Outbound Stack Fingerprint

What this does

Whether a company already runs cold outbound is the single most useful qualifier for anyone selling outbound tooling or services, and it is visible from the outside: sending domains, mail records, and the fingerprints of the tools that provision them. This skill reads that infrastructure and reports scale as well as presence.

Requirements

Check these before you run the skill. Nothing outside this table is needed.

Requirement	Needed	Used for	What it costs you
Apify account and API token (APIFY_TOKEN)	Required	Runs the live data actors	A free Apify account works. Each run bills your own Apify account at the actor's Store price: outbound-infrastructure-fingerprint 0.004 USD per domain.
Node.js 18 or newer	Required	The MCP tool calls	Free. It starts the Mamba Labs MCP server with npx.

Missing a required item? Stop before the live steps and tell the user which item is missing and what it is for. Do not run the step without it and do not present an empty result as an answer. Keys are read from the environment at run time and are never written into a file, a prompt or the output.

When to use it

• do they run cold outbound
• what sequencer do they use
• how many sending domains
• size a competitor's outbound
• qualify an outbound buyer

Inputs

• domain: the company domain
• depth: how thoroughly to probe for related sending domains

Shared context this skill reads

Before doing anything else, read whichever of these exist at the project root and use them instead of asking the user to repeat themselves:

• ICP.md

If none exist, do the work from what the user gives you, then offer to write the missing file so the next skill in the pack starts warmer.

Tool connection

The fingerprint reads mail records and related sending domains directly rather than inferring the stack from a website tag.

This skill calls live data through the Mamba Labs MCP server, which runs the actors on Apify with your own Apify token (https://console.apify.com/account/integrations).

• Installed as a plugin: the server is already wired, and the plugin asks for the token once.
• Installed by hand: copy .mcp.json from this folder into your project root and set APIFY_TOKEN in your environment, or run:

claude mcp add mamba-gtm-suite -e APIFY_TOKEN=<your token> -- npx -y @mambalabsdev/mcp-gtm-suite@1.12.0

Actor	MCP tool	Used for	Store page
Outbound Infrastructure Fingerprint	fingerprint_outbound_infrastructure	sending domain discovery and outbound tool fingerprinting	https://apify.com/mambalabs/outbound-infrastructure-fingerprint

Runnable example input, matched to the live tool schema:

fingerprint_outbound_infrastructure:

{
  "domain": "example.com",
  "scan_sending_domains": true,
  "sending_domain_depth": "deep",
  "check_deliverability": false
}

Cost line. Before any live call, state how many calls you plan and which actors they bill. After the run, report the calls made, the calls that failed, and the Apify usage where the tool reports it. Each actor bills the user's own Apify account at its Store price.

No token, no live data. If no Apify token is available, say so and stop the live steps. Never fill a live section from memory and present it as live.

Method

1. Read the primary domain's mail configuration first, which tells you who they receive with and often who they send with.
2. Discover related sending domains. The count is the scale signal, and it is more informative than the tool name.
3. Fingerprint the provisioning pattern. Domains bought in a batch, with the same registrar and the same record template, indicate a deliberate outbound program rather than incidental sending.
4. Report scale in bands rather than as a precise count, because discovery is never exhaustive and a precise number implies a completeness the method does not have.
5. Read absence carefully. No detected sending domains means none were found, which is different from none existing.
6. Turn it into a qualification: already running the motion, running it badly, or not running it, each of which is a different conversation.
7. Check the output with scripts/check-output.py before you return it.

Approval stop

This skill does not send email or write to a CRM. If the user asks it to, stop first: show what would be sent or written and wait for an explicit yes.

Output

The mail configuration, the discovered sending domain list with a scale band, the provisioning pattern read, and the qualification with its angle.

Check the output before you return it

Save the output to a file and run python3 scripts/check-output.py <file>. The contract it checks is scripts/output-contract.json.

• Exit 0, COMPLETE: return the output.
• Exit 2, INCOMPLETE: do not present the output as finished. Fill what you can, run the check again, and if parts stay missing, return the output under the heading Incomplete with every reason the check printed.

Quality bar

• Scale is reported as a band with the discovery limits stated
• No detection is reported as not found rather than as absence
• The provisioning pattern is assessed, not only the tool name
• The output ends in a qualification, not a tool list

Related skills

• tech-stack-signal-reader
• email-deliverability-audit
• gtm-signal-aggregator

Ships in the signal-based-selling, deliverability packs.