onlinecybertools-mcp-server

MCP (Model Context Protocol) server that lets AI agents — Claude Code, Codex, Cursor, Continue, etc. — use the Online Cyber Tools catalogue as a set of native MCP tools.

What it exposes

• One MCP tool per documented MCP-compatible /api/tools/{category}/{tool} operation. POST tools use their JSON request-body schema; compatible GET tools use OpenAPI query/path parameters. Schemas are taken straight from the site's OpenAPI 3.1 spec at /api/openapi.json, so agents get per-tool argument validation. When the spec declares them, a tool also carries MCP annotations (title plus readOnlyHint / destructiveHint / idempotentHint, sourced from x-mcp-annotations) and an outputSchema (the inline 200 response object schema).
• A search meta-tool that performs the same keyword search humans use, backed by GET /api/tools/search?q=....
• A describe_tool meta-tool that fetches the long page guidance, source links, page URL, API endpoint, and SEO description from GET /api/mcp/tool-docs/{tool_id}. It accepts either a menu ID such as ping or an MCP tool name such as network_ping.
• A report_bug meta-tool that files a structured bug report against POST /api/agent/bug-report (hard rate-limited).

Calls are proxied to the live HTTP API — no algorithm is re-implemented here. That guarantees agents see whatever the deployed site does. Generated tool descriptions are the operation's OpenAPI summary + description, nothing else — no menu-ID prefix or describe_tool pointer (both read as noise to a calling agent). The describe_tool meta-tool is still available for agents that want the full page guidance on demand.

Tools

This server exposes 279 tools across 15 categories: Encoding/Decoding, Binary/Text Conversion, Cryptography & Hashing, Web Dev Utilities, Text Utilities, OSINT Tools, Networking Tools, Security Tools, SEO Tools, Linux Tools, Date & Time, Math & Calculators, Data Tools, File Tools, Reverse Engineering.

• Full list (this repo): TOOLS.md — every tool, grouped by category.
• Live catalogue: https://onlinecybertools.com/#browse-the-full-inventory
• Machine-readable spec: https://onlinecybertools.com/api/openapi.json
• Pick a subset / build a config: https://onlinecybertools.com/integrations/mcp-plugin-builder

This section and TOOLS.md are auto-generated from the live menu on every release, so the count and list never drift.

Quick start

The package is published on npm as onlinecybertools-mcp-server, so any MCP client can launch it with npx -y onlinecybertools-mcp-server — no clone, no global install. The config snippets below work as-is and expose the full tool catalogue by default.

Prefer a guided setup? Generate a ready-made Claude Code plugin or Codex config block from the website's interactive builder:

https://onlinecybertools.com/integrations/mcp-plugin-builder

The builder lets you pick a subset of tools and emits the matching OCTOOLS_TOOLS filter for you (see Configuration).

Configuration

Configure via environment variables. All are optional.

Variable	Default	Purpose
OCTOOLS_BASE_URL	https://onlinecybertools.com	Site to proxy requests to.
OCTOOLS_TOOLS	(unset → all tools)	Comma-separated menu IDs (base64_encode,sha256,hash) to restrict the exposed surface. Leave unset to expose every tool — the examples below omit it on purpose.
OCTOOLS_STREAM_BYTE_CAP	262144 (256 KiB)	Max bytes accumulated from a streamed (x-mcp-compatible: stream-buffered) endpoint.
OCTOOLS_STREAM_TIME_CAP_MS	30000 (30 s)	Max wall-clock time spent buffering a streamed endpoint.

When OCTOOLS_TOOLS is set, the server appends ?tools=... to the spec fetch so the site returns a pre-filtered spec; the client also enforces the filter as defense-in-depth.

Running

Inspector (manual smoke test)

npx @modelcontextprotocol/inspector npx -y onlinecybertools-mcp-server

Open the inspector URL, click List Tools — you should see search, describe_tool, report_bug, plus one entry per compatible Symfony API operation. With no OCTOOLS_TOOLS set, the full catalogue is listed.

To hack on the server locally instead, clone and run from source:

git clone https://github.com/Jambozx/onlinecybertools-mcp-server.git
cd onlinecybertools-mcp-server
npm install
npx @modelcontextprotocol/inspector node index.mjs

Claude Code

Add to ~/.claude.json (or your project's .mcp.json):

{
  "mcpServers": {
    "octools": {
      "command": "npx",
      "args": ["-y", "onlinecybertools-mcp-server"]
    }
  }
}

This exposes every tool. To restrict the surface, add an env block with OCTOOLS_TOOLS:

{
  "mcpServers": {
    "octools": {
      "command": "npx",
      "args": ["-y", "onlinecybertools-mcp-server"],
      "env": {
        "OCTOOLS_TOOLS": "base64_encode,sha256,hash"
      }
    }
  }
}

Codex

Add to ~/.codex/config.toml:

[mcp_servers.octools]
command = "npx"
args = ["-y", "onlinecybertools-mcp-server"]

To restrict the surface, add an env line with OCTOOLS_TOOLS:

[mcp_servers.octools]
command = "npx"
args = ["-y", "onlinecybertools-mcp-server"]
env = { OCTOOLS_TOOLS = "base64_encode,sha256,hash" }

Cursor / Continue / generic MCP client

Most clients accept the same command/args/env shape. Point them at this package via npx -y onlinecybertools-mcp-server.

Streaming endpoints

Endpoints tagged x-mcp-compatible: stream-buffered in the spec (currently traceroute and proxy-test streams) are read to completion and returned as a single JSON envelope of accumulated SSE events. GET stream endpoints send tool arguments as query parameters; POST streams send JSON bodies. Hard caps:

• 256 KiB of buffered output (OCTOOLS_STREAM_BYTE_CAP)
• 30 s of wall-clock time (OCTOOLS_STREAM_TIME_CAP_MS)

Whichever cap fires first, the response envelope contains { "truncated": true } so the agent knows the output is partial.

Endpoints tagged x-mcp-compatible: none (multipart file uploads, etc.) are skipped at registration — they will not appear in tools/list.

Limitations

• Spec is fetched once at startup. If the site adds new endpoints, restart the server.
• stdio transport only; no HTTP server (avoids needing auth in front of a privileged endpoint).
• Published to npm as onlinecybertools-mcp-server (npx -y onlinecybertools-mcp-server). Installing straight from GitHub (npx -y github:Jambozx/onlinecybertools-mcp-server) still works for the bleeding edge.

License

MIT.