tomevault-io Retrieve Diff from Commit Skill
An input skill that retrieves code diff from local git commits. This is the entry point for reviewing local changes before they are pushed.
Role
- Extract: Get the diff content from a specific commit or range of commits
- Format: Prepare the diff in a format suitable for code review
- Context: Gather commit metadata (author, message, timestamp)
Inputs
| Input | Required | Description |
|---|---|---|
commit_sha |
Optional | Specific commit SHA to review (defaults to HEAD) |
commit_range |
Optional | Range of commits (e.g., main..HEAD, HEAD~3..HEAD) |
base_branch |
Optional | Compare current branch against base (e.g., main, develop) |
Outputs
| Output | Description |
|---|---|
diff |
The unified diff content |
files_changed |
List of files modified with change type (added/modified/deleted) |
commit_info |
Commit metadata (SHA, author, message, timestamp) |
stats |
Summary statistics (lines added, deleted, files changed) |
Usage
Review Single Commit
# Get diff for specific commit
git show <commit_sha> --format="%H%n%an%n%ae%n%s%n%b" --stat
# Get unified diff
git diff <commit_sha>^..<commit_sha>
Review Commit Range
# Get diff for range
git diff <base_commit>..<head_commit>
# Get list of commits in range
git log --oneline <base_commit>..<head_commit>
Review Branch Against Base
# Compare feature branch to main
git diff main...HEAD
# Get merge-base
git merge-base main HEAD
Step 1: Identify the Scope
Determine what to review:
| Scenario | Command | Use Case |
|---|---|---|
| Last commit | git diff HEAD~1..HEAD |
Quick review of latest change |
| All uncommitted | git diff |
Review before committing |
| Staged changes | git diff --cached |
Review what will be committed |
| Branch diff | git diff main...HEAD |
Full feature review |
| Specific commit | git show <sha> |
Review single commit |
Step 2: Extract Diff
Execute the appropriate git command:
# For comprehensive diff with context
git diff --unified=5 <base>..<head>
# Include file stats
git diff --stat <base>..<head>
# Get list of changed files
git diff --name-status <base>..<head>
Step 3: Gather Metadata
Collect commit information:
# Get commit details
git log --format="%H|%an|%ae|%at|%s" <base>..<head>
# Get file change summary
git diff --shortstat <base>..<head>
Step 4: Format Output
Structure the output for the review pipeline:
## Diff Retrieved
**Commit Range**: `<base>..<head>`
**Files Changed**: X
**Lines Added**: +Y
**Lines Deleted**: -Z
### Files
| Status | File |
|--------|------|
| M | src/auth/login.ts |
| A | src/utils/helper.ts |
| D | src/deprecated.ts |
### Diff Content
\`\`\`diff
<unified diff content>
\`\`\`
### Commit Info
| Field | Value |
|-------|-------|
| SHA | abc123... |
| Author | John Doe <john@example.com> |
| Date | 2024-01-15 10:30:00 |
| Message | feat: add login functionality |
Output Format
{
"source": "local-git",
"commit_range": {
"base": "<base_sha>",
"head": "<head_sha>"
},
"stats": {
"files_changed": 5,
"insertions": 120,
"deletions": 45
},
"files": [
{
"path": "src/auth/login.ts",
"status": "modified",
"additions": 50,
"deletions": 10
}
],
"commits": [
{
"sha": "abc123",
"author": "John Doe",
"email": "john@example.com",
"timestamp": "2024-01-15T10:30:00Z",
"message": "feat: add login functionality"
}
],
"diff": "<unified diff content>"
}
Integration with Review Pipeline
After retrieving the diff, pass the output to:
- codereview-orchestrator - For triage and routing
- Then to appropriate specialist skills based on the triage
Quick Reference
□ Identify Scope
□ Single commit, range, or branch?
□ Committed or uncommitted?
□ Extract Diff
□ Run appropriate git diff command
□ Include sufficient context (--unified=5)
□ Gather Metadata
□ Commit info (SHA, author, message)
□ File statistics
□ Format Output
□ Structure for review pipeline
□ Include all necessary context
Example Usage in Pipeline
1. retrieve-diff-from-commit (this skill)
↓
2. codereview-orchestrator (triage)
↓
3. Specialist skills (review)
↓
4. Output formatted findings
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