Implementation Gap Validation

<background_information>

• Mission: Analyze the gap between requirements and existing codebase to inform implementation strategy
• Success Criteria:
• Comprehensive understanding of existing codebase patterns and components
• Clear identification of missing capabilities and integration challenges
• Multiple viable implementation approaches evaluated
• Technical research needs identified for design phase

</background_information>

<instructions>

Core Task

Analyze implementation gap for feature $1 based on approved requirements and existing codebase.

Execution Steps

1. Load Context:

• Read {{KIRO_DIR}}/specs/$1/spec.json for language and metadata
• Read {{KIRO_DIR}}/specs/$1/requirements.md for requirements
• Core steering context: product.md, tech.md, structure.md
• Additional steering files only when directly relevant to the feature's domain rules, integrations, runtime prerequisites, compliance/security constraints, or existing product boundaries
• Relevant local agent skills or playbooks only when they clearly match the feature's host environment or use case and provide analysis-relevant context

1. Read Analysis Guidelines:

• Read rules/gap-analysis.md from this skill's directory for comprehensive analysis framework

Parallel Research

The following research areas are independent and can be executed in parallel:

1. Codebase analysis: Existing implementations, architecture patterns, integration points, extension possibilities
2. External dependency research: Dependency compatibility, version constraints, known integration challenges (when needed)
3. Context loading: Requirements, core steering, task-relevant extra steering, relevant local agent skills/playbooks, and gap-analysis rules

If multi-agent is enabled, spawn sub-agents for each area above. Otherwise execute sequentially.

After all parallel research completes, synthesize findings for gap analysis.

1. Execute Gap Analysis:

• Follow gap-analysis.md framework for thorough investigation
• Analyze existing codebase using Grep and Read tools
• Use WebSearch/WebFetch for external dependency research if needed
• Evaluate multiple implementation approaches (extend/new/hybrid)
• Use language specified in spec.json for output

1. Generate Analysis Document:

• Create comprehensive gap analysis following the output guidelines in gap-analysis.md
• Present multiple viable options with trade-offs
• Flag areas requiring further research

1. Write Gap Analysis to Disk:

Write the gap analysis to disk so it survives session boundaries and can be referenced during design phase.

• Save the gap analysis to {{KIRO_DIR}}/specs/$1/research.md
• If the file already exists, append the new analysis (separated by a horizontal rule ---) rather than overwriting previous research
• Verify the file was written by reading it back

Important Constraints

• Information over Decisions: Provide analysis and options, not final implementation choices
• Multiple Options: Present viable alternatives when applicable
• Thorough Investigation: Use tools to deeply understand existing codebase
• Explicit Gaps: Clearly flag areas needing research or investigation
• Context Discipline: Start with core steering and expand only with analysis-relevant steering or use-case-aligned local agent skills/playbooks

</instructions>

Tool Guidance

• Read first: Load spec, core steering, relevant local playbooks/agent skills, and rules before analysis
• Grep extensively: Search codebase for patterns, conventions, and integration points
• WebSearch/WebFetch: Research external dependencies and best practices when needed
• Write last: Generate analysis only after complete investigation

Output Description

Provide output in the language specified in spec.json with:

1. Analysis Summary: Brief overview (3-5 bullets) of scope, challenges, and recommendations
2. Document Status: Confirm analysis approach used
3. Next Steps: Guide user on proceeding to design phase

Format Requirements:

• Use Markdown headings for clarity
• Keep summary concise (under 300 words)
• Detailed analysis follows gap-analysis.md output guidelines

Safety & Fallback

Error Scenarios

• Missing Requirements: If requirements.md doesn't exist, stop with message: "Run /kiro-spec-requirements $1 first to generate requirements"
• Requirements Not Approved: If requirements not approved, warn user but proceed (gap analysis can inform requirement revisions)
• Empty Steering Directory: Warn user that project context is missing and may affect analysis quality
• Complex Integration Unclear: Flag for comprehensive research in design phase rather than blocking
• Language Undefined: Default to English (en) if spec.json doesn't specify language

Next Phase: Design Generation

If Gap Analysis Complete:

• Review gap analysis insights
• Run /kiro-spec-design $1 to create technical design document
• Or /kiro-spec-design $1 -y to auto-approve requirements and proceed directly

Note: Gap analysis is optional but recommended for brownfield projects to inform design decisions.