code-graph-impact

name	code-graph-impact
description	Run blast-radius impact analysis before making code changes. Shows all callers, dependents, and tests affected by a change. Requires code-review-graph MCP server.
risk	safe
source	inspired by GitNexus impact-analysis skill + code-review-graph tools
tags	["code-graph","impact-analysis","blast-radius","safety"]

Impact Analysis Before Changes

When to Use

• Before modifying a shared function, class, or module
• When planning a refactoring that touches multiple files
• User asks "what will break if I change X?"
• User asks "show me the impact of changing X"

Prerequisite: code-review-graph MCP server must be configured and graph must be built.

Instructions

Step 1: Get Minimal Context

get_minimal_context_tool(task="impact analysis for <target>")

This costs ~100 tokens and gives you the structural overview.

Step 2: Run Impact Analysis

get_impact_radius_tool(changed_files=["<path/to/file>"])

Or if analyzing a specific function:

query_graph_tool(pattern="callers_of", target="<function_name>", detail_level="minimal")

Step 3: Classify Impact by Depth

Present results using the risk depth model:

## Impact Analysis: <target>

### d=1 — WILL BREAK (direct callers/importers)
These files/functions directly call or import the target.
MUST be updated if the target's signature or behavior changes.

| File | Function | Relationship |
|------|----------|-------------|
| ... | ... | calls / imports / extends |

### d=2 — LIKELY AFFECTED (indirect dependents)
These depend on d=1 callers. Should be tested after changes.

| File | Function | Through |
|------|----------|---------|
| ... | ... | via <d=1 function> |

### d=3 — MAY NEED TESTING (transitive)
Transitive dependencies. Test if they're on a critical path.

### Test Coverage
| Changed Symbol | Has Tests? | Test File |
|---------------|-----------|-----------|
| ... | ✅/❌ | ... |

### Risk Summary
- **Total blast radius**: [count] files
- **Critical (d=1)**: [count] direct dependents
- **Risk level**: Low / Medium / High / Critical
- **Recommendation**: [proceed / proceed with caution / warn user first]

Step 4: Decision Gate

• If d=1 count > 10 or risk is High/Critical: Warn user before proceeding
• If any d=1 callers are in critical execution flows: Flag explicitly
• Provide concrete next steps: which files need updating, which tests need running

Error Handling

Situation	Resolution
Graph returns empty results	Graph may be stale: run build_or_update_graph_tool() first
Target not found in graph	Check spelling, or the file may not be parsed (check supported languages)
Very large blast radius (>50 files)	Suggest breaking the change into smaller, incremental steps