What does this PR do?

hermes mcp serve fails on NixOS and any other non-editable install with ModuleNotFoundError: No module named 'mcp_serve'. Root cause: the top-level mcp_serve.py module is not listed under [tool.setuptools] py-modules in pyproject.toml, so it is omitted from the built wheel. This PR adds it.

hermes_cli/mcp_config.py:749 does a top-level from mcp_serve import run_mcp_server. mcp_serve.py lives at the repo root and defines run_mcp_server at line 866. Setuptools' wheel build only includes top-level modules listed in py-modules. Every other top-level module that production code imports (run_agent, cli, batch_runner, hermes_bootstrap, …) is in that list — mcp_serve was the lone omission. Editable installs (pip install -e .) are unaffected because the repo root is on sys.path, which is why dev and CI did not catch it.

Related Issue

Fixes #22110

Type of Change

• 🐛 Bug fix (non-breaking change that fixes an issue)
• ✨ New feature (non-breaking change that adds functionality)
• 🔒 Security fix
• 📝 Documentation update
• ✅ Tests (adding or improving test coverage)
• ♻️ Refactor (no behavior change)
• 🎯 New skill (bundled or hub)

Changes Made

• pyproject.toml — add "mcp_serve" to [tool.setuptools] py-modules. Same fix shape as PR fix: : minisweagent_path.py missing from wheel #2098 (minisweagent_path).

How to Test

1. Build the wheel from a clean checkout: uv build --wheel
2. Inspect the artifact contains the module: unzip -l dist/hermes_agent-*.whl | grep mcp_serve.py
3. Inspect top_level.txt lists it: unzip -p dist/hermes_agent-*.whl hermes_agent-*.dist-info/top_level.txt | grep mcp_serve
4. Install into a fresh non-editable env and run hermes mcp serve — the ModuleNotFoundError is gone.

Before/after of the wheel artifact:

# Before
unzip -l hermes_agent-*.whl | grep mcp_serve.py    # no output
unzip -p hermes_agent-*.whl ...top_level.txt | grep -c mcp_serve    # 0

# After
unzip -l hermes_agent-*.whl | grep mcp_serve.py    # 31690 ... mcp_serve.py
unzip -p hermes_agent-*.whl ...top_level.txt | grep mcp_serve    # mcp_serve

Checklist

Code

• I've read the Contributing Guide
• My commit messages follow Conventional Commits (fix(scope):, feat(scope):, etc.)
• I searched for existing PRs to make sure this isn't a duplicate
• My PR contains only changes related to this fix/feature (no unrelated commits)
• I've run focused verification (wheel inspection — there is no pytest path for this packaging bug)
• I've added tests for my changes (required for bug fixes, strongly encouraged for features) — N/A, packaging-only fix verified via wheel inspection
• I've tested on my platform: macOS 15.x

Documentation & Housekeeping

• I've updated relevant documentation (README, docs/, docstrings) — N/A
• I've updated cli-config.yaml.example if I added/changed config keys — N/A
• I've updated CONTRIBUTING.md or AGENTS.md if I changed architecture or workflows — N/A
• I've considered cross-platform impact (Windows, macOS) per the compatibility guide — packaging fix is platform-independent
• I've updated tool descriptions/schemas if I changed tool behavior — N/A

Related / Positioning

• Fixes [Bug]: hermes mcp serve fails to start on NixOS #22110.
• Same fix shape as PR fix: : minisweagent_path.py missing from wheel #2098 (minisweagent_path) — top-level module omitted from py-modules, broke in non-editable installs.

Audited siblings: confirmed every other top-level .py module that production code imports (run_agent, cli, batch_runner, hermes_bootstrap, mcp_serve after this change, …) is now present in [tool.setuptools] py-modules. No widening needed.

Screenshots / Logs

File ".../site-packages/hermes_cli/mcp_config.py", line 749, in mcp_command
    from mcp_serve import run_mcp_server
ModuleNotFoundError: No module named 'mcp_serve'