Amend Commit

Modifies the most recent commit by adding staged changes, updating the message, or both. Follows Conventional Commits specification for message formatting.

When to use

Use this skill when the user needs to:

• Add forgotten files to the last commit
• Fix a typo in the last commit message
• Combine small fixes into the previous commit
• Update commit message to follow conventions

Instructions

Step 1: Check Current State

1. Run git log -1 --pretty=format:"%h %s" to show the last commit
2. Run git diff --cached --stat to see if there are staged changes
3. Run git diff --stat to see unstaged changes

Display to user:

Last commit: a1b2c3d feat(auth): add login form

Staged changes: 2 files
Unstaged changes: 1 file

Step 2: Determine Amend Type

Based on state and user intent:

Scenario	Action
Staged changes, no message provided	Add changes, keep message
No staged changes, message provided	Update message only
Staged changes + message provided	Add changes + update message
No staged changes, no message	Ask what user wants to do

Step 3: Handle Staged Changes

If there are staged changes to add:

1. Show the diff summary
2. Confirm these should be added to the last commit
3. Warn if changes seem unrelated to the original commit

Step 4: Handle Message Update

If updating the message:

1. Parse current message - Extract type, scope, description
2. Apply changes:
   • If user provides full message → use it
   • If user provides partial (e.g., just type) → merge with existing
3. Validate format - Ensure Conventional Commits compliance

Quick fixes:

• git:amend fix → Change type to fix, keep rest
• git:amend (api) → Change scope to api, keep rest
• git:amend "better description" → Update description only

Step 5: Confirm and Execute

Show the planned changes:

Amending commit a1b2c3d

Current:  feat(auth): add login form
New:      fix(auth): add login form validation

Adding: 2 files (+15, -3 lines)

Proceed? [Y/n]

If approved, run:

# Message change only
git commit --amend -m "<new message>"

# Changes only (keep message)
git commit --amend --no-edit

# Both
git commit --amend -m "<new message>"

Important: Do NOT add Co-Authored-By, Signed-off-by, or any other trailers to the commit message.

Step 6: Safety Checks

Before amending, verify:

1. Not pushed - Warn if commit exists on remote:

   ⚠️ Warning: This commit appears to be pushed to origin.
   Amending will require force push. Continue? [y/N]

2. Not a merge commit - Refuse to amend merge commits:

   ❌ Cannot amend merge commits. Use git revert instead.

3. Clean working tree - If there are unstaged changes, ask:

   You have unstaged changes. Options:
   1. Stage all and include in amend
   2. Amend with only currently staged changes
   3. Cancel

Error Handling

• If amend fails, show the error and suggest fixes
• If there's nothing to amend (no changes, same message), inform user
• If in rebase/merge state, refuse and explain

Arguments

• <args> - Optional. Can include:
  • New type: feat, fix, docs, etc.
  • New scope: (auth), (api)
  • New message: "full commit message"
  • --no-edit - Keep current message, just add staged changes

Examples:

• git:amend - Interactive: ask what to change
• git:amend --no-edit - Add staged changes, keep message
• git:amend fix - Change commit type to fix
• git:amend (api) - Change scope to api
• git:amend "feat(auth): add login validation" - Replace entire message