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Agent skill

Blitz List Builder

by growthenginenowoslawski in growthenginenowoslawski/coldoutboundskills

Use the Blitz API to find decision-makers at specific companies when you already have a list of company domains.

MITAuto-check passedSales & Support

Install Blitz List Builder

skills CLI
$ npx skills add growthenginenowoslawski/coldoutboundskills --skill blitz-list-builder -a claude-code

Project install by default; add -g for ~/.claude/skills/.

GitHub CLI
$ gh skill install growthenginenowoslawski/coldoutboundskills blitz-list-builder --agent claude-code

Project scope by default; add --scope user for a personal install. Needs GitHub CLI 2.90.0 or later (public preview).

Manual copy
$ git clone --depth 1 https://github.com/growthenginenowoslawski/coldoutboundskills.git skills-src && mkdir -p .claude/skills && cp -r skills-src/skills/blitz-list-builder .claude/skills/blitz-list-builder && rm -rf skills-src

Use ~/.claude/skills/ instead of .claude/skills for a personal install. The folder must contain SKILL.md.

Claude Code skills documentation · loads skills from .claude/skills/

Facts

Skill name
blitz-list-builder
GitHub stars
753
Token cost
~2k tokens
SKILL.md length
849 words
Files
2 (incl. scripts)
Skills in repo
49
Repo updated
First seen
Licence
MIT

At a glance

Use the Blitz API to find decision-makers at specific companies when you already have a list of company domains.

  • Works in 5 steps: Evaluates the first 10 with an AI… → You give corrections ("this one should… → Refines the prompt, runs next 10 → …
  • Your targeting is company-first (not title-first)
  • SKILL.md covers When to use Blitz vs Prospeo, Prerequisites, Inputs and Outputs, plus 12 more sections
  • Runs TypeScript scripts from its folder; calls npx; reaches acme.com and linkedin.com; needs BLITZ_API_KEY

What it does

Blitz List Builder is an agent skill from growthenginenowoslawski/coldoutboundskills. Use the Blitz API to find decision-makers at specific companies when you already have a list of company domains. Best for SMB owner-finding, domain-to-people lookup, or supplementing Prospeo results. Outputs a CSV you can feed to the /list-builder Phase 5 or directly to /cold-email-starter-kit for Smartlead upload. Use when your targeting is company-first (not title-first).

Its SKILL.md is about 2k tokens, which your agent loads only when the skill is triggered. The skill folder holds 2 other files, including scripts (for example `scripts/find-contacts.ts`).

It sits in Sales & Support, covering Cold outreach, Project scaffolding and CSV and tabular files. The repository describes itself as: Open-source Claude Code skills for cold email and outbound sales. Grade campaigns, export Prospeo searches, scrape Google Maps — all from Claude Code. The licence is MIT.

When your agent uses it

  • Your targeting is company-first (not title-first)
  • Tasks that involve Cold outreach
  • Tasks that involve Project scaffolding

Example prompts

  • “/blitz-list-builder”

Requirements

  • Node.js
  • A credential in BLITZ_API_KEY

Workflow steps

5 steps, taken from the first numbered list in SKILL.md.

  1. Evaluates the first 10 with an AI qualification prompt
  2. You give corrections ("this one should be NO because they're a competitor")
  3. Refines the prompt, runs next 10
  4. Stops after 2 rounds with zero corrections — prompt is tuned
  5. Apply the tuned prompt to the remaining leads to filter before paying for email enrichment

What it can do on your machine

Read from SKILL.md and the folder at commit 25c5d85. It shows what the files ask for, not the result of running them.

  • Tool permissions

    Pre-approves nothing: there is no allowed-tools line, so your agent's usual permission prompts apply.

    From allowed-tools in the SKILL.md frontmatter.

  • Runs code

    Ships 1 file in scripts/ (TypeScript), which the agent can run.

    Shell commands in SKILL.md call:

    • npx

    From the folder's file list and the shell code blocks in SKILL.md.

  • Network

    Hosts in commands or code, which the agent is likely to contact:

    • acme.com
    • linkedin.com

    From URLs in SKILL.md, links to its own repository left out.

  • Credentials

    Names these keys or tokens, usually read from environment variables:

    • BLITZ_API_KEY

    From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.

Context cost

Blitz List Builder loads about 2k tokens when it runs. Until then it costs about 99 tokens; SKILL.md has 849 words of instructions outside code blocks.

