# Mustache Template Engine MCP

> Mustache Template Engine MCP renders complex documents and emails by filling data into structured templates. You provide a template (using Mustache syntax) and raw JSON data, and the engine deterministically outputs final content—like complete HTML or formatted reports. It works universally across multiple programming languages like JavaScript, Python, and Go.

## Overview
- **Category:** loved-by-devs
- **Price:** Free
- **Tags:** templating, logic-less, data-binding, code-generation, document-automation

## Description

Generating standardized documents used to be a mess. Manually stitching together email bodies or invoices by concatenating strings is brittle; one missing bracket or misplaced tag breaks the entire layout. Worse, if your code hallucinates a variable name that doesn't exist in the data, your process fails silently or outright.

This MCP solves that problem using Mustache templates. These templates are designed to be logic-less—they only handle slots and data, never executing complex business logic. This means you get predictable output every time. Because it adheres to a universal specification, you can write the same template once and render it identically in JavaScript, Python, or any other language your team uses. You just feed it the raw JSON payload, and this MCP takes care of the rest, giving you clean, finished content right away.

## Tools

### render_mustache
Passes a Mustache template string and a JSON data object to deterministically render the final content, avoiding manual string errors.

## Prompt Examples

**Prompt:** 
```
Render this welcome email template with the new user's data: name, email, and activation link.
```

**Response:** 
```
HTML email rendered with all {{name}}, {{email}}, {{activationLink}} placeholders replaced.
```

**Prompt:** 
```
Generate an invoice PDF body with line items, subtotal, tax, and total from this JSON order.
```

**Response:** 
```
Invoice template rendered with itemized list, calculated totals, and formatted currency.
```

**Prompt:** 
```
Create a Slack notification message from this alert template and the monitoring event data.
```

**Response:** 
```
Slack message rendered with severity, service name, error message, and timestamp.
```

## Capabilities

### Generate structured emails
Renders full HTML email bodies by mapping data fields into predefined template slots.

### Process document sections
Handles conditional content rendering (e.g., showing a tax section only if the order total exceeds $100).

### Loop through lists of data
Iterates over arrays in your JSON payload, allowing you to generate itemized tables like product line items or user history.

### Maintain code safety
Because the templates are logic-less, they prevent common security risks associated with executing arbitrary code during rendering.

### Support multiple languages
The engine uses a single standard that guarantees consistent output regardless of whether your backend is written in Python or Java.

## Use Cases

### Generating a Welcome Email
A new user signs up. Instead of building an email body with hardcoded placeholders, the agent calls `render_mustache`, passing the HTML template and the user's JSON data (name, activation link). The result is a perfectly formatted welcome email ready to send.

### Creating an Invoice Document
The billing service needs to generate a PDF body. By providing the template with line item loops and total calculations in JSON format, calling `render_mustache` creates a fully itemized, mathematically correct invoice ready for printing.

### Building Automated Alerts
A monitoring system detects an error. The agent uses the template engine to render a detailed Slack notification message, pulling in the severity, service name, and timestamp from the event data payload.

## Benefits

- Reliability: You eliminate the risk of layout breaks. Instead of manually concatenating strings, using `render_mustache` ensures that complex HTML structures remain intact every time.
- Consistency: The universal spec means your templates work identically whether your primary language is Python or JavaScript. One template, guaranteed output across all platforms.
- Safety: Because Mustache is logic-less, the engine prevents code injection risks and stops you from accidentally trying to run server-side logic inside a document template.
- Complexity Handling: You don't need separate code for list items or conditional sections. The engine handles loops (`{{#section}}`) and optional elements automatically.
- Speed of Development: Instead of writing dozens of lines of data formatting code, you define the structure once in the template and let your agent handle the rendering.

## How It Works

The bottom line is that you stop writing complex rendering code and just focus on the data structure needed for the final output.

1. You provide the Mustache template string, which contains placeholders for data, and the structured JSON object containing all necessary variable values.
2. The MCP engine parses the template, executing the logic-less rules (like conditional sections or list loops) against your provided data.
3. It returns a finalized string—ready to be used as an HTML body, text message, or report section.

## Frequently Asked Questions

**What is the difference between Mustache Template Engine MCP and simple data binding?**
Simple data binding just replaces variables (e.g., {{name}}). This MCP handles complex structure, including conditional sections and loops over arrays, letting you generate entire lists of itemized content.

**Can I use Mustache Template Engine MCP to render PDFs?**
While it doesn't output a PDF file directly, it renders the clean HTML or structured text body that you can then easily pass to a separate service for final PDF conversion.

**Does Mustache Template Engine MCP support multiple data types?**
Yes. It handles standard JSON primitives (strings, numbers, booleans) and complex arrays/objects used in loops and conditional rendering.

**How do I use the render_mustache tool?**
You must provide two inputs: the template string containing your placeholders, and a corresponding JSON data object. The engine then processes both to generate the final output.

**Is Mustache Template Engine MCP safe from code injection?**
Yes. Because the templates are designed to be logic-less, they can only insert data; they cannot execute arbitrary code, making them inherently safer than full programming language templating systems.