plugin: Git subdirectory package fails to install from GitHub

Summary

A plugin configured from a GitHub monorepo subdirectory fails to install in the OpenCode beta server. OpenCode accepts the ::path: package syntax, but the NPM staging step attempts to read package.json from the repository root instead of the requested subdirectory.

Environment

• opencode version: 0.0.0-beta-19151
• OS: Darwin 25.6.0 (darwin arm64)
• Terminal: Ghostty, TERM=xterm-256color, COLORTERM=truecolor
• Shell: /bin/zsh
• Install/channel: beta
• Active plugins: Other configured local plugins load; the failing package is github:R44VC0RP/plugins#main::path:packages/ultra

Reproduction

1. Configure a plugin using a GitHub monorepo subdirectory:

   {
     "plugins": [
       "github:R44VC0RP/plugins#main::path:packages/ultra"
     ]
   }
   

2. Start or refresh the OpenCode server.

3. Alternatively, reproduce the package-manager failure directly:

   mkdir -p /tmp/opencode-plugin-test
   cd /tmp/opencode-plugin-test
   npm pack --dry-run --json \
     'github:R44VC0RP/plugins#main::path:packages/ultra'
   

Expected Behavior

OpenCode should install and load the package from packages/ultra, using:

packages/ultra/package.json

The plugin should then be imported and activated.

Actual Behavior

The install fails before the plugin module is imported:

NpmInstallFailedError:
Could not read package.json:
ENOENT: no such file or directory,
open .../.npm/_cacache/tmp/git-clone.../package.json

OpenCode reports the generic error:

Plugin failed to load

Additional Context

The server log entry for this failure was:

role=server
target=github:R44VC0RP/plugins#main::path:packages/ultra
ref=err_2d4d239b
cause=NpmInstallFailedError
cause detail=ENOENT reading .../.npm/_cacache/tmp/git-clone.../package.json

The referenced GitHub repository is public and contains:

packages/ultra/package.json
packages/ultra/index.ts

It does not contain a package.json at the repository root.

The failure is reproducible with both the GitHub shorthand and a full git+https URL. The NPM package argument parser recognises the ::path:packages/ultra suffix as a Git subdirectory, but the subsequent remote Git staging/read step still looks for the root package.json.

The OpenCode server itself is healthy, and the package dependency @opencode-ai/plugin@0.0.0-dev-19114 is available from NPM. No GitHub or NPM credentials are required for this public repository, and no credential-related error appears in the logs.

OpenCode's source contains a test for Git subdirectory installs using a local Git fixture in packages/core/test/npm.test.ts, suggesting that remote GitHub subdirectory handling is either incomplete or incompatible with the current NPM/pacote implementation.

A workaround is to use a local checkout of the subdirectory or publish the plugin as a standalone registry package.