It works on your files, not in a chat box.
Claude can work directly on the folders on your machine. ChatGPT can now do this too, in Work in its desktop app. The difference is in how it's set up, not whether it's possible.
Your work lives in folders: drawings, quotes, reports. Nobody has to copy and paste it into a chat and back out again.
It does the job while you're out, not just a reminder.
ChatGPT's scheduled tasks can't use custom GPTs. Claude's scheduled tasks run a full working session on their own, and can use your connected folders when the Claude desktop app is open.
You come back to the work done, not a note telling you it still needs doing.
It reads your whole reference pack, not a cut-down bit.
On paid plans, Claude Projects can hold up to about ten times more than fits in one chat, and pull in the parts that matter for each question.
Your standards, past jobs and house style all go in, so nothing important gets left out.
You can show a client where their data goes.
On business plans, both Anthropic and OpenAI say in writing that they don't train their models on your data by default. You control how long chats are kept: delete one and both companies say it's gone from their systems within 30 days, with narrow legal and safety exceptions.
When a client asks, you have the answer on paper, not a guess.
The ChatGPT and Claude details were checked against each company's own documentation on 11 October 2026. Both change fast, so treat this as a snapshot.
And a person still signs it off.
The agent drafts. One of your team checks it before it goes out. That's how the standard stays yours.
Questions
Straight answers.
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Is Claude better than ChatGPT for a small engineering firm?
For a small firm with rules about its data and work that lives in files, a properly set-up Claude usually does more. Both change quickly, so check the date at the foot of this page.
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Do I still need someone to set it up properly?
Yes, if the job has to hit your standard every time. Buying a login doesn't give you the rules, the files or the person who checks the work.
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Does Greycell lock you into Claude?
No. We build it, test it on your real work, then move it onto your own Claude or OpenAI subscription.
Weighing this up for your own firm? We'll tell you straight where you stand.
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