What is list-builder?

An end-to-end process for building a qualified lead list, meaning a list of potential customers who match a request. It covers finding companies, checking them against live websites, collecting contacts and email addresses, and removing duplicates.

Use it for requests that need a large, checked prospect list, from initial company discovery through approval, contact collection, email sourcing, and cross-run deduplication.

It brings the separate steps of list building into one repeatable workflow and can resume after failures. This helps avoid incomplete searches, poor-fit companies, missing contacts, and repeated domains.

list-builder — Skill for Claude Code and Codex by growthenginenowoslaw

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 growthenginenowoslawski/coldoutboundskills --skill list-builder

Clone the repo

git clone --depth 1 https://github.com/growthenginenowoslawski/coldoutboundskills

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.

README.md

[![agentmods](https://agentmods.dev/badge/skills/growthenginenowoslawski/coldoutboundskills/list-builder/github.svg)](https://agentmods.dev/skills/growthenginenowoslawski/coldoutboundskills/list-builder)

Your own site

<a href="https://agentmods.dev/skills/growthenginenowoslawski/coldoutboundskills/list-builder"><img src="https://agentmods.dev/badge/skills/growthenginenowoslawski/coldoutboundskills/list-builder/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.

Your own site · 80×15

<a href="https://agentmods.dev/skills/growthenginenowoslawski/coldoutboundskills/list-builder"><img src="https://agentmods.dev/badge/skills/growthenginenowoslawski/coldoutboundskills/list-builder.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 149 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.

When invoked 4,641 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 warn 7 Sept 2026

SkillSpector: 9 findings, up to medium

These are SkillSpector’s own severities. On a checked sample its high-severity flags on skills were ~96% false positives — a documented command, a public API, a “never do X” rule — so we show them as a caution to read, not a verdict. Why →

medium MCP Rug Pull · line 15
npx commands without a version suffix (e.g. @1.0.0) create a rug-pull risk if the upstream server is compromised and publishes a malicious update.

Fix: Pin the version: npx @scope/[email protected]
medium MCP Rug Pull · line 16
npx commands without a version suffix (e.g. @1.0.0) create a rug-pull risk if the upstream server is compromised and publishes a malicious update.

Fix: Pin the version: npx @scope/[email protected]
medium MCP Rug Pull · line 17
npx commands without a version suffix (e.g. @1.0.0) create a rug-pull risk if the upstream server is compromised and publishes a malicious update.

Fix: Pin the version: npx @scope/[email protected]
medium MCP Rug Pull · line 18
npx commands without a version suffix (e.g. @1.0.0) create a rug-pull risk if the upstream server is compromised and publishes a malicious update.

Fix: Pin the version: npx @scope/[email protected]
medium MCP Rug Pull · line 50
npx commands without a version suffix (e.g. @1.0.0) create a rug-pull risk if the upstream server is compromised and publishes a malicious update.

Fix: Pin the version: npx @scope/[email protected]
medium MCP Rug Pull · line 55
npx commands without a version suffix (e.g. @1.0.0) create a rug-pull risk if the upstream server is compromised and publishes a malicious update.

Fix: Pin the version: npx @scope/[email protected]
medium MCP Rug Pull · line 59
npx commands without a version suffix (e.g. @1.0.0) create a rug-pull risk if the upstream server is compromised and publishes a malicious update.

Fix: Pin the version: npx @scope/[email protected]
medium MCP Rug Pull · line 221
npx commands without a version suffix (e.g. @1.0.0) create a rug-pull risk if the upstream server is compromised and publishes a malicious update.

Fix: Pin the version: npx @scope/[email protected]
medium Excessive Agency · line 152
Skill enables autonomous high-impact decisions without human-in-the-loop verification. Critical operations (destructive commands, financial transactions, data deletion) should require explicit user confirmation.

Fix: Add human-in-the-loop confirmation for destructive, irreversible, or high-impact operations. Never auto-execute commands that modify files, send data, or alter system state.

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.

Model	Per session	Once invoked
Fable 5.1	$0.00149	$0.04641
Opus 5	$0.00075	$0.02320
Sonnet 5	$0.00030	$0.00928
Haiku 4.5	$0.00015	$0.00464

Measured 13d ago against content hash 1457d197c8c6, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-12, from the pricing page.

Security

Grade A, and why

list-builder 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.

The scan reads SKILL.md. This mod also ships 14 executable files (scripts/classify-batch.ts, scripts/contacts-merge.ts, scripts/contacts.ts, …), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

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/list-builder/SKILL.md · 274 lines

How it starts

The opening of the file, as written. The whole thing — 274 lines — stays where its author put it; the contents beside it link to each section on GitHub.

List Builder — the meta list-building process

⚡ OPERATE VIA THE RUNBOOK

The manual phase-by-phase flow below still documents the concepts, but the OPERATIONAL path is now three one-command scripts — see RUNBOOK.md in this skill directory for the decision table and failure playbook. In short:

npx tsx scripts/make-judge.ts --spec=judge-spec.json --out=prompt.txt   # judge (mandatory blocks)
npx tsx scripts/run-lane.ts  --config=lane.json                         # full lane, resumable
npx tsx scripts/snowball.ts  --config=lane.json                         # sweep until dry
npx tsx scripts/contacts.ts  --config=lane.json                         # contacts + emails after approval

Re-running the same command resumes after ANY failure. summary.md line 1 = READY / NOT READY with the next command. Cross-run dedup via the OPTIONAL list_builder_judged_domains Postgres registry (WAL-first; scripts/registry.ts; DDL in references/registry-schema.sql; leave LIST_REGISTRY_DB_URL unset and it degrades to per-run WAL dedup). Prospeo pacing is globally rate-limited across processes (lib.ts slot reservation — never tune it).

One entry point for every list request. This skill owns the PROCESS and delegates to tool skills that own the provider gotchas. Read the referenced skill whenever you touch its provider.

Layer	Delegate
Company discovery + qualification + snowball	`/list-expander` (scripts in its `scripts/`)
Prospeo filters/syntax	`/prospeo-search-api`
Blitz domain→people	`/blitz-list-builder` (`scripts/find-contacts.ts`)
GetLeads counts/exports	`scripts/getleads-client.ts` (counts are free) — optional, skipped without a key
Email validation	provider emails from GetLeads/Blitz/Prospeo → `leads-final.csv`; validate with MillionVerifier (`/cold-email-starter-kit`) before upload
Judge tuning	`/icp-prompt-builder`
Local/SMB discovery	`/google-maps-list-builder`
List QA before delivery	`/list-quality-scorecard`

Read the full file on GitHub · 274 lines

Files

What ships with it

18 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

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.

13d ago First seen · 274 lines · 149 tokens per session scan A 1457d197c8c6

Subscribe to this mod's changes

list-builder is a skill published in the GitHub repository growthenginenowoslawski/coldoutboundskills (702 stars, last pushed 25d ago), licensed MIT. It adds 149 tokens to every session and 4,641 once invoked, about $0.0007 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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