Jeremy Irons in Margin Call, seated beneath the subtitle speak as you might to a young child or a golden retriever

A Flesch–Kincaid skill for Claude

Claude, speak as you might to a young child or a golden retriever

Tired of Claude's verbose output? Meet f-k-readability. Drop in a draft. The skill finds the point, clears the fog, and checks the facts. The default target is 70 (higher is better).

F-K stands for Flesch–Kincaid. The name is harder to read than the output.

Download the skill See the evidence

Still from Margin Call (2011)

Three jobs, handled for every draft.

Finds the point.

The answer, next action, owner, and timing move up front.

Clears the fog.

Long sentences get shorter. Useful terms stay. Jargon gets the boot.

Checks the facts.

Numbers, duties, risks, exceptions, code, and clinical warnings stay put.

The receipts

Writing samples: Before and After

Thirteen deliberately dense drafts went in. The same scorer checked each one before and after. We also locked 51 facts, so a prettier score could not rewrite reality.

13test prompts

51facts preserved

9hit the requested score

4stopped to protect meaning

Pick your flavour of corporate fog. The number under each label is the score after rewriting.

Test 01 / Product

Product manager and leadership

Prompt: Rewrite this product brief so leaders can decide whether to fund the work. Use the default score.

Ease improved by 146.6 points

Source draft

Reading ease-67.4

In light of the multifactorial onboarding friction presently observable across the activation funnel, the product organisation recommends the operationalisation of a progressive-profile-completion initiative, contingent upon engineering capacity availability, in order to facilitate an improvement in conversion outcomes during the forthcoming planning horizon.

Rewritten

Reading ease79.2

New users stop when we ask for too much information at sign-up. We should test a shorter form next quarter. The test needs two weeks of engineering work. Leaders must decide by 18 September whether to fund it.

Met the 70+ target

Checked after rewriting

two weeks · 18 September · next quarter

F-K means Flesch–Kincaid

Customise your score. 70 is the default (higher is better).

A higher Flesch Reading Ease score is easier to read. Keep 70 for everyday work, go higher for public instructions, or lower for specialist text. The skill stops before simpler wording would damage the meaning.

Prompt, ready to pasteUse $f-k-readability. Aim for a Flesch Reading Ease score of 70 or higher.

What happens backstage

Four checks. Zero homework.

You get the rewrite and a compact scorecard. The machinery stays out of your way.

01
Reads the room
Identifies who will read the draft and what they need to decide or do.
02
Locks the facts
Records every number, deadline, duty, warning, exception, and fixed term.
03
Rewrites and scores
Puts the point first, shortens hard sentences, and measures the new draft.
04
Checks the meaning
Compares the protected facts and reports the final score, including any miss.

One sensible caveat

A score is useful. A score is not a lawyer.

The score can measure

Sentence length, syllables per word, and an estimated US school grade.

The score cannot measure

Truth, logic, tone, layout, prior knowledge, legal effect, or clinical safety.

Qualified review still matters

A lawyer or clinician should review any legal or clinical rewrite before publication.

Built fromPaul Graham: Writing, Briefly NHS: How we write The Economist: Writing with style Impeccable