L1

clearbit.com.

level 1: basic accessibility

Clearbit is a data enrichment platform that provides B2B marketing and sales teams with tools to enhance customer data. It enriches existing customer records with additional information, such as company details and contact information. This service can be used to improve lead scoring, personalize marketing campaigns, and identify buying intent from website visitors.
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 PASS
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
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 FAIL
Publishes an OpenAPI/Swagger specification for its API FAIL
Has comprehensive, machine-readable documentation FAIL
Primary content is text-based (not locked in images/videos/PDFs) PASS
Provides a structured REST or GraphQL API FAIL
API returns JSON responses with consistent schema FAIL
API supports search and filtering parameters FAIL
Has an A2A agent card at /.well-known/agent.json FAIL
Rate limits are documented and return proper 429 responses with Retry-After FAIL
API returns structured error responses with error codes and messages FAIL
Provides an MCP (Model Context Protocol) server FAIL
Supports WebMCP for browser-based agent interaction FAIL
API supports write operations (POST/PUT/PATCH/DELETE), not just reads FAIL
Supports agent-friendly authentication (API keys, OAuth client credentials) FAIL
Supports webhooks for event notifications FAIL
Write operations support idempotency keys FAIL
Supports event streaming (SSE, WebSockets) for real-time updates PASS
Supports agent-to-agent capability negotiation FAIL
Has a subscription/management API for agents FAIL
Supports multi-step workflow orchestration FAIL
Can proactively notify agents of relevant changes FAIL
Supports cross-service handoff between agents FAIL