Claude 5 Changed Prompting Forever — Fix Yours Now
Anthropic's Claude 5 models (Opus 5, Fable 5) invert the old prompting rules: being overly specific, spelling out steps, and telling the model to double-check its own work now degrade output. Simon Scrapes breaks down 7 new rules from Anthropic's own guidance. What to ADD: (1) replace step lists with a broader goal + success metric; (2) give the reason not only the request — intent lets the model make the 50 unstated decisions; (3) define 'done' explicitly because Claude 5 over-works (expands scope, adds unasked dashboards). What to REMOVE: (4) 'critical/always/never/must' + CAPS (over-triggers); (5) 'walk me through your reasoning' (Opus 5 already thinks; on Fable 5 it can trigger refusal) and 'double-check' (buys a second pass on done work); (6) state the boundaries — Claude 5 takes unrequested actions, so add 'report findings and stop'; (7) fix voice in one place — 'remove all mannered prose.' GPT-Astra agrees on goal+intent and over-checking, but has no action bias and ships a banned-words blocklist. Old skills need rewriting.























