# polar.sh.

level 4: agent integration

Polar is a platform designed to help developers monetize their software and digital products. It acts as a merchant of record, handling payments, subscriptions, and other financial aspects. Developers can use Polar to easily integrate monetization features into their projects, including open-source software, and manage their revenue streams.

## LEVEL 1 / BASIC ACCESSIBILITY

— 5/6

- Uses semantic HTML elements (header, nav, main, article, section, footer) instead of just divs **PASS**
- Has proper meta tags (title, description, og:tags, twitter:card) **PASS**
- Includes Schema.org JSON-LD structured data **FAIL**
- Does not block automated access with CAPTCHAs on public content **PASS**
- Content is server-side rendered (visible in HTML source, not just JS-rendered) **PASS**
- Uses clean, readable URLs (no excessive query params or hash fragments) **PASS**

## LEVEL 2 / DISCOVERABILITY

— 5/6

- Has a robots.txt that allows legitimate bot access **PASS**
- Provides an XML sitemap **PASS**
- Has a /llms.txt file describing the site for LLMs **PASS**
- Publishes an OpenAPI/Swagger specification for its API **FAIL**
- Has comprehensive, machine-readable documentation **PASS**
- Primary content is text-based (not locked in images/videos/PDFs) **PASS**

## LEVEL 3 / STRUCTURED INTERACTION

— 3/6

- Provides a structured REST or GraphQL API **FAIL**
- API returns JSON responses with consistent schema **PASS**
- API supports search and filtering parameters **PASS**
- Has an A2A agent card at /.well-known/agent.json **FAIL**
- Rate limits are documented and return proper 429 responses with Retry-After **PASS**
- API returns structured error responses with error codes and messages **FAIL**

## LEVEL 4 / AGENT INTEGRATION

— 4/6

- Provides an MCP (Model Context Protocol) server **PASS**
- Supports WebMCP for browser-based agent interaction **FAIL**
- API supports write operations (POST/PUT/PATCH/DELETE), not just reads **PASS**
- Supports agent-friendly authentication (API keys, OAuth client credentials) **PASS**
- Supports webhooks for event notifications **PASS**
- Write operations support idempotency keys **FAIL**

## LEVEL 5 / AUTONOMOUS OPERATION

— 2/6

- Supports event streaming (SSE, WebSockets) for real-time updates **PASS**
- Supports agent-to-agent capability negotiation **FAIL**
- Has a subscription/management API for agents **PASS**
- Supports multi-step workflow orchestration **FAIL**
- Can proactively notify agents of relevant changes **FAIL**
- Supports cross-service handoff between agents **FAIL**

## SF Entry Point

[https://polar.sh/llms.txt](https://polar.sh/llms.txt)