⚠️ AI Development, Part 7: When Cursor Hallucinates — How We Keep It Grounded

“It’s still like a junior dev — you have to check everything.”

AI pair programming is fast, powerful, and surprisingly creative.
But just like an overconfident intern, it can also go completely off the rails.

In this post, we’ll talk about:

• Real examples of hallucinations from Cursor
• What we’ve learned about preventing chaos
• How RIPER, memory banks, and good prompts can keep things safe
• When to hit undo, and when to start a new chat

🤯 What Is an AI Hallucination?

A “hallucination” is when the AI confidently invents something false.

For example:

• Creating a file that doesn’t exist
• Calling a service that has no relation to your feature
• Generating helper functions that no one asked for
• Misunderstanding the task and rewriting unrelated logic

Cursor is powerful — but it will follow bad prompts, make assumptions, or sometimes just guess.

🧟‍♂️ Real Hallucination Examples

🔄 1. Overeager File Modifications

“It changed more than it should.”

We once asked Cursor to update the authentication handler. Instead, it edited:

• Middleware files
• Route definitions
• A helper we hadn’t touched in months

The plan was clear, but it went beyond what we approved during execution.

🛡️ Fix: Always break execution into small, reviewable steps. Never execute an entire multi-step plan at once.

💡 2. Code That Doesn’t Exist — But Sounds Plausible

“It created a helper function that felt real, but we never wrote it.”

Cursor generated a helper called validateUserAndSession() and referenced it in three places. It seemed legitimate — except... it didn’t exist. Ever.

🛡️ Fix: If you see new code, ask Cursor:
/review did this helper exist before, or did you create it?

🔃 3. Going Off-Script During Execution

“It started writing code before we were done planning.”

Even in /plan mode, Cursor would occasionally switch to execution behavior if the prompt was too vague. In one case, it began modifying TypeScript files before we approved the checklist.

🛡️ Fix:

• Be explicit: “Do NOT write code yet.”
• Use /plan instead of open-ended chat mode
• Start in Ask mode if you’re unsure

🧰 How We Keep Cursor Grounded

“RIPER is not just a workflow — it’s a safety net.”

Here’s our toolbox for reducing hallucinations:

🛡️ 1. One Phase at a Time

• Never skip ahead
• Don’t do /execute without confirming the /plan
• Don’t blend research and implementation in one prompt

📏 2. Use the Rule Files

Remember:

• riper-workflow.mdc enforces mode behavior
• In /research, Cursor is told: “do not write code”
• In /review, it compares actions to the approved plan

The rules don’t stop it 100% — but they help align expectations.

📚 3. Keep Memory Focused

“Too much memory = confusion.”

If you add every .md file and half the codebase to the context, Cursor may:

• Struggle to prioritize
• Misconnect unrelated features
• Miss your main focus

✅ Instead:

• Tag only the memory bank files needed
• Trim prompts to the essentials
• Use @filename and @folder sparingly but deliberately

🧼 4. Review As You Go

Cursor has a tendency to “drift” if left unchecked for too long.

To prevent this:

• Execute in one step at a time
• After each code change, run /review
• Make the AI explain why it did what it did

If it can’t justify a change, don’t commit it.

🧨 5. Reset When Things Get Weird

“You can always start a new chat — don’t hesitate.”

If:

• Cursor starts contradicting itself
• You see clearly off-track output
• You’ve corrected it 3+ times in one session…

🚨 Start a new chat. Re-prompt from scratch. It’s faster than untangling AI confusion.

🧠 Final Tip: You’re Still the Engineer

AI tools like Cursor can:

• Save time
• Unblock you faster
• Write great boilerplate

But they still need a technical lead — and that’s you.

“The goal is not to trust the AI blindly — it’s to scale your thinking while keeping your standards.”

Coming Next: What’s Next for AI Development at GrowthSpace

In the final post, we’ll explore:

• Multi-repo support
• Shared memory banks across teams
• Integrations with GitHub, GCP, and internal tools
• Our plans for making Cursor work in group-wide workflows

Until then, try this:
/plan a one-step change to the login handler, and stop after planning
Then see if it tries to write code anyway. If it does — congrats. You’ve met your first hallucination.

🚀 AI Development, Part 8: What’s Next — Scaling AI Workflows Across Teams

“This isn’t just a dev tool anymore. It’s part of how we build.” Over the last seven posts, we’ve explored how AI tools like Cursor, when paired with a structured approach like RIPER, can transform the way we develop software. We’ve shown how to: * Use Cursor

Behind the BitNeil Kalman