Fen Ecosystem
Expert guidance for working in the Mechanic/Fen WoW addon development ecosystem.
The Reload Loop (MANDATORY)
After ANY addon code change, you MUST verify the changes in-game:
- Ask the user to
/reload in WoW (or trigger via keybinding CTRL+SHIFT+R)
- Wait for the user to confirm the reload is complete
- Then use the
addon.output MCP tool (agent_mode=true) to get errors, tests, and console logs
CRITICAL: Do NOT call addon.output immediately after changes. The timing between reload and SavedVariables sync is unpredictable. Always wait for user confirmation before pulling output.
Ecosystem Components
| Component |
Purpose |
Key Tools |
| Mechanic |
Development hub |
env.status, addon.output, reload.trigger |
| FenCore |
Pure logic library |
fencore.catalog, fencore.search, fencore.info |
| FenUI |
UI widget library |
Layout, Panel, Tabs, Grid, Buttons |
| MechanicLib |
Bridge library |
RegisterAddon, Print, RegisterTest |
Essential MCP Tools
| Task |
MCP Tool |
| Get Addon Output |
addon.output (agent_mode=true) |
| Lint Code |
addon.lint |
| Run Tests |
addon.test |
| Search APIs |
api.search |
| Search FenCore |
fencore.search |
| Env Status |
env.status |
AFD Core Principles
Mechanic follows Agent-First Development (AFD) — github.com/Falkicon/afd
- Tool-First: All functionality must exist as an MCP tool before being added to any UI.
- Structured Results: All tools return predictable JSON schemas with
success, data, and error.
- Agent Mode: Use
agent_mode=true for distilled, AI-optimized output.
Routing Logic
