NT (Agent Lang)

Language support for NT — a small declarative language (.nt files) for building AI agents. This extension gives .nt files syntax highlighting and full IntelliSense: go to definition, hover, completion, outline, and find references, across imported files.

• Docs: https://agent-lang.xyz
• CLI: @age.nt/nt
• Source: https://github.com/kartikmehta8/nt

Features

Syntax highlighting for import statements, declaration keywords (agent, subagent, sandbox, tool, mcp, skill, workflow, provider, config), entity names, field keys, env(...), block scalars, strings, and numbers.

IntelliSense (works within a file and across imported files):

• Go to Definition — F12 or Ctrl/Cmd-click a tool, selected MCP tool, subagent, sandbox, skill, workflow, or agent name to jump to its declaration, in the same file or another. Works on import ./path.nt paths too.
• Hover — see an entity's kind, description, and defining location. MCP servers show transport and selected MCP policies show approval. Built-in tools (fs_read, fs_write, fs_list, bash) show a description.
• Completion — inside tools: / subagents: / skills: lists and after sandbox:, suggests matching declarations, MCP servers, statically selected MCP tools, and built-in tools. At the start of a line, suggests declaration keywords.
• Outline & breadcrumbs — every declaration appears in the Outline view and the "Go to Symbol" (Ctrl/Cmd-Shift-O) picker.
• Find All References — right-click a name → Find All References.
• MCP snippets — stdio, bearer HTTP, and OAuth declarations. The extension stays offline and never connects to or executes an MCP server.

The index refreshes automatically as you edit, save, create, or delete .nt files, so definitions stay current across the whole workspace.

Install

In VS Code: open the Extensions view (Ctrl/Cmd-Shift-X), search for "NT (agent-lang.xyz)", and click Install. Or from a terminal:

code --install-extension KartikMehta.nt-agent-lang

In Cursor, Windsurf, or VSCodium: install from Open VSX (search "NT (Agent Lang)" in the Extensions view).

Any file ending in .nt is picked up automatically.

What is NT

NT lets you describe an AI agent — its model, tools, skills, sandbox, subagents, and typed input/output — in one clean .nt file, then run it with a single command:

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 you are given.
  input:
    clues: string
  output:
    age: number
    reason: string

Install the CLI with npm install -g @age.nt/nt and run nt run age. See the full guide at https://agent-lang.xyz.