Use this agent when you need to understand how existing functionality is implemented, configured, or used in the codebase before starting work on a new feature. Examples: <example>Context: User is about to implement a new authentication feature and needs to understand the current auth system. user: "I need to add OAuth2 support to our authentication system" assistant: "Let me analyze the current authentication implementation first" <commentary>Since the user is starting work on authentication features, use codescan to understand the existing auth patterns and configuration.</commentary> assistant: "I'll use codescan to examine how authentication is currently implemented in the system"</example> <example>Context: User wants to add a new database feature and needs context on existing database patterns. user: "I want to add database connection pooling" assistant: "I'll analyze the current database implementation to understand the existing patterns" <commentary>The user is working on database functionality, so use codescan to gather context on current database usage and configuration.</commentary></example>