# Route MCP tool calls with Claude: n8n workflow template

> Started by another system calling it, and works across Email and Google Sheets. It hands the judgement calls to Claude.

Source: https://millionrounds.com/workflow/route-mcp-tool-calls-with-claude (Millionrounds; every figure on the page links to its filing or article)

[Automation library](https://millionrounds.com/workflows) · [Data collection](https://millionrounds.com/workflows?category=Data+collection#library)

# Route MCP tool calls with Claude

Started by another system calling it, and works across Email and Google Sheets. It hands the judgement calls to Claude. 19 steps, 1 branch, 1 loop or waits: a working afternoon to understand properly.

Medium Calls a model: Claude

[Download free](https://millionrounds.com/login?next=%2Fapp%2Fworkflow%2Froute-mcp-tool-calls-with-claude)

**19 steps** Medium: a working afternoon

**1** Branch: places the flow splits

**1** Loop or waits

**2** Services it connects to

## The flow

Starts it 2 Model 2 Logic 9 Service 6

The steps in the order they run, from what starts it.

- 1 **Receive MCP Tool Request** Webhook *Starts it*
- 2 **Claude AI Model** Lm Chat Anthropic *Model*
- 3 **Validate Auth and MCP Schema** Code *Logic*
- 4 **Claude AI Intent and Safety Verification** Agent *Model*
- 5 **Lookup Tool in Registry** Google Sheets *Service*
- 6 **Parse Intent Verification Result** Code *Logic*
- 7 **Resolve Tool Config and Permissions** Code *Logic*
- 8 **Check Rate Limit and Quota** Google Sheets *Service*
- 9 **Wait For Result** Wait *Logic*
- 10 **Enforce Rate Limit and Build Execution Context** Code *Logic*
- 11 **Dry Run or Live Execution?** If *Logic*
- 12 **Execute Backend API Call** Http Request *Service*
- 13 **Build Dry Run Response** Code *Logic*
- 14 **Normalize Backend Response to MCP Schema** Code *Logic*
- 15 **Send Security Alert on High Risk Calls** Email Send *Service*
- 16 **Write Immutable Audit Log** Google Sheets *Service*
- 17 **Update Rate Limit Usage Log** Google Sheets *Service*
- 18 **Build Final MCP Tool Result** Code *Logic*
- 19 **Return MCP Tool Result to Caller** Respond To Webhook *Starts it*

## How it's built

- **Starts on:** Another system calling it
- **Steps:** 19, with 1 branch, 1 loop or waits
- **Size:** Medium: a working afternoon
- **Connects to:** Email, Google Sheets
- **Model:** Claude

## Questions

What does it need to run?

An n8n account, plus your own Email and Google Sheets accounts, and a key for Claude. You connect your own accounts after importing it; none are included.

What starts it?

It starts on another system calling it.

Does it use AI?

Yes. It calls Claude. Model calls are billed by the provider, not by n8n.

How long does it take to set up?

Plan an afternoon. 19 steps is enough that you should read each one before running it.

How do I import it?

Copy the workflow, open a new workflow in n8n and paste. The steps appear on the canvas, ready for your own accounts.

**Before you run it**

Nothing here has been tested by us. It is somebody's working automation, read and described from its own steps. Treat the connections it wants as a list of accounts it will touch, and read the 19 steps before you point it at anything that matters.

## Run it in n8n

- **Create your n8n account** Free to start. n8n is where the workflow runs. [Create an n8n account ↗](https://millionrounds.com/n8n)
- **Download the workflow** Free with a Millionrounds account. [Download free](https://millionrounds.com/login?next=%2Fapp%2Fworkflow%2Froute-mcp-tool-calls-with-claude)
- **Paste it into n8n** Open a new workflow in n8n and paste. Then connect your own accounts.

Stored with the author's traces removed: canvas notes, instance identifiers, saved credential names and any live document they had left behind.

## Connects to

Each opens the other workflows that use it.

[Email](https://millionrounds.com/workflows?service=Email#library)[Google Sheets](https://millionrounds.com/workflows?service=Google+Sheets#library)

## Workflows like it

Also data collection, with the same services where possible, closest in size first.

- [**AI-powered job search & application with OpenRouter and Gmail** 19 steps · calls a model · Gmail, Google Sheets](https://millionrounds.com/workflow/ai-powered-job-search-and-application-with-openrouter-and-gm)
- [**Analyze corporate action impact from NSE RSS** 19 steps · calls a model · Gmail, Google Sheets](https://millionrounds.com/workflow/analyze-corporate-action-impact-from-nse-rss)
- [**Analyze your stock portfolio daily with Google Sheets and RSS** 19 steps · calls a model · Gmail, Google Sheets](https://millionrounds.com/workflow/analyze-your-stock-portfolio-daily-with-google-sheets-and-rs)
- [**Automate WordPress contact form (CF7) responses** 19 steps · calls a model · Gmail, Google Sheets](https://millionrounds.com/workflow/automate-wordpress-contact-form-cf7-responses)
- [**Automate cybersecurity incident response with Claude** 19 steps · calls a model · Google Sheets](https://millionrounds.com/workflow/automate-cybersecurity-incident-response-with-claude)
- [**Automate email triage with OpenAI and Gmail** 19 steps · calls a model · Gmail, Google Sheets](https://millionrounds.com/workflow/automate-email-triage-with-openai-and-gmail)