MCP-to-OpenAI

Bridge an MCP chat tool to any OpenAI SDK compatible AI service API

Abstract

This is a small Command-Line Interface (CLI) for conveniently bridging an MCP chat tool to any OpenAI SDK compatible AI service API. It runs as an MCP stdio transport based server and remotely connects to the AI service API with the OpenAI SDK. It supports both the legacy OpenAI Completion API and the modern OpenAI Responses API. It allows accessing foreign LLMs from within MCP host applications, like Claude Code.

Installation

$ npm install -g mcp-to-openai

Usage

Usage: mcp-to-openai [options]

Bridge an MCP chat tool to any OpenAI SDK compatible AI service API

Options:
  -V, --version                 show program version information
  -s, --service <service>       name of AI service (env: SERVICE)
  -t, --mcp-tool <tool>         MCP tool name (env: MCP_TOOL)
  -u, --openai-url <url>        OpenAI API base URL (env: OPENAI_URL)
  -k, --openai-key <key>        OpenAI API access key (env: OPENAI_KEY)
  -a, --openai-api <api>        OpenAI API flavor to use (choices:
                                "completion", "responses", default:
                                "completion", env: OPENAI_API)
  -m, --openai-model <model>    OpenAI API model identifier (env: OPENAI_MODEL)
  -p, --openai-prompt <prompt>  OpenAI API system prompt (env: OPENAI_PROMPT)
  -T, --openai-timeout <ms>     OpenAI API request timeout (default: "30000",
                                env: OPENAI_TIMEOUT)
  -h, --help                    show this usage help

Example:
  $ claude mcp add \
    --scope user \
    --transport stdio \
    -- \
    chat-openai-chatgpt \
    mcp-to-openai \
      --service      "OpenAI ChatGPT" \
      --mcp-tool     chat-openai-chatgpt \
      --openai-url   https://api.openai.com/v1 \
      --openai-key   "sk-[...]" \
      --openai-api   responses \
      --openai-model gpt-5

License

Copyright — 2026 Dr. Ralf S. Engelschall (http://engelschall.com/)

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.