Nexa Language Extension for VSCode

Syntax highlighting and one-click build/run commands for the Nexa Agent-Native Programming Language.

Features

Syntax Highlighting

Full support for Nexa v2.2.1 syntax:

• Declarations: agent, tool, flow, protocol, test, type, struct, enum, trait, impl, fn, job, server, db, auth, kv
• Harness six-tuple (v2.0+): autoloop, with_context, try_agent, catch_correction, snapshot, restore, fork, merge, verify, satisfies, reflect, unharnessed, context_policy, context
• Lifecycle hooks: before_step, after_step, on_error, before_tool, after_tool
• Actor model: spawn, pass, await, receive, channel, parallel, race
• Control flow: if, else, for, each, in, while, match, intent, semantic_if, loop, until
• DAG operators: >>, |>>, ||, &>>, &&, ??, |>
• Error propagation (v1.2+): ?, otherwise, defer
• Pattern matching (v1.3.7+): let, destructuring patterns
• ADT (v1.3+): struct, enum, trait, impl, Option, Result
• Config (v2.1+): use config, include
• @tool annotation (v2.0+): zero-cost tool binding
• Secrets (.nxs files): config blocks, BASE_URL, API_KEY

One-Click Commands

Command	Shortcut	Description
Nexa: Build	Ctrl+Shift+B	Compile .nx to Python (nexa build)
Nexa: Run	F5	Build and execute (nexa run)
Nexa: Harness Check	—	Run Harness Validator (nexa harness-check --harness <mode>)
Nexa: Validate	—	Type-check and lint (nexa validate)

Commands are accessible via:

• Command Palette (Ctrl+Shift+P → "Nexa: ...")
• Editor title bar buttons (Build ▷, Run ▶)
• Right-click context menu
• Keyboard shortcuts

Output is streamed to the Nexa Output Channel.

Installation

From VSIX

code --install-extension nexa-lang-0.1.0.vsix

Or in VSCode: Extensions panel → ⋯ → "Install from VSIX..." → select nexa-lang-0.1.0.vsix.

Prerequisites

The extension requires the nexa CLI to be installed and on your PATH:

pip install nexa-lang

If nexa is not on PATH, set the full path in VSCode Settings → nexa.executable.

Configuration

Setting	Default	Description
nexa.executable	nexa	Path to the nexa CLI (use python -m src.cli if running from source)
nexa.harnessMode	warn	Default Harness validation mode: off, warn, or strict
nexa.proxyUrl	""	HTTPS proxy URL for agents needing network access (e.g. http://127.0.0.1:7897)

Usage

1. Open a .nx file in VSCode
2. Press Ctrl+Shift+B to build, or F5 to run
3. View output in the Nexa Output Channel (View → Output → select "Nexa")

Example

agent Researcher uses web_search {
    model: "deepseek/deepseek-chat",
    prompt: "Research the topic."
}

flow main {
    result = "quantum computing" >> Researcher;
    print(result);
}

Press F5 → extension runs nexa run main.nx → output streamed to channel.

File Types

Extension	Language ID	Description
.nx	nexa	Nexa source files
.nxlib	nexa	Nexa library files
.nxs	nexa-secrets	Nexa secrets/config files

License

AGPL-3.0 — see LICENSE.