Cursor Agent Rules for Code Modification

1. Pre-Edit Analysis Requirements

BEFORE making any code changes, MUST:

• Use mcp__get_document_symbols on the target file to understand its structure
• Use mcp__find_usages on any symbol being modified to identify all affected locations
• Use mcp__get_type_definition and/or mcp__go_to_definition for any types or symbols being modified
• Use mcp__get_hover_info to verify function signatures and type information

2. Impact Analysis Rules

BEFORE proceeding with changes:

1. If mcp__find_usages reveals usage in multiple files:

   • Must analyze each usage context
   • Must verify type compatibility across all uses
   • Must plan changes for all affected locations

2. If modifying interfaces or types:

   • Must use mcp__find_implementations to locate all implementations
   • Must ensure changes won't break implementing classes
   • Must verify backward compatibility or plan updates for all implementations

3. Type Safety Rules

MUST maintain type safety by:

1. Using mcp__get_type_definition for:

   • All modified parameters
   • Return types
   • Interface members
   • Generic constraints

2. Using mcp__get_hover_info to verify:

   • Function signatures
   • Type constraints
   • Optional vs required properties

4. Code Modification Sequence

When making changes:

1. First gather context:

// Example sequence
await mcp__get_document_symbols(file)
await mcp__find_usages(symbol)
await mcp__get_type_definition(symbol)
await mcp__get_hover_info(symbol)

2. Then analyze impact:

// For each usage found
await mcp__get_hover_info(usage)
await mcp__get_type_definition(relatedTypes)

3. Only then use edit_file

5. Post-Edit Verification

After making changes:

1. Use mcp__get_document_symbols to verify file structure remains valid
2. Use mcp__find_usages to verify all usages are still compatible
3. Use mcp__get_hover_info to verify new type signatures

6. Special Cases

When Modifying React Components:

1. Must use mcp__find_usages to:

   • Find all component instances
   • Verify prop usage
   • Check for defaultProps and propTypes

2. Must use mcp__get_type_definition for:

   • Prop interfaces
   • State types
   • Context types

When Modifying APIs/Functions:

1. Must use mcp__get_call_hierarchy to:
   • Understand the call chain
   • Identify dependent functions
   • Verify changes won't break callers

When Modifying Types/Interfaces:

1. Must use mcp__find_implementations to:
   • Locate all implementing classes
   • Verify compatibility
   • Plan updates if needed

7. Error Prevention Rules

1. NEVER modify a symbol without first:

await mcp__find_usages(symbol)
await mcp__get_type_definition(symbol)

2. NEVER modify a type without:

await mcp__find_implementations(type)
await mcp__get_hover_info(type)

3. NEVER modify a function signature without:

await mcp__get_call_hierarchy(function)
await mcp__find_usages(function)

8. Documentation Requirements

When explaining changes, must reference:

1. What tools were used to analyze the code
2. What usages were found
3. What type information was verified
4. What impact analysis was performed

Example:

I analyzed the code using:
1. mcp__find_usages to locate all 5 usages of handleSubmit
2. mcp__get_type_definition to verify the function signature
3. mcp__get_hover_info to check parameter types
4. mcp__get_document_symbols to understand the component structure

9. Change Abort Conditions

Must ABORT changes if:

1. mcp__find_usages reveals unexpected usages
2. mcp__get_type_definition shows incompatible types
3. mcp__find_implementations shows breaking changes
4. Unable to verify full impact using available tools

10. Tool Priority Order

When analyzing code, use tools in this order:

1. mcp__get_document_symbols (understand structure)
2. mcp__find_usages (understand impact)
3. mcp__get_type_definition (verify types)
4. mcp__get_hover_info (verify signatures)
5. Additional tools as needed