---
author: "Umesh Malik"
canonical: "https://umesh-malik.com/blog/tag/tool-calling"
description: "Explore articles tagged with Tool Calling by Umesh Malik — AI Engineer, LLM & GenAI Developer. Learn Tool Calling best practices, practical tips, and in-depth guides."
title: "Umesh Malik's Blog - Tool Calling Articles | Tool Calling Tutorials"
tokens: 146
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# Tool Calling

1 article

 [![The five sandbox tools a Gemini agent hook intercepts, against the two tool families it never sees](https://umesh-malik.com/blog/gemini-agent-hooks-fail-open-cover.png)

AI Security • Aug 19, 2026

### Gemini agent hooks fail open: how to block a tool call anyway

Gemini agent hooks fail open on every error path, and never fire for MCP or function tools. The deny contract, the coverage gap, and what to gate instead.

9 min read

Read more →](https://umesh-malik.com/blog/gemini-agent-hooks-fail-open)