How do I install the Diff skill?

Run npx skillmds@latest add tomevault-io/diff in your terminal (requires Node.js), paste this page's agent-chat prompt into Claude, Cursor, or any MCP-connected agent, or download the SKILL.md file and copy it into your agent's skills directory.

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Which AI agents work with Diff?

This skill is tagged as working with Claude Code, Claude.ai, OpenAI Codex. SKILL.md is an open format, so most agents that read a skills directory can load it too.

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tomevault-io (@tomevault-io) published this skill. Their other Agent Skills are listed on their SkillMD profile.

Diff by tomevault-io — Agent Skill

Name: Diff
Author: tomevault-io

Diff

This skill should be used when the user asks "analyze my changes", "what did I change", "review my diff", "impact of changes", "show changes", "git analysis", or wants semantic analysis of code changes. Use when this capability is needed.

tomevault-io Updated Sep 17, 2026

File contents

Semantic Diff Analysis

Analyze git changes semantically with classification, impact analysis, and risk assessment.

Arguments: $ARGUMENTS

Instructions

Parse optional arguments:
- --from REF → Starting git ref (default: HEAD~1 or staged changes)
- --to REF → Ending git ref (default: HEAD)
- --no-impact → Skip impact analysis (faster)

Use the mcp__mira__diff tool:

diff(from_ref="...", to_ref="...", include_impact=true)

Present results in sections:

Change Classification

NewFunction: Entirely new functions/methods
ModifiedFunction: Changed existing functions
DeletedFunction: Removed functions
NewFile: New files added
Refactored: Structural changes without behavior change

Impact Analysis

What callers are affected by these changes
Which modules depend on modified code
Potential ripple effects

Risk Assessment

Breaking changes: API signature changes, removed exports
Security relevance: Auth, input validation, crypto changes
Test coverage: Are changes covered by tests?

Examples

/mira:diff
→ Analyzes staged/working changes vs HEAD

/mira:diff --from main
→ Analyzes current branch vs main

/mira:diff --from v1.0 --to v1.1
→ Analyzes changes between tags

/mira:diff --no-impact
→ Quick classification without call graph analysis

Example Output

## Semantic Diff Analysis

### Changes (5 files, +142 -38 lines)

**New Functions:**
- `validate_token()` in src/auth.rs:45

**Modified Functions:**
- `handle_login()` in src/auth.rs:23 (added rate limiting)
- `create_session()` in src/session.rs:67 (changed return type)

### Impact Analysis
- `handle_login()` is called by 3 endpoints
- `create_session()` change affects 12 callers

### Risk Assessment
[WARNING] **Breaking**: `create_session()` return type changed
[SECURITY] **Security**: Rate limiting added (positive)

Converted and distributed by TomeVault — claim your Tome and manage your conversions.

---name: diffdescription: This skill should be used when the user asks "analyze my changes", "what did I change", "review my diff", "impact of changes", "show changes", "git analysis", or wants semantic analysis of code changes. Use when this capability is needed.---# Semantic Diff AnalysisAnalyze git changes semantically with classification, impact analysis, and risk assessment.**Arguments:** $ARGUMENTS## Instructions1. Parse optional arguments: - `--from REF` → Starting git ref (default: HEAD~1 or staged changes) - `--to REF` → Ending git ref (default: HEAD) - `--no-impact` → Skip impact analysis (faster)2. Use the `mcp__mira__diff` tool: ``` diff(from_ref="...", to_ref="...", include_impact=true) ```3. Present results in sections:### Change Classification- **NewFunction**: Entirely new functions/methods- **ModifiedFunction**: Changed existing functions- **DeletedFunction**: Removed functions- **NewFile**: New files added- **Refactored**: Structural changes without behavior change### Impact Analysis- What callers are affected by these changes- Which modules depend on modified code- Potential ripple effects### Risk Assessment- **Breaking changes**: API signature changes, removed exports- **Security relevance**: Auth, input validation, crypto changes- **Test coverage**: Are changes covered by tests?## Examples```/mira:diff→ Analyzes staged/working changes vs HEAD/mira:diff --from main→ Analyzes current branch vs main/mira:diff --from v1.0 --to v1.1→ Analyzes changes between tags/mira:diff --no-impact→ Quick classification without call graph analysis```## Example Output```## Semantic Diff Analysis### Changes (5 files, +142 -38 lines)**New Functions:**- `validate_token()` in src/auth.rs:45**Modified Functions:**- `handle_login()` in src/auth.rs:23 (added rate limiting)- `create_session()` in src/session.rs:67 (changed return type)### Impact Analysis- `handle_login()` is called by 3 endpoints- `create_session()` change affects 12 callers### Risk Assessment[WARNING] **Breaking**: `create_session()` return type changed[SECURITY] **Security**: Rate limiting added (positive)```---> Converted and distributed by [TomeVault](https://tomevault.io/claim/conarylabs) — claim your Tome and manage your conversions.

Frequently asked questions