Karbon MCP Server

Name: Karbon MCP Server
Author: Mad-Man-Dan

by Mad-Man-Danversion 0.2.4i★ –iRuns on your computer

Registry nameio.github.Mad-Man-Dan/karbon-mcp-server

Install

Overview

Description from the maker (original English)

Unofficial MCP server for Karbon practice management: contacts, work, time, invoices, payments.

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
UsageiVery new↓ 82/wk · ★ –

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: Runs on your computer
Transport: stdio
Category: Accounting, finance & tax
You need to fill in: KARBON_BEARER_TOKEN, KARBON_ACCESS_KEY

Install

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

Before you install

Basic checks: 1 of 1 passed
Runs on your computer with your user’s permissions (files, network, apps).
You fill in yourself: KARBON_BEARER_TOKEN, KARBON_ACCESS_KEY, KARBON_READ_ONLY, KARBON_ALLOW_PAYMENT_WRITES

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

You need

npmNode.js installed (for the npx command)

Which app do you use?

ClaudeClaude CodeCursorVS CodeChatGPT

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

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

{
  "mcpServers": {
    "karbon": {
      "command": "npx",
      "args": [
        "-y",
        "karbon-mcp-server"
      ],
      "env": {
        "KARBON_BEARER_TOKEN": "your-value",
        "KARBON_ACCESS_KEY": "your-value",
        "KARBON_READ_ONLY": "your-value",
        "KARBON_ALLOW_PAYMENT_WRITES": "your-value"
      }
    }
  }
}

Run this in your terminal

claude mcp add karbon --env KARBON_BEARER_TOKEN=your-value --env KARBON_ACCESS_KEY=your-value --env KARBON_READ_ONLY=your-value --env KARBON_ALLOW_PAYMENT_WRITES=your-value -- npx -y karbon-mcp-server

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": {
    "karbon": {
      "command": "npx",
      "args": [
        "-y",
        "karbon-mcp-server"
      ],
      "env": {
        "KARBON_BEARER_TOKEN": "your-value",
        "KARBON_ACCESS_KEY": "your-value",
        "KARBON_READ_ONLY": "your-value",
        "KARBON_ALLOW_PAYMENT_WRITES": "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": {
    "karbon": {
      "type": "stdio",
      "command": "npx",
      "args": [
        "-y",
        "karbon-mcp-server"
      ],
      "env": {
        "KARBON_BEARER_TOKEN": "your-value",
        "KARBON_ACCESS_KEY": "your-value",
        "KARBON_READ_ONLY": "your-value",
        "KARBON_ALLOW_PAYMENT_WRITES": "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.

This one runs on your computer, and ChatGPT can only connect to servers on the internet. Pick another app.

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

Values you fill in

KARBON_BEARER_TOKEN secret required env
Bearer token (Application Authorization Token) from Karbon → Settings → Connected Apps → API Applications
KARBON_ACCESS_KEY secret required env
Access key (JWT starting with 'ey') from Karbon → Settings → Connected Apps → API Applications
KARBON_READ_ONLY env
Set to 'true' to disable all create/update tools (they are not registered at all)
KARBON_ALLOW_PAYMENT_WRITES env
Set to 'true' to enable the payment write tools (create/delete/reverse manual payments); off by default

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

What it can do

Runs on your computer; the tool list appears in your AI app after you install it.

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 9, 2026

✓ Pass
Maker matches the repo
The registry name was verified with the GitHub account Mad-Man-Dan, which owns the repo
… 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 applicable
Endpoint responds
This one runs on your computer; there is no internet endpoint
– Not applicable
Sign-in with OAuth
Runs on your computer and uses local settings instead
… Not checked yet
No hidden instructions in tool descriptions
Runs on your computer; we can only read tool lists from internet endpoints

Compared with others in Accounting, finance & taxi

More stars than 0% of the other 2966 servers in this category
Published to the registry more recently than 20% of the other 2966 servers in this category
Basic checks equal to or better than 100% of the other 2966 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 Karbon MCP Server 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: KARBON_BEARER_TOKEN, KARBON_ACCESS_KEY

Does it run on my computer or in the cloud?