Always · name and description, kept in context so the agent knows when to use it
~99
When it runs · the whole SKILL.md, loaded when a task matches
~2k

Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.

Safety

Auto-check passed

The automated check found no risky patterns in SKILL.md.

Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); the scripts in this folder are not scanned.

SKILL.md

The full file from growthenginenowoslawski/coldoutboundskills at commit 25c5d85, republished under its MIT licence (© growthenginenowoslawski). 849 words, ~1,955 tokens.

Download SKILL.mdSave it as .claude/skills/blitz-list-builder/SKILL.md (or your agent's skills folder). This skill also uses 1 other file; get the full folder from GitHub.
name
blitz-list-builder
description
Use the Blitz API to find decision-makers at specific companies when you already have a list of company domains. Best for SMB owner-finding, domain-to-people lookup, or supplementing Prospeo results. Outputs a CSV you can feed to the /list-builder Phase 5 or directly to /cold-email-starter-kit for Smartlead upload. Use when your targeting is company-first (not title-first).

Blitz List Builder

Prospeo is title-first: "all VPs of Marketing in B2B SaaS." Blitz is domain-first: "for each of these 500 restaurant domains, find the owner."

If you already know the target companies (from Google Maps, a CSV of competitors, or a manually-curated list), Blitz finds the people for you.

When to use Blitz vs Prospeo

Your situationUse
"I have 5,000 domains, find the owners"Blitz
"Find all CFOs at US SaaS companies 100-500 employees"Prospeo
"I need to supplement Prospeo results with additional contacts at the same companies"Blitz
"I want the widest net possible in a vertical"Prospeo
"I'm targeting specific named accounts (ABM)"Blitz

Often: use Prospeo to build the initial list, then Blitz to add 1-2 more contacts per company.

Prerequisites

  • Blitz API key (env: BLITZ_API_KEY) — sign up at their website
  • List of target company domains (CSV with a company_domain column, or one domain per line)

Inputs

  • --domains-file=<path> — CSV or txt with company domains (one per line, or a column named company_domain)
  • --titles=<csv> — comma-separated title keywords to filter (default: owner,founder,ceo,president,cto,vp)
  • --out=<path> — CSV output path

Outputs

CSV with columns: company_domain, first_name, last_name, job_title, linkedin_url, email, email_source, company_name, company_industry, company_headcount, company_phone

Email will be populated when Blitz returns one. Use /list-builder Phase 5 (scripts/contacts.ts) on the output to fill in missing emails, then validate with MillionVerifier (/cold-email-starter-kit).

Usage

bash
export BLITZ_API_KEY=xxx

# Pull owner/founder/CEO contacts for 5000 SMB domains
npx tsx scripts/find-contacts.ts \
  --domains-file=restaurants.csv \
  --titles=owner,founder,ceo,general-manager \
  --out=restaurant-owners.csv

# Domain-first discovery with custom title match
npx tsx scripts/find-contacts.ts \
  --domains-file=saas-companies.txt \
  --titles=vp-marketing,head-of-growth,cmo,director-marketing \
  --out=saas-marketers.csv

API overview

Blitz has two main endpoints we use:

Company enrichment (find employees):

POST {BLITZ_BASE_URL}/api/enrichment/company
Body: { "domain": "acme.com" }
Response: { employees: [{ first_name, last_name, title, linkedin_url, email }], company: { name, industry, headcount, phone } }

Email enrichment (find email for a LinkedIn URL):

POST {BLITZ_BASE_URL}/api/enrichment/email
Body: { "linkedin_profile_url": "https://linkedin.com/in/..." }
Response: { email: "...", status: "verified" }

Rate limiting

The script throttles at 30 requests/second with concurrency 10. This matches Blitz's published limits. If you see 429s, lower the concurrency flag.

Hit rate expectations

Rough benchmarks (from real campaigns):

  • SMBs (restaurants, clinics, salons): 70-80% contact-found rate, 40-60% email-found
  • B2B tech (10-500 employees): 80-90% contact-found, 50-70% email-found
  • Enterprise (>1000 employees): 90%+ contact-found, but filtering for the RIGHT person matters more than the found-rate
  • Solo operators / micro-businesses: 30-50% — often no public LinkedIn

Title filtering — write specific keywords

Default keywords (owner, founder, ceo, president, cto, vp) are broad. Narrow them per campaign:

bash
# Restaurants
--titles=owner,operator,general-manager

# SaaS RevOps
--titles=revops,revenue-operations,vp-sales,director-sales

# Dental practices
--titles=dentist,owner,practice-manager

# Law firms
--titles=partner,managing-partner,principal

The script does case-insensitive substring match. "vp" matches "VP Sales" but also "VP Product" — narrow further if that's too loose.

