thinkhard.SI
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Get better answers from AI. Keep your work to yourself.

Free AI prompt tools for ChatGPT, Claude, Gemini and Copilot. Score and fix a prompt or start from one of 669 templates, then check the answer and hide private details before you paste.

Check a prompt Browse templates
  • No account to make
  • Most tools run in your browser
  • No ads or trackers
  • Nothing you type is kept unless you sync it
37 words Example
5 A startout of 10

Read on this page as you type. Nothing is sent. Check it yourself Share text here from any app

One prompt, from a guess to a checked answer

Scroll down and watch a real prompt get better, lose its private details, reach your AI and come back checked. The scores are worked out on this page by the Prompt Grader’s own checks.

Skip the walkthrough

  1. It starts as a guess

    Most prompts are one line. This one scores 1 out of 10, which the Grader calls Guess: the AI has to make up who the email is for, which facts to use, how long it runs and what to leave out.

    Score your own prompt

  2. Each answer fills a gap

    For each thing the AI would guess, the Prompt Grader asks one plain question and writes your answer in as a labeled line. Eight short lines take this prompt to 10 out of 10, Superintelligent, the top of the scale.

    Open the Prompt Grader Start from nothing with the Prompt Builder

  3. Private details come out first

    The prompt now names a person and an email address, and a chat log is no place for either. Safe Paste swaps each one for a placeholder like [NAME_1] on your device, and keeps the list so it can put them back later.

    Try Safe Paste

  4. It goes straight to the AI you choose

    Paste it into ChatGPT, Claude, Gemini or Copilot, or run it here with your own key. Either way it travels from your browser to the AI company, and thinkhard.si is not on the way.

    What each tool sends

  5. The answer gets checked as well

    The draft comes back sounding like AI, and with a figure you never gave it. The Robot-Speak Checker marks the stock phrases, and the Fact Check List flags the 40% to check before anyone reads it. Then Safe Paste puts the real name and email back.

Your turn.

Try it on your own promptSee every tool

Most of what you do here never reaches us, and you can check.

Many AI apps pass your words through their own server and keep a copy. Here, most tools run on your device, and when you run a prompt your browser talks to the AI company directly, with your own key. The engine tools and Pro’s included AI are exceptions you choose: they send your text to us only when you press their button, and we read it to answer you and keep none of it.

A typical AI appChat apps and AI writing tools
thinkhard.siMost tools, with your own key
An engine toolOnly when you press its button
Youyour device
Writes it
Writes it, and keeps the results
Writes it, then presses the button
The app’s serverthe company behind the app
Reads every prompt keeps a copy
Never sees it. thinkhard.si sends the page, then steps aside
Reads it to answer keeps nothing
The AI companyOpenAI, Anthropic, Google…
Reads it, on the app’s account
Reads it, straight from your browser with your own key
Not involved: our engine answers on its own
Copies the app keeps
Every prompt
None
None
Who sees your prompt. In a typical AI app, you write it, the app’s server reads every prompt and keeps a copy, and the AI company reads it on the app’s account. With thinkhard.si, the page is sent once and your browser then talks to the AI company directly with your own key, so the prompt never reaches thinkhard.si and no copy is kept. With an engine tool, pressing its button sends the text to our engine, which reads it to answer and keeps nothing; no AI company is involved.
  • Checked on your device. Safe Paste, the Grader’s score, the browser extension and the Office checks read your text where you typed it. Tool by tool
  • Counted while you type. The box above and Safe Paste count every request the page makes, from your browser’s own record. Paste something private and watch. Try Safe Paste
  • Fingerprinted. Every file of the extension is published with its fingerprint, so you can match the copy in your browser. Verify
  • Honest about the gaps. Not audited yet, and we say so, next to every law we follow. Trust center
What exactly reaches us, and what stays with you

Kept in your browser

  • Your API keys, sent only to the provider they belong to. Turn off “Remember” to keep a key for this tab only.
  • Prompts, test suites, runs and grades.
  • Drafts and settings. Export everything as one file, or delete it, from Settings.

What reaches thinkhard.si

  • The request for each page, as with any website.
  • Anonymous daily totals of page views and tool runs. What is counted.
  • Text you send with an engine tool’s button or Pro’s included AI: read to answer you, then forgotten. What is sent.
  • Your saved work, only if you have Pro and turn on sync.
  • Whatever you type into the waitlist, contact or repository unlock form.

No ads and no trackers, and no scripts from other companies except Paddle’s, on the checkout page, and Microsoft’s Office.js, inside the Office add-ins. An account, and its cookies, only if you sign in. Free keys from Google AI Studio, OpenRouter and Groq make every tool free to use.

Think you can beat the checks?

Two quick rounds. Tap what you would flag, then see what this site’s checks find, worked out on your device by the same rules as the tools.

Tap every phrase that sounds like AI wrote it.

Both rounds run in your browser. You can also paste your own text into the Robot-Speak Checker or Safe Paste.

Free AI tools, one for each job

Pick what you need to do, or describe it in your own words. Most of these need no API key, and most never send your text anywhere.

