# Codec Engine MCP

> Deterministic Codec Engine serializes and deserializes data perfectly, solving common problems in web development. It lets your AI client safely handle complex character encoding standards—including converting international domain names (IDNs) to strict Punycode ASCII, preventing cross-site scripting by encoding raw HTML tags, ensuring URLs are always properly percent-encoded, and managing Unicode offsets with mathematical precision.

## Overview
- **Category:** developer-tools
- **Price:** Free
- **Tags:** serialization, encoding, url-encoding, punycode, data-parsing, web-standards

## Description

When you build systems that move data across different platforms or web pages, character encoding is the first thing that breaks. Simple string logic often fails when dealing with non-ASCII characters or special formatting like angle brackets. This MCP solves that by delegating all bidirectional encoding tasks to a strict V8 parser engine. It handles complex requirements like translating foreign domain names into DNS-safe formats and automatically sanitizing HTML inputs, protecting your workflows from injection vectors. By centralizing these standards, you eliminate the guesswork inherent in mixing web protocols and character sets. You can connect this MCP via Vinkius's catalog to ensure absolute data integrity, regardless of whether you're talking to an agent running locally or a client connecting over the wire.

## Tools

### html_entities_codec
It encodes or decodes malicious HTML characters (<, >, &, \" ) into safe entity formats.

### punycode_codec
It converts internationalized domains (IDN) with special characters into DNS-compliant Punycode ASCII (e.g. xn--).

### unicode_escapes_codec
It transforms standard characters into strict Unicode escapes (\uXXXX) and vice versa.

### url_codec
It uses native V8 logic to safely encode or decode URL components, like converting spaces to %20.

## Prompt Examples

**Prompt:** 
```
Convert the domain 'maçã.com' to Punycode.
```

**Response:** 
```
Using the punycode_codec tool (action='encode'): The correct ASCII domain representation is 'xn--ma-wia.com'.
```

**Prompt:** 
```
Make this text URL safe: 'Hello World & AI!'
```

**Response:** 
```
Using the url_codec tool (action='encode'): The serialized URL string is 'Hello%20World%20%26%20AI!'.
```

**Prompt:** 
```
Decode this unicode sequence: \u00A9 2026
```

**Response:** 
```
Using the unicode_escapes_codec tool (action='decode'): The decoded text is '© 2026'.
```

## Capabilities

### Secure HTML Input
It encodes raw user input into safe HTML entities, preventing malicious scripts from executing in display layers.

### Convert International Domains
It translates specialized international domain names (IDNs) with accents or special characters into the strict ASCII format required by global DNS servers.

### Validate URL Safety
It deterministically encodes query parameters, ensuring absolute conformity when transferring data via web links.

### Manage Unicode Offsets
It transforms standard characters into strict Unicode escape sequences (\uXXXX) and back again for precise data handling.

## Use Cases

### Processing user-submitted domain names
A user submits 'maçã.com' as the target site in a form. Instead of failing DNS validation, your agent calls `punycode_codec` to get 'xn--ma-wia.com', allowing the system to proceed with accurate routing.

### Cleaning up API response data
You receive a text field containing raw HTML snippets that might include `<img src=...>` tags. Your agent runs this through `html_entities_codec` first, stripping the executable code and providing safe text for display.

### Building deep links from complex text
A user pastes a link containing special characters like '&' or spaces. Running the string through `url_codec` serializes it to 'Hello%20World%26AI!', ensuring the resulting URL works regardless of the operating system.

### Handling multilingual character data
You need to process a unique Unicode sequence like the copyright symbol. The agent uses `unicode_escapes_codec` to ensure it gets processed and stored correctly as \u00A9, avoiding platform-specific encoding errors.

## Benefits

- Stop worrying about broken URLs. The `url_codec` ensures that every space, ampersand, and special character in a query string is correctly percent-encoded for transport.
- Prevent XSS attacks automatically. Using the `html_entities_codec` encodes dangerous tags like `<script>`, ensuring raw user input displayed on a webpage can't execute malicious code.
- Support global users flawlessly. The `punycode_codec` converts domains with international characters (like Spanish or French letters) into the standard ASCII format required by every DNS server.
- Maintain data fidelity. If you need to convert a character set into a strict escape sequence, `unicode_escapes_codec` handles the transformation without losing any offset information.
- Eliminate guesswork. This MCP gives your agent a single source of truth for serialization rules, making complex data handling predictable and repeatable.

## How It Works

The bottom line is you stop debugging data corruption caused by conflicting character encoding rules.

1. You pass the raw string or data component to your AI agent, specifying which encoding format is needed (e.g., URL, HTML).
2. The MCP runs the request through its strict V8 parser, applying the mathematical rules of the requested standard.
3. Your agent receives the clean, encoded output that conforms exactly to web standards.

## Frequently Asked Questions

**Does the `url_codec` handle non-ASCII characters?**
Yes, it handles them correctly by first encoding the character set and then applying percent-encoding. This ensures that foreign letters or symbols are transmitted without corrupting the URI structure.

**What is the difference between `html_entities_codec` and raw escaping?**
The `html_entities_codec` converts characters into specific HTML entity formats (like `&lt;` for `<`). This is necessary because these entities are how browsers display text safely, whereas simple escapes might be interpreted differently.

**I have international domain names. Should I use `punycode_codec`?**
Yes, always run suspected IDNs through the `punycode_codec`. This tool guarantees they are converted to their strict ASCII format, which is mandatory for global DNS registration and routing.

**Can I use all four tools together in one pipeline?**
Yes. Because this MCP uses a strict V8 parser, you can chain these codecs—for example, running `html_entities_codec` followed by `url_codec`—knowing that the second tool will operate correctly on the output of the first.

**When I use `html_entities_codec`, does it prevent every possible XSS attack?**
While it doesn't stop every vulnerability, using the `html_entities_codec` prevents common injection vectors like `<script>` and `<img>` tags. It encodes them into safe HTML entities, rendering malicious input inert in a web context.

**What makes the performance of the `url_codec` so reliable?**
It uses native V8 runtime execution for encoding/decoding, guaranteeing microsecond speed. Because it's zero-dependency, you won't face slowdowns or errors from external NPM packages.

**If I use `unicode_escapes_codec` multiple times, will the data become double-encoded?**
No, the engine is built for strict bi-directional parsing. Running the encoder or decoder repeatedly on clean text maintains structural integrity and prevents accidental over-encoding.

**Is the output from `punycode_codec` safe to include in a standard URL query parameter?**
Yes. The `punycode_codec` converts complex Internationalized Domain Names (IDNs) into strict ASCII format, which is fully compliant with global DNS and web transmission standards.

**Why do I need Punycode conversion for domains?**
Global DNS servers only understand basic ASCII characters. If your AI agent tries to register, ping, or scrape a domain with special characters (like 'café.com'), the request will crash. Punycode translates it to a safe format ('xn--caf-dma.com') under the hood.

**Can it help protect my database from XSS attacks?**
Absolutely. By passing raw text through the `html_entities_codec` encoding tool, any potential injection characters like `` are instantly neutralized into safe entities like `&lt;script&gt;`.

**Does it use external Node libraries?**
No. The engine is built using standard native V8 Javascript mechanics (e.g., `encodeURIComponent` and the native `node:url` module), ensuring absolute zero dependency bloat.