Built into Salt of the Page

Meet your First Mate.

The checker that catches the slips, knows your story, and never forgets what you decided. It fixes obvious typos as you type, checks grammar, spelling and style on your device, runs reports on the whole book, and, if you connect your own AI, critiques chapters with notes tied to your pages. It never rewrites your voice.

Own it, $150 See what it checks

IncludedNo credits, no daily limits
On your deviceWorks with no internet
Fiction firstDialogue belongs to the character
RemembersA decision stays decided

The promise

Eight things First Mate will never do.

Most checkers are built for business email. First Mate is built for books, and for the person who wrote them.

It never rewrites your voice

Apart from obvious typo fixes (which you can switch off), nothing in your book changes until you accept it. AI suggestions are always shown as a before and after.

It leaves dialogue alone

With Fiction mode on, grammar and style rules skip what’s inside quotation marks. A character can say “ain’t” and talk in fragments.

Your book’s words are real words

Character names, places, ships, every Source of Truth entry and your book’s dictionary are never flagged or “corrected”.

It never asks twice

Ignore something, or mark it intentional, and it stays decided for that passage, for good, by every check and every AI report.

It works on your device first

Typo fixes, spelling, grammar, style and every report run on your computer or phone and work offline.

It has no meters

No credits, no daily caps, no locked suggestions, and no paying again per manuscript. Run it on the whole book as often as you like.

It shows its evidence

Every card says why. Every AI finding links to the exact passage it’s about, or it isn’t shown.

It stays quiet while you draft

No red lines while you write unless you turn them on. Review happens when you ask, in a panel beside the page that never covers your text.

As you type

Typos fixed before you notice.

First Mate fixes about 300 slips that only ever mean one thing (teh, adn, recieve, thier, alot, a lone i) the moment you type the space. A small chip by the cursor shows what changed, with Undo.

It doesn’t guess. It never changes your characters’ names, your book’s own words, a capitalised word mid-sentence or link text. Inside dialogue it only fixes pure keyboard slips.

Undo a fix and it learns. Press Undo, or Ctrl/⌘ Z right after, and First Mate never changes that word again in this book.

Tidy-ups, each with its own switch

Curly quotes and apostrophes
One space after a full stop
Turn -- into a dash (unavailable while your “No em dashes” house rule is on)
Turn ... into an ellipsis (…)

Grammar and spelling

Checked on your device. Built for fiction.

Before any rule runs, First Mate separates dialogue from narration, so the rules made for business email don’t trample your characters.

Spelling checks against your book’s dictionary, every name and alias in your Source of Truth, and the spellings each character is allowed to use. Give a character “gonna”, “wee” or “ain’t” and First Mate leaves it be.

Grammar runs on your device with a fast, private grammar engine. Nothing is sent anywhere, and it works on a plane.

The mix-ups that matter in fiction: were and we’re, their, there and they’re, its and it’s, lose and loose, then and than, affect and effect, breath and breathe, peak, peek and pique, rein and reign, led and lead. First Mate only changes one real word into another when the grammar around it is clear, and it leaves rare words alone (“benighted” stays “benighted”).

Your English. US, UK, Canadian, Australian or Indian English, set per book.

One card per problem. If spelling and grammar both catch the same word, you see one card, not two.

Fiction mode, on by default

The crew was tired, but there work wasn’t done.

Narration: checked

“Ain’t nobody sleeping tonight,” Ruth said. “Not till the nets is mended.”

Dialogue: the character’s voice, left alone

Silence. Then the bell.

Fragments on purpose? Mark them intentional once

The Captain’s Log

A decision stays decided.

Captain’s LogFirst Mate remembers 42 decisions in this book.

Ignored here“sea-plane”Chapter 4 · hyphenation
Intentional“Silence. Then the bell.”Chapter 7 · fragment · “on purpose, it’s the cliffhanger”
Kept as isThe letter from Ruth’s motherChapter 12 · no check touches it
Rule off in this bookPassive voiceWhole book
Word is fine“Caloosa”Added to the book’s dictionary
Never auto-fix“Ruthe”You pressed Undo on chapter 2

The number one complaint about grammar checkers is the flag that keeps coming back. You fix it, or decide it’s fine, and next time it’s there again.

The Captain’s Log is First Mate’s memory for your book. Every Ignore, every Intentional (with a note in your own words, if you like), every passage you keep as is, every rule you switch off and every word you say is fine is written down, and every part of First Mate obeys it, including the AI.

