provider.star — Language & Standard Library Reference

vx uses a two-phase execution model: provider.star files run as pure Starlark (no I/O), returning descriptor dicts that the Rust runtime interprets for actual downloads, installs, and execution. Providers are defined declaratively — no Rust code required for new tools.

Companion docs

• Manifest-Driven Providers — Getting-started tutorial
• Starlark Providers – Advanced Guide — Multi-runtime, hooks, system integration

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Quick Start — Minimal Provider

load("@vx//stdlib:provider.star",
     "runtime_def", "github_permissions",
     "github_rust_provider")

name        = "mytool"
description = "My awesome tool"
ecosystem   = "devtools"

runtimes    = [runtime_def("mytool")]
permissions = github_permissions()

_p = github_rust_provider("owner", "repo",
    asset = "mytool-{vversion}-{triple}.{ext}")

fetch_versions   = _p["fetch_versions"]
download_url     = _p["download_url"]
install_layout   = _p["install_layout"]
store_root       = _p["store_root"]
get_execute_path = _p["get_execute_path"]
environment      = _p["environment"]

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Navigation

I need to…	Go here
Understand the execution model, file structure, top-level variables, provider functions, and the ctx object	Core API →
Look up stdlib functions (env, platform, layout, github, templates…)	Standard Library →
Learn install layout types, version fetching strategies, and hooks	Layouts & Strategies →
Review Starlark syntax rules, coding conventions, and the new provider checklist	Language & Conventions →

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See Also

• Core API Reference — Execution model, file structure, provider functions, ctx object
• Standard Library — All 14 stdlib modules (env, platform, layout, templates…)
• Layouts & Strategies — Install layouts, version fetching, hooks
• Language & Conventions — Starlark subset, coding style, new provider checklist
• Manifest-Driven Providers — Getting-started guide
• Starlark Providers – Advanced Guide — Multi-runtime providers, custom version sources
• vx.toml Reference — Project configuration
• vx.toml Syntax Guide — Patterns and recipes