NT is a small declarative language (.nt files) and a runtime engine. Describe your models, agents, subagents, sandboxes, tools, MCP servers, skills and workflows in one clean file, and one command brings the whole ecosystem up.

npm install -g @age.nt/nt        # the nt CLI — needs Node >= 22.18
export ANTHROPIC_API_KEY=sk-ant-...

Editor support: install the NT extension from the VS Code Marketplace or Open VSX (Cursor, Windsurf, VSCodium) for highlighting and IntelliSense.

NT is not dependency-free. The engine exact-pins the official MCP client for protocol support, Ajv for JSON Schema validation, and Undici for guarded HTTP transport behavior. Your package manager installs them with the CLI.

mkdir my-agent && cd my-agent
nt setup            # writes age.nt + config.nt, then validates them
nt run age -m "bought the first iPhone at 22"

nt setup --template full writes a bigger starter instead: the same agent wired to a sandbox, a shell tool, a zero-dependency local MCP echo server, a skill, a subagent, and a workflow. Existing files are never overwritten unless you pass --force; the CLI prints the MCP trust and diagnostic commands needed before the first run.

A complete agent in one file:

# age.nt
agent age
  description: Guesses a person's age from clues.
  model: anthropic/claude-sonnet-5
  instructions: |
    Guess the person's most likely age from the clues.
  input:
    clues: string
  output:
    age: number
    reason: string

Run it:

nt run age -i '{"clues":"bought the first iPhone at 22"}'
# { "age": 39, "reason": "The first iPhone came out in 2007." }

Full guides and reference live in the docs (apps/docs, run with pnpm docs:dev):

• Get started — introduction, installation, your first agent
• Guides — agents, tools, MCP servers, skills, sandboxes, subagents, workflows, providers, the audit log
• Reference — the .nt syntax, the full API reference, and CLI commands

A pnpm monorepo whose published engine and CLI are compiled with TypeScript. Development tests use Node's type stripping; pnpm build produces package artifacts.

packages/engine     @age.nt/engine — the language + runtime
packages/cli        @age.nt/nt — the nt command
packages/vscode-nt  the VS Code extension
apps/docs           the documentation site
example/            the wired age example

pnpm install         # link @age.nt/engine into the nt CLI
pnpm nt:setup        # scaffold the full starter into .nt-demo/ (gitignored)
pnpm nt:validate     # validate the example ecosystem
pnpm test            # engine + CLI tests
pnpm typecheck
pnpm lint
pnpm format

Coding conventions live in CLAUDE.md. Contributions follow Conventional Commits.