Claude Uses TypeScript, Cursor Gives JavaScript
📖 Series Navigation — This post is part of the AI context isolation series. For the complete guide and 30-second sync setup, see How to Sync AI Context Between Cursor and Claude Code, or browse the topic hub.
I’m Yang Qing, an architect with 10 years of big tech experience turned solopreneur. I deconstruct business from a technical perspective to help you avoid common pitfalls.
The content I share covers: boosting efficiency with AI tools, taking independent products global, and solopreneurship methodologies.
Yesterday’s post blew up. Someone DM’d me with an even crazier story.
After I wrote that “AI amnesia” article, the comments section went wild.
Someone said: “You’re so right, I explain the same things every day.”
Another said: “I thought I was the only one. Turns out we’re all suffering.”
Then a DM came in that made my jaw drop.
He said:
“I told Claude to use TypeScript. Switched to Cursor, and it kept giving me JavaScript. Two tools acting like they have amnesia.”
This isn’t a joke. This actually happened.

The Problem: Claude Remembers, Cursor Doesn’t
I asked him: What was the scenario?
He said:
“I was working on a Next.js project. In Claude Code, I explicitly said ‘this project uses TypeScript, don’t give me JavaScript.’ Claude remembered. All the code after that was TS.”
“Then I wanted to try another feature in Cursor. Opened the same project, asked it a question.”
“And the code it generated was all JavaScript.”
“I was confused. Claude knew what I said. Cursor had no clue.”
“It’s like I told my wife I don’t eat cilantro. Then at a restaurant, the waiter asks her if she wants cilantro, she says no. But then the waiter turns to me, and I have to say it again.”
“The problem is, I can’t say it in every single tool.”
This scenario is way too real.
I’ve had similar experiences.
I told Claude Code “we use Prisma, not raw SQL.” Then switched to Windsurf, and it generated a bunch of raw SQL queries.
I spent an entire afternoon fixing that code.
Later I realized, the problem isn’t that AI isn’t smart enough.
It’s that every AI tool is an “island.”
The Root Cause: Rule File Fragmentation
Do you know how many AI coding tools are out there?
Claude Code, Cursor, Windsurf, Gemini CLI, GitHub Copilot, Codex CLI, Cline, Roo Code, Aider, Continue, Zed…
Each tool has its own “rule file”:
- Claude Code uses CLAUDE.md
- Cursor uses .cursorrules
- Windsurf uses .windsurfrules
- Gemini CLI uses GEMINI.md
- Copilot uses .github/copilot-instructions.md
How many projects do you have?
How many rule files per project?
How many files do you need to sync every time you change a rule?

Let’s Do the Math: Exponential Maintenance Cost
I did the math.
Let’s say you have 3 projects, using 4 AI tools.
Each project needs 4 rule files.
3 × 4 = 12 files.
Every time you change a rule, you update 12 places.
Miss one? Good luck debugging.
I asked a few indie dev friends. Their situations are even crazier.
One of them uses 5 tools across 6 projects.
That’s 30 rule files.
He said: “I’m not writing code. I’m maintaining an Excel spreadsheet of rule files.”

The Solution: ContextSync
So I started thinking about a question.
Can I just write one?
One rule file that all tools can read.
Say “use TypeScript” anywhere, and all tools know.
No need to re-explain every time you switch.
No need to maintain 6, 12, or 30 files.
Say it once, all tools remember.
I spent a week building a tool.
It’s called ContextSync.
It solves exactly this problem.
The principle is simple:
You write one rule file (~/.contextsync/rules.md), and it automatically syncs to all AI tools’ rule files.
CLAUDE.md, .cursorrules, .windsurfrules, GEMINI.md…
Change one place, update everywhere.
Besides rule syncing, it has another feature.
Memory sharing.
What you say in Claude Code, Cursor can know too.
For example, you say “we use Prisma.” That gets recorded.
Next time you ask Cursor a question, it automatically uses that as context.
No need to explain again.
User Feedback
A friend used it for two weeks and told me:
“Now I switch tools without any anxiety. Before, switching tools felt like getting a new assistant. Now it’s like the same assistant changed clothes.”
“Inside, it’s still the same assistant.”

Final Thoughts
If your workflow involves multiple AI tools.
If you’re tired of re-explaining every time you switch.
Give it a try.
The free version supports Claude Code + Cursor. That’s enough for most people.
Pro version supports 12+ tools, plus cloud sync.
Limited spots—only 20 left.
Beta perk: Join the beta and share your feedback, get one month of Pro free ($9 value).
Let’s actually connect your team’s AI memory.
Add WeChat (*dao24dao) — spots are first come, first served.
This article was first published on WeChat: View Original
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