Last week I asked an AI agent to prototype three small web apps. It spun up three Vite projects, configured Tailwind, and ran test builds.

Thirty minutes in, my laptop showed a low disk space alert.

The agent had downloaded three separate copies of React, Vite, TypeScript, and ESLint. Each project had its own 600 MB node_modules directory. If you run multiple subagents or test throwaway ideas during the week, you lose dozens of gigabytes to duplicate JavaScript packages.

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The default to npm

Language models learn from millions of public repositories, tutorials, and issue threads that tell people to run npm install. When an agent needs a library, it types npm i.

You can write "use pnpm" in your prompt. It works for a few messages. Then the context window rolls over, a subagent spawns without prompt history, or the model runs a one-off shell check and goes back to npm.

Hard links versus duplicate folders

Standard npm isolates each project by copying every package into the local node_modules folder. Five projects using TypeScript put five full copies of TypeScript on disk.

pnpm writes packages once to a global store at ~/.local/share/pnpm/store. Projects link to those files using filesystem hard links. Ten projects using the same library version share one physical copy on disk.

Storage Architecture: npm vs always-pnpm

Intercepting terminal commands

I built always-pnpm to stop fighting prompt instructions.

The tool hooks directly into the agent runtime. When Antigravity, Claude Code, OpenCode, or Codex runs a shell command starting with npm or npx, always-pnpm parses the string and rewrites it to pnpm in under three milliseconds.

Deterministic Hook Lifecycle Flow

Agent proposal:

npm install express lodash

Command executed in your shell:

pnpm add express lodash

The model gets its packages, the project runs, and your drive stores those files once.

Command mapping

The parser translates common flags and subcommands:

  • npm i -D <pkgs> becomes pnpm add -D <pkgs>
  • npx <cmd> becomes pnpm dlx <cmd>
  • npm ci becomes pnpm install --frozen-lockfile
  • npm cache clean --force becomes pnpm store prune
  • npm init <template> becomes pnpm create <template>

Commands that only mention npm inside strings or arguments, like git commit -m "fix npm bug" or grep -r "npm" ., stay untouched.

Setup

Run the installer to detect your agent runtimes and configure their native hooks:

curl -fsSL https://raw.githubusercontent.com/youxufkhan/always-pnpm/main/scripts/install.sh | bash

You can also target specific agents directly:

# Target Claude Code ./scripts/install.sh --claude # Target Antigravity ./scripts/install.sh --antigravity # Target OpenCode or Codex ./scripts/install.sh --opencode ./scripts/install.sh --codex

The repository and test suite are on GitHub: github.com/youxufkhan/always-pnpm.