Xzar

Name: Xzar
Author: xzar-si

by xzar-siversion 0.1.2i★ –iComputer or cloud

Registry namesi.xzar/xzar

Install

Overview

Description from the maker (original English)

Crash-test your AI agent on real professional decisions, graded against what actually happened.

PopNx MCP’s three pillars

These three are never merged into one score: opinions, measurements and popularity are different things.

User voiceiNo reviews yetReviews open together with accounts in a later step
Our basic checksi1 of 1 passedChecked from public information; code not scanned yet
UsageiNot measured yet★ –

What you can do with it

We have not written a plain-language summary for this one yet. Below are the facts we read from the registry.

Connection: Computer or cloud
Transport: stdio, Streamable HTTP
Category: Other
You need to fill in: XZAR_API_KEY

Install

Pick the AI app you use, then copy the settings.

Before you install

Basic checks: 1 of 1 passed
Runs on the maker’s server: what you ask it goes through their server.
You fill in yourself: XZAR_API_KEY, XZAR_API_URL

Values marked secret are keys to your account. Never share them or paste them into a chat.

You need

Runs in the cloudNothing to install; it connects over the internet
PyPIPython’s uv installed (for the uvx command)

Which app do you use?

ClaudeClaude CodeCursorVS CodeChatGPT

Pick your app above. We remember it, so next time the button says “Install in …”.

Works in Claude on the web, desktop and mobile:

Open Settings → Connectors
Press Add custom connector
Paste the address below and press Add
If it asks you to sign in, sign in with the maker

https://api.xzar.si/mcp

Or run it on your computer

Open Claude Desktop → Settings → Developer → Edit Config, and paste this into claude_desktop_config.json

{
  "mcpServers": {
    "xzar": {
      "command": "uvx",
      "args": [
        "xzar-mcp"
      ],
      "env": {
        "XZAR_API_KEY": "your-value",
        "XZAR_API_URL": "your-value"
      }
    }
  }
}

Run this in your terminal

claude mcp add --transport http xzar https://api.xzar.si/mcp

Or run it on your computer

claude mcp add xzar --env XZAR_API_KEY=your-value --env XZAR_API_URL=your-value -- uvx xzar-mcp

Fill in the empty values before running it.

Open in Cursor

Or copy the settings yourself

Paste into .cursor/mcp.json in your project, or ~/.cursor/mcp.json

{
  "mcpServers": {
    "xzar": {
      "url": "https://api.xzar.si/mcp"
    }
  }
}

Or run it on your computer

Open in Cursor

Or copy the settings yourself

Paste into .cursor/mcp.json in your project, or ~/.cursor/mcp.json

{
  "mcpServers": {
    "xzar": {
      "command": "uvx",
      "args": [
        "xzar-mcp"
      ],
      "env": {
        "XZAR_API_KEY": "your-value",
        "XZAR_API_URL": "your-value"
      }
    }
  }
}

Your browser asks to open the app, then the app shows the settings and asks you to confirm. Key values are left empty for you to fill in.

Open in VS Code

Or copy the settings yourself

Paste into .vscode/mcp.json in your project

{
  "servers": {
    "xzar": {
      "type": "http",
      "url": "https://api.xzar.si/mcp"
    }
  }
}

Or run it on your computer

Open in VS Code

Or copy the settings yourself

Paste into .vscode/mcp.json in your project

{
  "servers": {
    "xzar": {
      "type": "stdio",
      "command": "uvx",
      "args": [
        "xzar-mcp"
      ],
      "env": {
        "XZAR_API_KEY": "your-value",
        "XZAR_API_URL": "your-value"
      }
    }
  }
}

Your browser asks to open the app, then the app shows the settings and asks you to confirm. Key values are left empty for you to fill in.

ChatGPT connects only to servers on the internet:

Open ChatGPT on the web → Settings → Connectors (Apps)
Press Create or Add (some plans need Developer mode under Advanced first)
Paste the address below, give it a name and save
If it asks you to sign in, sign in with the maker

https://api.xzar.si/mcp

Menu names can differ slightly by plan and over time.

Your choice stays on this device in a cookie; no account needed.

Values you fill in

XZAR_API_KEY secret required env
Your Xzar API key (https://xzar.si/signup.html)
XZAR_API_URL env
Override the API base URL (default https://api.xzar.si); for local development only

These settings are generated from the maker’s registry entry. If the README says otherwise, follow the README.

What it can do

We have not read this server’s tool list yet; we check endpoints in rotation.

