Proofreader

Overview

This skill catches grammar errors, spelling mistakes, punctuation problems, inconsistent style, and tone mismatches in any written content—emails, reports, blog posts, essays, or marketing copy. It distinguishes between proofreading (surface-level errors) and copy editing (structural issues), applies common style guide rules, and flags commonly confused words. The output is a corrected version of the text with explanations of changes, or a marked-up list of issues depending on your preference.

When to Use

Final review before publishing a blog post or article
Checking an important email before sending
Reviewing a business report or proposal for errors
Polishing an essay or academic paper
Auditing marketing copy for consistency and tone
Verifying consistency in longer documents (capitalization, hyphenation, terminology)

When NOT to Use

When the content needs to be restructured, reorganized, or substantially rewritten (that's developmental or copy editing)
When the content is a rough draft that hasn't been reviewed by the author yet—proofread the near-final version
For technical accuracy checking (confirming facts, code correctness, data)
When you need a completely new version of the content

Quick Reference

Task	Approach
Grammar	Check subject-verb agreement, tense consistency, dangling modifiers
Punctuation	Oxford comma, em dash usage, apostrophes, semicolons
Commonly confused	affect/effect, its/it's, their/there/they're, that/which, who/whom
Style consistency	Capitalization, hyphenation, number formatting, terminology
Tone check	Formal/casual match, second-person consistency, active/passive balance
Markup	Strikethrough deleted text, bold/bracket insertions

Instructions

Clarify the style guide and tone. Before proofreading, establish:
- Style guide: AP, Chicago, MLA, APA, or house style?
- Audience tone: formal, professional-casual, or informal?
- Any document-specific conventions (e.g., always capitalize "Team" when referring to the product)?
Read for meaning first, errors second. On the first pass, read the entire piece to understand what it's trying to say. This prevents "correcting" deliberate stylistic choices.
Check grammar systematically. Focus on:
- Subject-verb agreement: "The data show" (data is plural) vs. "The data shows"
- Tense consistency: Don't switch between past and present within the same section
- Dangling modifiers: "Having finished the report, the coffee was cold." (Who finished the report? Not the coffee.)
- Sentence fragments: Incomplete sentences without a main verb
- Run-on sentences: Two independent clauses joined without proper punctuation
Check punctuation.
- Oxford comma: "We invited the manager, the developer, and the designer." (Use unless house style forbids it)
- Apostrophes: Possessives (it's = it is; its = possessive), plurals never get apostrophes
- Em dashes vs. en dashes: Em dash (—) for breaks in thought; en dash (–) for ranges (2019–2023)
- Semicolons: Connect two complete, related independent clauses
- Comma splices: "I finished the report, it looked great." → Use a period, semicolon, or conjunction

Flag commonly confused words:

Confused Pair	Rule
affect / effect	Affect = verb (to influence); Effect = noun (the result)
its / it's	its = possessive; it's = it is
their / there / they're	possessive / location / they are
that / which	"that" restricts (no comma); "which" adds info (comma before it)
who / whom	who = subject; whom = object
fewer / less	fewer = countable; less = uncountable
lay / lie	lay = to place something; lie = to recline
complement / compliment	complement = completes; compliment = praise
principal / principle	principal = main/head person; principle = rule/value
further / farther	farther = physical distance; further = metaphorical

Check style consistency throughout the document:
- Capitalization: Is "Director" always capitalized? Or never?
- Numbers: Spell out one through nine, numerals for 10+? Or always numerals?
- Hyphenation: "email" or "e-mail"? "decision-maker" or "decision maker"?
- Serial comma: used consistently throughout?
- Terminology: Same word used for the same concept every time?
Check tone and register.
- Does the formality level match the audience and context?
- Is second-person ("you") used consistently where applicable?
- Are there shifts from active to passive that weaken the writing?
- Does the tone stay consistent, or does it veer between professional and overly casual?
Output format. Choose one:
- Corrected version: Full rewritten text with all errors fixed (best for clean final copy)
- Marked-up version: Original text with inline corrections using conventions (best for showing what changed)
- Error report: Bulleted list of issues with original → corrected for each (best for learning/feedback)

Examples

Example 1: Proofreading a Business Report Paragraph

Input: "The team have successfully completed the Q3 objectives, which was a significant achievement given the projects complexity. Going forward, we need to focus on improving our response times, their currently averaging 48 hours which effects customer satisfaction scores. Its important that each team member understand there role in achieving this target by years end."

Output:

Corrected Version: "The team has successfully completed the Q3 objectives, which was a significant achievement given the project's complexity. Going forward, we need to focus on improving our response times—they're currently averaging 48 hours, which affects customer satisfaction scores. It's important that each team member understands their role in achieving this target by year's end."

Changes Made:

"have → has" — "team" is treated as a singular collective noun in American English
"projects → project's" — possessive requires apostrophe
"their → they're" — contraction of "they are"
"which effects → which affects" — "affects" (verb) is correct here; "effect" would be the noun
"Its → It's" — contraction of "it is"
"understand → understands" — subject "each team member" is singular
"there → their" — possessive pronoun for "their role"
"years end → year's end" — possessive requires apostrophe
Added em dash before "they're" to improve flow and separate the clause clearly

Example 2: Proofreading a Professional Email

Input: "Hi Marcus,

Thanks for meeting with myself and Sarah yesterday, we really enjoyed the conversation. Going forward I think theirs a real opportunity here for both our organizations. We would love to setup a more formal call to discuss the specifics of the proposal that was presented by you.

Looking forward to hearing your thoughts, Jennifer"

Output:

Corrected Version: "Hi Marcus,

Thanks for meeting with Sarah and me yesterday—we really enjoyed the conversation. Going forward, I think there's a real opportunity here for both of our organizations. We'd love to set up a more formal call to discuss the specifics of your proposal.