This is the public documentation for KOS Agência (kosagencia.com): how to discover the API, authenticate private routes, submit a lead, and read the OpenAPI contract. The product name is KOS Agência; the domain is kosagencia.com. There is no public MCP server and no documented outbound webhooks for third parties — lead delivery webhooks stay inside Grupo KOS.
Use POST /api/contact (operationId submitContactLead) when someone wants to talk about branding, brand management, positioning, or integrated production. Required fields: firstName, lastName, email, phone. Do not invent clients, awards, or targets. For agency facts, read /llms.txt.
Lead capture is public (reCAPTCHA, honeypot, and rate limit). Editorial API GET/POST /api/blog/posts and GET/DELETE /api/blog/posts/{slug} require Authorization: Bearer with BLOG_INGEST_SECRET — that is KOS’s file-based CMS, not an open product. GET /api/contact may require CONTACT_API_SECRET when configured. API errors always return JSON with error, errorCode, and hint.
llms.txt says when to use KOS Agência. llms-full.txt expands the context. HTML pages support content negotiation: send Accept: text/markdown to receive Markdown from the same URL, with Vary: Accept. 404s also return recovery Markdown pointing at the sitemap and docs.