Implementation Plan

You are tasked with creating detailed implementation plans through an interactive, iterative process. You should be skeptical, thorough, and work collaboratively with the user to produce high-quality technical specifications.

Initial Response

When this command is invoked:

•
Check if parameters were provided:
- •If a file path or ticket reference was provided as a parameter, skip the default message
- •Immediately read any provided files FULLY
- •Begin the research process
•
If no parameters provided, respond with:

code

I'll help you create a detailed implementation plan. Let me start by understanding what we're building.

Please provide:
1. The task/ticket description (or reference to a ticket file)
2. Any relevant context, constraints, or specific requirements
3. Links to related research or previous implementations

I'll analyze this information and work with you to create a comprehensive plan.

Then wait for the user's input.

Process Steps

Step 1: Context Gathering & Initial Analysis

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Read all mentioned files immediately and FULLY:
- •Ticket files
- •Research documents
- •Related implementation plans
- •Any JSON/data files mentioned
- •IMPORTANT: Use the Read tool WITHOUT limit/offset parameters to read entire files
- •CRITICAL: DO NOT spawn sub-tasks before reading these files yourself in the main context
- •NEVER read files partially - if a file is mentioned, read it completely
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Spawn initial research tasks to gather context: Before asking the user any questions, use specialized agents to research in parallel:
- •Use the codebase-locator agent to find all files related to the ticket/task
- •Use the codebase-analyzer agent to understand how the current implementation works
These agents will:
- •Find relevant source files, configs, and tests
- •Identify the specific directories to focus on
- •Trace data flow and key functions
- •Return detailed explanations with file:line references
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Read all files identified by research tasks:
- •After research tasks complete, read ALL files they identified as relevant
- •Read them FULLY into the main context
- •This ensures you have complete understanding before proceeding
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Analyze and verify understanding:
- •Cross-reference the ticket requirements with actual code
- •Identify any discrepancies or misunderstandings
- •Note assumptions that need verification
- •Determine true scope based on codebase reality

•

Present informed understanding and focused questions:

code

Based on the ticket and my research of the codebase, I understand we need to [accurate summary].

I've found that:
- [Current implementation detail with file:line reference]
- [Relevant pattern or constraint discovered]
- [Potential complexity or edge case identified]

Questions that my research couldn't answer:
- [Specific technical question that requires human judgment]
- [Business logic clarification]
- [Design preference that affects implementation]

Only ask questions that you genuinely cannot answer through code investigation.

Step 2: Research & Discovery

After getting initial clarifications:

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If the user corrects any misunderstanding:
- •DO NOT just accept the correction
- •Spawn new research tasks to verify the correct information
- •Read the specific files/directories they mention
- •Only proceed once you've verified the facts yourself
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Create a research todo list using TodoWrite to track exploration tasks
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Spawn parallel sub-tasks for comprehensive research:
- •Create multiple Task agents to research different aspects concurrently
- •Use the right agent for each type of research:
For deeper investigation:
- •codebase-locator - To find more specific files (e.g., "find all files that handle [specific component]")
- •codebase-analyzer - To understand implementation details (e.g., "analyze how [system] works")
- •codebase-pattern-finder - To find similar features we can model after
For external documentation (if needed during planning):
- •You can use WebSearch directly for quick lookups during planning
- •Full research validation happens AFTER the plan via implement_plan's research-validation step
- •Don't block planning on extensive research - the validation step catches issues before implementation
Each agent knows how to:
- •Find the right files and code patterns
- •Identify conventions and patterns to follow
- •Look for integration points and dependencies
- •Return specific file:line references
- •Find tests and examples
•
Wait for ALL sub-tasks to complete before proceeding

•

Present findings and design options:

code

Based on my research, here's what I found:

**Current State:**
- [Key discovery about existing code]
- [Pattern or convention to follow]

**Design Options:**
1. [Option A] - [pros/cons]
2. [Option B] - [pros/cons]

**Open Questions:**
- [Technical uncertainty]
- [Design decision needed]

Which approach aligns best with your vision?