Common gotchas

  • Domain must be just the bare domain. Blitz wants acme.com, not https://acme.com/ or sub.acme.com.
  • Huge companies return truncated employee lists. Blitz caps at ~50-100 employees per domain. For enterprise-heavy lists, use Prospeo or LinkedIn search instead.
  • Stale LinkedIn data. Blitz's cache can be 3-12 months old. Job titles may have changed. Validate with the email waterfall.
  • No email returned ≠ person unreachable. 40% of hits have no email. Feed them to /list-builder Phase 5 (scripts/contacts.ts), which tries GetLeads, Blitz and Prospeo in cost order.
  • Rate-limit errors. 429 = you hit the cap. Script retries with exponential backoff, but long bursts still fail.
Show full SKILL.md (393 more words)Show less

Required step: Qualify with /icp-prompt-builder

This is a required step. Do not skip it.

Before pulling more than 500 companies' worth of contacts, sample ~50 and run /icp-prompt-builder on them:

  1. Evaluates the first 10 with an AI qualification prompt
  2. You give corrections ("this one should be NO because they're a competitor")
  3. Refines the prompt, runs next 10
  4. Stops after 2 rounds with zero corrections — prompt is tuned
  5. Apply the tuned prompt to the remaining leads to filter before paying for email enrichment

Why it's required: Blitz contact-finding is cheap, but email enrichment downstream is not. A typical 5,000-contact run costs $150+ in email-finding API calls. If 40% of your list is wrong-fit, you burn ~$60 finding emails at companies that will never convert. The ICP prompt builder takes 10-15 min and saves that.

How to skip safely: you can't. If you're sure your list is already perfectly qualified (e.g., it came from a curated seed list of named accounts you want to pitch), run /icp-prompt-builder anyway on 10 of them and confirm your existing qualification matches — the prompt builder becomes a sanity check instead of a filter.

Cost

Per Blitz pricing (check their current rates):

  • Company enrichment: ~$0.02-0.05 per domain
  • Email enrichment: ~$0.05-0.10 per email

5,000 domains = ~$150 for contacts alone. Plan your budget.

Output → next step

Once you have the CSV, the typical flow:

  1. Deduplicate — remove duplicate emails, duplicate LinkedIn URLs
  2. Filter — drop rows where job_title doesn't cleanly match your ICP
  3. Fill missing emails — run /list-builder (Phase 5, emails) on rows with empty email
  4. Validate — run MillionVerifier on all emails (see /cold-email-starter-kit for the MillionVerifier script)
  5. Upload — pass to Smartlead via /cold-email-starter-kit script smartlead-add-leads.ts

Scripts

  • scripts/find-contacts.ts — main batch enrichment script

What to do next

Run /list-builder (Phase 5, emails) to fill in emails for rows Blitz didn't return. Then /list-quality-scorecard to grade the final list.

After the scorecard, proceed to /campaign-copywriting → /smartlead-campaign-upload-public.

Or wait: if the required /icp-prompt-builder step (above) showed <40% qualification rate, your source list of domains is off. Fix that before spending more Blitz credits.

  • /icp-prompt-builder — qualify the contacts this skill returns BEFORE running email waterfall
  • /prospeo-full-export — the title-first alternative
  • /google-maps-list-builder — for local-business domain lists
  • /disco-like — lookalike companies from seed domains
  • /list-builder (Phase 5, emails) — when Blitz doesn't return an email
  • /cold-email-starter-kit → 06-list-building-prospeo.md for broader list-building context

© growthenginenowoslawski, MIT. Rendered from Markdown: HTML in the file is shown as text, images as links, and headings moved down two levels. Raw file

Files

SKILL.md and 1 other file (scripts) in skills/blitz-list-builder of growthenginenowoslawski/coldoutboundskills.

  • SKILL.md
  • scripts/find-contacts.ts

Open the folder on GitHubat commit 25c5d85

Compare with similar skills

Blitz List Builder next to the 5 skills that share the most tags, products or categories with it. Stars are the repository's; “used in” counts other GitHub owners with a copy.

