The Last SaaS

The assistant is the interface. The Last SaaS is a server that holds records and files, tracks who is on the team and what each person can see, sends notifications, and logs the changes. It does not provide a user interface on its own; an assistant — Claude, ChatGPT, or any MCP client — connects over MCP and operates it.

demo.mp4

Most SaaS is built from the same parts: data, files, users, permissions, and notifications, with a user interface on top. That interface is a large part of what the subscription pays for, and it is work a model does well, so this server keeps the parts underneath. The assistant handles setup from a description of what's needed — gear tracking today, a client base tomorrow — and later changes, like a new field or a different rule, the same way.

What's in the box

• Records. Structured lists of anything from gear to invoices. Organizations own collections with dynamic schemas, and every record is validated against them.
• Files. Receipts and contracts, attached to the records they belong to (S3-compatible backends supported).
• People. Teammates join by invitation and work from the same records, each with their own assistant or none at all.
• Permissions. Rules apply down to the row and the field. The bookkeeper reads every invoice and cannot open payroll.
• Notifications. Due-date reminders and weekly digests, recurring or one-off, delivered by email.
• Audit logs. Changes are recorded with who made them and when, whether it was a person or an assistant.
• Agent access. An MCP endpoint with OAuth, plus a typed CLI that embeds an operator guide for agents.

Single TypeScript monorepo running on Bun. SQLite by default, PostgreSQL supported. The server compiles to one self-contained binary that also serves the CLI binaries for download.

Requirements

• Bun 1.2+

Quick start

bun install
cd packages/server
cp .env.example .env
DATABASE_URL=file:../data/lastsaas.db bunx prisma migrate deploy
bun run prisma:generate
bun run dev

The server listens on http://localhost:8787. Sign up at /auth/signup.

Connect an assistant

Assistants connect through the MCP endpoint at /v1/mcp, authorized via OAuth.

Claude (claude.ai or the desktop app): Settings → Connectors → Add custom connector. Paste your server's MCP address (https://your-server/v1/mcp), click Add, and approve the sign-in when Claude asks. New chats can use it right away; if you don't see it, enable it in the tools menu under the message box.

Claude Code:

claude mcp add --transport http lastsaas https://your-server/v1/mcp

Cursor and other MCP clients: add the same address wherever the client takes an MCP server URL, and approve the sign-in.

ChatGPT: in the desktop app, add a custom connector with the same address and approve the sign-in. On the web, custom MCP connectors currently require a Business, Enterprise, or Edu workspace, where an admin adds the connector under workspace settings. A listing in the ChatGPT apps directory is planned.

From there, setup is a conversation:

"Set up gear tracking for the studio. Anyone on the team can check equipment out, but purchase prices stay between us."

The CLI embeds an operator guide for agents (saas skills).

CLI

bun run build:client        # produces dist/saas
dist/saas login --server http://localhost:8787
dist/saas orgs create "My Org"
dist/saas collections create tasks --schema '{"title": {"type": "string"}}'
dist/saas records insert tasks --data '{"title": "First task"}'

A running server also serves prebuilt CLI binaries and an installer at /auth/install. See agent_docs/lastsaas-cli-commands.md for the full command reference.

Configuration

Everything is configured through environment variables; see agent_docs/config.md. Notable options: SMTP for email notifications, Google OAuth, S3-compatible file storage, and rate limiting.

PostgreSQL

Point DATABASE_URL at a postgres:// URL, apply the schema with bun run --cwd packages/server prisma:push:postgres, and build with bun run build:server:postgres. Details in agent_docs/config.md.

Production build

bun run build:server        # dist/saas-server, a single self-contained binary

The binary embeds the CLI builds for all supported platforms. Copy it to a server, set the environment variables, and run it.

Development

bun test                    # all packages
bun run typecheck
bun run lint

Implementation notes live in agent_docs/.