Post-Implementation Documentation Skill

Automatically update repository documentation to reflect code changes. This skill ensures that when code is implemented, the documentation stays in sync with the actual codebase.

Variables

Variable	Default	Description
UPDATE_README	true	Update README.md for new features/APIs
UPDATE_CHANGELOG	true	Add entries to CHANGELOG.md
UPDATE_DOCS_FOLDER	true	Update files in docs/ that reference changed code
UPDATE_DOCSTRINGS	true	Update inline docstrings for changed functions/classes
CHANGELOG_FORMAT	conventional	conventional, keep-a-changelog, simple
COMMIT_DOCS	true	Commit documentation changes with code

Instructions

MANDATORY - Follow the Workflow steps below in order. Do not skip steps.

1. Analyze what code changes were made (git diff)
2. Determine documentation impact
3. Update README if new features/APIs added
4. Update CHANGELOG with change summary
5. Scan docs/ folder for references to changed symbols
6. Update inline docstrings for modified functions/classes

Red Flags - STOP and Reconsider

If you're about to:

• Update documentation without understanding the code changes
• Add CHANGELOG entries for trivial changes (typos, formatting)
• Update README for internal implementation details
• Modify docstrings without verifying the behavior changed

STOP -> Review the diff -> Understand the impact -> Then document

Workflow

1. Gather Change Context

Analyze what was changed in the current implementation:

# Get changed files
git diff --name-only HEAD~1 HEAD

# Get change summary
git diff --stat HEAD~1 HEAD

# Get detailed changes for documentation
git diff HEAD~1 HEAD -- "*.py" "*.ts" "*.js" "*.go" "*.rs"

2. Classify Changes

Determine the type and scope of changes:

Change Type	README Impact	CHANGELOG Entry	Docs Update
New feature	Add to Features section	feat: entry	If documented
Bug fix	No change	fix: entry	If affects behavior
Breaking change	Update usage examples	BREAKING: entry	Update all refs
API addition	Add to API section	feat: entry	Add API docs
Deprecation	Add deprecation note	deprecate: entry	Update examples
Performance	No change	perf: entry	No
Refactor	No change	refactor: entry	No
Docs only	N/A	No entry	N/A
Tests only	No change	test: entry	No

3. Update README.md

Only update README for significant changes:

Add new feature to Features section:

## Features

- **New Feature Name** - Brief description of what it does

Add new API to API/Usage section:

## API

### `newFunction(param: Type): ReturnType`

Description of the function and its purpose.

Update usage examples if API changed:

## Usage

```python
# Updated example reflecting new API
result = module.new_function(param="value")

4. Update CHANGELOG.md

Add entry following the project's format:

Conventional Changelog:

## [Unreleased]

### Added
- Add user authentication endpoint (#123)

### Changed
- Update database connection pool size for better performance

### Fixed
- Fix race condition in async queue processor (#124)

### Deprecated
- Deprecate `old_function()` in favor of `new_function()`

### Removed
- Remove support for Python 3.8

### Security
- Fix XSS vulnerability in user input handling

Keep a Changelog format:

## [Unreleased]

### Added
- New feature description

### Changed
- Change description

5. Update docs/ Folder

Scan documentation files for references to changed symbols:

# Find docs that reference changed functions/classes
grep -r "changed_function\|ChangedClass" docs/

For each match:

1. Verify if the documentation is still accurate
2. Update parameter descriptions if signature changed
3. Update examples if behavior changed
4. Update cross-references if file moved

6. Update Inline Docstrings

For each modified function/class with docstrings:

Python:

def function(param: str) -> bool:
    """Updated description reflecting new behavior.

    Args:
        param: Updated parameter description.

    Returns:
        Updated return value description.

    Raises:
        ValueError: If param is invalid (new error case).
    """

TypeScript/JavaScript:

/**
 * Updated description reflecting new behavior.
 *
 * @param param - Updated parameter description
 * @returns Updated return value description
 * @throws {Error} If param is invalid (new error case)
 */
function func(param: string): boolean {

Cookbook

README Updates

• IF: Adding new public feature
• THEN: Read cookbook/readme-updates.md
• RESULT: Updated feature list and examples

CHANGELOG Entries

• IF: Writing CHANGELOG entries
• THEN: Read cookbook/changelog-formats.md
• RESULT: Properly formatted entries

Docstring Standards

• IF: Updating inline documentation
• THEN: Read cookbook/docstring-standards.md
• RESULT: Consistent docstring format

Quick Reference

What to Document

Change	README	CHANGELOG	docs/	Docstrings
New public API	Yes	Yes	Yes	Yes
New internal function	No	Maybe	No	Yes
Bug fix	No	Yes	If behavior docs exist	If signature changed
Performance improvement	No	Yes	No	No
Breaking change	Yes	Yes	Yes	Yes
Deprecation	Yes	Yes	Yes	Yes

Conventional Commit to CHANGELOG Mapping

Commit Type	CHANGELOG Section
feat:	Added
fix:	Fixed
perf:	Changed
refactor:	Changed
deprecate:	Deprecated
BREAKING CHANGE:	Changed (with breaking note)
security:	Security
docs:	(skip)
test:	(skip)
chore:	(skip)

Integration Points

This skill is invoked:

1. By lane-executor: After completing implementation tasks
2. By test-engineer: After significant test additions
3. Before PR creation: Ensure docs are current

Example Integration in Lane Executor

## Post-Implementation Steps

After completing implementation:
1. Run `dependency-sync` skill to update manifests
2. Run `post-impl-docs` skill to update documentation
3. Verify build/tests still pass
4. Commit all changes together

Output

Documentation Update Report

{
  "status": "success",
  "updates": {
    "readme": {
      "updated": true,
      "sections_modified": ["Features", "API"]
    },
    "changelog": {
      "updated": true,
      "entries_added": [
        {"type": "feat", "description": "Add user authentication endpoint"}
      ]
    },
    "docs_folder": {
      "files_updated": ["docs/api.md", "docs/getting-started.md"],
      "references_fixed": 3
    },
    "docstrings": {
      "functions_updated": 5,
      "classes_updated": 2
    }
  },
  "commit_sha": "abc123"
}

No Changes Report

{
  "status": "no_changes",
  "reason": "Changes are internal implementation only",
  "analysis": {
    "change_type": "refactor",
    "public_api_affected": false,
    "documentation_impact": "none"
  }
}