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