Should I use Ownhand, Grammarly or Jasper to write in my voice?

Use Jasper if a marketing team needs one brand voice across many writers and channels, and Grammarly if you want tone and style feedback as you type in your browser and desktop apps, including its Rewrite in my voice feature on paid plans; use Ownhand if your AI agent drafts the messages you send under your own name and you want each one rewritten from your real writing, fitted to the occasion, and learned from the exact text you sent.

By Jordan Gibbs, founder of Ownhand at Thalient Labs. Updated 4 October 2026.

Grammarly and Jasper facts come from their own sites, help centers and developer docs as of 4 October 2026. I run Ownhand. Click through and check me.

Who each one is built for

Jasper sells to marketing departments. Its pages talk to product marketers, content marketers, brand marketers and PR teams. Brand Voice sits inside what Jasper calls Brand IQ, next to visual guidelines and a style guide. The job is keeping a company sounding like itself when twenty people and a pile of AI agents write blog posts, ads and landing pages in several languages.

Grammarly started as a checker that runs wherever you type, and its team features still work that way. An admin sets brand tones and style rules once. Everyone on the team then sees suggestions in their browser and desktop apps. Grammarly also builds a voice profile for each user from what they write, which is the closest thing either company has to Ownhand.

Ownhand is for one person whose agent writes for them. Claude Code drafts the PR description, ChatGPT drafts the reply to a client, Cursor drafts the Slack DM. Ownhand rewrites each draft as you would have written it, from things you actually sent. There is no admin, no shared brand and no team plan.

Side by side

What Grammarly does with voice

There are three separate pieces, and people mix them up.

Brand tones. An admin or group manager answers a few questions about how the company should sound. Grammarly proposes a tone profile from a fixed set of tones, such as formal, casual or confident, and marks each one on-brand or off-brand. Team members get tone feedback as they write. You can limit the feedback to certain websites, so customer-facing email gets it and internal chat doesn't. Pro gets one profile. Higher plans can give each team its own.

Style rules. A list of swaps: this phrase becomes that phrase, with a note explaining why. Product names, banned terms, house spelling. You can upload them from a spreadsheet. Pro gets one rule set and Business up to 50.

Voice profile. This one is personal. Grammarly watches what you write, describes your style back to you, and keeps one profile for documents and another for messages. You can set your role and dialect and delete traits it got wrong. Highlight text, choose Rewrite in my voice, and it rewrites the selection in that style. It is on Pro and higher plans, in Grammarly for Windows, Mac and Chrome.

If you write mostly by hand in Gmail and Google Docs, that last feature covers a lot of what people want from Ownhand, and you may already pay for it.

What Jasper does with voice

A Jasper Brand Voice describes how a company sounds. In Jasper's API, creating one takes a name and a written description of the voice. Jasper then uses it when generating content, together with audiences, knowledge assets and a style guide, and flags copy where the tone drifts off-brand. Pro includes one seat and two Brand Voices. Business has unlimited voices, admin controls and API access.

Jasper also has an MCP server, which is the part most relevant here. Its generate-content tool writes with the workspace's voices, audiences, style rules and knowledge, and falls back to the workspace defaults when the agent names none. Setup is documented for Claude, ChatGPT, Cursor, VS Code and Windsurf. So an agent can produce on-brand copy from inside the editor. That copy is the brand's, written for an audience segment. A reply to your cofounder in Slack is a different job.

What Ownhand does differently

A brand voice is written down on purpose: a description, a tone list, a set of rules. Your own voice mostly isn't. You don't decide to drop capitals in Slack or to sign client emails with an initial. Ownhand copies those habits from samples, then keeps the pieces a brand tool has no reason to care about.

