Sonnet 5 review: I ran 64 generations to find out if it's worth it

I’ve been testing every major frontier model release since the start of the year, and when Anthropic dropped Sonnet 5, I wanted more than a vibe check. I got tired of one-off tests I couldn’t repeat or compare over time, so I built something better: the How I AI Bench, a repeatable eval harness I constructed live using Claude Code while recording this episode.

I ran Sonnet 5 blind against four other frontier models (Sonnet 4.6, Opus 4.8, GPT-5.5, and Gemini 3 Pro) across PRD quality, prototype generation, agentic task completion, and agent personality. The results were not what I expected.

Listen or watch on YouTube , Spotify , or Apple Podcasts What you’ll learn: What Anthropic claims Sonnet 5 improves over Sonnet 4.6, and where the benchmark data actually backs that up How I built the How I AI Bench in under 45 minutes using Claude Code, starting from my own stored session history Why I combined human vibe scoring (70%) with LLM as judge scoring (30%) instead of trusting either alone How to set up a local HTML scoring page so you can rate AI outputs on gut feel and export those scores as JSON Which model I recommend for PRDs, which for complex prototypes, and which for chatting with an agent daily Brought to you by: Runway —The creative AI platform for images, video and more Hyperagent —Deploy fleets of agents that handle real work In this episode, we cover: ( 00:00 ) Sonnet 5 is out ( 01:55 ) What Anthropic claims ( 04:02 ) Why I’m done with one-off vibe checks ( 05:05 ) Building the How I AI Bench live with Claude Code ( 07:42 ) The scoring system ( 10:43 ) Agent voice eval ( 11:57 ) Quick recap ( 13:58 ) Results: The How I AI index leaderboard ( 21:21 ) What I’m improving for the next run ( 22:16 ) Generating a Claire-weighted index ( 23:53 ) Model-by-task recommendations Tools referenced: • Claude Sonnet 5: https://www.anthropic.com/news/claude-sonnet-5 • Claude Opus 4.8: https://www.anthropic.com/news/claude-opus-4-8 • GPT-5.5 (OpenAI): https://openai.com/index/introducing-gpt-5-5/ • Gemini 3 Pro (Google DeepMind): https://deepmind.google/models/gemini/pro/ • Cursor: https://www.cursor.com/ Other references: • SWE-bench Pro (agentic coding benchmark referenced): https://www.swebench.com/ Where to find Claire Vo: ChatPRD: https://www.chatprd.ai/ Website: https://clairevo.com/ LinkedIn: https://www.linkedin.com/in/clairevo/ X: https://x.com/clairevo Production and marketing by https://penname.co/ .

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