Free prompt optimiser
Claude Prompt Optimiser
Give Claude the role, context and reasoning space it uses well: a structured prompt with explicit constraints and a clear output format.
Runs with Local Rules, free, in your browser — no sign-up needed.
What this optimiser checks
- Whether the prompt names who the output is for and why
- Whether the objective is stated instead of assumed
- Whether the source material or its boundaries are described
- Whether length, tone or structure constraints are given
- Whether Claude is told how to handle uncertainty or missing information
Example prompt
Summarise this quarterly report for my manager.
"Summarise this quarterly report for my manager" reads like a task, but Claude doesn't know which report, how long the summary should be, what your manager cares about, or what to do if a figure is unclear. Claude tends to reward precise, well-scoped instructions with correspondingly precise answers.
Local Rules rewrites the prompt into a labelled structure — role, objective, context, requirements and constraints, output format, and a quality check — and flags exactly which of those seven elements were missing. For Expert mode, it adds explicit edge-case handling, which matters for Claude when the input data might be incomplete or ambiguous.
Frequently asked questions
- Does this call the Anthropic API for me?
- Only if you pick the Claude/Anthropic direct option and supply your own API key. Local Rules, the default, never sends your prompt anywhere — the rewrite happens in your browser.
- Why does Claude need more context than other models?
- It doesn't need more so much as it uses what you give it more literally. A vague prompt gets a generically safe answer; a prompt with real constraints and context gets an answer shaped to your actual situation.
- Can I use this for long documents Claude needs to summarise?
- Yes — paste your instruction (not the whole document) into the optimiser. The rewrite will prompt you, through its structure, to specify what the source is and what to do about anything it doesn't cover.
Free — no sign-up needed. Bring your own key for direct AI analysis, or stay local.