tab

Name: tab
Author: paidwithtab

by paidwithtabversion 3.0.0i★ –iRuns on your computer

Registry nameio.github.paidwithtab/tab

Install

Overview

Description from the maker (original English)

Agents pay per call over HTTP 402 and x402: 8,600+ API routes, signed budgets and receipts.

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: Runs on your computer
Transport: stdio
Category: Other

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: TAB_AGENT, TAB_MANDATE, TAB_MAX_PER_CALL, TAB_CATALOG

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": {
    "tab": {
      "command": "npx",
      "args": [
        "-y",
        "paidwithtab",
        "mcp"
      ],
      "env": {
        "TAB_AGENT": "your-value",
        "TAB_MANDATE": "your-value",
        "TAB_MAX_PER_CALL": "your-value",
        "TAB_CATALOG": "your-value"
      }
    }
  }
}

Run this in your terminal

claude mcp add tab --env TAB_AGENT=your-value --env TAB_MANDATE=your-value --env TAB_MAX_PER_CALL=your-value --env TAB_CATALOG=your-value -- npx -y paidwithtab 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": {
    "tab": {
      "command": "npx",
      "args": [
        "-y",
        "paidwithtab",
        "mcp"
      ],
      "env": {
        "TAB_AGENT": "your-value",
        "TAB_MANDATE": "your-value",
        "TAB_MAX_PER_CALL": "your-value",
        "TAB_CATALOG": "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": {
    "tab": {
      "type": "stdio",
      "command": "npx",
      "args": [
        "-y",
        "paidwithtab",
        "mcp"
      ],
      "env": {
        "TAB_AGENT": "your-value",
        "TAB_MANDATE": "your-value",
        "TAB_MAX_PER_CALL": "your-value",
        "TAB_CATALOG": "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

TAB_AGENT env
Agent key file. Default ~/.tab/agent.json, which `npx paidwithtab init` creates with a mandate and starter credits.
TAB_MANDATE env
Owner-signed mandate file. Default ~/.tab/mandate.json.
TAB_MAX_PER_CALL env
Refuse any single call priced above this many dollars, e.g. 0.05.
TAB_CATALOG env
Catalog to search. Default https://paidwithtab.com.

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 7, 2026

✓ Pass
Maker matches the repo
The registry name was verified with the GitHub account paidwithtab, 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 Otheri

More stars than 0% of the other 32606 servers in this category
Published to the registry more recently than 89% of the other 32606 servers in this category
Basic checks equal to or better than 100% of the other 32606 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 tab 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?

The registry does not list a required key, though some servers ask you to sign in on first use.

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 (3.0.0) reached the registry 4 days 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: Spec Driven Development, Remote Desktop Commander, Georgia MCP

Alternatives

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Georgia MCP

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An MCP server for Georgian public data, read from the organizations that publish it.

Computer or cloudUpdated today

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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.

Payments for software agents.

Give an agent a wallet with rules, instead of giving it your wallet.

Quickstart · Run a company · For agents · For sellers · Protocol · Deployment · @paidwithtab

What is tab · Why tab · Mandates · New in 3.0 · How a payment works · Quickstart · For API providers · For agent developers · Companies · Settlement · x402 · Security model · Testing · Architecture · Roadmap

What is tab

tab is an open payment protocol for software agents.

It lets an agent discover a paid HTTP service, receive a price, authorize the purchase against rules set by its owner, pay, and receive the result. No human has to create an account, enter a card, or copy an API key.

Owners define those rules once, in a signed mandate:

Constraint	Purpose
Total budget	Caps lifetime spend
Maximum price per request	Blocks a single expensive call
Allowed sellers	Restricts where money can go
Spending window	Resets the budget each UTC day, or keeps one lifetime total
Expiration	Ends the authority automatically

The owner signs once. The agent then transacts on its own, and it cannot exceed what the owner authorized.

Owner

│ │ signs mandate ▼ Agent │ │ HTTP request ▼ Gateway ────────► API │ │ verifies mandate │ enforces budget │ settles payment ▼ USDG

Why tab

Software agents can already call APIs and use tools. Paying for those services is the part that still requires a person.

