hermes-agent/website/docs/developer-guide/contributing.md

sidebar_position	title	description
4	Contributing	How to contribute to Hermes Agent — dev setup, code style, PR process

Contributing

Thank you for contributing to Hermes Agent! This guide covers setting up your dev environment, understanding the codebase, and getting your PR merged.

Contribution Priorities

We value contributions in this order:

1. Bug fixes — crashes, incorrect behavior, data loss
2. Cross-platform compatibility — macOS, different Linux distros, WSL2
3. Security hardening — shell injection, prompt injection, path traversal
4. Performance and robustness — retry logic, error handling, graceful degradation
5. New skills — broadly useful ones (see Creating Skills)
6. New tools — rarely needed; most capabilities should be skills
7. Documentation — fixes, clarifications, new examples

Common contribution paths

• Building a custom/local tool without modifying Hermes core? Start with Build a Hermes Plugin
• Building a new built-in core tool for Hermes itself? Start with Adding Tools
• Building a new skill? Start with Creating Skills
• Building a new inference provider? Start with Adding Providers

Development Setup

Prerequisites

Requirement	Notes
Git	With --recurse-submodules support, and the git-lfs extension installed
Python 3.11+	uv will install it if missing
uv	Fast Python package manager (install)
Node.js 20+	Optional — needed for browser tools and WhatsApp bridge (matches root package.json engines)

Clone and Install

git clone --recurse-submodules https://github.com/NousResearch/hermes-agent.git
cd hermes-agent

# Create venv with Python 3.11
uv venv venv --python 3.11
export VIRTUAL_ENV="$(pwd)/venv"

# Install with all extras (messaging, cron, CLI menus, dev tools)
uv pip install -e ".[all,dev]"

# Optional: browser tools
npm install

Configure for Development

mkdir -p ~/.hermes/{cron,sessions,logs,memories,skills}
cp cli-config.yaml.example ~/.hermes/config.yaml
touch ~/.hermes/.env

# Add at minimum an LLM provider key:
echo 'OPENROUTER_API_KEY=sk-or-v1-your-key' >> ~/.hermes/.env

Run

# Symlink for global access
mkdir -p ~/.local/bin
ln -sf "$(pwd)/venv/bin/hermes" ~/.local/bin/hermes

# Verify
hermes doctor
hermes chat -q "Hello"

Run Tests

pytest tests/ -v

Code Style

• PEP 8 with practical exceptions (no strict line length enforcement)
• Comments: Only when explaining non-obvious intent, trade-offs, or API quirks
• Error handling: Catch specific exceptions. Use logger.warning()/logger.error() with exc_info=True for unexpected errors
• Cross-platform: Never assume Unix (see below)
• Profile-safe paths: Never hardcode ~/.hermes — use get_hermes_home() from hermes_constants for code paths and display_hermes_home() for user-facing messages. See AGENTS.md for full rules.

Cross-Platform Compatibility

Hermes officially supports Linux, macOS, WSL2, and native Windows (early beta — via PowerShell install). Native Windows uses Git Bash (from Git for Windows) for shell commands. A few features require POSIX kernel primitives and are gated: the dashboard's embedded PTY terminal pane (/chat tab) is WSL2-only. The native-Windows path is new and moves fast — if you're doing Windows-heavy dev, expect to hit and fix rough edges.

When contributing code, keep these rules in mind:

• Don't add unguarded signal.SIGKILL references. It's not defined on Windows. Either route through gateway.status.terminate_pid(pid, force=True) (the centralized primitive that does taskkill /T /F on Windows and SIGKILL on POSIX), or fall back with getattr(signal, "SIGKILL", signal.SIGTERM).
• Catch OSError alongside ProcessLookupError on os.kill(pid, 0) probes. Windows raises OSError (WinError 87, "parameter is incorrect") for an already-gone PID instead of ProcessLookupError.
• Don't force the terminal to POSIX semantics. os.setsid, os.killpg, os.getpgid, os.fork all raise on Windows — gate them with if sys.platform != "win32": or if os.name != "nt":.
• Open files with an explicit encoding="utf-8". The Python default on Windows is the system locale (often cp1252), which mojibakes or crashes on non-Latin text.
• Use pathlib.Path / os.path.join — never manually concat with /. This matters less for strings the OS gives us back and more for strings we construct to hand to subprocesses.

Key patterns:

1. termios and fcntl are Unix-only

Always catch both ImportError and NotImplementedError:

try:
    from simple_term_menu import TerminalMenu
    menu = TerminalMenu(options)
    idx = menu.show()
except (ImportError, NotImplementedError):
    # Fallback: numbered menu
    for i, opt in enumerate(options):
        print(f"  {i+1}. {opt}")
    idx = int(input("Choice: ")) - 1

2. File encoding

Some environments may save .env files in non-UTF-8 encodings:

try:
    load_dotenv(env_path)
except UnicodeDecodeError:
    load_dotenv(env_path, encoding="latin-1")

3. Process management

os.setsid(), os.killpg(), and signal handling differ across platforms:

import platform
if platform.system() != "Windows":
    kwargs["preexec_fn"] = os.setsid

4. Path separators

Use pathlib.Path instead of string concatenation with /.

Security Considerations

Hermes has terminal access. Security matters.

Existing Protections

Layer	Implementation
Sudo password piping	Uses shlex.quote() to prevent shell injection
Dangerous command detection	Regex patterns in tools/approval.py with user approval flow
Cron prompt injection	Scanner blocks instruction-override patterns
Write deny list	Protected paths resolved via os.path.realpath() to prevent symlink bypass
Skills guard	Security scanner for hub-installed skills
Code execution sandbox	Child process runs with API keys stripped
Container hardening	Docker: all capabilities dropped, no privilege escalation, PID limits

Contributing Security-Sensitive Code

• Always use shlex.quote() when interpolating user input into shell commands
• Resolve symlinks with os.path.realpath() before access control checks
• Don't log secrets
• Catch broad exceptions around tool execution
• Test on all platforms if your change touches file paths or processes

Pull Request Process

Branch Naming

fix/description        # Bug fixes
feat/description       # New features
docs/description       # Documentation
test/description       # Tests
refactor/description   # Code restructuring

Before Submitting

1. Run tests: pytest tests/ -v
2. Test manually: Run hermes and exercise the code path you changed
3. Check cross-platform impact: Consider macOS and different Linux distros
4. Keep PRs focused: One logical change per PR

PR Description

Include:

• What changed and why
• How to test it
• What platforms you tested on
• Reference any related issues

Commit Messages

We use Conventional Commits:

<type>(<scope>): <description>

Type	Use for
fix	Bug fixes
feat	New features
docs	Documentation
test	Tests
refactor	Code restructuring
chore	Build, CI, dependency updates

Scopes: cli, gateway, tools, skills, agent, install, whatsapp, security

Examples:

fix(cli): prevent crash in save_config_value when model is a string
feat(gateway): add WhatsApp multi-user session isolation
fix(security): prevent shell injection in sudo password piping

Reporting Issues

• Use GitHub Issues
• Include: OS, Python version, Hermes version (hermes version), full error traceback
• Include steps to reproduce
• Check existing issues before creating duplicates
• For security vulnerabilities, please report privately

Community

• Discord: discord.gg/NousResearch
• GitHub Discussions: For design proposals and architecture discussions
• Skills Hub: Upload specialized skills and share with the community

License

By contributing, you agree that your contributions will be licensed under the MIT License.