# MCP Integration for Wrdler

## Overview

Wrdler exposes AI word generation functionality as an **MCP (Model Context Protocol) tool** when running locally. This allows AI assistants and other MCP clients to generate vocabulary words for custom topics.

## What is MCP?

The Model Context Protocol (MCP) is a standard for integrating AI assistants with external tools and data sources. Gradio 5.0+ has built-in MCP server support, making it easy to expose functions as MCP tools.

**Reference:** [Building MCP Server with Gradio](https://www.gradio.app/guides/building-mcp-server-with-gradio)

## Available MCP Tools

### `generate_ai_words`

Generate 75 AI-selected words (25 each of lengths 4, 5, 6) related to a specific topic.

**Availability:** Only when running locally with `USE_HF_WORDS=false`

#### Input Parameters

```json
{
  "topic": "Ocean Life",          // Required: Theme for word generation
  "model_name": null,              // Optional: Override default AI model
  "seed": null,                    // Optional: Random seed for reproducibility
  "use_dictionary_filter": true,  // Optional: Filter against dictionary (legacy parameter)
  "selected_file": null            // Optional: Word list file for dictionary context
}
```

#### Output Format

```json
{
  "words": [
    "WAVE", "TIDE", "FISH", ...    // 75 words total (25 × 4-letter, 25 × 5-letter, 25 × 6-letter)
  ],
  "difficulties": {
    "WAVE": 0.45,                  // Difficulty score for each word
    "TIDE": 0.32,
    ...
  },
  "metadata": {
    "model_used": "microsoft/Phi-3-mini-4k-instruct",
    "transformers_available": "True",
    "gradio_client_available": "True",
    "use_hf_words": "False",
    "raw_output_length": "2048",
    "raw_output_snippet": "...",
    "ai_initial_count": "75",
    "topic": "Ocean Life",
    "dictionary_filter": "True",
    "new_words_saved": "15"
  }
}
```

## Setup

### 1. Environment Configuration

Set the `USE_HF_WORDS` environment variable to enable local mode:

```bash
# Linux/Mac
export USE_HF_WORDS=false

# Windows (PowerShell)
$env:USE_HF_WORDS="false"

# .env file
USE_HF_WORDS=false
```

### 2. Run Gradio App

```bash
python gradio_app.py
```

You should see:

```
===========================================================================
?? MCP SERVER ENABLED (Local Mode)
===========================================================================
MCP tools available:
  - generate_ai_words: Generate AI vocabulary words for topics

To use MCP tools, connect your MCP client to this Gradio app.
See: https://www.gradio.app/guides/building-mcp-server-with-gradio
===========================================================================
```

### 3. Connect MCP Client

Configure your MCP client to connect to the Gradio server:

```json
{
  "mcpServers": {
    "wrdler": {
      "url": "http://localhost:7860",
      "transport": "gradio"
    }
  }
}
```

## Usage Examples

### Example 1: Basic Topic Generation

**Input:**
```json
{
  "topic": "Space Exploration"
}
```

**Output:**
```json
{
  "words": [
    "STAR", "MARS", "MOON", "SHIP", "ORBIT", "COMET", ...
  ],
  "difficulties": {
    "STAR": 0.25,
    "MARS": 0.30,
    ...
  },
  "metadata": {
    "model_used": "microsoft/Phi-3-mini-4k-instruct",
    "topic": "Space Exploration",
    "ai_initial_count": "75",
    ...
  }
}
```

### Example 2: With Custom Model and Seed

**Input:**
```json
{
  "topic": "Medieval History",
  "model_name": "meta-llama/Llama-3.1-8B-Instruct",
  "seed": 42
}
```

### Example 3: Using MCP via Claude Desktop

If you have Claude Desktop configured with MCP:

1. Add Wrdler to your MCP configuration
2. In Claude, use natural language:

```
Can you generate vocabulary words about Ancient Rome using the generate_ai_words tool?
```

Claude will automatically call the MCP tool and return the results.

## Technical Details

### Implementation

The MCP integration is implemented in `wrdler/word_loader_ai.py` using Gradio's `@gr.mcp_server_function` decorator:

```python
@gr.mcp_server_function(
    name="generate_ai_words",
    description="Generate 75 AI-selected words...",
    input_schema={...},
    output_schema={...}
)
def mcp_generate_ai_words(...) -> dict:
    # Wrapper for generate_ai_words()
    ...
```

The Gradio app (`gradio_app.py`) enables the MCP server by setting `mcp_server=True` in the launch configuration:

```python
demo.launch(
    server_name="0.0.0.0",
    server_port=7860,
    mcp_server=True,  # Enable MCP server
    ...
)
```

### Conditional Registration

The MCP function is **only registered when**:
- ? Gradio is available
- ? `USE_HF_WORDS=false` (local mode)

When deployed to Hugging Face Spaces (`USE_HF_WORDS=true`), the MCP function is **not registered** to avoid conflicts with the remote API.

### Word Generation Pipeline

1. **AI Generation**: Use local transformers models or HF Space API
2. **Validation**: Filter words to lengths 4, 5, 6 (uppercase A-Z only)
3. **Distribution**: Ensure 25 words per length
4. **Difficulty Scoring**: Calculate word difficulty metrics
5. **File Saving**: Save new words to topic-based files
6. **Return**: Provide words, difficulties, and metadata

## Troubleshooting

### MCP Function Not Appearing

**Check 1: Environment Variable**
```bash
echo $USE_HF_WORDS  # Should be "false"
```

**Check 2: Gradio Logs**
```
? word_loader_ai module loaded (MCP functions may be registered)
? MCP server function 'generate_ai_words' registered (local mode)
```

**Check 3: Gradio Version**
```bash
pip show gradio  # Should be >= 5.0.0
```

### Model Loading Issues

If you see warnings about model loading:
```
?? Transformers not available; falling back to dictionary words.
```

Install transformers:
```bash
pip install transformers torch
```

### Port Conflicts

If port 7860 is in use, modify `gradio_app.py`:
```python
launch_kwargs = {
    "server_port": 7861,  # Change port
    ...
}
```

## Remote vs Local Mode

| Feature | Local Mode (`USE_HF_WORDS=false`) | Remote Mode (`USE_HF_WORDS=true`) |
|---------|-----------------------------------|-----------------------------------|
| MCP Server | ? Enabled | ? Disabled |
| AI Models | Local transformers | HF Space API |
| Word Saving | ? Saves to files | ? Saves to files |
| Best For | Development, MCP clients | Production deployment |

## Security Notes

- MCP tools run with **full local file system access**
- Only enable MCP server in **trusted environments**
- Generated words are saved to `wrdler/words/` directory
- Model weights are cached in `TMPDIR/hf-cache/`

## Further Reading

- [Gradio MCP Guide](https://www.gradio.app/guides/building-mcp-server-with-gradio)
- [MCP Specification](https://modelcontextprotocol.io/)
- [Wrdler Requirements](../specs/requirements.md)

---

**Last Updated:** 2025-11-30
**Version:** 0.1.5