It runs on your computer. Your AI app starts it when needed, and data does not pass through the maker’s servers (unless it calls an online service itself).

Is it still maintained?

The GitHub repo last changed –, and the latest version (0.2.4) reached the registry 4 months ago.

Which apps can use it?

Apps that support MCP, such as Claude Desktop, Claude Code, Cursor and VS Code. You also need Node.js on your computer.

What can I use instead?

In the same category: Finance Toolkit, SolidInvoice, Korea Tax Calculator

Alternatives

Servers in the same category from other makers, sorted by stars.

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

Finance Toolkit

500+ transparent financial methods calculated from raw statements, not third-party endpoints.

by JerBoumaWidely used↓ 15.5K/wk★ 5.5KUpdated 2 days ago

Computer or cloud

Install

SolidInvoice

Create and send invoices and quotes, manage clients, and track payments in SolidInvoice.

by SolidInvoiceGrowing★ 981Updated 10 days ago

Runs in the cloud✓ solidinvoice.co

Install

Korea Tax Calculator

Korean tax calculation and tax-audit judgment MCP: 96 tools with statutory citations.

by UpstageAIGrowing↓ 3.2K/wk★ 97Updated today

Runs on your computer

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.

Karbon MCP Server

🚧 Early release — this project is brand new and we're actively making updates over the next few days. Things may change quickly; pin a version if you need stability, and check back soon.

An unofficial Model Context Protocol server for Karbon practice management. Connect Claude Code, Claude Desktop, GitHub Copilot, or any MCP-compatible client to your Karbon instance and work with contacts, work items, time, invoices, payments, files, and more using natural language.

Disclaimer: This is a community project and is not affiliated with or endorsed by Karbon. Use at your own risk.

Features

Area	Tools
Contacts	`list_contacts`, `get_contact`, `create_contact`, `update_contact`
Organizations	`list_organizations`, `get_organization`, `create_organization`, `update_organization`
Client groups	`list_client_groups`, `get_client_group`, `create_client_group`, `update_client_group`
Work items	`list_work_items`, `get_work_item`, `get_estimate_summary`, `create_work_item`, `update_work_item`
Notes & comments	`get_note`, `create_note`, `get_comment`
Timesheets	`list_timesheets`, `get_timesheet`, `list_time_entries`, `get_time_entry` (read-only)
Invoices	`list_invoices`, `get_invoice` (read-only)
Payments	`list_payments`, `get_payment`; plus `create_manual_payment`, `delete_manual_payment`, `reverse_manual_payment` behind `KARBON_ALLOW_PAYMENT_WRITES=true`
Business cards	`get_business_card`, `update_business_card` — contact details (email, phone, address)
Custom fields	`list_custom_fields`, `get_custom_field_values`, `set_custom_field_values`, `create_custom_field`, `delete_custom_field`
Files	`list_entity_files`, `download_file`, `upload_file`
Teams	`list_teams`, `get_team`, `add_team_members`, `remove_team_member`
Work schedules	`get_work_schedule`, `create_work_schedule`, `update_work_schedule`
Users	`list_users`, `get_user`
Account	`get_tenant_settings`, `list_work_templates`, `get_work_template`

get_contact, get_organization, and get_client_group can also look records up by your own UserDefinedIdentifier instead of the Karbon key — handy if you sync IDs from your tax software.

All list tools support OData filtering ($filter), ordering ($orderby), and pagination ($top/$skip) — so you can ask things like *"show my in-progress work items due this month"* and the AI can express that as a precise query.

Prerequisites

Node.js 18+
Karbon API credentials. In Karbon go to Settings → Connected Apps → API Applications and copy your Bearer Token and Access Key. (Karbon help article)

Setup

Step-by-step walkthroughs for Claude Desktop, claude.ai/Cowork, and ChatGPT (written for non-developers) are in docs/client-guides.md.