Edit the sentence next to a decision and it still holds. Rewrite the flagged words themselves and the old entry quietly goes grey, so you can see the passage changed. Remove any entry to bring that check back.

The log syncs with the book, so a co-author sees the same decisions.

Review

One pass at a time.

Instead of one wall of 4,000 flags, First Mate walks you through the book in passes: spelling and typos, grammar, consistency, style, dialogue, continuity, then story. Each pass shows its count and how far you’ve got.

Run any pass on this chapter, a range of chapters or the whole book. Build your own, too: a “Final polish” pass of spelling, consistency and house rules, saved for every book.

Every card shows the sentence, the chapter, a before and after, and one line saying why. When a rule has a threshold, the card shows the number (“58% glue words; your target is 45%”), so nothing is a mystery score.

↓ ↑next / previous card
Enteraccept
Iignore
Nintentional
Kkeep the passage
Ffix everywhere
Escback to the page

Spelling and typos6 of 6
Grammar3 of 11
Consistency0 of 4
Style0 of 18
Dialogue0 of 5
Continuity0 of 2
Storywith your AI

GrammarChapter 3

The gulls circled and ~~there~~ their cries carried over the harbour.

Use “their” for something that belongs to them.

AcceptIgnoreIntentional…Keep this passageWhy?

Reports

Fifteen reports on the whole book. Unlimited.

All of them run on your device, with no AI and no internet, on a chapter or the entire manuscript, as often as you like.

Manuscript dashboard

Words, chapters, reading time, dialogue share, sentence length, readability and what’s left to review, with a strip of the whole book coloured by any measure.

Readability

Four standard readability scores, with each paragraph tinted against the target for your genre.

Sentence variety

A length chart per chapter, and runs of four or more sentences the same length.

Sticky sentences

Sentences heavy with glue words, with the threshold shown and yours to change.

Overused words

Your own repeated and weak words per 1,000, against your own average for the book.

Echoes and repeated starts

The same word too close together, and paragraphs that start the same way.

Pacing

A scene-by-scene strip of paragraph length, dialogue, introspection and action. Slow stretches are marked, never judged.

Dialogue

Said-ratio, unusual tags, tags with adverbs, and dialogue share per chapter and per character.

Emotion tells

“She was scared.” Places where an emotion is told rather than shown, in narration only.

Passive voice

Each passive sentence, and a percentage per chapter.

Sensory balance

Sight, sound, touch, smell and taste per scene, as a small five-bar chart.

Clichés and redundancies

“Nodded his head”, “shrugged her shoulders”, and the phrases every reader has seen before.

Diction and transitions

Vague words like thing, stuff and very, transition variety, and paragraphs that start with a pronoun.

Consistency

The same thing written two ways across the book, fixed everywhere in one click.

House rules

Your own rules (“no em dashes”, “never ‘okay’”), each with the reason you wrote, shown on its cards.

Compared with you, not a hidden average. Each number shows this chapter against your book’s own average and your earlier books on the shelf (“Your average sentence here is 19 words; your book average is 14”). Every target is visible, set by genre (thriller, romance, literary, fantasy, YA, middle grade, historical, memoir and more), and yours to change. Every number links to the passages behind it.

Consistency

The same thing, the same way, every time.

One click reads the whole book and finds everything you’ve written two ways: spellings, hyphens, capitals, numbers, quote and ellipsis styles, and any near-miss of a character, place or ship from your Source of Truth.

Pick the winning form and Fix everywhere changes the rest in one go. You see every change in a preview first, and Undo puts it all back.

Examples of consistency fixes
Found both	Kind
grey / gray	Spelling variants
towards / toward	Spelling variants
sea-plane / seaplane	Hyphenation
the Captain / the captain	Capitals
twenty-one / 21	Numbers in narration
“ ” / " "	Quote styles
Calloway / Caloway	Source of Truth names

With your own AI (optional)

The story layer: critique you can check.

Connect Claude, ChatGPT, Gemini or a model on your own computer, and First Mate can read for story, not just sentences. Before anything is sent, it shows you exactly what will go (“chapter 7, 4,210 words, your Source of Truth and your decisions”) and waits for you to press Send.

Proofread with my AI

Small fixes only. First Mate asks three times (five in Careful mode) and only shows the fixes most answers agree on, with the agreement on the card: 3 of 3 agree. It never rewrites your sentences, and it never touches dialogue beyond a typo.

