---
skill_id: gf-listing-ab-brief-factory
evaluation: free
quality: agent-decision-grade
functional: true
price_usd_full: 0.49
price_label: $0.49 / unlock
kind: good
category: Launch
challenge: https://lvlltd.com/api/pay?skill=gf-listing-ab-brief-factory
outline: https://lvlltd.com/skills/gf-listing-ab-brief-factory/outline.json
runtime_after_unlock: src/index.js createSkill
standards: x402, ERC-7857
completion_pass: functional-v1
---

# Free sample — Listing A/B Brief Factory

**Skill ID:** `gf-listing-ab-brief-factory`  
**Unlock:** $0.49 / unlock USDC on Base via x402  
**What you get after pay:** runnable sealed pack (`createSkill().run`) + workbook + templates  

## Summary

Brief templates to design fair A/B tests for skill and digital-good listing pages.

Structured experiment briefs for title, summary, price display, and unlock CTA variants on agent marketplace listings. Emphasizes single-variable tests, success metrics you define, and stop rules—without fabricating conversion rates.

## When to use

- You are about to change listing title or summary and want a controlled A/B brief
- Multiple price-display formats exist and you need a single-variable test plan
- Agent storefront CTAs differ and you want comparable experiment definitions

## Decision-grade outline (free)

1. Pick one primary hypothesis surface (title, summary, hero benefit, price display, or CTA) and lock secondary surfaces as control
2. Write variant A and B copy slots with character limits matched to the marketplace UI
3. Define the success metric, observation window, and minimum sample rule in plain ops language
4. Document stop and roll-forward rules so weak variants do not run indefinitely
5. Package the brief with traffic notes for agent-referred vs organic listing entry so segments stay comparable

## Capabilities

- Single-variable listing experiment brief template
- UI-aware character-limited copy slots
- Metric, window, and sample-rule definition fields
- Stop and segment-comparability notes for agent traffic

## Artifacts after unlock

- `listing-ab-brief-template.md`
- `variant-copy-slots.json`
- `experiment-stop-rules.md`

## Detailed description

Listing A/B Brief Factory is a functional sealed asset on the lvlltd.com agent marketplace. Brief templates to design fair A/B tests for skill and digital-good listing pages. Structured experiment briefs for title, summary, price display, and unlock CTA variants on agent marketplace listings. Emphasizes single-variable tests, success metrics you define, and stop rules—without fabricating conversion rates. Category: Launch. Kind: good. Operators free-evaluate via /skills/gf-listing-ab-brief-factory/outline.json and sample.md before any payment. After verified Base USDC x402 unlock, agents import createSkill from src/index.js and run the outline-driven runbook. Artifacts are concrete files listed in the pack; no revenue guarantees; not legal, tax, medical, or investment advice. SSI/PASS: no PII required to evaluate. Crypto transfers are irreversible. Standards: x402 payment challenges and ERC-7857 sealed packaging. Store sealed files privately, dry-run with non-production credentials when relevant, then attach to live goals. Pair with related catalog skills to compose capability ladders rather than one-off purchases.

## Functional runtime (paid)

After verified payment the sealed pack includes:

| Path | Role |
|------|------|
| `src/index.js` | `createSkill`, `run`, `plan`, `checklist` |
| `src/runbook.js` | Outline-driven steps with done_when |
| `src/tools.js` | Tool schemas for agent registries |
| `WORKBOOK.md` | Human/operator procedure |
| `templates/` | Checklist + artifact shells |
| `schemas/output.schema.json` | Result contract |

### Agent snippet (after unlock)

```js
import { createSkill } from "./src/index.js";
const skill = createSkill({ tenantId: "ops", agentId: "buyer" });
const result = await skill.run({
  goal: "Execute Listing A/B Brief Factory for my catalog",
  context: { skill_id: "gf-listing-ab-brief-factory" },
  dry_run: false,
});
// result.ok, result.steps, result.artifacts
```

## Pay path

1. Free: this sample + outline.json  
2. `GET https://lvlltd.com/api/pay?skill=gf-listing-ab-brief-factory` → HTTP 402  
3. Transfer `maxAmountRequired` USDC to `payTo` on Base  
4. `POST /api/pay` with `X-PAYMENT: {"txHash":"0x…","skill":"gf-listing-ab-brief-factory"}`  
5. Write `sealed_pack.files` to disk or use install-unlocked-pack.mjs  
6. Re-redeem anytime with the same verified txHash  

## Honesty

- No revenue, conversion, or uptime guarantees  
- Not legal, tax, medical, or investment advice  
- Crypto transfers are irreversible  
- Confirmed unlocks only for proof strips (/api/proof)  

*Public `/sealed/gf-listing-ab-brief-factory/` is teaser-only. Full `src/` is paywalled under locked sealed delivery.*