• The occasion. Your agent says where the text goes: chat_dm, email_cold, review_comment and so on. Each sets length, greeting, sign-off and formatting, and each has checks.
• The person. Your Hand remembers who you write to, by email or name. A rule like "never sign off Best with Dana" applies only to Dana.
• The thread. For a reply, the agent passes recent messages and Ownhand matches how you write in that thread. The thread is never stored.
• What you sent. After you send, the agent reports the final text. Repeated edits become rules you can read, pin or reject. See how Ownhand learns from what you send.

Here is a team announcement an agent drafted, rewritten by two demo writers:

These examples are real output from the live API. Each AI draft was rewritten by a demo Hand: a fictional writer (an engineer, a founder, an ops lead, a designer or a consultant) built from a handful of samples.

Same facts, same date. One writer types in lowercase and skips the welcome. The other keeps capitals and adds one word. A brand voice would push both toward one house style, which is right for a company blog and wrong for a message from you.

Which one to pick

• Pick Jasper if you run marketing content for a company, more than one person writes it, and the brand has to sound the same across channels and languages.
• Pick Grammarly if you do most writing by hand in a browser or Office, want spelling and tone help as you type, or need an admin to roll a style guide out to a team.
• Pick Ownhand if an agent drafts your messages, emails, PR descriptions and review comments, and you want them to read like you before you send.

If you only need the model to sound less stiff, try a free style note first: Ownhand vs custom instructions shows where to put one. For another personal-voice tool that runs over MCP, see Ownhand vs Idiolect.

Follow-up questions

Does Grammarly learn my personal voice?

On Pro and higher plans, yes. Grammarly's help center says it detects a voice profile from your writing, keeps separate profiles for documents and messages, and updates them as you write. You can remove traits you disagree with. The Rewrite in my voice option uses that profile. It runs in Grammarly for Windows, Mac and Chrome.

Can Jasper Brand Voice be one person's voice?

It can hold any voice you describe. Through Jasper's API a voice is a name plus a written description. The product is pitched at marketing teams, and the Pro plan includes two Brand Voices for one seat, so a solo writer can set one up for themselves.

Can my agent use Jasper or Grammarly the way it uses Ownhand?

Jasper, yes. It runs an MCP server with a generate-content tool that writes with your workspace voices, audiences and style rules, and it documents setup for Claude, ChatGPT, Cursor, VS Code and Windsurf. Grammarly works differently: it runs inside the apps where you type, and the pages I read describe no agent connector.

Can I use Grammarly and Ownhand together?

Yes, and they don't overlap much. Ownhand rewrites the draft your agent hands you. If you then paste it into Gmail or Slack with Grammarly running, Grammarly still checks spelling, your style rules and your brand tone before you hit send.

Sources

Checked on 4 October 2026. If something here is out of date, email hi@thalientlabs.ai and we will fix it.

• Grammarly: plans: Free, Pro and Enterprise; Pro lists one style guide and one brand tone, Enterprise unlimited
• Grammarly: brand tones: custom tone profiles for a brand, one per team, real-time feedback
• Grammarly Support: set brand tones: who can set them, on-brand and off-brand tones, URL allow list, one profile on Pro
• Grammarly Support: create style rules: original text, replacement and explanation; CSV upload; one rule set on Pro, up to 50 on Business
• Grammarly Support: view and customize your voice profile: voice profile detected from your writing, Rewrite in my voice, Windows, Mac and Chrome
• Grammarly: AI features: desktop, mobile, browser extensions, Microsoft Office and Google Docs
• Jasper: Brand Voice: brand voice at scale for marketers, flags off-brand tone
• Jasper: Brand IQ: Brand Voice, Visual Guidelines and Style Guide for marketing teams
• Jasper: pricing: Pro is one seat with 2 Brand Voices; Business adds unlimited voices, API access and admin controls; 7-day trial
• Jasper developer docs: Jasper MCP server: server URL, OAuth or API key, tool list including generate-content, supported clients
• Jasper API reference: create a voice: a voice is a name and a description
• Ownhand source code: occasions, people, the reply fingerprint, the checker and the feedback loop