https://alamrafiul.com/tags/opus/ Recent content in Opus on Rafiul Alam https://alamrafiul.com/papermod-cover.png https://alamrafiul.com/papermod-cover.png Hugo -- gohugo.io en Fri, 12 Jun 2026 00:00:00 +0000 https://alamrafiul.com/posts/claude-fable-5-vs-mythos-vs-opus/ Fri, 12 Jun 2026 00:00:00 +0000 https://alamrafiul.com/posts/claude-fable-5-vs-mythos-vs-opus/ <p>Anthropic&rsquo;s lineup got two new names recently — <strong>Claude Fable 5</strong> and <strong>Claude Mythos 5</strong> — sitting above an already-strong Opus tier (Opus 4.6, 4.7, and 4.8). The marketing pages don&rsquo;t really tell you what to use when, and the API differences are significant enough that a naive model-string swap will break production code. This post is the guide I wish existed: what these models are, how they relate to each other, exactly what changes at the API level, what changes behaviorally, and how to decide which one your workload actually needs.</p>