# Change Impact Analysis (change-impact)

> Maps the impact surface from real dependencies before a change, then compares the actual diff with the plan afterwards.

- Category: [Architecture Tuning](https://www.myskills.tools/en/categories/architecture-tuning/)
- Source: Community · Affaan Mustafa
- Repository: https://github.com/affaan-m/ECC/tree/main/skills/change-impact (commit 4f08958)
- SKILL.md: https://github.com/affaan-m/ECC/blob/main/skills/change-impact/SKILL.md
- Install command: `npx skills add affaan-m/ECC --skill change-impact`
- License: MIT
- Compatible with: Claude Code, Codex, Cursor, Copilot, OpenCode
- Permissions: read-repo ✓, write-files ✗, shell ✓, network ✗
- Status: Scan passed
- A rule scan cannot catch every risk. Read this skill's SKILL.md and check its permissions before installing.

## Core rule

Prove dependencies from real imports and calls, never from directory names; mark unknowns as unverified.

## Execution Phases

1. **Establish evidence** — Treat the request, repo docs and executable dependency evidence as truth, using git grep, git diff and tests.
2. **Map before the change** — Answer code, data, interfaces, tests, documentation and release in order, including deploy order, compatibility window and rollback.
3. **Route decisions** — Send durable decisions to ADRs, cross-client interfaces to contract-first, and regression to module checks; missing rollback info is a blocker.
4. **Align after implementation** — Check whether the diff exceeds scope, evidence covers the success criteria, docs are in sync, and temporary code remains.

## Permissions (summarised from SKILL.md)

| Capability | Needed | Details |
|---|---|---|
| File writes | Limited | Read-only by default; reports stay in the response, and a repo location is confirmed before writing. |
| Command execution | Limited | Gathers evidence with git grep, git diff and existing tests; other commands need host policy and explicit user approval. |
| Network outbound | Not required | No network access unless host policy allows it and the user explicitly approves. |

## SKILL.md frontmatter (YAML)

```yaml
---
name: change-impact
description: >-
  Perform evidence-backed impact analysis before changing code, data, interfaces, or governance documents, then compare the planned impact with the actual diff after implementation. Covers call paths, data and schema, API contracts, tests, documentation, ADRs, deployment, migration, and rollback. Use for cross-module or high-risk changes, database migrations, authentication, public interfaces, blast-radius questions, pre-change checks, and post-implementation alignment.
---
```

Home: https://www.myskills.tools/en/ · URL: https://www.myskills.tools/en/skills/change-impact/