Skill: Pre-Commit Documentation Sync

Purpose

Ensure project documentation is fully aligned with code changes BEFORE committing.
This skill acts as a pre-commit gate, guaranteeing that:

• README.md serves as a complete, executable SOP for running the application
• project_architecture.md accurately reflects system structure and flow

The commit should only proceed once documentation parity is achieved.

This skill is designed for pre-commit discipline, documentation hygiene, and agent reliability.

When to Run

Run this skill immediately before a commit is created, when:

• The user is about to commit changes
• The user asks to prepare or review documentation before committing
• The user wants to ensure documentation is up to date prior to version control

Primary objective: no commit without correct documentation.

Inputs & Sources of Truth

Use the following as the authoritative source of change:

• git diff --staged → primary source (changes about to be committed)
• git diff → only if explicitly requested by the user

Never infer changes from memory or assumptions—only from diffs.

Execution Workflow

Step 1: Analyze the Change Set

From the diff, classify changes into one or more of the following:

• New Feature
  • New modules, services, endpoints, configs, UI elements, or capabilities
• Bug Fix
  • Corrected behavior, logic errors, crashes, or incorrect outputs
• Refactor
  • Renames, file moves, or structural changes without behavior change
• Removal / Deprecation
  • Deleted features, APIs, flags, or obsolete workflows

Extract:

• What changed
• Where it changed
• How it affects users, developers, or system operation

Step 2: Update README.md (MANDATORY SOP)

Location: README.md (repository root)

Role of README.md

README.md is not a marketing summary.
It must function as a complete operational SOP that a future developer can follow from zero to running system without external explanation.

Creation Rules

• If the file does not exist, create it.
• If it exists, update all impacted sections.
• Never assume prior knowledge of the project.

Required Sections (Enforced)

README.md MUST include and maintain:

1. Project Overview

   • What the system does
   • Who it is for (developers / operators)

2. Prerequisites

   • Required tools (e.g. Docker, Docker Compose, Node, Python, Make, etc.)
   • Minimum versions if relevant

3. Environment Setup

   • Required environment variables
   • .env files (what exists, what is required, examples)
   • Secrets or credentials needed (without exposing values)

4. How to Run the Application (Local)

   • Step-by-step commands
   • Clear ordering
   • Expected outcome per step (what “success” looks like)

5. How to Run the Application (Docker / Containerized)

   • Docker build & run commands
   • Docker Compose usage if applicable
   • Ports, volumes, networks explained briefly

6. Configuration & Runtime Behavior

   • Important flags, configs, or modes
   • Anything that materially affects runtime behavior

7. Common Changes Introduced by This Commit

   • New setup steps added
   • Removed or changed commands
   • Migration or breaking changes (if any)

Constraints

• Step-by-step, copy-paste friendly
• Clear ordering (no missing steps)
• No architectural deep dives
• Remove or rewrite anything that is no longer true

README.md must be sufficient as a standalone SOP.

Step 3: Update project_architecture.md

Location: .cursor/project_architecture.md

Creation Rules

• Create .cursor/ if missing
• Create project_architecture.md if missing

Required Sections

• Overview
  • High-level system description, updated to include new or modified components
• Components / Modules
  • Add new files, services, or layers
  • Update responsibilities of modified components
• Data Flow / APIs
  • Document new or changed endpoints, events, pipelines, or integrations
• Deprecated / Removed
  • Explicitly list removed or obsolete components (or fully delete them if no longer relevant)

Constraints

• Architecture-level detail only
• Clear, structured, agent-readable
• No setup instructions or tutorials

Step 4: Validation Rules (Strict)

• ❌ Do NOT change code
• ❌ Do NOT create, amend, or execute commits
• ❌ Do NOT invent features, fixes, or future plans
• ❌ Do NOT allow the commit to proceed with incomplete SOP documentation

Documentation must reflect exactly what the staged diff proves.

Quality Checklist

Before allowing the commit, verify:

• Changes were derived strictly from git diff --staged
• README.md can be followed end-to-end by a new developer
• Docker and local run paths are documented if applicable
• Environment setup is explicit and complete
• project_architecture.md reflects current structure and flow
• No outdated, misleading, or speculative content remains

File Reference

Expected Outcome

After running this skill:

• Documentation is accurate, complete, and commit-ready
• README.md acts as a living SOP, not a summary
• Commits never introduce documentation debt
• Future developers can onboard and run the system without tribal knowledge