hermes-ui/DEVELOPMENT.md

Development Guidelines

This document defines project-level development rules for hermes-ui. It is tool-agnostic and applies to all contributors and coding agents.

Prerequisites

• Node.js >=23 (see engines in package.json).
• Python with hermes-agent installed. The Hermes CLI is not bundled; point HERMES_BIN at the executable or make hermes resolvable from PATH.
• A C/C++ toolchain, but only on Linux: python3, make, g++. See "Platform Notes" below.

Commands

npm ci --ignore-scripts
npm rebuild node-pty
npm run dev
npm run test
npm run test:coverage
npm run test:e2e
npm run build

• npm ci --ignore-scripts installs exactly what package-lock.json pins. Do not upgrade dependencies.
• npm rebuild node-pty is required, not optional. npm ci --ignore-scripts skips every install script, and node-pty's install script is what puts a loadable native module in place. Skipping it leaves the terminal feature silently disabled — the server logs a warning and keeps running.
• npm run dev starts the Vite client and Koa server together.
• npm run test runs Vitest unit tests.
• npm run test:coverage is what the Build workflow runs before npm run build.
• npm run test:e2e runs Playwright browser tests against a mocked BFF API.
• npm run build type-checks and builds both client and server.

Platform Notes

The server runs on Windows, macOS, and Linux. The parts that differ are isolated behind process.platform checks, so the same source runs everywhere.

node-pty

node-pty ships prebuilt binaries for Windows and macOS only:

Platform	Where the native module comes from	Build step
Windows	prebuilds/win32-<arch>/ (shipped in the npm tarball)	not needed
macOS	prebuilds/darwin-<arch>/ (shipped in the npm tarball)	not needed
Linux	none — must be compiled from source	npm rebuild node-pty

On Linux, npm rebuild node-pty compiles node-pty from source and needs python3, make, and g++ on the machine. The Dockerfile installs exactly those for this reason.

On macOS the prebuilt spawn-helper may arrive without its executable bit. The server repairs that at startup (packages/server/src/routes/hermes/terminal.ts), and bin/hermes-ui.mjs does the same for the installed CLI.

Other platform differences

• Terminal shell: powershell.exe on Windows, $SHELL (falling back to /bin/zsh then /bin/bash) on macOS and Linux.
• Agent Bridge transport: a Unix domain socket at ipc:///tmp/hermes-agent-bridge.sock on macOS and Linux, a TCP port (tcp://127.0.0.1:18765) on Windows, which has no Unix socket support in Node.
• Python interpreter: python3 on macOS and Linux, python on Windows. Virtualenv layout differs too (venv/bin/python3 vs venv\Scripts\python.exe).
• Gateway process tree: taskkill /T on Windows, process-group signals on macOS and Linux.
• Hermes home: ~/.hermes on macOS and Linux; on Windows, an existing %LOCALAPPDATA%\hermes or %APPDATA%\hermes takes priority.

Verification

Linux is covered by the Build and Playwright workflows, which run on ubuntu-latest. macOS is not covered by any hosted runner; the macOS Verification workflow (workflow_dispatch only) runs the same checks when a macOS runner is available.

Architecture

• Frontend code lives under packages/client/src.
• Server code lives under packages/server/src.
• Hermes-specific client code stays under hermes namespaces: API modules, views, stores, and components.
• Server routes should stay thin. Put request handling in controllers and reusable behavior in services.
• The chat runtime is Socket.IO based and lives under packages/server/src/services/hermes/run-chat.
• Web UI state lives under HERMES_WEB_UI_HOME or HERMES_WEBUI_STATE_DIR, defaulting to ~/.hermes-web-ui.
• Hermes state.db is read-only. Never open it from Node-side code.

Coding Rules

• Prefer existing local patterns over new abstractions.
• Keep changes scoped to the requested behavior.
• Do not mix unrelated refactors into feature or bugfix commits.
• Do not reintroduce deprecated compatibility switches without a current caller.
• Use structured APIs and parsers for structured data instead of ad hoc string edits when possible.
• Add comments only where they explain non-obvious behavior or constraints.

Frontend Rules

• Use Vue 3 Composition API with <script setup lang="ts">.
• Use Pinia setup stores.
• Use the shared API request helper in packages/client/src/api/client.ts.
• Add user-facing strings to all locale files (zh.ts and en.ts are the only two).
• Keep component styles scoped with SCSS unless the style is intentionally global.
• Use Arco Design Vue components and follow existing Arco patterns. Do not add new naive-ui imports and do not introduce another UI library.

Server Rules

• Register local API routes before proxy catch-all routes.
• Keep auth behavior centralized in packages/server/src/services/auth.ts.
• Use config.appHome for Web UI state paths.
• Keep Hermes home paths separate from Web UI home paths.
• Use getActiveProfileDir() or related profile helpers for Hermes profile files.
• Avoid shell string construction for CLI calls; prefer execFile/spawn with argument arrays, routed through execHermesWithBin/spawnHermesWithBin.

Red Lines

• packages/server/src/services/hermes/agent-bridge/python/ is vendored and read-only. The HERMES_DESKTOP checks in bridge_runtime.py are the one exception and must stay.
• The /chat-run Socket.IO event contract is frozen: no changes to event names, field names, field types, or emission timing. Adding optional fields is allowed.
• Changes under services/hermes/group-chat/, lib/context-compressor/, or services/hermes/context-engine/ require a docs/chat-chain-changes/<date>-<slug>.md fragment.

Testing Rules

• Add focused Vitest coverage for server and store logic changes.
• Add Playwright coverage for browser-visible flows and routing/auth regressions.
• For frontend browser tests, prefer API/socket mocks over real external services.
• Before opening a PR, run the smallest relevant tests plus npm run build.
• For broad changes, run:

npm run test:coverage
npm run test:e2e
npm run build

Commit And PR Rules

• Branch from main for new work.
• Use short, descriptive branch names such as fix/login-token or feat/group-chat-copy.
• Commit only files that belong to the change.
• Use concise commit messages that describe the change, for example fix login token storage or add group chat clone naming.
• Keep commits focused. Do not bundle unrelated cleanup with feature work unless the cleanup is required.
• Push the branch and open a PR against main unless the issue explicitly targets another base.
• Prefer draft PRs while validation is still running or when the change needs review before merge.
• Mark a PR ready only after the relevant tests and build pass.
• Keep PR titles concrete and scoped, for example make Web UI state directory configurable.
• Link issues in the PR body with Closes #123, Fixes #123, or Refs #123 as appropriate.
• PR descriptions should include:
  • what changed
  • why it changed
  • user or developer impact
  • validation commands run
  • known limitations or follow-up work, if any
• Do not overwrite or revert unrelated user changes.

Use this PR body shape by default:

## Summary
- ...
- ...

Closes #123

## Validation
- `npm run test:coverage`
- `npm run build`