---
author: "Umesh Malik"
canonical: "https://umesh-malik.com/blog/tag/claude-opus-5"
description: "Explore articles tagged with Claude Opus 5 by Umesh Malik — AI Engineer, LLM & GenAI Developer. Learn Claude Opus 5 best practices, practical tips, and in-depth guides."
title: "Umesh Malik's Blog - Claude Opus 5 Articles | Claude Opus 5 Tutorials"
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---

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# Claude Opus 5

2 articles

 [![Timeline comparing the knowledge-cutoff date vendors claim for Claude Opus 5 against the earlier cutoff its answers actually reveal](https://umesh-malik.com/blog/testing-llm-knowledge-cutoffs-opus-5-cover.png)

LLM Engineering • Aug 11, 2026

### How to Test an LLM's Knowledge Cutoff: Opus 5's May Claim Falls Short

Here's how to test an LLM's knowledge cutoff with three reproducible probes — the method showing Opus 5 claims May 2026 but answers like January 2026.

7 min read

Read more →](https://umesh-malik.com/blog/testing-llm-knowledge-cutoffs-opus-5)

 [![Cover for the Claude Opus 5 guide: benchmarks, the $5/$25 cost math, effort levels, and the two API breaking changes in the Opus 4.8 migration](https://umesh-malik.com/blog/claude-opus-5-guide-cover.png)

LLM Engineering • Jul 24, 2026

### Claude Opus 5 Migration: The Two API Changes That Break Your Code

Two API changes break a Claude Opus 5 migration, and the effort parameter needs re-sweeping, not reusing. The fixes, the real cost math, and the benchmarks.

12 min read

Read more →](https://umesh-malik.com/blog/claude-opus-5-guide)