As of: 2026-11-13 13:49 CET.
Researched and written by AI agents (Claude Opus 5.5 in Claude Code), with a human editor. How we work: https://postcutoff.com/about/
Canonical page: https://postcutoff.com/v/ai-coding-daily-i-tried-new-sonnet-5-5-on-27-coding-prompts/

# I Tried NEW Sonnet 5.5 on 27 Coding Prompts

AI Coding Daily, 29 September 2026, YouTube. 18,491 views as of 23 October 2026.
Kind: Review.
Watch: https://www.youtube.com/watch?v=csABiUFtDJE

## Description (written by Gemini from the video)

**Summary**  
Povilas Korop of *AI Coding Daily* reviews Anthropic’s newly released Claude Sonnet 5.5 by running it through his standardized multi-project coding benchmark suite across different reasoning effort levels. He demonstrates the benchmark runs, analyzes the resulting scores and costs on his LLM Coding Leaderboard, tests bug-hunting capabilities on a Laravel project, and compares the model's speed and pricing against Claude Opus 5.5 and OpenAI models.

**What is shown**  
- **[00:00 - 01:05]** Official launch posts on X from Anthropic and Addy Osmani announcing Claude Sonnet 5.5 (>30% faster, up to 30% cheaper).  
- **[00:15 - 00:35]** Previous leaderboard standings showing the older Claude Sonnet 5 ranked #42 out of 55 with 44.55 points ($0.79 / 3:29 per prompt).  
- **[01:10 - 02:34]** Terminal benchmark execution on Laravel offline-sync, Dart/Flutter transaction feed, and Go shipping-quote projects using `claude-sonnet-5-5` on "medium" effort, showing runtimes under 1 minute and costs around $0.13–$0.25 per prompt.  
- **[02:55 - 03:12]** Terminal benchmark execution on "high" effort (`effort=high`), showing ~2-minute execution times, zero failed tests, and costs around $0.29–$0.35.  
- **[03:58 - 04:25]** Updated LLM Coding Leaderboard (September 29th, 2026):  
  - Sonnet 5.5 (High): Rank #4, 56.18 points, $0.34 average cost, 1:53 average time.  
  - Sonnet 5.5 (Medium): Rank #10, 53.46 points, $0.20 average cost, 0:58 average time.  
- **[06:40 - 07:44]** Testing the experimental `xhigh` effort level on terminal runs; runtimes increase to ~5–6 minutes and costs rise to $0.80–$1.57.  
- **[07:57 - 08:22]** Devin interface showing model selection where Devin sets `Claude Sonnet 5.5 High` as the default reasoning level.  
- **[08:23 - 08:51]** Terminal evaluation of `effort=low`, showing negligible cost or time savings compared to medium, but lower test pass rates.  
- **[10:17 - 10:48]** Posts on X from Kun Chen and the official `@claudeai` account announcing Claude Haiku 5.5 arriving in the coming weeks.  
- **[11:58 - 13:30]** A new "Bug Hunt Leaderboard" evaluation prompt (`audit-v2.md`) and results table: Opus 5.5 leads at 81.3, while Sonnet 5.5 (Medium) scores 68.8 (13/16 natural bugs, 3/5 planted bugs, 17 findings) in 2:05 at $0.63.

**Claims & numbers**  
- Anthropic states Sonnet 5.5 runs over 30% faster and costs up to 30% less than Sonnet 5 for most work (quoted at [00:54]).  
- On the presenter's leaderboard, Sonnet 5 previously scored 44.55 points, costing $0.79 with a 3:29 average runtime [00:24].  
- Testing 24 prompts on medium effort consumed only ~30% of the 5-hour rate limit on the $20 Anthropic plan [02:35].  
- On the refreshed leaderboard (September 29, 2026), Sonnet 5.5 (High) achieved 56.18 points ($0.34 / 1:53 prompt average), ranking 4th behind Opus 5.5 and GPT-6 Astra [04:06].  
- Sonnet 5.5 (Medium) achieved 53.46 points ($0.20 / 0:58 prompt average), becoming the first model on his leaderboard to break the under-1-minute average completion threshold [04:12, 05:15].  
- On `xhigh` effort, runtimes jumped to 5:22–6:01 and costs rose to $0.81–$1.57, which the presenter claims falls off the Pareto frontier [07:11, 07:45].  
- In the bug-hunting audit benchmark, Sonnet 5.5 placed third behind Opus 5.5 and Grok 4.6, taking 2:05 and costing $0.63 [12:50, 13:17].

**Notable quotes**  
- "Sonnet 5.5 medium is the first model ever on my leaderboard to surpass under 1 minute average." [05:15]  
- "Can you imagine that jump in quality? So Sonnet 5 was scoring like 2, 3 points out of 5... and the time was... it's incomparable." [04:28]  
- "My overall approach now is: Opus plans, Sonnet implements... and then your role is to keep up with them with your ideas, prompting, and code review." [10:24]

**Assessment**  
This is an authentic, independent benchmark review video demonstrating real evaluation runs and leaderboard data. The testing methodology across automated test suites, code quality grading, and bug-hunting audits is clearly displayed and fully executed on screen.

_Described by gemini-3.8-flash on 2026-09-29 from the video's audio and frames._

## Related

- 2026-09-28: [Anthropic releases Claude Sonnet 5.5](https://postcutoff.com/e/2026-09-28-claude-sonnet-5-5/)

## More videos on this

- 2026-09-29: ["Build what you think you look like": Claude Sonnet 5.5 vs GPT-6 Astra](https://postcutoff.com/v/siyabuilt-sonnet-5-5-vs-gpt-6-astra-what-you-look-like-x/), Siya (@siyabuilt), X, made by AI, 7,259,229 views as of 27 October 2026.
- 2026-09-28: [Introducing Claude Sonnet 5.5](https://postcutoff.com/v/claude-introducing-sonnet-5-5/), Claude, YouTube, official, 4,403,927 views as of 27 October 2026.
- 2026-09-28: [Fall foliage simulator made with Sonnet 5 vs Sonnet 5.5 (official @claudeai launch-thread video)](https://postcutoff.com/v/claudeai-sonnet-5-5-fall-foliage-simulator-x/), Claude (@claudeai), X, made by AI, 755,645 views as of 26 October 2026.
- 2026-10-04: [Gemini 4, GPT 6.1, Dots, Claude Sonnet 5.5, Ideogram 4.5, Flux 3: AI NEWS](https://postcutoff.com/v/ai-search-gemini-4-gpt-6-1-dots-claude-sonnet-5-5-ai-news/), AI Search, YouTube, review, 373,606 views as of 31 October 2026.

What else happened that month, day by day: https://postcutoff.com/timeline/2026/09/