Deduction Studio — Investigate Any Text, Sherlock Holmes Style
🕵️ A Sherlock Holmes tool — The consulting detective himself
Lay the facts before Holmes and watch the method work. Deduction Studio reads your text the way he would: it records every clue in your own words and highlights it in the text, draws inferences, tests three to five competing explanations against every clue, and strikes out the impossible. What remains becomes the verdict, with its chain of reasoning, a confidence score and the one test that would settle the matter. Then Mycroft cross-examines it. It works on classic puzzles and on everyday texts alike: a suspicious invoice email, a sudden resignation, a parcel that was "delivered". Ask Holmes follow-up questions, keep your cases in a casebook, and export any report.
- ✅ Free
- ✨ AI features with a free Google sign-in
- 🌐 Runs in your browser
What it does
Clues from your own words
Every clue quotes your text and is highlighted in it, so you can see exactly what Holmes noticed, and what was missing.
Eliminating the impossible
Competing explanations are tested against every clue in an evidence matrix; the ones the facts rule out are struck through.
A verdict that is cross-examined
Mycroft attacks the conclusion. What survives comes with a calibrated confidence, the open questions, and the single test that would settle it.
How to use it
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1
Paste the facts (or open one of the sample cases) and, if you like, ask a specific question.
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2
Choose Quick or Thorough, then press Investigate and watch the three stages run.
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3
Read the verdict, trace the board, check the evidence in your text, and ask Holmes anything that remains.
How Holmes investigates your text
Holmes's method has three movements, and the Studio runs them as three separate stages. First comes observation: what does the text actually say? Every clue is quoted word for word and marked in your text, and anything conspicuously missing is recorded as a clue of its own, like the dog that did nothing in the night-time.
Then reasoning. From the clues come inferences, and from the inferences come several competing explanations, always including the most ordinary one. Each is tested against every clue: which it explains, and which contradict it. The explanations the evidence rules out are eliminated, and the survivor becomes the verdict, with a numbered chain of reasoning that cites its clues.
Finally, cross-examination. Mycroft argues the strongest case against the verdict, Sherlock answers or concedes, and the confidence is revised. You also get the open questions and the one check that would settle the matter.
Not only for murders
The method works on anything whose real story is not on the surface. Paste an email that asks you to pay a new bank account in a hurry, a colleague's unexplained resignation, a delivery that was "left in a safe place" somewhere that is not your house, or a news story that does not quite add up. Ask a direct question if you have one, such as "Is this email genuine?", and the investigation will be aimed at it.
Holmes reasons only from what you give him, and says so when the facts cannot support a firm answer. The original Deduction Board, with its living p5 canvas, is still here for anyone who prefers it.
Frequently asked questions
How is Deduction Studio different from the original Deduction Board?
The original board is a living canvas: clues become draggable nodes, with consultants, voice calls and a dozen extras. Deduction Studio is focused on one job, which is investigating a text and reaching a defensible conclusion. It quotes every clue from your text, tests several explanations side by side, cross-examines its own verdict and presents the result as a clear report.
Is it free?
Yes. It needs a free Google sign-in for the AI, the same as every AI tool on the site. A thorough investigation uses three AI requests, and a quick one uses two.
Can it be wrong?
Yes, and it tells you how sure it is. Holmes only reasons from what you give him, so missing facts mean a lower confidence and a list of what would settle it. Treat the verdict as a well-argued reading of the evidence, not a certainty.
Are my cases saved?
Your last twelve cases are kept in your own browser's casebook, along with any questions you asked Holmes. You can export any report as Markdown or print it.
What should I paste in?
Anything with a puzzle in it: a mystery story, a set of witness statements, an odd email or message, a workplace situation, notes from an incident. More detail gives Holmes more to observe. Up to about 3,000 words works well.