Add MCP Tool

Add MCP Tool to Envoy

Steps for adding a new MCP tool:

1. Add the tool function inside _register_tools() in EnvoyExt.py

   • Function signature and docstring define the MCP schema (parameter names, types, descriptions)
   • Treat these as API contracts - changes break client integrations
   • The tool function queues the operation for main-thread execution

2. Add a handler case in _onRefresh() for the TD operation

   • This is where the actual TouchDesigner operations execute (on the main thread)
   • Wrap TD operations in try/except, return {'error': str(e)} dicts on failure
   • Validate all inputs before passing to TD

3. Update EXPECTED_ENVOY_TOOLS in dev/embody/unit_tests/test_agent_contract.py

   • The Tier-1 agent contract test fails on inventory drift in either direction -- same commit as the tool change
   • Tools register on the MCPServer instance at Envoy START -- restart Envoy before believing a mismatch

4. Update the MCP tools reference

   • Update the /mcp-tools-reference skill in .claude/skills/mcp-tools-reference/SKILL.md
   • Update the corresponding template DAT if it exists

5. Update documentation

   • Add to the root CLAUDE.md if the tool is significant
   • Update text_claude.md template DAT for user projects

6. Test via MCP Inspector or Claude Code

   • Verify the tool appears in the tool list
   • Test with valid and invalid inputs
   • Check error handling