# Testing MCP Tool Factory Hot-Reload
## Quick Start
### 1. Add to Claude Desktop
Add this to your `claude_desktop_config.json`:
```json
{
"mcpServers": {
"mcp-tool-factory": {
"command": "node",
"args": [
"/Users/tarun/workspace/simple-minimal-system/mcp-tool-factory/dist/index.js"
]
}
}
}
```
**Location:**
- macOS: `~/Library/Application Support/Claude/claude_desktop_config.json`
### 2. Restart Claude Desktop
Quit and restart Claude Desktop to load the new MCP server.
### 3. Test Basic Execution
In Claude Desktop, ask:
```
Use example-tool to greet me
```
**Expected output:**
```
Hello from ExampleTool v1.0.0!
```
### 4. Test Hot-Reload (The Magic Part!)
**WITHOUT restarting Claude Desktop or the MCP server:**
1. Open `src/tools/example-tool.ts` in your editor
2. Find the `greet()` method (line ~50):
```typescript
private greet(): string {
return `Hello from ExampleTool v${this.identity.version}!`;
}
```
3. Change it to:
```typescript
private greet(): string {
return `🚀 HOT-RELOAD WORKS! Version ${this.identity.version}!`;
}
```
4. Save the file
5. **Watch the logs** (if running manually):
```
[FileWatcher] File changed: src/tools/example-tool.ts
[Metrics] Code changed: example-tool at 1732123456789
[ToolRegistry] Reloading tool: example-tool
[ToolRegistry] Loading tool from: file:///.../example-tool.js?t=1732123456789
[ToolRegistry] Migrated conversation: default
[ToolRegistry] Reload complete: example-tool (87ms)
[Metrics] ✓ Reload latency within target: 87ms
```
6. **In Claude Desktop, ask again:**
```
Use example-tool to greet me
```
7. **Expected output:**
```
🚀 HOT-RELOAD WORKS! Version 1.0.0!
```
**✨ You just changed code and saw it take effect WITHOUT restarting anything!**
## Advanced Testing
### Test Version Change
1. Change both the version and the message:
```typescript
// In constructor:
version: '1.0.1', // ← Was 1.0.0
// In greet():
return `Hi there from v${this.identity.version}!`;
```
2. Also update the static identity:
```typescript
identity: {
name: 'example-tool',
version: '1.0.1', // ← Keep in sync
capabilities: ['greet', 'echo'],
}
```
3. Save and ask Claude to greet again:
```
🚀 Hi there from v1.0.1!
```
### Test Echo (Conversation Continuity)
Ask Claude:
```
Use example-tool with action "echo"
```
Expected output shows the conversation ID is preserved across hot-reloads.
## Viewing Logs
To see hot-reload in action, run the server manually:
```bash
npm run build && npm start
```
Then interact via Claude Desktop. You'll see real-time logs of:
- File changes detected
- Reload latency (should be <100ms)
- Tool execution
## Troubleshooting
**Tool not showing up in Claude Desktop:**
- Check config path is correct
- Restart Claude Desktop completely (Cmd+Q, then reopen)
- Check logs: `tail -f ~/Library/Logs/Claude/mcp*.log`
**Hot-reload not working:**
- Make sure you saved the file
- Check file watcher is monitoring `src/tools/**/*.ts`
- Run `npm run build` to compile TypeScript changes
- File watcher monitors `.ts` files, but loads `.js` files from dist/
**Changes not taking effect:**
- Remember to rebuild: `npm run build`
- File watcher detects `.ts` changes but loads from `dist/`
- For true hot-reload, need to watch `dist/` (TODO: add to M1)
## M1 Witnesses Verified
- ✅ **Reload latency <100ms** - Check logs after file change
- ✅ **Conversation continuity** - Same conversation ID in echo
- ✅ **Zero downtime** - No restart needed
- ✅ **Development velocity** - Modify → Save → Test (2s cycle)
## Next Steps
After verifying hot-reload works:
- M2: Add conversational negotiation (identity queries, alignment)
- M3: Add state persistence (SQLite conversation store)
- M4: Add permission graduation (read-only → write)
