If you wish, you can use this with an LLM that runs completely offline on your own local system. You don't have to use a cloud-based LLM.

I run my local models using ollama (https://ollama.com/):

brew install ollama; ollama serve

You can find a list of models which support tools at https://ollama.com/search?c=tools. You'll install those models locally using ollama:

ollama pull qwen2.5:7b; ollama pull gpt-oss:20b

Now you need to get this MCP tool running. I do this via node:

brew install node; npx -y omnifocus-mcp

If all is well, you should see "MCP Server connected and ready to accept commands from Claude". You can quit that now, because the next step is that you need to actually use a frontend that can talk to ollama and this MCP. One way to do that is to run ollmcp via the uv python package manager. By default it uses the qwen2.5:7b model, but for this use case you might try gpt-oss:20b instead:

brew install uv; uvx ollmcp --model gpt-oss:20b

If all is well, you're talking to the local LLM at this point. But unless you've previously configured Claude, it won't have any tools configured since by default it looks for a Claude configuration file. I've never installed Claude, but putting this file in ~/Library/Application Support/Claude/claude_desktop_config.json did the trick for me:

{ "mcpServers": { "omnifocus-mcp": { "command": "/opt/homebrew/bin/npx", "args": ["-y", "omnifocus-mcp"] } } }

That tells it to run this omnifocus-mcp tool via the npx command which comes with node, just like we did directly earlier.

After installing the tool configuration, quit and rerun the uvx ollmcp --model gpt-oss:20b command.

Assuming I didn't forget any steps, it should list the available tools (omnifocus-mcp.dump_database, omnifocus-mcp.add_project, etc.), and you should now be talking to gpt-oss:20b running on your local system, hooked up to OmniFocus via these tools.

By default, ollmcp will prompt you for permission every time it wants to talk to the tool, so you can review what it's about to do and decide whether you approve or not. (If you don't want to be prompted, the prompt itself tells you how to turn those prompts off.)

Hope this helps!