Basic checksi

We check information anyone can see; we have not read the code. Checks that do not apply are left out of the count. · Checked Nov 7, 2026

✓ Pass
Maker matches the repo
The registry name was verified against the domain xzar.si (the registry checks domain ownership)
… Not checked yet
Still maintained
We have not read this repo from GitHub yet
… Not checked yet
Has a licence
We have not read this repo from GitHub yet
… Not checked yet
Endpoint responds
Not checked yet; we check endpoints in rotation
… Not checked yet
Sign-in with OAuth
Not checked yet; we check endpoints in rotation
… Not checked yet
No hidden instructions in tool descriptions
Not checked yet; we read the tool list when we check the endpoint

Compared with others in Otheri

More stars than 0% of the other 32744 servers in this category
Published to the registry more recently than 63% of the other 32744 servers in this category
Basic checks equal to or better than 100% of the other 32744 servers in this category

Compared with every active server in this category in the registry. Stars count only when the publisher owns the repo.

Common questions

Is Xzar safe?

It passed 1 of 1 applicable basic checks. We have not read the code. Before adding a key or token, see what access the server asks for and use a key with only the permissions you need.

What keys or codes does it need?

You need to fill in: XZAR_API_KEY

Does it run on my computer or in the cloud?

Either way works: install it on your computer or connect to the cloud version.

Is it still maintained?

The GitHub repo last changed –, and the latest version (0.1.2) reached the registry 22 days ago.

Which apps can use it?

Apps that support MCP, such as Claude Desktop, Claude Code, Cursor and VS Code. It connects by URL, so apps that accept remote MCP servers work too, such as ChatGPT in developer mode.

What can I use instead?

In the same category: Spec Driven Development, Remote Desktop Commander, Date Math

Alternatives

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Reading a card:★ GitHub starsiThree pillars: reviews · checks · usageiUpdated = latest version published to the registryi

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MCP Server that facilitates spec-driven development workflows, not just Vibe Coding.

Runs on your computer★ 440MITUpdated 14 months ago

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Remote Desktop Commander

by desktop-commander

Remote Desktop Commander: use files, terminal and processes on your own computers from any AI app.

Runs in the cloud★ 211Updated 2 days ago

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Date Math

by JowenDelaPena

Exact date/time math for agents: business days, holidays, time zones, cron, RRULE, SLA. x402 paid.

Runs in the cloudUpdated today

Install

README from the maker

Open the README

Copied from the maker’s repo as written. PopNx MCP has not reviewed or endorsed it. HTML, images and scripts are removed. Links lead off this site.

Xzar MCP server

Crash-test your AI agent on real professional decisions. Xzar gives your agent real cases, cut at the moment of decision, and grades its answer against what the professional actually decided. Most cases were decided after current models were trained, so they can't have been memorized; fresh ones are added monthly.

Live today:

Tariff classification: real U.S. classification decisions, graded exactly at 2, 4, 6, 8 and 10 digits, with a consistency check (the same case asked twice). Testing a tariff classifier? See https://xzar.si/scorecard
Patent examination: first action, response and appeal.

More fields are on the way; ask for yours at https://xzar.si.

Setup

Get an API key (with $5 of free credit) at https://xzar.si/signup.html
Add the server to your MCP client:

"mcpServers": { "xzar": { "command": "uvx", "args": ["xzar-mcp"], "env": { "XZAR_API_KEY": "your-key" } } } }

Hosted connector (no install)

In Claude or any MCP client that supports remote servers: add https://api.xzar.si/mcp and sign in with your Xzar API key.

Claude plugin

The plugin/ folder is the Xzar plugin for Claude. It bundles the hosted connector with two skills: crash-test, which runs a task end to end and explains the score, and xzar-request, for custom tests, pilots, quotes and training access. In Claude Code:

/plugin install xzar --marketplace xzar-si/xzar-mcp

Tools

Tool	What it does
`start_task`	Start a task: the case, the instructions and the tool budget
`search_library`	Search the case's reference library
`read_publication`	Read one library item
`search_rules`	Search the professional rulebook for the task
`read_rule`	Read one rulebook section
`submit_answer`	Submit the decision; returns the exact score and the grade receipt
`request_service`	Ask for a custom test for your field, a pilot, a quote, or training access; get a reference and next steps
`get_scorecard`	Your agent's scorecard across tasks
`get_usage`	Credit balance and usage

Answer keys never leave Xzar's servers. This package holds no tasks; it calls the Xzar API with your key.

Pricing

Prepaid credits, charged per task. See https://xzar.si/docs.html. Pilots and ongoing testing: https://xzar.si.

Xzar

Overview

PopNx MCP’s three pillars

What you can do with it

Install

Before you install

Or run it on your computer

Or run it on your computer

Or run it on your computer

Or run it on your computer

Values you fill in

What it can do

Basic checksi

Maker matches the repo

Still maintained

Has a licence

Endpoint responds

Sign-in with OAuth

No hidden instructions in tool descriptions

Compared with others in Otheri

Common questions

Alternatives

Spec Driven Development

Remote Desktop Commander

Date Math

README from the maker

Xzar MCP server

Setup

Hosted connector (no install)

Claude plugin

Tools

Pricing