Cursor vs JetBrains AI / JunieUpdated 2026-03-16

SUMMARY

Cursor (IDE) uses mdc configuration while JetBrains AI / Junie (IDE) uses markdown. They differ on 6 of 11 compared features. Both tools provide AI-assisted development but take different approaches to project configuration.

FEATURE COMPARISON

FeatureCursorJetBrains AI / Junie
Config formatmdcmarkdown
Hierarchy support
Global config
Project config
Subdirectory scoping
File inclusion / imports
Ignore file.cursorignore.aiignore
IDE integration
Schema / structureHybrid (MDC frontmatter + Markdown)Free-form (Markdown)
Git committed
EncodingUTF-8UTF-8

FILE MAPPING

PurposeCursorJetBrains AI / Junie
Project rules.cursor/rules/*.mdc.aiassistant/rules/*.md
Ignore patterns.cursorignore.aiignore

SIDE-BY-SIDE CODE SAMPLES

Cursor
.cursor/rules/*.mdc
mdc
---
description: React component conventions and patterns
globs: "*.tsx"
alwaysApply: false
---

# React Component Rules

- Use functional components with explicit return types
- Define props interface directly above the component
- Export components as named exports, never default
- Use Tailwind CSS utility classes exclusively
JetBrains AI / Junie
.aiassistant/rules/*.md
markdown
# Kotlin Conventions

## Language Features
- Use Kotlin 2.x with coroutines for async work
- Prefer data classes for DTOs and value objects
- Use sealed classes/interfaces for domain errors
- Extension functions over utility classes

## Spring Boot
- Constructor injection (no field injection)
- Use @ConfigurationProperties over @Value
- Prefer WebFlux for reactive endpoints
- Use Spring Security with method-level security

## Testing
- JUnit 5 with Kotest assertions
- MockK for mocking (not Mockito)
- Testcontainers for integration tests
- Use @Nested for test organization

KEY DIFFERENCES

1. Config format

Cursor: mdc. JetBrains AI / Junie: markdown.

2. Hierarchy support

Cursor: Supported. JetBrains AI / Junie: Not supported.

3. Global config

Cursor: Supported. JetBrains AI / Junie: Not supported.

4. Subdirectory scoping

Cursor: Supported. JetBrains AI / Junie: Not supported.

5. Ignore file

Cursor: .cursorignore. JetBrains AI / Junie: .aiignore.

6. Schema / structure

Cursor: Hybrid (MDC frontmatter + Markdown). JetBrains AI / Junie: Free-form (Markdown).

WHICH SHOULD I USE?

Recommendation

Choose based on your IDE/CLI preference. If you use Cursor, configure .cursorrules. If you use JetBrains AI / Junie, configure .aiassistant/rules/*.md. Many projects include config files for multiple tools so each team member can use their preferred editor.

PORTABILITY TIP

sync-instructions.sh
bash
# Maintain a single source of truth:
cp AI-INSTRUCTIONS.md CLAUDE.md
cp AI-INSTRUCTIONS.md .cursorrules
cp AI-INSTRUCTIONS.md AGENTS.md

SEE ALSO

agentconfig.ing2026-03-16COMPARE(1)