Stiff prose is the most common complaint writers raise about AI drafts after the first reading. The grammar is fine, the argument is competent, and yet every paragraph reads like a board memo. That cadence is not random. It is the formal register the model defaults into when it does not know who the reader is, and it carries five specific patterns: uniform sentence length, no contractions, register that stays formal on casual topics, long subordinate clauses that bury the verb, and a preference for abstractions over concrete detail. Fix those five and the prose loosens almost immediately. Inside: the five-step scan-and-rewrite workflow, the read-aloud test that catches what the eye misses, and the three AI rewriter modes for the sections that resist a manual pass.
The order is deliberate. Scan first so the rewrite has a target. Identify before you change anything so the edit addresses the actual pattern. Rewrite by hand on the flagged sentences so judgement stays in the loop. Layer in your specifics after the cadence is already loosened. Re-detect at the end and read aloud, because the ear catches stiffness the eye lets slide.
Paste the AI draft into TextSight at app.textsight.ai. You get an overall 0 to 100 AI score, a per-sentence highlight map, and a bundled Plagiarism Risk score in the same scan. Capture both numbers and screenshot the highlight map; the before-and-after is how you know the rewrite worked. Most untouched AI drafts arrive at 90 percent or higher. Editing without scanning first is editing blind. You burn time polishing lines the detector did not flag and miss the ones carrying the cadence.
Walk the highlight map sentence by sentence. For each red line, label which of the five patterns is at work: uniform sentence length, no contractions, formal-only register, long subordinate clauses, or abstract over concrete. A single sentence usually carries one or two patterns. Labelling forces you to look at structure rather than read for vibes, and it tells you precisely what the rewrite has to change. Skip this step and you end up rewriting lines that were already fine.
Rewrite each flagged sentence against the pattern you labelled. Add contractions where you would speak them in conversation. Break a paragraph of four 18-word sentences into one long sentence, one five-word punchline, and two mid-length lines. Cut long subordinate clauses at the first comma where the thought finishes. Lower the register on casual topics so it sounds like a person, not a manager. The manual pass is slow but it keeps judgement on the load-bearing lines.
Replace abstractions with specifics. Instead of "many writers" write "the three writers I spoke with last week." Instead of "in recent years" write "between January 2024 and March 2026." Add at least one short personal anecdote per section: the line that starts "I tried this on a 1,200-word post for my newsletter last Sunday" is voice that no AI rewriter would have produced. The cadence shifts the moment a real specific lands.
Run the edited draft back through the detector and compare the new score and map to the starting screenshot. A genuine rewrite usually moves 90 percent into the 25 to 45 percent band. Then read the piece aloud at normal speed. Stiff prose feels mechanical in the mouth: the jaw stiffens, the breath runs out, the pauses land in awkward places. Any sentence the ear catches goes back through one more pass.
Stiff prose is not one problem. It is five overlapping habits the model defaults into. Fix the ones a sentence carries and the cadence loosens; chase the wrong pattern and the rewrite is busywork. Here is the working taxonomy.
AI prose clusters between 16 and 22 words a sentence with quiet consistency. Four lines in a row at that length is the cadence of a corporate report, and the reader hears it even without naming the pattern. The fix is variation, not uniformity in the other direction. Take two adjacent 18-word lines and merge them into one 30-word sentence; follow it with a five-word punchline that lands the point. Then leave the next two sentences alone. Human writing alternates length, and the contrast is most of what carries voice.
It is, do not, would not, will not, cannot. AI drafts default to the full form everywhere because the training signal rewards formality. Real writing contracts on casual claims and leaves the full form for emphasis. The fix is to contract where you would speak the contraction aloud, not on every line. Mechanical contraction-sprinkling is its own tell because detectors trained on humanised output have learned to flag the pattern. The honest test is the ear: if the sentence sounds stiff with the full form and natural with the contraction, contract.
Register is the level of formality the prose holds. AI drafts hold one register, usually formal, even on topics that ask for warmth or play. A piece about teaching your kid to ride a bike that reads like a HR memo is a register problem, not a vocabulary problem. The fix is to drop the register where the topic asks for it. Use a contraction. Use "kid" instead of "child" if that is how you would say it. Let one sentence be funny. Let the next be plain. Register is a dial, not a setting, and AI defaults the dial to neutral-professional whatever the prompt asked.
