Optimising App Performance with Claude Code and Opus 5.5

X postEmanuele Di PietroDemo

Emanuele Di Pietro shares a prompt for Claude Code that enabled Opus 5.5 to run for three hours, identifying and fixing several overlooked performance bugs in his Electron app Synara.

Key points

  1. Di Pietro executed Claude Code with the Opus 5.5 model on 'Extra High' for three hours on his Electron application Synara.
  2. The prompt instructed the agent to improve startup times, screen transitions, and scrolling, requiring empirical benchmarks before and after every fix.
  3. The model identified four overlooked performance bugs, allowing large chats to open 27% faster and view switching to run twice as fast.
  4. Scrolling through older messages requires 20% less work with 98% fewer scroll jumps, while reloads fetch chat data once instead of twice.

Why it matters

This case shows how autonomous coding agents can be leveraged for sustained profiling and iterative code refinement when strictly constrained by empirical before-and-after benchmarks.

Analysis

The critical directive in Di Pietro's prompt is requiring benchmark validation for each change. Rather than applying speculative refactoring, the model must confirm real performance gains. For engineers maintaining complex client applications, combining reasoning-heavy models with strict measurement criteria provides a solid pattern for debugging performance bottlenecks.

Original post

Emanuele Di Pietro

@emanueledpt · 13 October 2026

Paste this into Claude Code if you want to make your app faster. Opus 5.5 on Extra High ran it on my app for 3 hours and found 4 performance bugs I’d missed: Big chats open 27% faster. Switching back is 2x faster. 98% fewer scroll jumps. Reloads fetch the chat once, not twice. t.co/oHZj3lXNUn

1.1k likes17 replies3.3k bookmarks181.4k views

View on X
More posts in the thread (4)
  1. @fedemas damn
  2. @arthuryuzbashev lmk!
  3. @byte_the_dev @fedemas synara uses very few ram for being an electron app
  4. This is the app i tested this on: t.co/817Lrhjkjz
Selected replies (5)
  • @fedemas @emanueledpt or just switch to GPUI :) seriously, have Claude rewrite the app in Rust + GPUI and keep going until it matches the original, every screen and every feature. you won't go back.
  • @arthuryuzbashev @emanueledpt done! sent to my IOS app agent
  • @byte_the_dev @fedemas @emanueledpt @emanueledpt I know it’s a lot but please do it. Like with Claude opus 5.5 max. Synara uses a lot of ram sense it’s electron and GPUI would make working with Synara so much better.
  • @Lollo2016_ @emanueledpt "Claude make it faster"
  • @sirmiemuigai @emanueledpt @grok is this factual? If it is breakdown in point forms

Mentioned links

Summary generated by AI (Gemini 3.8 Flash, 16 October 2026). It may contain errors – the original source is authoritative.

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