What to try — counterparty

# WHAT TO TRY — Item 4, Counterparty Check

**Owner-test staging, per the Owner-Test Rule.** Two things to try, in order.
Total owner time: ~2 minutes for #1 now; ~10 minutes for #2 at the sitting.

## 1. Read the packet (available now, ~2 minutes)

Open: `COUNTERPARTY-CHECK.md` in this folder
(`~/workspace/horizon-works/q-branch-2026-10-31/04-counterparty/`).

Try judging it the way you'd use it: you're at a show, a new seller wants
cash for a card, he texts you his number. Does the "when to run a check"
section match when you'd actually want it? Do the three grades
(CARRIER/REGION · SPAM SIGNAL · REGISTRATION HINTS) read clear at a glance?
The 6-step workflow is written to be followed mid-show — flag any step that
wouldn't work on a noisy floor.

## 2. The F-2 fixture sitting (~10 minutes, when you're ready — not before)

Open: `fixture-f2.sh` in this folder. It is **staged and UNRUN** on purpose.

In the sitting, Muse walks you through it one step at a time (Code
Breakdown Rule — each command explained before you run it):

1. The script makes a fresh venv and installs the four pinned libraries
   into it — colorama 0.4.6 · phonenumbers 8.13.42 · requests 2.32.3 ·
   beautifulsoup4 4.12.3. This is the deliberate house install; the tool
   itself was edited (F-1) so it can never install anything.
2. It runs exactly **one** lookup, on **+1 202-555-0100** — the fictional
   555-01xx range. No real person's number is involved, on the script's
   face and in fact.
3. Together we grade the output line by line (right / wrong / filler) into
   FIXTURES-4.md. Expected: US / Washington DC region right; carrier blank
   or unknown — which is *correct* for a fictional number.

That grade — not this packet — decides what the house trusts the check for.

## What you will NOT be asked to try

- No lookup on any real number — not yours, not a seller's, not a test on
  a friend. The fence holds until the fixture is graded and you rule
  otherwise.
- No Neutrino signup, no API key, nothing that costs money. $0 throughout.