list-building-tips

list-building-tips is a skill for Claude Code, Codex from swan-gtm/gtm-skills. It costs 49 tokens per session (639 once invoked), scanned A, original, MIT.

A practical guide to building business prospect lists, which are lists of potential customers, from multiple data sources and then improving their accuracy.

In plain words
What is it for?
Use it when collecting prospects, enriching company and contact data, improving email coverage, reducing bounced emails, or diagnosing list-quality problems.
Why use it?
It helps avoid unreliable or incomplete lists by covering enrichment, email verification, duplicate removal, fit checks, and campaign-readiness checks.

Skill for Claude CodeCodex

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

Good fit Use it when collecting prospects, enriching company and contact data, improving email coverage, reducing bounced emails, or diagnosing list-quality problems.

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Install with agentmods
npx agentmods add skills/swan-gtm/gtm-skills/list-building-tips
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 swan-gtm/gtm-skills --skill list-building-tips
Clone the repo
git clone --depth 1 https://github.com/swan-gtm/gtm-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 list-building-tips

README.md
[![agentmods](https://agentmods.dev/badge/skills/swan-gtm/gtm-skills/list-building-tips/github.svg)](https://agentmods.dev/skills/swan-gtm/gtm-skills/list-building-tips)
Your own site
<a href="https://agentmods.dev/skills/swan-gtm/gtm-skills/list-building-tips"><img src="https://agentmods.dev/badge/skills/swan-gtm/gtm-skills/list-building-tips/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 list-building-tips

Your own site · 80×15
<a href="https://agentmods.dev/skills/swan-gtm/gtm-skills/list-building-tips"><img src="https://agentmods.dev/badge/skills/swan-gtm/gtm-skills/list-building-tips.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 49 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 639 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. Third-party audits
  • NVIDIA SkillSpector pass 7 Sept 2026
How audits are shown
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 $0.00049 $0.00639
Opus 5 $0.00024 $0.00319
Sonnet 5 $0.00010 $0.00128
Haiku 4.5 $0.00005 $0.00064

Measured 13d ago against content hash 0032d7b4010f, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-12, from the pricing page.

Security

Grade A, and why

list-building-tips 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 13d ago.

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/alex-vacca/list-building-tips/SKILL.md · 110 lines

How it starts

The opening of the file, as written. The whole thing — 110 lines — stays where its author put it; the contents beside it link to each section on GitHub.

List Building Pro Tips

Core Principles

1. Mix Sources

  • Don't rely on just one data provider
  • Each source has different strengths/coverage
  • Combine for maximum coverage

2. Scraping = Step 1

  • Raw scraped data is just the beginning
  • Still need Clay enrichment for:
    • Email verification
    • Phone numbers
    • Company data
    • Custom signals

3. Templates Are Modular

  • Start with proven templates
  • Adjust for specific campaign goals
  • Don't rebuild from scratch

4. Don't Reinvent the Wheel

  • Use existing Clay templates
  • Modify rather than create
  • Learn from what works

Data Quality Hierarchy

1. Verified email (bounced < 2%)
2. Direct phone number
3. Recent activity signal
4. ICP fit confirmed
5. Company enrichment complete

Efficiency Benchmarks

Task Manual Time With Clay
100 prospects 8-10 hours 30 min
500 prospects 40+ hours 1-2 hours
1000 prospects 80+ hours 2-3 hours

Quality Checklist

Before launching any campaign:

  • Email bounce rate < 2%
  • At least 70% email coverage
  • ICP criteria verified
  • Recent signals tagged
  • Duplicates removed
  • Competitor customers flagged
  • Do-not-contact list checked

Common Mistakes

  1. Single source reliance - Limits coverage
  2. Skipping verification - Kills deliverability
  3. Over-filtering - Shrinks TAM too much
  4. Under-filtering - Wastes outreach on bad fits
  5. Ignoring signals - Missing hot prospects

Combines with

Skill Why
lead-sources-guide Choose right sources
clay-enrichment-9step Full enrichment workflow
email-metrics-benchmarks Track deliverability
clay-buying-signals-5 Add signals to lists

Example prompts

Review my list building workflow against the quality checklist.
What's the fastest way to build a 500-prospect list for fintech CFOs?
How do I diagnose why my email bounce rate is above 2%?

Read the full file on GitHub · 110 lines

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. 13d ago First seen · 110 lines · 49 tokens per session scan A 0032d7b4010f

Subscribe to this mod's changes

list-building-tips is a skill published in the GitHub repository swan-gtm/gtm-skills (150 stars, last pushed 2d ago), licensed MIT. It adds 49 tokens to every session and 639 once invoked, about $0.0002 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 2026-08-30.

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