hermes - 💡(How to fix) Fix mcp add / mcp test raise NameError when mcp package not installed

Summary

hermes mcp add and hermes mcp test both raise NameError: name 'StdioServerParameters' is not defined when the mcp Python package is not installed in the pipx venv.

Environment

• Hermes Agent: v0.14.0 (2026.5.16)
• Python: 3.14.4
• Platform: macOS (darwin 25.5.0, arm64)
• Install method: pipx

Steps to reproduce

# Fresh pipx install (mcp not in Requires-Dist, so not auto-installed)
pipx install hermes-agent

# Add an mcp server to config.yaml manually or via add command
hermes mcp add   # or: hermes mcp test <server-name>

Expected behavior

A clear error message: mcp package not installed — run pipx inject hermes-agent mcp to enable MCP support.

Actual behavior

✗ Connection failed (7925ms): name 'StdioServerParameters' is not defined

Root cause

tools/mcp_tool.py imports StdioServerParameters inside a module-level try/except ImportError block. When the mcp package is absent, the import fails silently (_MCP_AVAILABLE stays False) and StdioServerParameters is never bound. The mcp test and mcp add code paths then reference StdioServerParameters directly without first checking _MCP_AVAILABLE, producing a NameError instead of an actionable message.

Fix

Either:

1. Add mcp as an optional extras dependency (hermes-agent[mcp]) and document pipx inject hermes-agent mcp for manual installs, or
2. Guard all references to StdioServerParameters (and the other lazy-imported names) behind if not _MCP_AVAILABLE: raise RuntimeError("mcp package required — run: pipx inject hermes-agent mcp")

Workaround (confirmed working)

pipx inject hermes-agent mcp

After inject, hermes mcp test <server> connects and discovers tools correctly (tested with a local stdio MCP server, 30 tools discovered in ~1s).