Blitz List Builder compared with similar skills
SkillStarsUsed inTokensAuto-checkLicenceRepo updated
Blitz List Builder this skillgrowthenginenowoslawski/coldoutboundskills753—~2kAutomated safety check: PassMIT
Cold Email Local Businessgmapsscraper/google-maps-agent-skills132—~1.2kAutomated safety check: PassMIT
Cold Email VerifierVarnan-Tech/opendirectory674—~810Automated safety check: PassMIT
Cold Email Outreachgooseworks-ai/goose-skills1.2k1 repos~3.4kAutomated safety check: NotesMIT
Apify Buying Signal Detectionapify/awesome-skills266—~5.1kAutomated safety check: NotesApache-2.0
Email Generationextruct-ai/gtm-skills109—~1.7kAutomated safety check: PassNone

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Categories

Questions about Blitz List Builder

What does Blitz List Builder do?

Use the Blitz API to find decision-makers at specific companies when you already have a list of company domains. Blitz List Builder is an agent skill from growthenginenowoslawski/coldoutboundskills. Use the Blitz API to find decision-makers at specific companies when you already have a list of company domains.

When should I use Blitz List Builder?

Blitz List Builder fits situations like: your targeting is company-first (not title-first); tasks that involve Cold outreach; tasks that involve Project scaffolding.

How do I install Blitz List Builder in Claude Code?

Run `npx skills add growthenginenowoslawski/coldoutboundskills --skill blitz-list-builder -a claude-code`. Or copy the skill folder (skills/blitz-list-builder in growthenginenowoslawski/coldoutboundskills) into .claude/skills/blitz-list-builder in your project. Claude Code loads it when a task matches its description.

How do I install Blitz List Builder in Codex?

Run `npx skills add growthenginenowoslawski/coldoutboundskills --skill blitz-list-builder -a codex`. Or copy the skill folder (skills/blitz-list-builder in growthenginenowoslawski/coldoutboundskills) into .agents/skills/blitz-list-builder in your project. Codex loads it when a task matches its description.

Can I use Blitz List Builder in Cursor, Gemini CLI or GitHub Copilot?

Cursor, Gemini CLI, GitHub Copilot and OpenCode also load SKILL.md folders. With the skills CLI, run `npx skills add growthenginenowoslawski/coldoutboundskills --skill blitz-list-builder -a cursor` (or -a gemini-cli, github-copilot or opencode for the others). To copy it by hand, put the folder in .cursor/skills/blitz-list-builder, .gemini/skills/blitz-list-builder, .github/skills/blitz-list-builder and .opencode/skills/blitz-list-builder in your project.

What does Blitz List Builder need to run?

Going by SKILL.md and its folder, Blitz List Builder needs TypeScript for the scripts in its folder, the command-line tools its instructions call (npx) and credentials named BLITZ_API_KEY. Our summary lists: Node.js; A credential in BLITZ_API_KEY.

Does Blitz List Builder access the network?

SKILL.md names 2 domains. In commands or code: acme.com and linkedin.com; the agent is likely to contact these when it follows the instructions. This is read from the text; nothing was executed.

Is Blitz List Builder safe to install?

Our automated static check of SKILL.md found no risky patterns, such as piping downloads into a shell, reading credential files or hidden Unicode. It is not a guarantee. The check reads SKILL.md only: the scripts in the folder are not scanned, so read them before running anything.

What licence does Blitz List Builder use?

Blitz List Builder is published under the MIT licence (the repository's licence). It allows redistribution, so the full SKILL.md is shown on this page.

How many tokens does Blitz List Builder use?

About 2k tokens (SKILL.md is roughly 7.8k characters). Agents keep only the skill's name and description in context until a task matches; then they load SKILL.md in full.

What are the alternatives to Blitz List Builder?

Skills that share tags, products or a category with Blitz List Builder: Cold Email Local Business (gmapsscraper/google-maps-agent-skills, 132 stars), Cold Email Verifier (Varnan-Tech/opendirectory, 674 stars), Cold Email Outreach (gooseworks-ai/goose-skills, 1.2k stars) and Apify Buying Signal Detection (apify/awesome-skills, 266 stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.

Who maintains Blitz List Builder?

growthenginenowoslawski (a GitHub user) maintains it in growthenginenowoslawski/coldoutboundskills, which has 753 GitHub stars. The repository holds 49 skills in this directory. The repository was last updated on October 5, 2026.

Source: growthenginenowoslawski/coldoutboundskills on GitHub. Facts on this page come from the repository at the commit we read; the author's words are quoted as theirs.