Claude Desktop: one-click bundle

Download karbon-mcp-server.mcpb from the latest release and double-click it. Claude Desktop opens a form for your two Karbon keys (stored securely by your OS) plus a read-only toggle — no terminal needed. Walkthrough.

One-line install (nothing to download first)

No Node.js? These check for it (installing via winget/Homebrew where possible), then run the setup wizard straight from npm — no repo clone, no manual download:

# Windows (PowerShell)

irm https://raw.githubusercontent.com/Mad-Man-Dan/karbon-mcp-server/main/scripts/install.ps1 | iex

# macOS / Linux

curl -fsSL https://raw.githubusercontent.com/Mad-Man-Dan/karbon-mcp-server/main/scripts/install.sh | bash

Quickest with Node.js installed: automatic setup

npx -y karbon-mcp-server setup

Setup asks a few quick questions — project or user-level install, your API keys (skippable), and whether to enable read-only mode — then does everything else automatically:

This project (the default): writes .mcp.json (Claude Code), plus .vscode/mcp.json and .cursor/mcp.json if those folders exist in the project.
User account: detects which MCP clients are installed on your machine — Claude Code, Codex, Claude Desktop, VS Code, Cursor — and adds the server to each (for Claude Code and Codex it uses their own mcp add CLI).

It then offers to take your two Karbon keys (Enter skips either one):

Input is masked — you see a * per character, then a first-4/last-4 preview (like 1a2b****5c6d, the same style Karbon's site uses) so you can confirm what was entered, with a gentle warning if the format looks off (the Bearer Token is a GUID; the Access Key starts with ey...).
Keys are written only to your MCP client's local config file on your machine — the same file a manual setup would use. They are never sent anywhere else.
If you skip, placeholder values are written and setup tells you exactly which file(s) to edit later.

It backs up every existing config file before touching it, merges rather than overwrites, and never replaces real credentials with placeholders (re-running and skipping the prompts keeps your existing keys). If you go project-level, gitignore the config files — your keys live in them in plain text.

Options:

npx -y karbon-mcp-server setup --scope project          # skip the question

npx -y karbon-mcp-server setup --scope user npx -y karbon-mcp-server setup --read-only # disable all write tools npx -y karbon-mcp-server setup --client vscode,cursor # only these clients

ids: claude-code, codex, claude-desktop, vscode, cursor

npx -y karbon-mcp-server setup --print # just print the JSON

One-click installs

The Install in VS Code / Cursor badges above create the server entry for you with placeholder credentials. After installing, replace YOUR_BEARER_TOKEN and YOUR_ACCESS_KEY with your real keys — in VS Code via the Command Palette → MCP: Open User Configuration, in Cursor by editing ~/.cursor/mcp.json.

If you run the server before replacing the placeholders, it starts fine and every tool responds with setup instructions instead of failing cryptically — so you can even ask your AI assistant "why isn't Karbon working?" and it will tell you what to do.

Prefer to configure things by hand? Each client is below.

Claude Code

claude mcp add karbon \

--env KARBON_BEARER_TOKEN=your-bearer-token \ --env KARBON_ACCESS_KEY=your-access-key \ -- npx -y karbon-mcp-server

Claude Desktop

Add to claude_desktop_config.json:

"mcpServers": { "karbon": { "command": "npx", "args": ["-y", "karbon-mcp-server"], "env": { "KARBON_BEARER_TOKEN": "your-bearer-token", "KARBON_ACCESS_KEY": "your-access-key" } } } }

VS Code (GitHub Copilot)

Add to .vscode/mcp.json in your workspace (or your user mcp.json):

"servers": { "karbon": { "command": "npx", "args": ["-y", "karbon-mcp-server"], "env": { "KARBON_BEARER_TOKEN": "your-bearer-token", "KARBON_ACCESS_KEY": "your-access-key" } } } }

Cursor

Add to ~/.cursor/mcp.json (or use the install badge above):

