# ✅ All Errors Fixed - Server Working
## Issues Found and Fixed
### Issue 1: Wrong Module Path
**Error:** `ModuleNotFoundError: No module named 'mcp.server.mcpserver'`
**Fix:** Changed import from old API to new API
```python
# Before (incorrect)
from mcp.server.mcpserver import MCPServer
# After (correct)
from mcp.server import FastMCP
```
### Issue 2: Wrong Variable Names
**Error:** `ERROR: No server object found in calculator_server.py`
**Fix:** FastMCP CLI requires specific variable names. Changed all variable names:
```python
# Before (incorrect)
calculator = FastMCP("Calculator")
@calculator.tool()
def add(...):
...
# After (correct)
mcp = FastMCP("Calculator")
@mcp.tool()
def add(...):
...
```
The CLI looks for `mcp`, `server`, or `app` as variable names.
## All Files Updated
✅ **calculator_server.py** - All fixed:
- Correct FastMCP import
- Correct variable name: `mcp`
- Correct decorators: `@mcp.tool()`
- Correct run call: `mcp.run()`
✅ **README.md** - Code example updated
## Server Status
**✅ Server is working and ready to use!**
### Working Commands
1. **Run the server directly:**
```bash
python calculator_server.py
```
The server will start and wait for connections on stdio.
2. **Install to Claude Desktop:**
```bash
uv run mcp install calculator_server.py --name "Calculator"
```
3. **Run with MCP Inspector (requires Node.js):**
```bash
uv run mcp dev calculator_server.py
```
*Note: This requires Node.js/npm to be installed for the web UI*
## Important Notes
⚠️ **Always activate the virtual environment first:**
```bash
# Windows
.\.venv\Scripts\Activate.ps1
# macOS/Linux
source .venv/bin/activate
```
✅ **All 4 Calculator Tools Working:**
- `add(a, b)` - Addition
- `subtract(a, b)` - Subtraction
- `multiply(a, b)` - Multiplication
- `divide(a, b)` - Division (with error handling)
## Next Steps
1. **Run the server:** `python calculator_server.py`
2. **Install to Claude:** `uv run mcp install calculator_server.py --name "Calculator"`
3. **Extend it:** Add more tools to the `@mcp.tool()` decorated functions
---
**All errors resolved. Server is fully operational!** ✅
