Architecture

Architecture

AssessmentOS is a TypeScript monorepo (pnpm + Turborepo).

Packages and apps

Package / app	Role
@assessment-os/core	Session state machine, timers, plugin registry, shared types
@assessment-os/richtext	TipTap rich prompts (quotes, code blocks, images)
@assessment-os/db	Postgres schema (Drizzle) + migrations
@assessment-os/sdk	Typed HTTP client for the API
@assessment-os/ui	Candidate assessment shell (nav + timers)
@assessment-os/question-mcq	MCQ plugin + React builder/renderer/reviewer
@assessment-os/question-coding	Coding + Monaco; I/O + unit via Judge0/mock
@assessment-os/question-sql	SQLite SQL plugin
@assessment-os/question-text	Short-answer plugin
@assessment-os/question-*	Stubs (video, design, file)
@assessment-os/runner	Judge0 client + mock runner + sql.js
@assessment-os/api	Fastify API (cookie + Bearer auth, orchestration)
@assessment-os/web	Next.js admin + candidate UI
@assessment-os/mcp	Recruiter MCP server for agents

Request flow

Admin / Candidate (web)
        │
        ▼
   @assessment-os/sdk  ──HTTP──►  API (Fastify)
                                      │
                    ┌─────────────────┼─────────────────┐
                    ▼                 ▼                 ▼
                 Postgres         Runner            Mailer /
                 (Drizzle)     (mock|Judge0)       Turnstile

• Recruiter admin uses cookie session (credentials: include).
• MCP / agents use Bearer API tokens (aos_…).
• Candidate flows use invite token URLs (/t/:token) plus OTP; no recruiter session.

Session mutations go through @assessment-os/core helpers — the API must not invent a parallel state machine. See Contributing.