"mcpServers": { "karbon": { "command": "npx", "args": ["-y", "karbon-mcp-server"], "env": { "KARBON_BEARER_TOKEN": "your-bearer-token", "KARBON_ACCESS_KEY": "your-access-key" } } } }

Codex (OpenAI Codex CLI)

codex mcp add karbon \

--env KARBON_BEARER_TOKEN=your-bearer-token \ --env KARBON_ACCESS_KEY=your-access-key \ -- npx -y karbon-mcp-server

Or add to ~/.codex/config.toml:

[mcp_servers.karbon]

command = "npx" args = ["-y", "karbon-mcp-server"]

[mcp_servers.karbon.env] KARBON_BEARER_TOKEN = "your-bearer-token" KARBON_ACCESS_KEY = "your-access-key"

ChatGPT, claude.ai chat & Claude Cowork (remote connectors)

These clients can't launch local servers — they only connect to a remote MCP server over HTTPS. This package includes a streamable-HTTP mode for exactly that, so a firm can self-host it and keep their Karbon keys in their own infrastructure:

KARBON_BEARER_TOKEN=... KARBON_ACCESS_KEY=... KARBON_HTTP_SECRET=some-long-random-string \

npx -y karbon-mcp-server --http --port 8787

This serves the MCP endpoint at /mcp/ (plus a /health check). Expose it over HTTPS however you like — the quickest free option is a Cloudflare Tunnel:

cloudflared tunnel --url http://localhost:8787

Then add the URL (e.g. https://your-tunnel.trycloudflare.com/mcp/your-secret) as:

claude.ai / Cowork: Settings → Connectors → Add custom connector (Pro/Max/Team/Enterprise plans)
ChatGPT: Settings → Connectors (requires developer mode for full tool access)

Security notes: anyone with the full URL has the same Karbon access as your API keys, so use a long random KARBON_HTTP_SECRET, always front it with HTTPS, and consider KARBON_READ_ONLY=true for remote use. There is deliberately no shared/hosted instance of this server — your keys should only ever live on infrastructure you control.

Configuration

Environment variable	Required	Description
`KARBON_BEARER_TOKEN`	Yes	Bearer token from Karbon Connected Apps
`KARBON_ACCESS_KEY`	Yes	Access key (JWT) from Karbon Connected Apps
`KARBON_READ_ONLY`	No	Set to `true` to disable all create/update tools
`KARBON_ALLOW_PAYMENT_WRITES`	No	Set to `true` to enable the payment write tools (create/delete/reverse manual payments). Off by default
`KARBON_API_BASE_URL`	No	Override the API base URL (default `https://api.karbonhq.com/v3`)
`KARBON_HTTP_SECRET`	No	HTTP mode only: secret path segment for the endpoint (`/mcp/` )
`PORT`	No	HTTP mode only: port to listen on (default 8787; `--port` wins)

Read-only mode

If you want a guarantee that the AI can never modify your Karbon data, set KARBON_READ_ONLY=true (or pass --read-only). Write tools are not registered at all in this mode, so the AI never sees them. This also disables download_file — it doesn't change Karbon, but it writes to the local disk, and read-only means no writes anywhere. The setup wizard asks about this.

Changing it later: setup always writes the toggle explicitly ("KARBON_READ_ONLY": "true" or "false"), so the switch is right there i

Only the beginning is shown; read the rest in the repo

Karbon MCP Server

Overview

PopNx MCP’s three pillars

What you can do with it

Install

Before you install

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 Accounting, finance & taxi

Common questions

Alternatives

Finance Toolkit

SolidInvoice

Korea Tax Calculator

README from the maker

Karbon MCP Server

Features

Prerequisites

Setup

Claude Desktop: one-click bundle

One-line install (nothing to download first)

Quickest with Node.js installed: automatic setup

ids: claude-code, codex, claude-desktop, vscode, cursor

One-click installs

Claude Code

Claude Desktop

VS Code (GitHub Copilot)

Cursor

Codex (OpenAI Codex CLI)

ChatGPT, claude.ai chat & Claude Cowork (remote connectors)

Configuration

Read-only mode