[Bug] Installer's PATH fallback tells you to run npm bin -g, removed in npm 9

[vaporwavie]

Affected area

Installation or updates

What happened?

The installer finished, could not find prime-agent on PATH, and printed this:

The prime-agent command was installed, but it is not on your PATH yet.
Check npm's global bin directory with:

  npm bin -g

Then add that directory to your shell PATH.

npm bin was removed in npm 9.0.0 (October 2022, npm/cli#5696), so on any currently supported npm the suggested command fails:

$ npm bin -g
Unknown command: "bin"

That leaves the recovery path a dead end, which is the one moment the user has nothing else to go on.

The PATH check itself was correct in my case, so this is only about the advice text.

Steps to reproduce

1. Use a setup where npm's global bin directory is not on PATH in a plain sh. Mine is fnm lazy-loaded from .zshrc through shell functions, so curl | sh never sees fnm's bin dir. Any lazy-loaded version manager or a custom prefix= in ~/.npmrc will do it.
2. Run curl -fsSL https://app.primeintellect.ai/prime-agent/install.sh | sh.
3. Let the install finish. It prints the "not on your PATH yet" block above.
4. Run npm bin -g as instructed.
5. npm answers Unknown command: "bin".

Expected behavior

The installer should print a command that works on npm 9 and newer, or better, print the resolved directory directly since the script can already compute it.

Modern equivalent:

npm prefix -g   # global bin is $(npm prefix -g)/bin

Prime Agent version

0.8.0

Environment

Fedora 43 (Linux 7.1.8-100.fc43.x86_64), zsh, kitty 0.48.2

Additional context

The installer run under /bin/sh (bash 5.x in POSIX mode). npm 11.19.0 on Node v26.7.0 ran the install, prefix set to an fnm-managed Node v24.13.1 via npmrc.

Working around it was a one-line symlink once I knew where npm had put the binary, which npm prefix -g tells you and npm bin -g no longer does.

[awhite0030]

Investigated this report and produced a candidate fix, validated on a fork of this repository.

Root cause, fix and validation from the working notes:

Root cause: The installer fallback message tells users to run npm bin -g when prime-agent is not on PATH, but npm bin was removed in npm v9.
Fix: Replaced npm bin -g with a computed directory path $(npm prefix -g 2>/dev/null)/bin using the modern npm prefix command.
Validation: Ran cd packages/coding-agent && npx tsx ../../node_modules/vitest/dist/cli.js --run test/suite/regressions/1707-npm-prefix.test.ts and npm run check. Both passed.
Upstream discussion: #1707

Diff: awhite0030/prime-agent@main...fix-installer-npm-path-10377379710657237341
Full pull request: awhite0030#1

The change passes npm run check and the focused regression tests against current main. If a fix for this is still wanted, I can open a pull request.