How to Share Context Across Cursor, Claude Code, and Cline

The Multi-Tool Context Problem

Most serious AI developers use more than one tool. Claude Code for autonomous agent tasks. Cursor for IDE-integrated editing. Cline for model-agnostic VS Code work. Windsurf for its autonomous Cascade mode.

The problem: each tool has its own context format. CLAUDE.md for Claude Code. .cursorrules for Cursor. .clinerules for Cline. Windsurf workspace rules. If these files aren't in sync, each tool operates with a different understanding of your project — and they'll give you contradictory results.

The agent that established the right pattern in a Claude Code session doesn't automatically communicate it to Cursor. You get a Cursor session that proposes the approach Claude Code already rejected.

This is the multi-tool context problem, and it's a hidden cost of using multiple AI coding tools.

The Solution: AGENTS.md as Universal Source of Truth

AGENTS.md is an emerging standard for tool-agnostic AI agent instructions. Like CLAUDE.md for Claude Code, AGENTS.md is read by an increasing number of AI coding tools as a shared baseline context file.

Key difference: CLAUDE.md is Claude Code-specific. AGENTS.md is meant to work across tools — it's the universal instruction file.

As of 2026, tool support for AGENTS.md:

• Claude Code: reads AGENTS.md alongside CLAUDE.md
• Cursor: can be configured to read AGENTS.md via rules
• Cline: reads AGENTS.md as a context source
• Windsurf: reads AGENTS.md via workspace rules

The strategy: maintain AGENTS.md as the single canonical source of truth, then use tool-specific files for tool-specific instructions.

A Unified Context Strategy in 4 Steps

Step 1: Create AGENTS.md as the Canonical Source

AGENTS.md at your project root becomes the definitive record of architectural decisions. Write it the same way you'd write a comprehensive CLAUDE.md:

# Project: [Name] — Agent Instructions

## What This Project Is
[One paragraph: what it does, who uses it, key constraints]

## Tech Stack
- Framework: Next.js 15.3, App Router only
- Language: TypeScript 5.8, strict mode
- Database: PostgreSQL via Prisma 7
- Auth: Auth0 v3 (@auth0/nextjs-auth0)
- Styling: Tailwind CSS 3.4
- Testing: Vitest + @testing-library/react

## Commands
- Dev: npm run dev
- Test: npm run test
- Build: npm run build
- Lint: npm run lint
- DB: npm run db:migrate | npm run db:generate

## Architecture Decisions
- Auth: Auth0 only — NOT NextAuth, NOT Passport, NOT local sessions
- Database: Prisma only — no raw SQL, no other ORM
- API: Next.js route handlers in app/api/ — no tRPC
- Error: return { data, error } from handlers — do not throw
- State: Zustand for complex state — no Redux, no Context API for non-trivial state

## DO NOT
- Use localStorage or sessionStorage for auth state (XSS risk)
- Use class components — hooks only
- Add npm dependencies without approval
- Touch .env files directly — reference by name only
- Use the Pages Router — all routes in app/

## Testing Standards
- Tests co-located: foo.ts → foo.test.ts (same directory)
- Mock external services with vi.mock()
- Test user behavior, not implementation details

This is your ground truth. When a decision changes, you update AGENTS.md.

Step 2: Create CLAUDE.md as a Claude Code-Specific Layer

CLAUDE.md can either mirror AGENTS.md or extend it with Claude Code-specific instructions:

# See AGENTS.md for full project context.

## Claude Code-Specific Instructions
- Use /clear between unrelated tasks
- Always run npm run test after file changes
- Hook: context-keeper runs at session end to capture decisions
- Ask before any git push to production branches

## MCP Servers Available
- postgres: query the development database
- github: create PRs and read issues

This way, CLAUDE.md extends rather than duplicates. If CLAUDE.md is empty or minimal, Claude Code falls back to AGENTS.md.

Step 3: Create a .cursorrules Wrapper

Cursor reads .cursorrules. Make it reference AGENTS.md and add Cursor-specific context:

<!-- .cursorrules -->
See AGENTS.md for the canonical project context. All decisions there apply here.

## Cursor-Specific Notes
- When using Composer, always show the diff for review before accepting
- Use @AGENTS.md in chat to reference the project context
- Tab completion: accept multi-line suggestions for standard patterns

## File-Specific Rules
- app/api/**/*.ts: always validate input, check auth, return {data, error}
- components/**/*.tsx: React 19 hooks only, no class components

Step 4: Create Cline Rules

Cline reads .clinerules (or clinerules.md):

# Cline Agent Instructions

Refer to AGENTS.md for the full project context.

## Cline-Specific Configuration
- Update memory-bank/activeContext.md at end of each session
- Update memory-bank/systemPatterns.md when new patterns are established
- Use Claude Sonnet for implementation; Claude Opus for architectural planning

Keeping Context In Sync Automatically

Manual synchronization of context files is a maintenance burden. Two automation approaches:

Option 1: Context Keeper Auto-Capture

Context Keeper captures architectural decisions from Claude Code session transcripts and syncs them to both CLAUDE.md and AGENTS.md. When you make a decision in a Claude Code session, it automatically surfaces in both files — and by extension, in Cursor and Cline that read those files.

Configure Context Keeper to update both files:

context-keeper capture --targets CLAUDE.md,AGENTS.md

Option 2: Post-Session Update Skill

Create a Claude Code skill that updates all context files at session end:

# .claude/commands/sync-context.md

Review this session's decisions and sync context files:

1. Read AGENTS.md, CLAUDE.md, and .cursorrules
2. Identify any new architectural decisions established in this session
3. Add them to AGENTS.md under the appropriate section
4. Sync the key decisions to CLAUDE.md and .cursorrules
5. Show the diff before writing

Keep AGENTS.md as the authoritative source. 
The tool-specific files should extend, not duplicate it.

Run /sync-context at the end of each significant session.

Validating Sync Across Tools

A quick sanity check to verify all tools are aligned:

1. Open a Claude Code session: "What auth strategy does this project use?"
2. Open Cursor Chat: "What auth strategy does this project use?"
3. Open Cline: "What auth strategy does this project use?"

All three should give the same answer from your context files. If they don't, your files are out of sync.

What to Put in AGENTS.md vs Tool-Specific Files

Key Takeaways

• Multi-tool context fragmentation is real: each tool with different context produces contradictory results
• AGENTS.md is the universal source of truth — read by Claude Code, Cursor (via rules), Cline, and Windsurf
• Tool-specific files (CLAUDE.md, .cursorrules, .clinerules) extend AGENTS.md rather than duplicating it
• Automated sync (via Context Keeper or a session-end skill) removes the maintenance burden
• Validate alignment by asking all tools the same question and comparing answers

Related: AGENTS.md vs CLAUDE.md: The Agent Instruction File Standard · Cursor Memory & Rules: How to Set Up · Best AI Coding Agents in 2026