable verification results: valid only. Handle risky/catch-all results separately (lower volume, extra monitoring). Discard invalid results.
For a single lookup:
Contact: John Smith, Acme Corp
Email: [email protected]
Source: LeadMagic Email Finder
Status: Verified — valid
Confidence: High
For batch enrichment, produce a CSV with columns:
email, email_source, email_confidence, verification_status
Skipping verification. Unverified emails cause bounces. Bounces damage sender reputation. Recovery takes weeks. Always verify after finding.
Single-provider dependency. One provider covers 60-75% max. Running only Apollo leaves 25-40% of contacts unreachable. Always waterfall.
Using pattern-guessed emails. Constructing [email protected] without confirmation creates 40-60% bounce rates. Never guess. Verify.
Running waterfall in wrong order. An expensive provider first burns budget on contacts a cheaper provider would have found. Sort by cost-per-hit.
Not normalizing company names. "Acme Inc" vs "Acme, Inc." vs "Acme Corporation" create duplicate lookups. Match on domain, not name.
No LinkedIn URLs in input. Adding LinkedIn URLs improves match rates by 15-25 percentage points across all providers. Run a LinkedIn URL finder column before email finding when URLs are missing.
references/framework-notes.md — Named frameworks and reference tablestemplates/output-template.md — Deliverable shell for agent outputscripts/check-output.py — Lightweight deliverable validatornpx claudepluginhub leadmagic/gtm-skillsBuilds verified business email lists from Google Maps, Google SERPs, or URL lists with built-in email verification. Replaces tools like Apollo or Hunter.
Enriches LinkedIn profiles from people-search with verified emails and phones via Prospeo or Fullenrich. Supports single-provider and waterfall modes, outputs a contact CSV.
Automates Hunter.io email intelligence: search domains for emails, find specific contacts, verify deliverability, manage leads, and monitor usage via natural language commands through Composio MCP.