How does it compress the guide?

It splits the guide into individual rules, strips filler and duplicate guidance, rewrites each as a short imperative, and keeps adding rules in priority order until your token budget is reached. The result is a tight list of actionable instructions rather than prose.

Style rules compete with your actual content for context window and cost money on every call. A budget forces the block down to the rules that change the output, so you are not paying to repeat a 2,000-word guide on every request.

Will it lose important rules?

It keeps rules in the priority order you set, so the most important sections survive truncation. If the budget is too tight for everything, raise it or tighten the source guide — the tool tells you how many rules it kept versus dropped.

Where should I put the block?

A system message is ideal because it persists across the conversation. If your tool has no system role, prepend the block to the user prompt above your actual instruction.

Style Guide Prompt Injector

Style guide prompt injector

Brand voice docs are written for humans — long, hedged, full of examples and rationale. An LLM does not need any of that; it needs a short list of concrete rules it can follow. Pasting the whole guide on every request burns context and money while burying the instructions that actually change the output. This tool turns a sprawling style guide into a tight, injectable block of imperatives that fits a token budget you choose.

How it works

The tool breaks your guide into individual rules — one per line or bullet — then cleans each one: it drops filler (“we generally try to”), removes near duplicates, and rewrites the rule as a short imperative (“Use active voice”). It then assembles the block in priority order, adding rules until your token budget is reached, so the sections you marked as most important survive even if everything cannot fit. You get a compact block plus a count of how many rules were kept and dropped, runnable as a system message or prompt prefix.

Tips and example

Feed it bullets, not essays. A guide already written as short rules compresses cleanest. If yours is prose, the tool will still extract rules but you will get more from it after a quick tidy.
Prioritise voice over formatting. Tone and word-choice rules change output the most; spacing and punctuation conventions matter less to a model. Rank accordingly when the budget is tight.
Use it as a system message. Persisting the block in the system role keeps the style on across a long conversation without re-sending it each turn.
Tune the budget to the job. Short social copy can spare more budget for style than a long document where rules compete with your content.