Use this agent when you need to research, analyze, and create comprehensive implementation plans for new features, system architectures, or complex technical solutions. This agent should be invoked before starting any significant implementation work, when evaluating technical trade-offs, or when you need to understand the best approach for solving a problem. Examples: <example>Context: User needs to implement a new authentication system. user: 'I need to add OAuth2 authentication to our app' assistant: 'I'll use the planner agent to research OAuth2 implementations and create a detailed plan' <commentary>Since this is a complex feature requiring research and planning, use the Task tool to launch the planner agent.</commentary></example> <example>Context: User wants to refactor the database layer. user: 'We need to migrate from SQLite to PostgreSQL' assistant: 'Let me invoke the planner agent to analyze the migration requirements and create a comprehensive plan' <commentary>Database migration requires careful planning, so use the planner agent to research and plan the approach.</commentary></example> <example>Context: User reports performance issues. user: 'The app is running slowly on older devices' assistant: 'I'll use the planner agent to investigate performance optimization strategies and create an implementation plan' <commentary>Performance optimization needs research and planning, so delegate to the planner agent.</commentary></example>

Use this agent when:\n- A test suite fails repeatedly despite multiple fix attempts\n- A critical bug is discovered in production or staging\n- An implementation approach proves fundamentally flawed and requires complete redesign\n- External dependencies (APIs, services, libraries) cause blocking issues\n- Performance bottlenecks are discovered that significantly impact user experience\n- Security vulnerabilities are identified\n- Database migrations fail or cause data integrity issues\n- CI/CD pipelines break unexpectedly\n- Integration conflicts arise between major system components\n- Technical debt reaches a critical threshold requiring immediate attention\n- A feature implementation takes significantly longer than estimated\n- Architectural decisions prove problematic in practice\n\nExamples:\n<example>\nContext: After implementing a new payment webhook handler, tests are failing with intermittent database connection errors.\nuser: "The Sepay webhook tests keep failing with connection timeouts. I've tried increasing the pool size and timeout values but it's still happening randomly."\nassistant: "This sounds like a significant technical difficulty that should be documented. Let me use the journal-writer agent to capture this issue with full context and emotional honesty."\n<uses Task tool to launch journal-writer agent>\n</example>\n\n<example>\nContext: A critical security vulnerability was discovered in the GitHub access management system.\nuser: "We just realized that the GitHub invitation system doesn't properly validate user permissions before granting repository access. This could allow unauthorized users to access private repos."\nassistant: "This is a critical security issue that needs immediate documentation. I'm going to use the journal-writer agent to record this vulnerability, the emotional impact, and the urgency of the situation."\n<uses Task tool to launch journal-writer agent>\n</example>\n\n<example>\nContext: A major refactoring effort failed and needs to be rolled back.\nuser: "The database schema migration we planned completely broke the order processing system. We need to roll back and rethink our approach."\nassistant: "This is a significant setback that should be documented honestly. Let me use the journal-writer agent to capture what went wrong, why it failed, and the emotional toll of this failure."\n<uses Task tool to launch journal-writer agent>\n</example>