# File Writer Tool
## Description
The `file_writer` tool is a Go-based gRPC service that writes specified content to a file on the local filesystem.
> **Warning:** This tool will **overwrite** the file if it already exists. This action is irreversible and can lead to data loss. Use with caution.
## Security
For security, this tool has a built-in safeguard to prevent directory traversal attacks. It cleans the provided file path and denies any request that attempts to access parent directories using `..`. All file access is sandboxed within the project's working directory.
## Parameters
The tool accepts the following arguments in a JSON object:
| Parameter | Type | Required | Description |
|------------|----------|----------|----------------------------------------------------------------|
| `filepath` | `string` | **Yes** | The path to the file to be written (e.g., `docs/new_notes.txt`). |
| `content` | `string` | **Yes** | The content to write to the file. |
## Response
* **Successful Write:** If the file is written successfully, the tool returns a success message indicating the number of bytes written and the file path (e.g., `"Successfully wrote 50 bytes to docs/new_notes.txt"`).
* **Error:** If the path is invalid, a write error occurs, or access is denied, the tool returns an error message.
## Usage Example
Here is an example of how to use the `file_writer` tool to create a new file and write content to it. This example uses `curl` to interact with the MCP server's HTTP/REST gateway.
**Request:**
```bash
curl -X POST http://localhost:8002/v1/tools:run \
-d '{
"name": "file_writer",
"arguments": {
"filepath": "data/new_file.txt",
"content": "This is a new line of text written by the tool."
}
}'
```
**Successful Response:**
```json
{
"result": {
"stringValue": "Successfully wrote 49 bytes to data/new_file.txt"
}
}
```
## Configuration
The tool's configuration is managed through a `config.json` file located in the tool's directory.
**Example `config.json`:**
```json
{
"port": 50055,
"command": ["go", "run", "."]
}
```
* `port`: The port on which the tool's gRPC server will listen.
* `command`: The command and arguments to execute the tool.
## Health and Logging
* **Health Checks:** This tool implements the standard gRPC Health Checking Protocol.
* **Logging:** The tool uses a structured JSON logger (`slog`) for observability.
## Testing
To test the tool, you can run the provided integration tests. Navigate to the tool's directory and run:
```bash
go test ./...
```
