Optimize context window usage in Cursor. Triggers on "cursor context",
"context window", "context limit", "cursor memory", "context management". Use when working with cursor context management functionality. Trigger with phrases like "cursor context management", "cursor management", "cursor".
Optimize how Cursor AI uses context to produce accurate, relevant responses. Context is everything the model sees when generating a response -- managing it well is the single biggest lever for output quality.
Context Sources
Cursor assembles context from multiple sources before each AI request:
┌─ Always Included ─────────────────────────────────────┐
│ System prompt (Cursor internal) │
│ Active .cursor/rules/*.mdc with alwaysApply: true │
│ Current file (for Tab, Inline Edit) │
└───────────────────────────────────────────────────────┘
┌─ Conditionally Included ──────────────────────────────┐
│ Selected code (highlighted before Cmd+L/Cmd+K) │
│ @-mention targets (@Files, @Folders, @Code) │
│ Glob-matched rules (.mdc with matching globs) │
│ Conversation history (prior turns in chat) │
│ Open editor tabs (lightweight reference) │
└───────────────────────────────────────────────────────┘
┌─ On-Demand (explicit @-mention) ──────────────────────┐
│ @Codebase → semantic search across indexed files │
│ @Docs → crawled external documentation │
│ @Web → live web search results │
│ @Git → uncommitted diff or branch diff │
│ @Lint Errors → current file lint diagnostics │
└───────────────────────────────────────────────────────┘
Context Pills
Active context appears as pills at the top of the Chat/Composer panel:
Adding too many pills fills the context window, degrading response quality
@-Mention Strategy by Task
Code Understanding
@src/auth/middleware.ts @src/types/user.ts
Explain how the JWT validation works and what happens when a token expires.
Use @Files for specific files. Avoid @Folders unless you need the full directory -- it consumes a lot of context.
Bug Investigation
@src/hooks/useCart.ts @Lint Errors @Recent Changes
The cart total is NaN after the latest changes. What broke?
@Recent Changes + @Lint Errors gives the model forensic context.
Architecture Questions
@Codebase where are database queries made?
@Codebase triggers semantic search across the indexed codebase. Good for discovery when you do not know which files are relevant. Costs more context than targeted @Files mentions.
Using External Knowledge
@Docs Prisma @Web prisma client extensions 2025
How do I add soft-delete as a Prisma Client extension?
@Docs uses pre-indexed documentation. @Web does a live search. Combine both for comprehensive answers about third-party tools.
Context Budget Management
Each model has a context limit. Overloading it causes the model to drop information silently:
Model
Context Window
Practical Limit
GPT-4o
128K tokens
~80K usable
Claude Sonnet
200K tokens
~150K usable
Claude Opus
200K tokens
~150K usable
cursor-small
8K tokens
~5K usable
Signs of Context Overflow
Model forgets instructions from earlier in the conversation
Responses become generic or repetitive
Model contradicts what it said 3 turns ago
Suggested code ignores file context you provided
Mitigation Strategies
Start new conversations frequently. One topic per conversation.
Use specific @Files, not @Folders.@src/api/users.ts is better than @src/api/.
Remove context pills you no longer need. Click x to drop stale files.
Avoid @Codebase for narrow questions. It pulls in many code chunks. Use @Files when you know the location.
Break large tasks into steps. Ask for the type definitions first, then the implementation, then the tests -- in separate turns or chats.
Automatic vs Manual Context
Cursor automatically includes context in some cases:
Feature
Automatic Context
Tab Completion
Current file + open tabs + recent edits
Inline Edit (Cmd+K)
Selected code + surrounding file
Chat (Cmd+L)
Conversation history + explicitly added context
Composer (Cmd+I)
Referenced files + codebase search
For Chat and Composer, you control context through @-mentions. Tab and Inline Edit manage their own context automatically.
.cursorignore for Context Control
Prevent files from ever being included in AI context:
# .cursorignore (project root)
# Secrets and credentials
.env
.env.*
**/secrets/
**/credentials/
# Large generated files
dist/
build/
node_modules/
*.min.js
*.bundle.js
# Data files that consume context budget
*.csv
*.sql
*.sqlite
fixtures/
Note:.cursorignore is best-effort. It prevents files from appearing in indexing and AI features, but is not a security boundary for protecting secrets. Use .gitignore and environment variables for actual secret management.
Advanced: Scoped Rules as Context
Project rules automatically inject context when relevant files are opened:
# .cursor/rules/database-patterns.mdc
---
description: "Database query patterns and conventions"
globs: "src/db/**/*.ts,src/repositories/**/*.ts"
alwaysApply: false
---
# Database Conventions
- Use parameterized queries exclusively
- All queries go through repository pattern
- Wrap multi-table operations in transactions
- Use connection pooling (pool size: 10)
This rule automatically loads when editing database files, giving the AI the right conventions without you manually adding context each time.
Enterprise Considerations
Data sensitivity: Use .cursorignore to exclude files with PII, credentials, or regulated data
Privacy Mode: Ensures code sent as context has zero data retention at model providers
Conversation hygiene: Train teams to start new chats per task to avoid context bleed
Cost awareness: Larger context = more tokens = higher API costs when using BYOK
