Write new code from scratch
Coding
Give the language, the behaviour and an input-output example, and get code with explanation kept minimal.
Fill the blanks and it copies as you filled it
Write new code that does the following. This isn't a fix to existing code. - Language: - What it should do: - Input and output example: - Constraints, if any: - Code only. Two lines of explanation above it at most
0 of 4 blanks filled · anything left blank copies with its brackets
What this prompt does
Compared with asking the same thing without the length and format lines.estimate
Estimated output tokens
700
Asked loosely
180
This prompt
Energy (Wh)
1.215
Asked loosely
0.423
This prompt
Tokens estimated from characters; energy measured by Jegham et al. 2025.
What that saves
15.8 Wh · 5.54 gCO₂e · 74 mL — assuming 20 uses a day — the global average is 3.7 (Chatterji et al. 2025)
Tap a card for how the conversion was done.
Reported backfire — Specifying output lengthSpecifying a length longer than needed backfires (a 34% increase in 11% of scenarios)
Reported backfire — Specifying output formatA 78% increase in one GPT-4o scenario. The paper classifies this one as apply-selectively
Where these figures come from
Published figures for the rule itself — not what this prompt saves.
Specifying output length
38.7%mean reduction · 95% CI 29.7–47.7%
Podder et al. 2026 BP#5 · 18 use cases / 57 prompts
by modelGPT-4o 35%Command R+ 49%Mistral-7B 32%
Reduced in every scenario. No backfire reported
Specifying output format
49%mean reduction · 95% CI 37–61%
Podder et al. 2026 BP#6 · 14 use cases / 45 prompts
by modelGPT-4o 40%Command R+ 50%Mistral-7B 57%