# gut

Answers the small judgement questions an agent keeps hitting: spam or not, which team, how urgent. You get YES, NO or UNSURE.

- MCP server · `type=mcp` · Claude Code, Codex, Cursor, GitHub Copilot, Windsurf (Devin Desktop), Cline, Zed, Gemini CLI · ★ 7
- Author: Kungie
- License: Apache-2.0 · policy=link-only · description only; the file stays with the author
- Source: https://github.com/Kungie/gut
- Updated: 2026-10-13
- HTML: https://affpapa.org/en/nevibecode/mcp/gut

## What it does

gut turns a judgement call into one line: `gut.likely(comment, "is spam")` returns yes or no, `gut.classify(ticket, Team)` picks one member of an Enum, `gut.rate(ticket, ["can wait", "this week", "right now"])` places the subject on a scale. Nothing is generated as prose, so there is no text to parse — the answer arrives as the model's own probabilities. Pass `ask_human=True` and an uncertain case comes back as `gut.UNSURE` instead of a guess, which is what you want before escalating an angry customer email.

The MCP server ships as `gutfeel-mcp` on top of the `gutfeel` Python package and runs through `uvx`. The backend is configuration, not a rewrite: Jev from TypeSafe AI, Jev routed through OpenRouter, a local NLI model on your CPU, a small LLM on your machine, or any OpenAI-compatible endpoint such as Ollama, vLLM or llama.cpp. `Cascade` asks the cheapest backend first and forwards only the cases it could not settle. Jev needs `TYPESAFE_API_KEY`, OpenRouter needs `OPENROUTER_API_KEY`; a local backend runs without either.

Pre-1.0, Apache-2.0. The PyPI package is `gutfeel` because `gut` was taken, while the import stays `import gut`. For tests, `gut.FakeBackend` returns answers from fixtures so no model is involved.

## Requirements
- Needs: Python and uv (commands run via uvx)
- Environment variables: `TYPESAFE_API_KEY`, `GUT_BACKEND`, `GUT_MODEL`, `GUT_BASE_URL`, `OPENROUTER_API_KEY` — keys and tokens: ask the human for the values, never commit them or put them in shared files.

## Install

### Claude Code (native platform)

**Platform CLI**
```bash
claude mcp add --env TYPESAFE_API_KEY=<TYPESAFE_API_KEY> --env GUT_BACKEND=<GUT_BACKEND> --env GUT_MODEL=<GUT_MODEL> --env GUT_BASE_URL=<GUT_BASE_URL> --env OPENROUTER_API_KEY=<OPENROUTER_API_KEY> --transport stdio gut -- uvx gutfeel-mcp
```
Replace <…> with your own values. uvx runs the command named after the package; if the README names another one, use uvx --from gutfeel-mcp <command>

### Codex

**Platform CLI**
```bash
codex mcp add gut --env TYPESAFE_API_KEY=<TYPESAFE_API_KEY> --env GUT_BACKEND=<GUT_BACKEND> --env GUT_MODEL=<GUT_MODEL> --env GUT_BASE_URL=<GUT_BASE_URL> --env OPENROUTER_API_KEY=<OPENROUTER_API_KEY> -- uvx gutfeel-mcp
```
Replace <…> with your own values. uvx runs the command named after the package; if the README names another one, use uvx --from gutfeel-mcp <command>

### Cursor

**Config file**
File `.cursor/mcp.json`:
```json
{
    "mcpServers": {
        "gut": {
            "command": "uvx",
            "args": [
                "gutfeel-mcp"
            ],
            "env": {
                "TYPESAFE_API_KEY": "<TYPESAFE_API_KEY>",
                "GUT_BACKEND": "<GUT_BACKEND>",
                "GUT_MODEL": "<GUT_MODEL>",
                "GUT_BASE_URL": "<GUT_BASE_URL>",
                "OPENROUTER_API_KEY": "<OPENROUTER_API_KEY>"
            }
        }
    }
}
```
Replace <…> with your own values. uvx runs the command named after the package; if the README names another one, use uvx --from gutfeel-mcp <command>

### GitHub Copilot

**Config file**
File `.vscode/mcp.json`:
```json
{
    "servers": {
        "gut": {
            "type": "stdio",
            "command": "uvx",
            "args": [
                "gutfeel-mcp"
            ],
            "env": {
                "TYPESAFE_API_KEY": "<TYPESAFE_API_KEY>",
                "GUT_BACKEND": "<GUT_BACKEND>",
                "GUT_MODEL": "<GUT_MODEL>",
                "GUT_BASE_URL": "<GUT_BASE_URL>",
                "OPENROUTER_API_KEY": "<OPENROUTER_API_KEY>"
            }
        }
    }
}
```
Replace <…> with your own values. uvx runs the command named after the package; if the README names another one, use uvx --from gutfeel-mcp <command>

### Gemini CLI

**Platform CLI**
```bash
gemini mcp add -e TYPESAFE_API_KEY=<TYPESAFE_API_KEY> -e GUT_BACKEND=<GUT_BACKEND> -e GUT_MODEL=<GUT_MODEL> -e GUT_BASE_URL=<GUT_BASE_URL> -e OPENROUTER_API_KEY=<OPENROUTER_API_KEY> gut uvx gutfeel-mcp
```
Replace <…> with your own values. uvx runs the command named after the package; if the README names another one, use uvx --from gutfeel-mcp <command>

## When to use it
- filter spam out of user comments without regex rules
- route a ticket to the right team
- rank an inbox by urgency
- check whether an agent has finished its task
- judge a thousand files or search results in one command

## Example prompts
- Use gut to check whether this comment is spam and hide it if it is
- Ask gut which team should own this ticket
- Pipe the file list through gut and keep only the ones about retrying failed requests

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