[macOS] STDIO extensions fail: "chown: command not found" and "env: node: No such file or directory" in Hermit bootstrap

[pilpat]

Describe the bug

STDIO-type extensions that use npx mcp-remote fail to initialize on macOS (Apple Silicon) due to two issues in the Hermit bootstrap and Node.js PATH resolution:

1. chown: command not found (exit 127) — The Hermit install script (install-<sha>.sh) calls chown without a full path. On macOS, chown lives in /usr/sbin/, which is not included in the PATH inherited by GUI-launched apps (Electron). The bootstrap script at ~/.config/goose/mcp-hermit/bin/hermit does not add /usr/sbin to PATH before invoking the install script.

2. env: node: No such file or directory — Even after Hermit successfully bootstraps and installs Node.js, the npx shim fails because node is not in PATH at runtime. Root causes:

   • The generated hermit.hcl contains a hardcoded env.PATH that overrides Hermit's automatic PATH management, preventing it from adding the Node.js binary directory.
   • Hermit sets NPM_CONFIG_PREFIX to ~/.config/goose/mcp-hermit/.hermit/node/, and adds .hermit/node/bin/ to PATH — but this directory does not contain actual node/npx/npm binaries. The real binaries are in ~/.config/goose/mcp-hermit/cache/pkg/node-<version>/bin/.

Note: The node-setup-common.sh script in Goose.app/Contents/Resources/bin/ only runs hermit install node and does NOT activate the Hermit environment on macOS (activation is Linux-only per the conditional on line ~113). This means npx is invoked via the Hermit shim (bin/npx → symlink to bin/hermit), which relies on hermit exec to set up the environment — but the hardcoded PATH in hermit.hcl breaks this mechanism.

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To Reproduce

1. Install Goose Desktop on macOS (Apple Silicon)
2. Add a new STDIO extension with command: npx mcp-remote https://block.gitmcp.io/goose/
3. Save and observe "Failed to add extension" error
4. Check /tmp/mcp.log for detailed error output

First run shows:

Bootstrapping .../cache/pkg/hermit@stable/hermit from https://github.com/cashapp/hermit/releases/download/stable
/var/folders/.../tmp.XXXXXXXX: line 67: chown: command not found
An error occurred. Exiting with status 127.

After manually fixing the chown PATH issue, subsequent runs show:

Node setup (common) completed successfully.
Executing 'npx' command with arguments: mcp-remote https://block.gitmcp.io/goose/
env: node: No such file or directory
Failed to execute 'npx' with arguments: mcp-remote https://block.gitmcp.io/goose/

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Expected behavior

The extension should initialize successfully. Hermit bootstrap should complete without chown errors, and npx should be able to find node in PATH when executing MCP extensions.

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Screenshots

(Extension panel showing 6/7 loaded, "Goose Docs" failed with red indicator)

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Please provide the following information

• OS & Arch: macOS 25.3.0 aarch64 (Apple Silicon)
• Interface: UI
• Version: 1.28.0
• Extensions enabled: code_execution, tom, summon, todo, Extension Manager, analyze, goose Docs
• Provider & Model: openrouter – moonshotai/kimi-k2-thinking

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Additional context

Environment details

• The GUI app's PATH (via launchctl getenv PATH) was: /opt/homebrew/bin:/usr/local/bin:/usr/bin:/bin — missing /usr/sbin and /sbin
• macOS system /etc/paths correctly includes /usr/sbin and /sbin, but these are not inherited by Electron apps in all configurations

Workarounds applied

Three manual fixes were required to get the extension working:

Fix 1 — Added /usr/sbin and /sbin to PATH in ~/.config/goose/mcp-hermit/bin/hermit:

# After "set -eo pipefail", added:
export PATH="/usr/sbin:/sbin:${PATH}"

Fix 2 — Removed hardcoded PATH override from ~/.config/goose/mcp-hermit/bin/hermit.hcl:

# Changed from:
env = {
  "PATH": "/usr/local/bin:/usr/bin:/bin:/usr/sbin:/sbin",
}
# To:
env = {
}

Fix 3 — Created symlinks in ~/.config/goose/mcp-hermit/.hermit/node/bin/ pointing to the actual Node.js binaries in ~/.config/goose/mcp-hermit/cache/pkg/node-<version>/bin/:

ln -sf .../cache/pkg/node-24.14.0/bin/node  .../hermit/node/bin/node
ln -sf .../cache/pkg/node-24.14.0/bin/npm   .../hermit/node/bin/npm
ln -sf .../cache/pkg/node-24.14.0/bin/npx   .../hermit/node/bin/npx
ln -sf .../cache/pkg/node-24.14.0/bin/corepack .../hermit/node/bin/corepack