Today a human creates an account, enters payment information, generates an API key, configures billing, and hands credentials to the agent. tab replaces all of that with an HTTP payment.

Without tab With tab

Agent calls API

HTTP/1.1 402 Payment Required

Account signup, card on file, API key handoff, billing setup.

Agent pays through tab

HTTP/1.1 200 OK Tab-Receipt: evm:0x...

No account. No card details. No shared owner key. No unrestricted wallet.

Mandates

A mandate is a signed spending authorization from an owner to an agent.

Field	Example
Agent	`7f2c...`
Budget	`$25.00`
Maximum per call	`$0.05`
Allowed sellers	`api.example.com`
Expires	`2026-10-01`

The owner key never has to be online while the agent is working. Every payment is checked independently by the seller's gateway against the signed mandate, so changing the agent's prompt cannot increase its authority.

New in 3.0

Five things an owner can do after the mandate is signed, all optional, all backward compatible with 2.x mandates, clients and receipts.

Feature	What it does	From the CLI
Instant revoke	The owner signs a revocation; gateways refuse the mandate, and every sub-mandate under it, within seconds. Gateways pass revocations to each other.	`tab mandate revoke --key owner.json --mandate m.json --gateway https://pay.example.com`
Sub-mandates	An agent hands a narrower slice of its mandate to another agent key. Every limit stays inside the parent's, spend counts against every level, chains stop at three delegations.	`tab mandate delegate --agent-key agent.json --mandate m.json --to helper.json --budget 0.25`
Approval above a threshold	`approve_above` on the mandate: a bigger payment waits for a fresh approval the owner signs for exactly that call. The agent retries and it pays once.	`tab mandate issue ... --approve-above 0.50`, then `tab mandate approve --owner owner.json --request req.json --gateway ...`
Pay on delivery	On routes that offer it, the buyer's payment is held until the seller delivers a result, then released with a receipt that binds the request to the result. Undelivered by the deadline, it comes back.	`tab fetch --escrow --wait 300 -X POST -d '{...}' https://pay.example.com/jobs/essay`
Payment channels	One deposit, then a signed voucher per call with no transaction per call, settled once at close. Metered routes charge per token, second or unit, a fraction of a cent at a time.	`tab channel open --gateway https://pay.example.com --deposit 1.00`, then `tab fetch --channel ...`

In tab OS each one has a home: a Revoke button on runs and agents, delegated budgets on a manager's card, payment approvals in the Inbox (with a thumb sized Approve on a phone), orders paid on delivery in Receipts, and channels in the Wallet. SPEC.md sections 2.1, 2.2, 5.4, 5.5 and 5.6 are the wire format.

How a payment works

tab uses standard HTTP payment semantics. A priced endpoint answers with 402 Payment Required and a signed challenge describing the purchase. The agent checks the price against its mandate and signs a credential bound to that exact request.

The gateway then runs the full lifecycle:

Step	Action
1	Verify the challenge
2	Verify the mandate
3	Verify the agent
4	Verify the exact request
5	Reserve the budget
6	Call the upstream service
7	Settle only after a successful response
8	Return a signed receipt

If the upstream service fails, the payment is voided.

The receipt is signed by a key the gateway publishes, and it binds the whole purchase together: the mandate that allowed it, the exact request the agent signed, a hash of the response body that came back, the seller, and the payment (on Robinhood Chain, the transaction hash). So a receipt proves what was bought, not just that money moved. The client checks it against the bytes it received, and any edit breaks it.

Quickstart

Requires Node.js 22.13 or newer.

Give an agent a tab in one command:

npx paidwithtab init

This creates an owner key and an agent key in ~/.tab, signs a mandate ($1.00 per day, $0.05 per call, 90 days), and claims $1.00 of starter credits on the public gateway at pay.paidwithtab.com. Nothing to fund, no chain, no API keys.

Those credits buy real things: 8,638 routes across 484 services, from web search, translation and speech to text to block explorers for 42 chains, market data from 20 exchanges, Wikipedia in 48 languages, SEC filings, US Treasury data, genomes, proteins and chemistry, package registries, RDAP and DNS, weather and space weather, between $0.001 and $0.02 a call. The full list with prices is in the quickstart.

