dev%3adiff（DEV 3adiff 搜索）

Compatibility: Designed for Claude Code only. This skill uses hooks or ${CLAUDE_SKILL_DIR} which are not available on other platforms. Run on Claude Code or adapt before using elsewhere.

Compare the current repository with another repository to identify changes and insights.

Overview

The /diff skill enables comparison between the current repository and a target repository specified by URL. It identifies structural similarities, conducts detailed file-by-file analysis, and produces a comprehensive diff report with meaningful insights.

Skill Syntax

/diff <repository-url>

Target repository: $ARGUMENTS

Parameters:

• repository-url (required): Git repository URL to compare against (HTTPS or SSH)

Workflow

Step 1: Gather Context

1. Ask the user for the diff objective using AskUserQuestion:

- "What is the purpose of this comparison?" - Provide options: - "Track changes from template/fork" - Identify modifications made after forking - "Architectural comparison" - Compare design patterns and structure - "Migration analysis" - Understand differences for migration planning - "Code review" - Review changes between similar projects - "Custom" - User provides specific objective

1. Store the user's objective for the report

Step 2: Clone Target Repository

1. Create a temporary directory using system temp location: mktemp -d
2. Clone the target repository into the temp directory: git clone <repository-url> <temp-dir>/target-repo
3. Handle clone errors gracefully:

- Authentication failures - Invalid URLs - Network issues - Repository not found

Step 3: Analyze Repository Structure

1. Map directory structures for both repositories:

- Use find or directory traversal to build tree structures - Identify top-level directories and organization patterns - Note framework/language indicators (package.json, Cargo.toml, go.mod, etc.)

1. Calculate structural similarity:

- Compare directory hierarchies - Identify common file patterns - Determine if repositories share a template/forking relationship

1. Classification:

- Similar structure (>60% overlap): Proceed with detailed file-by-file diff - Different structure (<60% overlap): Focus on architectural comparison

Step 4: Detailed Analysis

For Similar Structures (Template/Fork Relationship)

1. File-level comparison:

- Generate list of all files in both repos - Categorize files: - Modified files (exist in both, different content) - Added files (only in current repo) - Removed files (only in target repo) - Identical files (same content)

1. Conduct file-by-file diff:

- Use git diff --no-index for meaningful files - Focus on source code, configuration, and documentation - Skip binary files, dependencies (node_modules, vendor, etc.) - Capture line-level changes for key files

1. Group changes meaningfully:

- By feature/functionality (auth changes, UI updates, etc.) - By file type (configuration, source code, tests, docs) - By impact level (breaking, enhancement, refactor, fix)

1. Extract insights:

- Identify patterns in modifications - Detect new features or capabilities - Note removed functionality - Highlight configuration differences

For Different Structures (Architectural Comparison)

1. Architectural analysis:

- Identify framework and language differences - Compare project organization patterns - Note build system differences - Identify dependency management approaches

1. Design pattern comparison:

- Frontend architecture (if applicable) - Backend architecture (if applicable) - State management approaches - API design patterns - Testing strategies

1. Coding style analysis:

- Language/framework choices - Naming conventions - Code organization philosophy - Documentation approaches - Error handling patterns

Step 5: Generate Diff Report

Check for changelog: Look for CHANGELOG.md, CHANGELOG, or RELEASES.md in both repos. If found, scan recent entries to guide characterization of changes — they often name features and breaking changes explicitly.

Determine the output filename: .codevoyant/diffs/{YYYY-MM-DD}-{target-repo-name}.md

Write the report using references/report-template.md as the structure. Keep each section to 5 bullets or fewer. File trees should show * next to modified/added files. Only include sections that have meaningful content.

Step 6: Cleanup

1. Remove the temporary directory: rm -rf <temp-dir>
2. Confirm successful cleanup
3. Report: ✓ Diff saved to.codevoyant/diffs/{filename}

Error Handling

1. Clone failures:

- Display clear error message - Suggest authentication setup if needed - Verify repository URL format

1. Permission issues:

- Check write access to temp directory - Verify.claude/ directory exists and is writable

1. Large repositories:

- Warn if repository is very large (>1GB) - Ask user to confirm before proceeding - Consider shallow clone: git clone --depth=1

1. Binary file handling:

- Skip binary files in detailed diff - List binary files separately in report

1. Memory/performance:

- Use streaming for large diffs - Limit diff context for very large files - Sample files if repository has thousands of files