# Keystone

> Probe-verified (tier 2 of 3). Last checked 2026-08-23. 5 of 5 capability checks passed.

- host: key-stone.app
- url: https://key-stone.app/
- category: shopify apps
- type: saas
- language: en

## Probe-verified · tier 2 of 3

Probed live on 2026-08-23 against rubric v1. 5 of 5 checks passed.

- PASS — Markdown negotiation
- PASS — Markdown twin at a predictable URL
- PASS — llms.txt
- PASS — API catalog
- PASS — MCP server answers

## Unverified actions

Read from the page's own content, with the wording each was drawn from. Inference is kept separate from tested facts; an agent completing the action is tier 3.

- **contact** — "use the contact form on https://key-stone.app/" → `https://key-stone.app/`
- **query_api** — "GET https://key-stone.app/api/changelog?app=<slug>&locale=<code>&limit=<n>" → `https://key-stone.app/api/changelog`
- **register** — "POST https://key-stone.app/api/agent/register — agent self-registration" → `https://key-stone.app/api/agent/register`

## Summary

Keystone offers three Shopify apps for loyalty and referrals, product options and variants, and AI-powered SEO optimization with free plans and trials.

## Context

4 sites in this index share the category "shopify apps"; 4 are transactional.

## How we grade

- tier 1 — **Declared**: The site says agents are welcome in its robots.txt. A permission, not a capability.
- tier 2 — **Probe-verified** (this site): We fetched the site and tested each signal ourselves. Dated, repeatable, re-checked on a schedule.
- tier 3 — **Behaviourally verified**: An agent completed the action end to end — booked, bought, submitted — and it worked.

## About this record

Known-Good probes sites live and publishes what was tested and when.
Method: https://knowngood.sh/about.md · Rubric: https://knowngood.sh/benchmark