---
skill_id: gf-grow-proof-strip-builder
evaluation: free
quality: agent-decision-grade
functional: true
price_usd_full: 2.99
price_label: $2.99 / unlock
kind: good
category: Launch
challenge: https://lvlltd.com/api/pay?skill=gf-grow-proof-strip-builder
outline: https://lvlltd.com/skills/gf-grow-proof-strip-builder/outline.json
runtime_after_unlock: src/index.js createSkill
standards: x402, ERC-7857
completion_pass: functional-v1
---

# Free sample — Proof-Strip Builder for Skill Pages

**Skill ID:** `gf-grow-proof-strip-builder`  
**Unlock:** $2.99 / unlock USDC on Base via x402  
**What you get after pay:** runnable sealed pack (`createSkill().run`) + workbook + templates  

## Summary

Build honest on-page proof strips: free outline, sample, x402 challenge, network, and public proof endpoint—without fake social proof or revenue claims.

Launch UI/content pack for proof strips on skill and landing pages: field order, honest empty states, and agent-readable microdata. Free outline; full builder via x402 Base USDC. No conversion guarantees.

## When to use

- Skill pages lack a clear free-vs-paid proof strip above the fold
- Need consistent proof components across a batch of new goods-factory SKUs
- Replacing vanity testimonials with verifiable pay-path and outline links

## Decision-grade outline (free)

1. Define strip fields in order: skill id, free outline URL, sample URL, price_label, network/asset, challenge URL, public proof URL
2. Write empty-state copy for zero unlocks that still looks trustworthy (no fake counters)
3. Specify agent-readable attributes or JSON-LD-ish notes so buyers can parse the strip
4. Add a “last verified” timestamp field operators refresh after deploy smoke tests
5. Produce embed snippets (markdown + minimal HTML) and a QA script checklist for broken links

## Capabilities

- Ordered proof-strip field schema
- Honest zero-unlock empty states
- Markdown/HTML embed snippets
- Post-deploy link verification checklist

## Artifacts after unlock

- `proof-strip-schema.json`
- `proof-strip-embeds.md`
- `proof-strip-qa-checklist.md`

## Detailed description

Proof-Strip Builder for Skill Pages is a functional sealed asset on the lvlltd.com agent marketplace. Build honest on-page proof strips: free outline, sample, x402 challenge, network, and public proof endpoint—without fake social proof or revenue claims. Launch UI/content pack for proof strips on skill and landing pages: field order, honest empty states, and agent-readable microdata. Free outline; full builder via x402 Base USDC. No conversion guarantees. Category: Launch. Kind: good. Operators free-evaluate via /skills/gf-grow-proof-strip-builder/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 Proof-Strip Builder for Skill Pages for my catalog",
  context: { skill_id: "gf-grow-proof-strip-builder" },
  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-grow-proof-strip-builder` → HTTP 402  
3. Transfer `maxAmountRequired` USDC to `payTo` on Base  
4. `POST /api/pay` with `X-PAYMENT: {"txHash":"0x…","skill":"gf-grow-proof-strip-builder"}`  
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-grow-proof-strip-builder/` is teaser-only. Full `src/` is paywalled under locked sealed delivery.*