# mcp-stdio-wrapper
This project is a pipeline-oriented command-line tool designed to process data. It reads input from standard in (`stdin`), processes this data concurrently using a system of workers, and then writes the results to standard out (`stdout`).
The core functionality involves an `McpStreamClient` (defined in `src/streamer.rs`) which is used by `mcp_workers.rs` to send processed data to an external service. It also handles receiving Server-Sent Events (SSE) in response from this external service. The application's configuration is managed through `src/config.rs`, which integrates settings from command-line arguments and environment variables.
## Collaboration Diagram
Here is a high-level overview of the module collaboration:
```mermaid
graph TD
subgraph "Input"
A[stdio_reader]
end
subgraph "Processing"
B[main.rs]
C[mcp_workers]
D[mcp_client]
E[streamer]
end
subgraph "Output"
F[stdio_writer]
end
subgraph "Configuration"
G[config.rs]
H[config_from_cli.rs]
I[config_from_env.rs]
J[config_defaults.rs]
end
A -- "data" --> B
B -- "spawns" --> C
B -- "spawns" --> A
B -- "spawns" --> F
C -- "uses" --> D
D -- "uses" --> E
C -- "results" --> F
B -- "uses" --> G
G -- "uses" --> H
G -- "uses" --> I
G -- "uses" --> J
```
## Logic Diagram
Here is a diagram showing the logic of the utility:
```mermaid
graph TD
subgraph "Input"
A[stdin] --> B(stdio_reader);
end
subgraph "Processing Pipeline"
B --> C{Input Channel};
C --> D1(Worker 1);
C --> D2(Worker 2);
C --> D3(...);
C --> Dn(Worker N);
D1 --> E{MCP Server};
D2 --> E;
D3 --> E;
Dn --> E;
E --> F1(Worker 1);
E --> F2(Worker 2);
E --> F3(...);
E --> Fn(Worker N);
F1 --> G{Output Channel};
F2 --> G;
F3 --> G;
Fn --> G;
end
subgraph "Output"
G --> H(stdio_writer);
H --> I[stdout];
end
```
## Testing
To verify the functionality of the `mcp-stdio-wrapper`, you can use the provided test scripts in the `scripts/` directory.
Start gateway with:
```
make compose-up
```
before running test scripts.
### `test-fast-time-curl.sh`
This script directly interacts with the virtual server of the MCP Gateway using `curl`. It's useful for verifying that the MCP Gateway is running and responding as expected.
```bash
./scripts/test-fast-time-curl.sh
```
### `test-fast-time-wrapper.sh`
By default, the test scripts run against the release version of the `mcp-stdio-wrapper`. If you need to test a development version, you must update the executable path within the relevant test script to point to your development build.
This script utilizes the `mcp-stdio-wrapper` to send requests to the MCP Gateway. It demonstrates how the wrapper processes input and communicates with the gateway.
```bash
./scripts/test-fast-time-wrapper.sh
```
```
**Note** Update the PORT and SERVER_ID variables at the top of each script to match your environment, or set them as environment variables before execution.
