Description

Starting from v0.13.0, hermes update --yes on Windows reports:

→ Building web UI...
  ⚠ Web UI build failed (hermes web will not be available)
  Build error:
  'rm' is not recognized as an internal or external command,
  operable program or batch file.

The built-in Web UI was building successfully in prior versions.

Root Cause

The web/package.json sync-assets script uses Unix-only commands (rm -rf, cp -r) that are not available on Windows:

"sync-assets": "rm -rf public/fonts public/ds-assets && cp -r node_modules/@nous-research/ui/dist/fonts public/fonts && cp -r node_modules/@nous-research/ui/dist/assets public/ds-assets"

This script is called by both predev and prebuild hooks, so both npm run dev and npm run build fail on Windows.

Suggested Fix

Replace with cross-platform Node.js built-in fs API (available since Node 16.7+):

"sync-assets": "node -e \"const fs=require('fs');function rm(d){if(fs.existsSync(d))fs.rmSync(d,{recursive:true,force:true})}function cp(s,d){fs.cpSync(s,d,{recursive:true})}rm('public/fonts');rm('public/ds-assets');cp('node_modules/@nous-research/ui/dist/fonts','public/fonts');cp('node_modules/@nous-research/ui/dist/assets','public/ds-assets')\""

This uses fs.rmSync() and fs.cpSync() which work on all platforms without additional dependencies.

Alternative approaches

• Use shx (npx shx rm -rf ...) — adds a dependency
• Use rimraf + cpy-cli — adds dependencies
• Create a scripts/sync-assets.mjs helper — cleanest but more files

Environment

• OS: Windows 11
• Node.js: v20+
• Hermes Agent: v0.13.0
• Install method: ZIP download (non-git)

Workaround

Users can manually edit web/package.json after each update, or automate the patch in their launcher script.