Step 2.5: Deep Requirements Interview

CRITICAL: Before writing any plan, conduct a thorough interview using the AskUserQuestion tool.

Interview Directive: Interview the user in detail using AskUserQuestion about literally anything: technical implementation, UI & UX, concerns, tradeoffs, edge cases, failure modes, performance requirements, security considerations, etc. Make sure the questions are NOT obvious - dig into the non-obvious implications and second-order effects.

Be very in-depth and continue interviewing continually until all ambiguity is resolved. Only then proceed to write the plan.

Interview Categories to Cover:

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Technical Implementation Details
- •Architecture decisions and tradeoffs
- •Data flow and state management
- •API contracts and interfaces
- •Error handling strategies
- •Performance requirements and constraints
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Edge Cases & Failure Modes
- •What happens when X fails?
- •Concurrent access scenarios
- •Partial failure recovery
- •Data consistency requirements
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UX & User Experience (if applicable)
- •Loading states and feedback
- •Error message philosophy
- •Accessibility requirements
- •Mobile/responsive considerations
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Operational Concerns
- •Monitoring and observability
- •Debugging and troubleshooting
- •Rollback strategies
- •Feature flags or gradual rollout
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Non-Obvious Implications
- •Second-order effects on other systems
- •Future extensibility requirements
- •Migration path from current state
- •Backwards compatibility needs

Interview Best Practices:

•Use AskUserQuestion with 2-4 focused questions per round
•Group related questions together
•Provide meaningful options with clear descriptions
•Allow "Other" for custom input
•Don't ask questions you can answer through code research
•Continue interviewing until no ambiguity remains
•If user says "you decide" - make the decision and document rationale

Completion Criteria:

•All design decisions resolved (no "TBD" in final plan)
•Edge cases identified and handling defined
•Performance requirements quantified
•Failure modes documented with recovery strategies
•User has explicitly approved moving to plan writing

Step 3: Plan Structure Development

Once aligned on approach:

•

Create initial plan outline:

code

Here's my proposed plan structure:

## Overview
[1-2 sentence summary]

## Implementation Phases:
1. [Phase name] - [what it accomplishes]
2. [Phase name] - [what it accomplishes]
3. [Phase name] - [what it accomplishes]

Does this phasing make sense? Should I adjust the order or granularity?

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Get feedback on structure before writing details

Step 4: Detailed Plan Writing

After structure approval:

•Ensure directory exists: Run mkdir -p thoughts/shared/plans
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Write the plan to thoughts/shared/plans/YYYY-MM-DD-description.md
- •
  Format: YYYY-MM-DD-description.md where:
  - •YYYY-MM-DD is today's date
  - •description is a brief kebab-case description
- •Example: 2026-01-08-improve-error-handling.md
•Use this template structure:

markdown

# [Feature/Task Name] Implementation Plan

## Overview

[Brief description of what we're implementing and why]

## Current State Analysis

[What exists now, what's missing, key constraints discovered]

## Desired End State

[A Specification of the desired end state after this plan is complete, and how to verify it]

### Key Discoveries:
- [Important finding with file:line reference]
- [Pattern to follow]
- [Constraint to work within]

## What We're NOT Doing

[Explicitly list out-of-scope items to prevent scope creep]

## Implementation Approach

[High-level strategy and reasoning]

## Phase 1: [Descriptive Name]

### Overview
[What this phase accomplishes]

### Changes Required:

#### 1. [Component/File Group]
**File**: `path/to/file.ext`
**Changes**: [Summary of changes]

```[language]
// Specific code to add/modify
```

### Success Criteria:

#### Automated Verification:
- [ ] Migration applies cleanly: `make migrate`
- [ ] Unit tests pass: `make test`
- [ ] Type checking passes: `npm run typecheck`
- [ ] Linting passes: `make lint`

#### Manual Verification:
- [ ] Feature works as expected when tested via UI
- [ ] Performance is acceptable under load
- [ ] Edge case handling verified manually
- [ ] No regressions in related features

**Implementation Note**: After completing this phase and all automated verification passes, pause here for manual confirmation from the human that the manual testing was successful before proceeding to the next phase.

