System prompts beat user prompts: taming verbose Claude Opus 5

IndyDevDan · youtube · 2026-08-17

IndyDevDan argues Claude Opus 5 is one of the best models ever but one of the worst to talk to — verbose, stuffed with filler, torching output tokens. His fix isn't a new model but prompt engineering, focused on the system prompt rather than user prompts.

Key techniques:

The system prompt applies across every exchange, making it the highest-leverage place to control verbosity, cost and quality regardless of which SOTA model ships next. The fix repo is open on GitHub.

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