Chapter and manuscript critique

Opening hook, scene purpose, tension, point of view, character, dialogue, pacing, setting and ending. For the whole book, a beat map, character arcs, themes and open threads. Notes land in the margin, and you can reply, mark one done, or mark it intentional. Each run is saved as a round, so you can compare drafts.

Grounded in your pages

Every finding must quote your text and name its chapter, or it’s thrown out. Names are checked against your Source of Truth, chapter numbers come from the app (not the AI), and one reading of the story feeds every report, so they can’t contradict each other. Strengths and problems are separate lists, so it can’t flatter you.

Continuity

Facts can change over time (“Ruth is 34” until her birthday in chapter 20). On your device, First Mate flags passages that contradict what’s true at that point. With AI it also checks the timeline, who knows what, where things are, point of view and tense, and keeps a ledger of setups that never pay off.

Beta readers, on demand

The genre fan

Reads 50 books a year in your genre. Wants the promise of the cover kept.

The skeptic

Looks for plot holes and things that don’t add up. Always in a full read, so feedback is never all praise.

The editor

Structure, pacing and clarity.

The first-time reader

Confusion, names, and who’s who.

Write your own

Who they are, what they care about, and how blunt: gentle, honest or brutal.

Readers react in the margin at the moment it happens (“Lost track of who’s speaking here”, “Didn’t see that coming”, “Put the book down here”), then say whether they’d keep reading. A reader map shows where each one was hooked, confused or bored.

What the story layer costs

A few cents a chapter.

You pay your own AI company directly, by the request, or nothing at all with a model on your own computer. First Mate never adds a fee or a credit system on top.

Estimated cost per request, worked out from each AI company’s published prices, checked October 2026. Includes the rulebook your AI reads every time, and about 1¢ per web search for Research. Your provider’s bill is the final word. Everything except the story layer is free, on your device.
Where you use it	Budget AIClaude Haiku, GPT-6 Luna, Gemini Flash-Lite	Everyday AIClaude Sonnet, Gemini Pro	Top-of-the-line AIClaude Opus or Fable, GPT-6 Astra
First Mate proofreadOne paragraph, checked 3 times so only agreed fixes show	about 0.1¢	about 2¢	up to 12¢
First Mate chapter critiqueOne chapter with your Source of Truth, notes tied to the page	about 0.3¢	about 5¢	up to 26¢
First Mate beta readerOne reader reacts to one chapter	about 0.2¢	about 4¢	up to 20¢
First Mate manuscript critiqueA whole 80,000-word book, chapter by chapter	about 3¢	about 52¢	up to $2.60

See the cost of every AI feature

Works your way

Your book, your rules.

Already use another checker?

Keep it. In the web app, Grammarly’s or ProWritingAid’s browser extension can usually keep working in the Salt of the Page editor. If you see double marks, turn off First Mate’s “Show marks while I write”.

Want a deeper check?

Connect LanguageTool Premium or your own LanguageTool server for an extra grammar pass. It’s off by default and only sends the paragraphs you choose.

Private by default

Nothing leaves your device unless you switch on a deeper check or an AI feature and press its button. Your decisions live in the book, so backups and sharing cover them. Exports never include First Mate’s notes.

Questions

About First Mate.

Does First Mate cost extra?

No. It’s part of Salt of the Page, whether you own it for $150 or stay current for $10 a month. There are no credits and no limits. The only optional cost is your own AI company’s bill if you use the story layer, typically a few cents a chapter.

Will it change my writing?

Only obvious typos as you type, and you can switch that off. Everything else is a suggestion you accept or don’t. AI suggestions are always shown as a before and after and never applied by themselves.

Does it work for fiction and dialogue?

That’s what it’s built for. Fiction mode is on by default: grammar and style rules skip dialogue, characters can have their own allowed spellings, and fragments you mean can be marked intentional once.

Does it need the internet?

No. Typo fixes, spelling, grammar, style, consistency and all fifteen reports run on your device and work offline. Only the optional deeper check and the AI features go online, and only when you press their button.

Do I have to use AI?

No. Everything except the story layer works with AI switched off. If you do connect one, you choose the company, and First Mate shows you what will be sent before anything goes.

Can I keep using Grammarly or ProWritingAid?

Yes. In the web app their browser extensions can usually keep working beside First Mate. If you see double marks, turn off “Show marks while I write” in First Mate.

Bring a First Mate aboard.

It comes with Salt of the Page: own it for $150, or stay current for $10 a month.

Own it, $150 See the writing room