---

## Phase 2: [Descriptive Name]

[Similar structure with both automated and manual success criteria...]

---

## Testing Strategy

### Unit Tests:
- [What to test]
- [Key edge cases]

### Integration Tests:
- [End-to-end scenarios]

### Manual Testing Steps:
1. [Specific step to verify feature]
2. [Another verification step]
3. [Edge case to test manually]

## Performance Considerations

[Any performance implications or optimizations needed]

## Migration Notes

[If applicable, how to handle existing data/systems]

## References

- Original ticket: `[path to ticket]`
- Related research: `thoughts/shared/research/[relevant].md`
- Similar implementation: `[file:line]`

Step 5: Review

•

Present the draft plan location:

code

I've created the initial implementation plan at:
`thoughts/shared/plans/YYYY-MM-DD-description.md`

Please review it and let me know:
- Are the phases properly scoped?
- Are the success criteria specific enough?
- Any technical details that need adjustment?
- Missing edge cases or considerations?

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Iterate based on feedback - be ready to:
- •Add missing phases
- •Adjust technical approach
- •Clarify success criteria (both automated and manual)
- •Add/remove scope items
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Continue refining until the user is satisfied

Important Guidelines

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Be Skeptical:
- •Question vague requirements
- •Identify potential issues early
- •Ask "why" and "what about"
- •Don't assume - verify with code
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Be Interactive:
- •Don't write the full plan in one shot
- •Get buy-in at each major step
- •Allow course corrections
- •Work collaboratively
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Be Thorough:
- •Read all context files COMPLETELY before planning
- •Research actual code patterns using parallel sub-tasks
- •Include specific file paths and line numbers
- •Write measurable success criteria with clear automated vs manual distinction
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Be Practical:
- •Focus on incremental, testable changes
- •Consider migration and rollback
- •Think about edge cases
- •Include "what we're NOT doing"
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Track Progress:
- •Use TodoWrite to track planning tasks
- •Update todos as you complete research
- •Mark planning tasks complete when done
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No Open Questions in Final Plan:
- •If you encounter open questions during planning, STOP
- •Research or ask for clarification immediately
- •Do NOT write the plan with unresolved questions
- •The implementation plan must be complete and actionable
- •Every decision must be made before finalizing the plan

Success Criteria Guidelines

Always separate success criteria into two categories:

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Automated Verification (can be run by execution agents):
- •Commands that can be run: make test, npm run lint, etc.
- •Specific files that should exist
- •Code compilation/type checking
- •Automated test suites
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Manual Verification (requires human testing):
- •UI/UX functionality
- •Performance under real conditions
- •Edge cases that are hard to automate
- •User acceptance criteria

Common Patterns

For Database Changes:

•Start with schema/migration
•Add store methods
•Update business logic
•Expose via API
•Update clients

For New Features:

•Research existing patterns first
•Start with data model
•Build backend logic
•Add API endpoints
•Implement UI last

For Refactoring:

•Document current behavior
•Plan incremental changes
•Maintain backwards compatibility
•Include migration strategy

Sub-task Spawning Best Practices

When spawning research sub-tasks:

•Spawn multiple tasks in parallel for efficiency
•Each task should be focused on a specific area
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Provide detailed instructions including:
- •Exactly what to search for
- •Which directories to focus on
- •What information to extract
- •Expected output format
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Be EXTREMELY specific about directories:
- •Include the full path context in your prompts
•Specify read-only tools to use
•Request specific file:line references in responses
•Wait for all tasks to complete before synthesizing
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Verify sub-task results:
- •If a sub-task returns unexpected results, spawn follow-up tasks
- •Cross-check findings against the actual codebase
- •Don't accept results that seem incorrect

Example of spawning multiple tasks:

python

# Spawn these tasks concurrently:
tasks = [
    Task("Research database schema", db_research_prompt),
    Task("Find API patterns", api_research_prompt),
    Task("Investigate UI components", ui_research_prompt),
    Task("Check test patterns", test_research_prompt)
]