1. Pay for something from the shell.

npx paidwithtab fetch "https://pay.paidwithtab.com/wikipedia/api/rest_v1/page/summary/Lisbon"

paid 0.001 (ledger:cpKKYHocOLKlDW8n)

{"type":"standard","title":"Lisbon", ...}

2. Let Claude Code spend.

claude mcp add --scope user tab -- npx -y paidwithtab mcp

Then ask Claude for something it needs to pay for, for example "find the weather in Lisbon through tab". It searches the catalog at paidwithtab.com/catalog, pays per request, and can never exceed the mandate.

3. See a price tag.

curl -i https://pay.paidwithtab.com/fx/latest?base=USD

HTTP/1.1 402 Payment Required

WWW-Authenticate: Tab challenge="eyJ2ZXIiOiJ0YWIvMCIs..."

The starter credits are sandbox money on that one gateway. For real money, fund an agent with USDG on Robinhood Chain: docs/buyers.md.

Want the whole stack on your machine? git clone https://github.com/paidwithtab/tab && cd tab && npm install && npm run demo starts a paid API, a gateway, a catalog and a local wallet. [Full walkthrough](docs/quickstart.md)

For API providers

Any HTTP API becomes payable with a small JSON specification. Leave out rail to run on sandbox balances while you develop.

"realm": "api.example.com", "recipient": " ", "rail": "evm", "evm": { "rpc": "https://rpc.testnet.chain.robinhood.com", "chain_id": 46630, "token": "0x5B6C7cAF7F99f99154fD8375ec935Fcf03F326f5", "decimals": 6, // the token's decimals, 0 to 18; USDG and USDC have 6 "recipient": " " }, "upstream": "http://127.0.0.1:8080", "routes": [ { "method": "GET", "path": "/v1/things/:id", "price": "0.01" }, { "method": "POST", "path": "/v1/generate", "price": "0.002" } ] }

Start the gateway:

tab serve \

--spec spec.json \ --announce https://paidwithtab.com

The gateway handles payment negotiation, authorization, settlement, receipts, and proxying. Your application keeps serving normal HTTP.

[Read the seller documentation](docs/sellers.md)

For agent developers

1. Create an agent key.

tab key new --out agent.json

2. Issue it a mandate.

tab mandate issue \

--owner owner.json \ --agent agent.json \ --budget 5.00 \ --window day \ --max-per-call 0.05 \ --allow 'api.example.com' \ --out mandate.json

3. Spend within those limits.

import { TabClient, receiptOf } from 'paidwithtab/client';

const client = new TabClient({ agent, mandate, maxPerCallUsd: '0.05', });

const url = 'https://api.example.com/v1/things/42'; const res = await client.fetch(url); const body = new Uint8Array(await res.arrayBuffer());

console.log(receiptOf(res)?.ref); console.log(await client.verify(url, res, body)); // { ok: true }

Or skip the key handling: npx paidwithtab init does all three steps and claims starter credits on the public gateway.

tab also exposes five MCP tools, so compatible agents can discover and purchase services without ever receiving the owner's private key:

Tool	Purpose
`tab_search`	Find services in a catalog
`tab_discover`	Inspect a service and its pricing
`tab_fetch`	Make a paid request
`tab_balance`	Check remaining budget
`tab_limits`	Read the active mandate constraints

[Read the buyer documentation](docs/buyers.md)

Hooking tab into a particular agent, with the MCP JSON for Cursor, Codex, Windsurf and Claude Desktop, framework tools, Python by subprocess, and where keys live in production: [docs/agents.md](docs/agents.md)

Companies

tab 2.2 runs a company of agents on top of the payment layer: tab company and the dashboard at app.paidwithtab.com. A company has a mission, a budget, agents with roles, and tickets. An agent is Claude, running on the Anthropic API key you add to the company with the five tab tools and nothing else, or

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

tab

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 Otheri

Common questions

Alternatives

Spec Driven Development

Remote Desktop Commander

Georgia MCP

README from the maker

Contents

What is tab

Why tab

Mandates

New in 3.0

How a payment works

Quickstart

For API providers

For agent developers

Companies