# three.ws Tutor

Reads the itemized tab of a Pay-As-You-Learn tutoring session and seals it with an attested invoice. Neither call costs the learner anything.

- MCP server · `type=mcp` · Claude Code, Codex, Cursor, GitHub Copilot, Windsurf (Devin Desktop), Cline, Zed, Gemini CLI · ★ 249
- Author: nirholas
- License: Apache-2.0 · policy=link-only · description only; the file stays with the author
- Source: https://github.com/nirholas/three.ws/tree/HEAD/packages/tutor-mcp
- Updated: 2026-10-24
- HTML: https://affpapa.org/en/nevibecode/mcp/threews-tutor

## What it does

Two tools arrive over stdio. `load_session` takes an opaque `sessionId` and hands back the running tab: each question, its level, output tokens, per-item price and the total so far. `close_session` flips the session from open to closed, attaches a SHA-256 attestation and stops any further billing.

Repeating the close on the same session returns the same total, so that call is safe to retry. Reading is not: new answered questions keep adding lines. The paid action is the per-question answer, handled elsewhere, and these tools move no funds.

No signer and no API key — the session is addressed by its identifier alone. You need Node.js 20 or newer and network reach to `https://three.ws` or to whatever deployment sits behind `THREE_WS_BASE`. An identifier with nothing stored comes back as an empty open session with `questionCount: 0` instead of an error.

## Requirements
- Needs: Node.js (commands run via npx)
- Environment variables: `THREE_WS_BASE`, `THREE_WS_TIMEOUT_MS` — 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 THREE_WS_BASE=<THREE_WS_BASE> --env THREE_WS_TIMEOUT_MS=<THREE_WS_TIMEOUT_MS> --transport stdio tutor-mcp -- npx -y @three-ws/tutor-mcp
```
Replace <…> with your own values

### Codex

**Platform CLI**
```bash
codex mcp add tutor-mcp --env THREE_WS_BASE=<THREE_WS_BASE> --env THREE_WS_TIMEOUT_MS=<THREE_WS_TIMEOUT_MS> -- npx -y @three-ws/tutor-mcp
```
Replace <…> with your own values

### Cursor

**Config file**
File `.cursor/mcp.json`:
```json
{
    "mcpServers": {
        "tutor-mcp": {
            "command": "npx",
            "args": [
                "-y",
                "@three-ws/tutor-mcp"
            ],
            "env": {
                "THREE_WS_BASE": "<THREE_WS_BASE>",
                "THREE_WS_TIMEOUT_MS": "<THREE_WS_TIMEOUT_MS>"
            }
        }
    }
}
```
Replace <…> with your own values

### GitHub Copilot

**Config file**
File `.vscode/mcp.json`:
```json
{
    "servers": {
        "tutor-mcp": {
            "type": "stdio",
            "command": "npx",
            "args": [
                "-y",
                "@three-ws/tutor-mcp"
            ],
            "env": {
                "THREE_WS_BASE": "<THREE_WS_BASE>",
                "THREE_WS_TIMEOUT_MS": "<THREE_WS_TIMEOUT_MS>"
            }
        }
    }
}
```
Replace <…> with your own values

### Gemini CLI

**Platform CLI**
```bash
gemini mcp add -e THREE_WS_BASE=<THREE_WS_BASE> -e THREE_WS_TIMEOUT_MS=<THREE_WS_TIMEOUT_MS> tutor-mcp npx -y @three-ws/tutor-mcp
```
Replace <…> with your own values

## When to use it
- read a session's line items and running total
- see what each answered question cost
- close a session and get an attested invoice
- lock billing once a tutoring session ends
- confirm nothing has been charged on a session yet

## Example prompts
- Show the line items and total for session `learn-abc123`
- Close `learn-abc123` and give me the attested invoice
- Load the tab for the `sessionId` the learner sent

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From the same set: [nirholas/three.ws](https://affpapa.org/en/nevibecode/by/nirholas/three.ws.md) — 43 cards

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