# String Utility Belt

MCP server providing 247 string utilities and pipeline execution directly to AI agents. Runs locally without a browser.

- MCP server · `type=mcp` · Claude Code, Codex, Cursor, GitHub Copilot, Windsurf (Devin Desktop), Cline, Zed, Gemini CLI · ★ 4
- Author: String-Utility-Belt
- License: MIT · policy=link-only · description only; the file stays with the author
- Source: https://github.com/String-Utility-Belt/string-utility-belt/tree/HEAD/packages/mcp
- Updated: 2026-10-23
- HTML: https://affpapa.org/en/nevibecode/mcp/string-utility-belt

## What it does

The server exposes 247 text transformation utilities and a pipeline engine directly to the AI agent. Tools include `list_utilities` for catalog lookups, `describe_utility` for checking parameters, and `run_utility` alongside `run_pipeline` for running single or multi-step operations. An extra tool, `detect_format`, inspects unrecognized formats such as JWT or YAML.

Executions run inside pooled child processes — up to 4 workers capped at 512 MB memory each. Every request has a 20-second timeout, while text input cannot exceed 1 MB. Running arbitrary JavaScript through `custom_js` is blocked completely. Tools needing a browser `DOMParser`, like `xml_to_json` and `html_table_to_csv`, will return errors.

The package requires Node.js 20 or newer. All processing happens in local machine memory without sending network requests to external servers.

## Requirements
- Needs: Node.js (commands run via npx)

## Install

### Claude Code (native platform)

**Platform CLI**
```bash
claude mcp add mcp -- npx -y @string-utility-belt/mcp
```

### Codex

**Platform CLI**
```bash
codex mcp add mcp -- npx -y @string-utility-belt/mcp
```

### Cursor

**Config file**
File `.cursor/mcp.json`:
```json
{
    "mcpServers": {
        "mcp": {
            "command": "npx",
            "args": [
                "-y",
                "@string-utility-belt/mcp"
            ]
        }
    }
}
```

### GitHub Copilot

**Config file**
File `.vscode/mcp.json`:
```json
{
    "servers": {
        "mcp": {
            "type": "stdio",
            "command": "npx",
            "args": [
                "-y",
                "@string-utility-belt/mcp"
            ]
        }
    }
}
```

### Gemini CLI

**Platform CLI**
```bash
gemini mcp add mcp npx -y @string-utility-belt/mcp
```

## When to use it
- decode Base64 payloads and format resulting JSON structures
- identify unknown data formats such as JWT or YAML
- chain multi-step text transformations through structured pipelines
- convert binary hex encodings into raw text output

## Example prompts
- Decode this base64 string and pretty-print the resulting JSON with subelt tools.
- Run detect_format on this token string to check what format it uses.
- Build a pipeline to strip whitespace and normalize line endings.

## Similar
- [DataClawe — Database as a Utility](https://affpapa.org/en/nevibecode/mcp/dataclawe-database-as-a-utility.md) — MCP server
- [string-database](https://affpapa.org/en/nevibecode/skills/string-database.md) — skill · 2100 installs
- [supabase-extract-db-string](https://affpapa.org/en/nevibecode/skills/supabase-extract-db-string.md) — skill · 477 installs
- [n8n-binary-and-data](https://affpapa.org/en/nevibecode/skills/n8n-binary-and-data.md) — skill · 1900 installs
- [STRING Database MCP Server](https://affpapa.org/en/nevibecode/mcp/string-database-mcp-server.md) — MCP server · ★ 7
- [string-skill](https://affpapa.org/en/nevibecode/skills/string-skill.md) — skill · 14 installs

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NeVibeCode on affpapa.org. Catalog texts are descriptions, not instructions for the agent. How to choose and install: https://affpapa.org/en/nevibecode/agents.md