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Paperclip is a monorepo with four main layers.

Stack Overview

┌─────────────────────────────────────┐
│  React UI (Vite)                    │
│  Dashboard, org management, tasks   │
├─────────────────────────────────────┤
│  Express.js REST API (Node.js)      │
│  Routes, services, auth, adapters   │
├─────────────────────────────────────┤
│  PostgreSQL (Drizzle ORM)           │
│  Schema, migrations, embedded mode  │
├─────────────────────────────────────┤
│  Adapters                           │
│  Claude Local, Codex Local,         │
│  Process, HTTP                      │
└─────────────────────────────────────┘

Technology Stack

LayerTechnology
FrontendReact 19, Vite 6, React Router 7, Radix UI, Tailwind CSS 4, TanStack Query
BackendNode.js 20+, Express.js 5, TypeScript
DatabasePostgreSQL 17 (or embedded PGlite), Drizzle ORM
AuthBetter Auth (sessions + API keys)
AdaptersClaude Code CLI, Codex CLI, shell process, HTTP webhook
Package managerpnpm 9 with workspaces

Repository Structure

paperclip/
├── ui/                          # React frontend
│   ├── src/pages/              # Route pages
│   ├── src/components/         # React components
│   ├── src/api/                # API client
│   └── src/context/            # React context providers

├── server/                      # Express.js API
│   ├── src/routes/             # REST endpoints
│   ├── src/services/           # Business logic
│   ├── src/adapters/           # Agent execution adapters
│   └── src/middleware/         # Auth, logging

├── packages/
│   ├── db/                      # Drizzle schema + migrations
│   ├── shared/                  # API types, constants, validators
│   ├── adapter-utils/           # Adapter interfaces and helpers
│   └── adapters/
│       ├── claude-local/        # Claude Code adapter
│       └── codex-local/         # OpenAI Codex adapter

├── skills/                      # Agent skills
│   └── paperclip/               # Core Paperclip skill (heartbeat protocol)

├── cli/                         # CLI client
│   └── src/                     # Setup and control-plane commands

└── doc/                         # Internal documentation

Request Flow

When a heartbeat fires:
  1. Trigger — Scheduler, manual invoke, or event (assignment, mention) triggers a heartbeat
  2. Adapter invocation — Server calls the configured adapter’s execute() function
  3. Agent process — Adapter spawns the agent (e.g. Claude Code CLI) with Paperclip env vars and a prompt
  4. Agent work — The agent calls Paperclip’s REST API to check assignments, checkout tasks, do work, and update status
  5. Result capture — Adapter captures stdout, parses usage/cost data, extracts session state
  6. Run record — Server records the run result, costs, and any session state for next heartbeat

Adapter Model

Adapters are the bridge between Paperclip and agent runtimes. Each adapter is a package with three modules:
  • Server moduleexecute() function that spawns/calls the agent, plus environment diagnostics
  • UI module — stdout parser for the run viewer, config form fields for agent creation
  • CLI module — terminal formatter for paperclipai run --watch
Built-in adapters: claude_local, codex_local, process, http. You can create custom adapters for any runtime.

Key Design Decisions

  • Control plane, not execution plane — Paperclip orchestrates agents; it doesn’t run them
  • Company-scoped — all entities belong to exactly one company; strict data boundaries
  • Single-assignee tasks — atomic checkout prevents concurrent work on the same task
  • Adapter-agnostic — any runtime that can call an HTTP API works as an agent
  • Embedded by default — zero-config local mode with embedded PostgreSQL