  1. Write a prompt from scratchAnswer a few plain questions and get a prompt that scores 10 out of 10, laid out for the AI you use.Prompt BuilderOn your device
  2. Fix a prompt that gives weak answersA score out of 10 as you type, with what is missing and how to add it.Prompt GraderOn your device
  3. Stop explaining yourself in every chatStanding instructions for ChatGPT, Claude, Gemini and Copilot, and where each one goes.Custom InstructionsOn your device
  4. Make an AI draft sound like youSee every phrase that sounds machine-made, and fix the easy ones in one click.Robot-Speak CheckerOn your device
  5. Paste an AI answer into Word or Slack, cleanThe stars and hashes become real formatting for Word, Google Docs, email or Teams.Copy CleanerOn your device
  6. Check an AI answer before you use itEvery number, quote, source and link in the answer, riskiest first, with a search link for each.Fact Check ListOn your device
  7. Ask AI for help without sharing private detailsSwap names, emails, phone and account numbers for placeholders, then put them back in the answer.Safe PasteOn your device
  8. See whether the AI did what you askedEvery rule the answer kept or broke, and the facts it added that you never gave it.Instruction CheckOn your press
  9. Set up a custom GPT, Project or GemInstructions, first messages, settings and tests that keep it to its rules.Assistant BuilderOn your press
  10. Plan a bigger job as a chain of promptsThe steps in order, with an expert prompt for each and every answer carried into the next.Workflow PlannerOn your press

On your device reads your text where you type it and sends none of it.

On your press sends it to our server only when you press the tool’s button, to answer you, and keeps none of it. The Grader and the Builder also have a deep check you can press. What every tool sends

Every tool, by what you want to do, with a finder that takes your own words. The newest tool, the Prompt Improver, rebuilds a rough prompt in one step.

For building with AI: Model Compare, Prompt Tester, Chatbot Safety Test, Token Counter, AI Cost Calculator, Version Compare, Prompt Linter, Library Audit, Agent Brief Check, My Prompts.

Use it where you already write

The same checks inside your browser, your Office apps, your documents and your AI assistant. Free, with no account.

Your prompt’s score inside ChatGPT and Claude, with Prompt Score for ChromeYour prompt’s score inside ChatGPT and Claude: send Prompt Score to your computerYour prompt’s score inside ChatGPT and Claude: Prompt Score is coming to Firefox

  • Browser extension for Chrome and Edge, with Firefox in reviewScore a prompt and hide client details inside ChatGPT, Claude, Gemini and Copilot. It makes no network requests.
  • Office add-ins for Word, Excel, PowerPoint and OutlookCheck a draft, and send text to ChatGPT or Claude with names and numbers swapped out on your device.
  • Google Docs add-onCheck an AI draft for robotic phrasing, claims to verify, leftover markdown and private details.
  • WordPress pluginPublish Check reads a post written with AI before it goes live.
  • MCP server for Claude, ChatGPT, Cursor and VS CodeSearch 669 work prompts and grade one out of 10 from your assistant. No key.
  • REST API for your own codeSearch, fetch and grade prompts from curl, JavaScript, Python or any language that speaks HTTP. No key.

Start from one of 669 prompt templates

Expert prompts for work, grouped by the work they do. Each has blanks for your own facts and a note on how to check the answer, and works in ChatGPT, Claude, Gemini and Copilot.

The same request, before and after

Before

Write a launch email for our new invoicing feature. Make it good and not too long.

1/10 Needs work

  • Has: What to make
  • Missing: Who it's for
  • Missing: Background facts
  • Missing: Length
  • Missing: Format
  • Missing: What to avoid
  • Missing: What good looks like
  • Missing: An example
  • Missing: If unsure
  • Missing: Layout

After, with what was added marked

<context> We are launching [FEATURE NAME]. What it does: [WHAT IT DOES]. The email goes to existing customers who give it about ten seconds. </context> <task> Write the launch email. Its one aim is a click on Try it, so lead with the customer's problem. </task> <constraints> - Body of 90 to 130 words, because most readers will not scroll. - Use only the facts above. Where a detail is missing, leave a note in brackets. </constraints>

6/10 Good

  • Has: What to make
  • Has: Who it's for
  • Has: Background facts
  • Has: Length
  • Missing: Format
  • Has: What to avoid
  • Missing: What good looks like
  • Missing: An example
  • Missing: If unsure
  • Has: Layout

Scored with the Prompt Grader's ten checks. The strong version leaves blanks for the facts only you know.

Pick your work

Packs for the job at hand: a presentation, an assistant’s week, report cards and performance reviews.

All templates By team and industry The prompt course

Free stays free.

Pro adds included AI runs and sync across your devices for $8 a month when it opens. Team is next: one library of approved prompts, one click away in everyone’s assistant.

See the plans

Fair questions

Do I need to be technical to use this?

No. If you can write an email, you can use the templates, the Prompt Grader’s score and the AI Cost Calculator. Underlined words open a plain explanation, and the Start here page points you to the right tool in a minute.

What is an API key, and do I need one?

It is a code from an AI company, such as Google, Anthropic or OpenAI, that lets these tools send your prompt to their model, billed to your own account, usually a fraction of a cent per run. You only need one to run prompts on real models. Google AI Studio, OpenRouter and Groq give free ones. The full explanation.

Is it really free?

Yes. Most tools run in your browser, and the engine behind the rest is light to run, so serving them costs very little. Model calls are billed by your provider on your own key. Google AI Studio, OpenRouter and Groq all give free keys with free models, so you can use every tool without paying anyone.

What does the score out of 10 mean?

A count, not an opinion. A prompt meets ten checks: what to make, who it is for, background facts, length, format, what to avoid, what good looks like, an example, what to do if unsure, and a layout the AI reads well. Each one it covers adds a point. Each score has a thinking level, from Guess at 1, where the AI has to guess nearly everything, to Superintelligent at 10, where it has nothing left to guess.

How will this make money?

Through paid plans for what needs a server. Team, being shaped now, shares a team’s tested prompts inside the AI tools it already uses; a later plan for builders adds scheduled test runs, prompt CI and managed credits. The free tools stay free. See the plans.

Do you train on my prompts?

No. Most tools never send your prompts to us, and the few that do, when you press their button, read them only to answer you and keep nothing. What happens to your prompts at the model provider is set by that provider’s terms. Paid API traffic is generally not used for training, but some free tiers and free models may log or use what you send, so keep sensitive data off free keys and check your provider’s policy.