"Although it is important to recognise that, in many cases, the factors involved can vary considerably depending on context, the underlying pattern remains consistent." This is one sentence and it buries the verb three commas deep. AI prose reaches for the construction because it lets the model hedge while still sounding authoritative. Real writing breaks the load. Cut at the first comma where the thought finishes. The 30-word original becomes "The factors vary by context. The underlying pattern stays the same." Two short sentences read sharper than one long one in almost every case.
"Many organisations have begun to explore innovative approaches to remote collaboration." That is grammatical, hedged, and entirely empty. A reader could not picture a single thing it describes. The fix is to swap the abstraction for a concrete: a date, a name, a number, a moment. "By April 2026, three of the five startups I track had moved to async-first stand-ups." Same length, real content. Abstractions are the most reliable AI tell across registers because the model does not have your specifics, and the moment one real detail lands, the prose stops sounding generic.
The ear catches stiffness the eye lets slide. After every editing pass, read the draft aloud at normal speaking speed. The body tells you what the score takes a scan to confirm. Three things to listen for.
If your jaw works hard on a sentence, the cadence is stiff. Long subordinate clauses force the jaw into more shapes than a natural sentence ever asks for, and missing contractions stretch the vowels in unnatural ways. Mark every sentence that makes the jaw stiff and rewrite those first. The pattern is almost always either pattern four (long clauses) or pattern two (no contractions). The fix is mechanical, but the test only works out loud.
Read the paragraph in one breath if you can. The lines you cannot finish without gulping air are too long, and the lines you finish with breath to spare are too uniform. Real prose has a rhythm of breath. Stiff AI prose forgets the body altogether because the model has no body to consult. If half a paragraph runs you out of air, the variance is wrong, and the rewrite is to break the longest sentence at the first natural pause.
Where do you naturally pause when reading aloud? Real writing places pauses at the joints of meaning. Stiff prose places them at commas the model inserted for hedging. If you find yourself pausing because the sentence demanded it rather than because the meaning earned it, that is a candidate for a rewrite. Punctuation should follow thought, not the other way around, and the ear is the only reliable judge of which direction the sentence is running.
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The TextSight AI rewriter offers three intensity modes. Picking the right one for stiff prose matters because the wrong mode either leaves the cadence intact or rewrites so aggressively the meaning drifts. Start with Standard, then adjust based on what you read in the output.
Light keeps the prose close to the original. Use it on drafts where the rhythm is already varied and only one or two patterns linger, usually the no-contractions habit or the occasional long subordinate clause. Light typically moves the AI score by 15 to 25 points and preserves more of the original phrasing than the other modes. It is the right choice when the risk of the rewrite drifting from your meaning is higher than the cost of a slightly residual stiffness signal.
Standard rewrites more aggressively while still keeping the structure of the draft intact. It is the right starting point for most stiff-prose work because it addresses all five patterns without rewriting the argument. Standard usually moves the score by 35 to 55 points on a heavy AI draft. If the output drifts from your meaning, drop to Light; if the cadence is still stiff, escalate to Maximum on the remaining sections.
Maximum rewrites the most, replacing structure and phrasing while attempting to keep the ideas. It is right for drafts where every sentence carries the formal register and the prose reads like a compliance document. Maximum typically moves the score by 50 to 70 points. The trade-off is that the rewrite sometimes paraphrases a specific point into something more general, so a manual read-through after Maximum is non-negotiable. Reserve this mode for sections rather than whole drafts.
The five-step workflow for editing AI drafts to authentic voice: four manual patterns, three AI rewriter modes, the voice layer.
Open the workflowSurgical edits to keep most of a ChatGPT draft and pass detection. Four editing levels, a decision rule, a worked example.
Read the guideHow the 0-to-100 metric is computed and what each tier means for graded or published work.
Read the guideThe tool itself. Three modes, sentence-level diff view, free quota every day with no card.
Open the AI rewriterDetector, AI rewriter, and sentence-level highlights in one workflow. Free to try with no card. 3 detector scans and 1,500 AI rewriter words on the free tier, every day.