cff-version: 1.2.0 message: "If you reference this work, please cite it as below." title: "Claude's Hidden Toolkit: The Definitive Guide to Claude.ai's Undocumented Internal Tools" type: software authors: - family-names: "Marinoni Moretto" given-names: "Francesco" orcid: "" version: "1.3" date-released: "2026-02-16" url: "https://github.com/n1-ai/claude-hidden-toolkit" license: "CC-BY-4.0" keywords: - claude - anthropic - ai-tools - reverse-engineering - internal-tools - tool-use - model-context-protocol - claude-ai abstract: >- Comprehensive reverse-engineering documentation of 28 undocumented internal tools in Claude.ai's consumer interfaces (browser, desktop app, mobile app). Covers complete parameter schemas, confirmed response formats, platform-specific behavior differences, and a three-tier tool loading architecture across three client surfaces. Based on 35+ manual tests with empirical verification.