impact

name	impact
description	Analyze blast radius of a code change — find all call sites, test mocks, and consumers. Use before modifying shared functions, interfaces, or modules.
disable-model-invocation	true
argument-hint	<function, file, class, or method name>
allowed-tools	Read, Glob, Grep, Agent
effort	medium

Analyze the blast radius of changing a function, method, class, or file before making the change.

$ARGUMENTS is the target to analyze. Can be:

• A function name: enqueue_email
• A file path: src/modules/documents/services.py
• A class: SupplierInvitation
• A method: Tender.clone

Steps

1. Resolve the target — find the definition:

   • Use Grep to locate the function/class/method definition
   • Read the file to understand its signature (params, return type)
   • Note any recent signature changes (new optional params, changed return type)

2. Find all call sites — everywhere the target is used:

   • Grep for the function/class name across the entire codebase
   • Group results by module: API services, routes, worker tasks, tests, frontend hooks
   • For each call site, note whether it passes all current params or relies on defaults

3. Find all test mocks — tests that patch or mock the target:

   • Grep for patch("...target_name"), mock_target_name, AsyncMock references
   • Grep for vi.mock and vi.fn in frontend test files that reference the endpoint
   • Note which mock factories would need updating if the signature changes

4. Find frontend consumers (if the target is a route or service behind a route):

   • Identify the API endpoint(s) that call this function
   • Grep frontend hooks/ and lib/ for the endpoint path
   • Check TypeScript types in types/api.ts that would need updating

5. Find downstream dependencies — other functions that depend on the target's return value:

   • If the target returns an ORM object or dict, find code that accesses specific fields of that return value
   • If the target writes to DB, find queries that read from the same table

6. Report — print a structured summary:

## Impact Analysis: `<target>`

### Definition
- File: <path>:<line>
- Signature: <current signature>

### Call Sites (<count>)
| File | Line | Passes all params? |
|---|---|---|
| ... | ... | ✅ / ❌ missing: param_x, param_y |

### Test Mocks (<count>)
| Test file | Mock pattern | Needs update? |
|---|---|---|

### Frontend Consumers (<count>)
| File | Hook/Function | Endpoint |
|---|---|---|

### Downstream Dependencies
- <any functions that consume this target's return value>

### Risk Assessment
- **Blast radius**: small (≤3 files) / medium (4-10 files) / large (>10 files)
- **Recommended approach**: <one-line suggestion>

Do NOT make any code changes. This skill is read-only analysis.