Hippycampus

A LangChain-based CLI and MCP server that supports dynamic loading of OpenAPI specifications and integration with Langflow.

Prerequisites

Python 3.12.9
UV package manager
Google AI Studio API key
Langflow (for visual workflow creation)

Installation

## Install UV if you haven't already
curl -LsSf https://astral.sh/uv/install.sh | sh

## Create and activate virtual environment
uv venv
source .venv/bin/activate  # On Windows use: .venv\Scripts\activate

## Install hippycampus and its dependencies
uv pip install -e .

## Install langflow
uv pip install langflow

Configuration

Google AI Studio API Key

Visit Google AI Studio
Click “Create API Key” in the top right
Copy the generated key and set it as an environment variable:

export GOOGLE_API_KEY='your-api-key-here'

Running the Applications

CLI Mode (no MCP server)

uv run hippycampus-cli

MCP Server Mode (SSE)

uv run hippycampus-server --transport sse --port 8000

Langflow Server

Ensure the MCP server is running before starting Langflow.

Set the components path environment variable:

## Get your current working directory
pwd
## Use the output to set the components path
export LANGFLOW_COMPONENTS_PATH="/output/from/pwd/langflow/components"

Start the Langflow server (add --dev for development mode):

uv run langflow run

Open your browser and navigate to http://localhost:7860

Using Custom Components in Langflow

In the Langflow UI, locate the custom components:
- OpenApi Service: For loading OpenAPI specifications
- Hippycampus MCP Server: For connecting to the MCP server over SSE
Configure the components:
- OpenApi Service: Use https://raw.githubusercontent.com/APIs-guru/unofficial_openapi_specs/master/xkcd.com/1.0.0/openapi.yaml for testing
- MCP Server: Use http://localhost:8000/sse

See the Screencast Demo for a visual guide. Screencast Demo

Note that the official XKCD swagger files contain an error and specify the comic_id field as a number instead of an integer, there is a fixed version in the test folder.

Troubleshooting

Authentication errors: Check if GOOGLE_API_KEY is set correctly
Missing components in Langflow: Verify LANGFLOW_COMPONENTS_PATH points to the correct directory
Connection issues: Ensure the MCP server is running before connecting via Langflow
If components don’t appear in Langflow, try restarting the Langflow server
Use the cli to debug openapi_builder/spec_parser and agent interaction issues before running in MCP/Langflow.

License

MIT License

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the “Software”), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.