PromptLint · Free Chrome extension
Fix Weak Prompts As You Type
PromptLint is a free ChatGPT prompt helper extension for Chrome that underlines the weak spots in your prompt as you type, in ChatGPT, Claude, Gemini and Perplexity, before you hit Enter.
- 19 users
- Version 1.2.0
- Updated 16 Aug 2026
- Free · 100% local
A real-time prompt linter for ChatGPT, Claude, Gemini and Perplexity
Ever asked ChatGPT to "improve this" and got mush back? The problem usually is not the model, it is the prompt. PromptLint works like a spell checker for prompts. It reads your draft in the composer of ChatGPT, Claude, Gemini or Perplexity and underlines the parts that are likely to produce a vague or unfocused answer, so you can fix them before you send.
What PromptLint checks in your prompt
PromptLint looks for the patterns that most often lead to weak answers:
- Vague asks with no object or goal
- Missing output format: in what shape, and how long?
- Dangling references, such as "fix this" when it is unclear what "this" is
- Multi-ask overload, like four questions in one breath
- Missing context or audience
- Contradictions, such as "brief but comprehensive"
- Token-waste filler
- Unbounded open-ended asks
How the Prompt Strength score and fixes work
PromptLint checks your draft before it is sent, so fixing a weak prompt costs nothing: no wasted reply and no follow-up message to correct a misunderstanding. Using it takes a few seconds per prompt:
- Start typing in ChatGPT, Claude, Gemini or Perplexity as you normally would.
- Weak spots are underlined in your draft in real time.
- A live Prompt Strength score from 0 to 100 sits at the corner of the composer.
- Click the score to see the full issue list with a fix suggestion for each one.
- Or click "Restructure prompt" to reorganise your own words into a clean prompt skeleton in one step.
Who this prompt checker is for
PromptLint suits anyone who writes prompts in ChatGPT, Claude, Gemini or Perplexity and wants a better answer on the first try, rather than a round of follow-up corrections. It is also a quick way to learn what a strong prompt looks like, because each underline names the specific problem and the issue list suggests how to fix it. Restructuring keeps your own words, so the prompt still says what you meant.
100% local: nothing leaves your browser
PromptLint analyses your prompt locally inside Chrome. Nothing leaves your browser, so your drafts are not sent to a separate service for checking. That makes it reasonable to use on prompts that contain work material or unpublished drafts. The extension is free to install from the Chrome Web Store.
About PromptLint
Frequently asked questions
Which AI chat sites does PromptLint work on?
PromptLint works in ChatGPT, Claude, Gemini and Perplexity. It underlines weak spots in your draft as you type in the composer of each of these sites and shows a live Prompt Strength score in the corner of the composer.
What does the Prompt Strength score mean?
The Prompt Strength score is a live rating from 0 to 100 that sits at the corner of the composer while you type, giving you a quick read on how strong your draft is. Click the score to open the full list of issues PromptLint found, each with a suggested fix.
What does "Restructure prompt" do?
"Restructure prompt" reorganises your own words into a clean prompt skeleton with one click. It does not replace your request with a generic template; it takes what you wrote and arranges it so the role, context and task are clear.
Does PromptLint send my prompts anywhere?
No. PromptLint is 100% local, and nothing leaves your browser. Your prompt is analysed inside Chrome while you type, so your drafts are not sent to an outside service for checking.
Why do vague prompts give poor answers?
When a prompt has no clear goal, output format, context or audience, the model has to guess, and the answer usually comes back generic. PromptLint flags those gaps, along with dangling references, contradictions and multi-ask overload, so you can fix them before sending.
Is PromptLint free?
Yes. PromptLint is a free Chrome extension. Install it from the Chrome Web Store, open ChatGPT, Claude, Gemini or Perplexity and start typing; the underlines and the Prompt Strength score appear in the composer straight away.