Instruction file imported from ryanmosz/Studybara (.cursor/rules/custom-rules/mcp-quick-patterns.mdc). Copyright stays with the author.

MCP Quick Patterns

Description: Common patterns and examples for effective MCP usage with direct database access

Quick Command Templates

1. Adding a Database Column

"Add a [column_name] to the [table_name] table with:
- Direct migration via MCP
- Updated TypeScript types
- UI changes in relevant components"

2. Creating a New Feature

"Build [feature_name] with:
- Database schema (create and apply via MCP)
- Component structure
- Service functions
- Full implementation"

3. Debugging Database Issues

"Debug why [issue]. Check:
- Current schema via MCP
- Query data directly
- View logs
- Security advisors"

4. Schema Analysis

"Analyze current database structure and:
- List all tables
- Check RLS policies
- Review security issues
- Suggest improvements"

Common Patterns by Task Type

Database Operations (Direct via MCP)

Agent Executes Directly:

// Query current schema
mcp_supabase_list_tables({ schemas: ["public"] })

// Create and apply migration
mcp_supabase_apply_migration({
  name: "add_favorites_table",
  query: `CREATE TABLE favorites (...)`
})

// Verify changes
mcp_supabase_execute_sql("SELECT * FROM favorites LIMIT 1")

UI Development

Agent Executes Everything:

• Creates components
• Implements features
• Installs packages
• Updates types
• Tests locally

Debugging with MCP

Agent Can Now:

// Check data
mcp_supabase_execute_sql("SELECT COUNT(*) FROM messages WHERE sender_id IS NULL")

// View logs
mcp_supabase_get_logs({ service: "postgres" })

// Get security issues
mcp_supabase_get_advisors({ type: "security" })

Local + Database Setup

Agent Executes All:

# Local setup
npm install @supabase/supabase-js

# Database setup via MCP
mcp_supabase_apply_migration({
  name: "initial_schema",
  query: "CREATE TABLE ..."
})

# Verify and commit
git add .
git commit -m "feat: complete setup"

Effective MCP Usage

Direct Database Access

• mcp_supabase_execute_sql() - Query data directly
• mcp_supabase_apply_migration() - Create schema changes
• mcp_supabase_list_tables() - Inspect structure
• mcp_supabase_get_advisors() - Check security

Project Analysis (RepoPrompt)

• mcp_RepoPrompt_get_codemap() - Analyze code structure
• mcp_RepoPrompt_search() - Find patterns
• mcp_RepoPrompt_read_file() - Read specific files

Combined Power

// 1. Check current schema
const tables = mcp_supabase_list_tables()

// 2. Search for related code
const usage = mcp_RepoPrompt_search({ 
  pattern: "supabase.from('messages')",
  mode: "content"
})

// 3. Apply migration
mcp_supabase_apply_migration({
  name: "update_messages_table",
  query: "ALTER TABLE messages ADD COLUMN ..."
})

// 4. Update code locally
edit_file("src/types/database.ts", updatedTypes)

Pro Tips

1. Query Before Migrating: Always check current state first
2. Verify After Changes: Use execute_sql to confirm
3. Monitor Security: Regular advisor checks
4. Use Branches: Test big changes on dev branches
5. Combine MCPs: Use both for complete solutions

Example: Full Feature Flow

Request: "Add a favorites feature"

Agent executes everything:

// 1. Check schema
mcp_supabase_list_tables({ schemas: ["public"] })

// 2. Create migration
mcp_supabase_apply_migration({
  name: "create_favorites_table",
  query: `
    CREATE TABLE favorites (
      id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
      user_id UUID REFERENCES profiles(id),
      message_id UUID REFERENCES messages(id),
      created_at TIMESTAMPTZ DEFAULT NOW(),
      UNIQUE(user_id, message_id)
    );
    
    CREATE POLICY "Users manage own favorites"
    ON favorites FOR ALL
    TO authenticated
    USING (auth.uid() = user_id);
  `
})

// 3. Verify it worked
mcp_supabase_execute_sql("SELECT * FROM pg_tables WHERE tablename = 'favorites'")

// 4. Generate TypeScript types
mcp_supabase_generate_typescript_types()

// 5. Create service
create_file("src/services/favorites.ts", favoriteService)

// 6. Create UI
create_file("src/components/FavoriteButton.tsx", component)

// 7. Test with query
mcp_supabase_execute_sql("SELECT * FROM favorites WHERE user_id = 'test-id'")

// 8. Commit
git_commit("feat: add favorites feature with database")

Division of Labor (Updated)

Agent Handles (via MCP):

• ✅ Database queries (SELECT)
• ✅ Schema migrations
• ✅ Security analysis
• ✅ Log viewing
• ✅ Type generation
• ✅ All local operations

Human Only Needed For:

• Production deployment approval
• API key management
• Authentication provider setup
• Billing/usage monitoring
• Custom domain configuration

Remember

• Agent has direct database access via MCP
• Most operations are now fully automated
• No more copy-paste SQL workflows
• Instant verification of changes
• Better debugging with logs and queries
• Security monitoring built-in