PostMind AI is a content-intelligence platform that compresses the blank-page-to-publish loop. A 6-agent Mastra pipeline (Persona Analyst → Trend Research → Content Generator) produces 5–7 personalized briefs per request. A Writing-DNA engine extracts 15+ quantitative voice metrics from a user's existing posts at zero LLM cost, with 100% reproducibility, and an adaptive feedback loop weights 6 implicit behavioral signals on a 14-day recency decay. The stack is a Turborepo monorepo with 3 packages, 40+ shared TypeScript interfaces, 11 RESTful API modules with Swagger, 3-tier rate limiting, and 13 MongoDB collections. The Next.js 14 frontend ships 10+ pages including a real-time chat and an AI co-writing editor.

• →Generate on-voice content that doesn't read as generic LLM output
• →Keep cost per request bounded while staying personalized
• →Ship a production monorepo with safe rollouts

• →Writing-DNA engine extracting 15+ voice metrics at zero LLM cost
• →6-agent sequential pipeline with implicit behavioral signals + recency decay
• →Docker image trimmed 2.66 GB → 338 MB (87%) via 4-stage builds; SHA-tagged versioning and health-check gated CI/CD