# How to connect Mercury MCP to Claude Cowork

```json
{
  "title": "How to connect Mercury MCP to Claude Cowork",
  "toolkit": "Mercury MCP",
  "toolkit_slug": "mercury_mcp",
  "framework": "Claude Cowork",
  "framework_slug": "claude-cowork",
  "url": "https://composio.dev/toolkits/mercury_mcp/framework/claude-cowork",
  "markdown_url": "https://composio.dev/toolkits/mercury_mcp/framework/claude-cowork.md",
  "updated_at": "2026-06-18T09:41:42.133Z"
}
```

## Introduction

Cowork is Anthropic's AI agent for knowledge work. Think of it as Claude Code for everything else. It works autonomously with your computer, local files, and applications to accomplish complex tasks.
This guide walks you through the easiest and most secure way to connect your Mercury MCP account to Cowork via Composio Connect, enabling it to list Mercury accounts and current balances, summarize recent Mercury card transactions, find last month’s Mercury bank statements, and more such actions on your behalf without compromising your account security.

## Also integrate Mercury MCP with

- [Codex](https://composio.dev/toolkits/mercury_mcp/framework/codex)

## Connect Mercury MCP to Claude Cowork

### Connecting Mercury MCP to Claude Cowork
1. Open Customize
In Claude Desktop, click Customize in the left sidebar, then select Connectors and click the + icon at the top.
2. Add the Composio MCP server
Click Add custom connector and paste in the Composio MCP server URL:

```bash
https://connect.composio.dev/mcp
```

## What is Claude Cowork?

Claude Cowork is Anthropic's agent for general knowledge work. It can use your computer, files, and connected applications to complete longer-running tasks across your work tools.
With Composio Connect, Cowork can securely access apps like Mercury MCP through MCP without you sharing account credentials directly with the agent.

## What is the Mercury MCP MCP server, and what's possible with it?

The Mercury MCP MCP server is an implementation of the Model Context Protocol that connects your AI agent and assistants like Claude, Cursor, etc directly to your Mercury MCP account. It provides structured and secure access so your agent can perform Mercury MCP operations on your behalf.

