Cursor vs JunieUpdated 2026-03-16

SUMMARY

Cursor (IDE) uses mdc configuration while Junie (Agent) uses markdown. They differ on 7 of 11 compared features. Both tools provide AI-assisted development but take different approaches to project configuration.

FEATURE COMPARISON

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

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
Junie
.junie/guidelines.md
markdown
# Project Guidelines

## Language & Framework
- Kotlin with Spring Boot 3.x
- Gradle with Kotlin DSL
- JDK 21 with virtual threads

## Architecture
- Hexagonal architecture (ports & adapters)
- Domain events for cross-module communication
- CQRS for read-heavy endpoints

## Code Standards
- Follow Kotlin coding conventions
- Use data classes for DTOs
- Prefer sealed classes for domain errors
- Extension functions over utility classes

## Testing
- JUnit 5 with Kotest assertions
- Testcontainers for integration tests
- MockK for mocking (not Mockito)

## Build & Run
- Build: ./gradlew build
- Test: ./gradlew test
- Run: ./gradlew bootRun

KEY DIFFERENCES

1. Config format

Cursor: mdc. Junie: markdown.

2. Hierarchy support

Cursor: Supported. Junie: Not supported.

3. Global config

Cursor: Supported. Junie: Not supported.

4. Subdirectory scoping

Cursor: Supported. Junie: Not supported.

5. Ignore file

Cursor: .cursorignore. Junie: Not supported.

6. IDE integration

Cursor: Supported. Junie: Agent.

7. Schema / structure

Cursor: Hybrid (MDC frontmatter + Markdown). 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 Junie, configure .junie/guidelines.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)