analyze-impact

What this skill does

# Analyze Impact

Analyze the impact of a proposed change on existing features, dependencies, and documentation.

## Input

Change description: $ARGUMENTS (optional - will prompt if not provided)

## Context

**You must load the following skills and read the following files before proceeding.**

### Skills
- `katachi:iterative-development` - Impact analysis workflow

### Feature documentation
- `docs/feature-specs/README.md` - Feature capability index
- `docs/feature-designs/README.md` - Feature design index
- Read specific feature-specs/ and feature-designs/ docs as needed

### Decision indexes
- `docs/architecture/README.md` - Architecture decisions (ADRs)
- `docs/design/README.md` - Design patterns (DES)

## Pre-Check

Verify framework is initialized:
- If `docs/planning/` doesn't exist, explain this command requires initialized framework
- If minimal features exist, note the analysis may be limited

## Process

### 1. Capture Change Description

If not provided in arguments, ask:
```
"Describe the change you're considering:
- What are you planning to change?
- Why is this change needed?
- What areas do you think might be affected?"
```

### 2. Dispatch Impact Analyzer

```python
Task(
    subagent_type="katachi:impact-analyzer",
    prompt=f"""
Analyze the impact of this proposed change.

## Change Description
{change_description}

## Feature Specs Index
{feature_specs_readme}

## Feature Designs Index
{feature_designs_readme}

## Feature Spec Paths
{list_of_feature_spec_paths}

## Feature Design Paths
{list_of_feature_design_paths}

## ADR Index
{adr_readme}

## DES Index
{des_readme}
"""
)
```

### 3. Present Findings

Show the analysis results in a clear format:

```
## Impact Analysis

### Change Summary
[What's being changed]

### Risk Level: [Isolated | Moderate | Significant | Structural]

### Directly Affected Features
| Feature | Impact | Reason |
|---------|--------|--------|
| CORE-001 | High | [reason] |
| API-002 | Medium | [reason] |

### Transitively Affected Features
| Feature | Path | Impact |
|---------|------|--------|
| UI-003 | CORE-001 → UI-003 | Medium |

### Documents Requiring Updates
- docs/feature-specs/CORE-001.md - Update acceptance criteria for X
- docs/feature-designs/API-002.md - Revise data flow for Y
- docs/architecture/ADR-005.md - Consider superseding

### Recommendations
1. [Action item]
2. [Action item]
```

### 4. Discuss Next Steps

Based on risk level, offer appropriate next steps:

**Isolated (1-2 features, no transitive):**
```
"This is a contained change. You can proceed with implementation.

Would you like to:
A) Start implementing (update affected specs first)
B) See more details about affected features
C) Cancel and reconsider"
```

**Moderate (3-5 features or limited transitive):**
```
"This change has moderate impact. I recommend reviewing affected specs before proceeding.

Would you like to:
A) Review affected specs
B) Create an ADR to document this decision
C) See the full dependency chain
D) Cancel and reconsider"
```

**Significant (5+ features or broad transitive):**
```
"This is a significant change with broad impact.

I recommend:
1. Creating an ADR to document the decision and rationale
2. Reviewing all affected specs and designs

Would you like to:
A) Create an ADR for this change
B) Review affected documents
C) Cancel and reconsider"
```

**Structural (architecture or cross-cutting):**
```
"This change affects core architecture and has structural implications.

Before proceeding, I strongly recommend:
1. Creating an ADR with thorough alternatives analysis
2. Reviewing all affected areas in detail

This is a significant decision. Would you like to:
A) Start a detailed architecture discussion
B) Create an ADR to explore options
C) See affected areas in detail
D) Cancel and reconsider"
```

### 5. Execute Chosen Action

**Review affected specs:**
- Read and summarize each affected spec
- Highlight which acceptance criteria are impacted
- Ask which to update

**Create ADR:**
- Transition to `/katachi:decision`
- Pre-fill context with impact analysis

## Integration with Other Commands

This command integrates with:
- `/katachi:decision` - For documenting significant changes as ADR or DES
- `/katachi:add-delta` - When change requires new work (delta) to implement
- Direct feature spec/design updates - When updating existing feature documentation

## Workflow

This is an informational command:
- Gather change description
- Dispatch agent for analysis
- Present findings clearly
- Offer appropriate next steps based on risk
- Execute user's chosen action