## Supported Tools

| Tool slug | Name | Description |
|---|---|---|
| `MERCURY_MCP_GET_ACCOUNT` | Getaccount | Get account by ID |
| `MERCURY_MCP_GET_ACCOUNT_CARDS` | Getaccountcards | Retrieve all debit and credit cards associated with a specific account. |
| `MERCURY_MCP_GET_ACCOUNTS` | Getaccounts | Retrieve a paginated list of accounts. Supports cursor-based pagination with limit, order, start_after, and end_before query parameters. |
| `MERCURY_MCP_GET_ACCOUNT_STATEMENTS` | Getaccountstatements | Retrieve a paginated list of monthly statements for a specific account. Supports cursor-based pagination with limit, order, start_after, and end_before query parameters, as well as date range filtering with start and end parameters. |
| `MERCURY_MCP_GET_ATTACHMENT` | Getattachment | Retrieve attachment details including download URL |
| `MERCURY_MCP_GET_CURRENT_DATE` | Getcurrentdate | Get the current date in the format. Example: Fri Oct 31 2025 |
| `MERCURY_MCP_GET_CUSTOMER` | Getcustomer | Retrieve details of a specific customer by their ID |
| `MERCURY_MCP_GET_INVOICE` | Getinvoice | Retrieve details of an invoice by its ID |
| `MERCURY_MCP_GET_ORGANIZATION` | Getorganization | Retrieve information about your organization including EIN, legal business name, and DBAs. |
| `MERCURY_MCP_GET_RECIPIENT` | Getrecipient | Retrieve details of a specific recipient by ID |
| `MERCURY_MCP_GET_RECIPIENTS` | Getrecipients | Retrieve a paginated list of all recipients. Use cursor parameters (start_after, end_before) for pagination. |
| `MERCURY_MCP_GET_SAFE_REQUEST` | Getsaferequest | Retrieve a specific SAFE request by its ID. |
| `MERCURY_MCP_GET_SAFE_REQUESTS` | Getsaferequests | Retrieve all SAFE (Simple Agreement for Future Equity) requests for your organization. |
| `MERCURY_MCP_GET_TRANSACTION` | Gettransaction | Get transaction by ID |
| `MERCURY_MCP_GET_TRANSACTION_BY_ID` | Gettransactionbyid | Retrieve a single transaction by its ID. Returns full transaction details including attachments, check images, and related metadata. |
| `MERCURY_MCP_GET_TREASURY` | Gettreasury | Retrieve a paginated list of all treasury accounts associated with the authenticated organization. Use cursor parameters (start_after, end_before) for pagination. |
| `MERCURY_MCP_GET_TREASURY_STATEMENTS` | Gettreasurystatements | Retrieve a paginated list of statements for a specific treasury account. Supports cursor-based pagination and filtering by document type. |
| `MERCURY_MCP_GET_TREASURY_TRANSACTIONS` | Gettreasurytransactions | Retrieve paginated treasury transactions for a specific treasury account. |
| `MERCURY_MCP_GET_USER` | Getuser | Get user by ID |
| `MERCURY_MCP_GET_USERS` | Getusers | Get all users |
| `MERCURY_MCP_GET_WEBHOOK` | Getwebhook | Retrieve details of a specific webhook endpoint by ID |
| `MERCURY_MCP_GET_WEBHOOKS` | Getwebhooks | Retrieve a paginated list of all webhook endpoints for your organization. Supports filtering by status. |
| `MERCURY_MCP_LIST_CATEGORIES` | Listcategories | Retrieve a paginated list of all available custom expense categories for the organization. Supports cursor-based pagination with limit, order, start_after, and end_before query parameters. - These categories are custom and different from the values for "mercuryCategory". |
| `MERCURY_MCP_LIST_CREDIT` | Listcredit | Retrieve a list of all credit accounts for the organization. |
| `MERCURY_MCP_LIST_CUSTOMERS` | Listcustomers | Retrieve a paginated list of customers. Supports cursor-based pagination with limit, order, start_after, and end_before query parameters. |
| `MERCURY_MCP_LIST_INVOICE_ATTACHMENTS` | Listinvoiceattachments | Retrieve a list of all attachments for a specific invoice |
| `MERCURY_MCP_LIST_INVOICES` | Listinvoices | Retrieve a paginated list of invoices. Supports cursor-based pagination with limit, order, start_after, and end_before query parameters. |
| `MERCURY_MCP_LIST_RECIPIENTS_ATTACHMENTS` | Listrecipientsattachments | Retrieve a paginated list of all recipient tax form attachments across all recipients in the organization. Use cursor parameters (start_after, end_before) for pagination. |
| `MERCURY_MCP_LIST_SEND_MONEY_APPROVAL_REQUESTS` | Listsendmoneyapprovalrequests | Retrieve a paginated list of send money approval requests for the authenticated organization. Supports filtering by account and status. |
| `MERCURY_MCP_LIST_TRANSACTIONS` | Listtransactions | Retrieve a paginated list of all transactions across all accounts. Supports advanced filtering by date ranges, status, categories, and cursor-based pagination. CRITICAL TRUNCATION RULE - READ THIS FIRST: ================================================================================ IF YOU SEE "Result too long" IN THE RESPONSE: 1. IMMEDIATELY STOP - Do not analyze or use the truncated data 2. The data is INCOMPLETE and any analysis will be WRONG 3. Start over with a smaller limit (reduce by 50%) 4. Paginate through ALL pages until you have complete data 5. NEVER provide answers based on truncated results ================================================================================ MANDATORY PAGINATION FOR COMPLETE RESULTS: When a user asks ANY question requiring complete data (totals, balances, aggregates, "most/least", "all transactions", comparisons, or any calculation across transactions): CRITICAL: Incomplete pagination will produce WRONG ANSWERS for questions about totals, spending categories, balances, minimums, maximums, or "most/least". You must fetch everything before calculating or answering. 1. Start with a limit of 300 transactions. 2. You MUST automatically paginate through ALL pages WITHOUT asking the user 3. Continue calling listTransactions using the page.nextPage value from each response 4. Keep fetching until page.nextPage is not present 5. If pagination would take more than 3 tool calls, ask the user to narrow down to a smaller time period 6. It is a CRITICAL ERROR to answer before having fetched ALL pages FILTERING: - IMPORTANT: WHEN FILTERING BY DATE, ALWAYS CHECK THE CURRENT DATE FIRST and ensure you're using the current year for current year queries - Unless specified otherwise or queried for "all transactions", ONLY include transactions with "status: sent" - To get transactions for a specific account, use the accountId parameter to filter by accountId PAGINATION MECHANICS: - Use the limit parameter to control page size - If page.nextPage is returned, use it as the start_after parameter in your next call - Keep fetching until page.nextPage is null/undefined - The page.nextPage value is a transaction ID to start after (exclusive) COMPUTATIONAL REQUIREMENTS: - For any query requiring: - Sums, totals, averages, medians, modes, ranges, most/least, or other aggregations across accounts/transactions - Calculations involving currency amounts - Comparisons of financial metrics - You MUST: - Create an artifact that processes the data programmatically - Parse the JSON response and use JavaScript/Python to calculate - Display intermediate steps for verification - Never rely on mental arithmetic for financial calculations - Example: "What's my total balance?" - CORRECT: Create artifact that parses accounts, maps to balances, uses reduce() to sum - INCORRECT: Manually adding up balance values For queries about 'last two months' or 'this year', calculate dates based on the actual current date Use the getCurrentDate tool to get the current date. Use the getTransaction tool to get more details about a specific transaction. |

## Supported Triggers

None listed.

## Creating MCP Server - Stand-alone vs Composio SDK

The Mercury MCP MCP server connects Claude Cowork to your Mercury MCP account through Composio. Once connected, Cowork can use the available Mercury MCP tools and triggers to complete tasks on your behalf.

## Complete Code

None listed.

## How to build Mercury MCP MCP Agent with another framework

- [Codex](https://composio.dev/toolkits/mercury_mcp/framework/codex)

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- [Altoviz](https://composio.dev/toolkits/altoviz) - Altoviz is a cloud-based billing and invoicing platform for businesses. It streamlines online payments, expense tracking, and customizable invoice management.
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## Frequently Asked Questions

### What are the differences in Tool Router MCP and Mercury MCP MCP?

With a standalone Mercury MCP MCP server, the agents and LLMs can only access a fixed set of Mercury MCP tools tied to that server. However, with the Composio Tool Router, agents can dynamically load tools from Mercury MCP and many other apps based on the task at hand, all through a single MCP endpoint.

### Can I use Tool Router MCP with Claude Cowork?

Yes, you can. Claude Cowork fully supports MCP integration. You get structured tool calling, message history handling, and model orchestration while Tool Router takes care of discovering and serving the right Mercury MCP tools.

### Can I manage the permissions and scopes for Mercury MCP while using Tool Router?

Yes, absolutely. You can configure which Mercury MCP scopes and actions are allowed when connecting your account to Composio. You can also bring your own OAuth credentials or API configuration so you keep full control over what the agent can do.

### How safe is my data with Composio Tool Router?

All sensitive data such as tokens, keys, and configuration is fully encrypted at rest and in transit. Composio is SOC 2 Type 2 compliant and follows strict security practices so your Mercury MCP data and credentials are handled as safely as possible.

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