Documentation Knowledge Base

Quick reference for technical documentation types, audiences, and best practices.

Documentation Types

By Purpose

Type	Audience	Goal	Examples
README	New users	Quick start	badges, install, basic usage
Architecture	Developers	System understanding	layers, components, decisions
API	Integrators	Integration	endpoints, params, responses
ADR	Team	Decision history	context, decision, consequences
Getting Started	Beginners	First success	step-by-step tutorial
Reference	All	Quick lookup	methods, options, configs
Troubleshooting	Users	Problem solving	FAQ, error messages, solutions
CHANGELOG	All	Version history	features, fixes, breaking

Documentation Pyramid

        /\
       /  \
      / ADR \          ← Why (decisions)
     /________\
    /   Arch    \      ← How (structure)
   /______________\
  /    API Ref     \   ← What (details)
 /____________________\
/        README        \← Quick start

Audience Analysis

Developer Personas

Persona	Needs	Tone
Evaluator	Quick value assessment	Benefits, features
Beginner	Step-by-step guidance	Simple, encouraging
Intermediate	Best practices, patterns	Technical, practical
Expert	Advanced configs, internals	Concise, complete
Contributor	Setup, conventions	Technical, detailed

Content Mapping

Evaluator → README (badges, features, comparison)
Beginner → Getting Started, Examples
Intermediate → API Reference, Guides
Expert → Architecture, Internals
Contributor → CONTRIBUTING, ADRs

Structure Principles

README Structure (Recommended)

# Project Name

Brief description (1-2 sentences)

## Badges
[Build][Coverage][Version][License]

## Features
- Feature 1
- Feature 2

## Installation
```bash
composer require ...

Quick Start

// minimal working example

Documentation

Links to detailed docs

Contributing

Link to CONTRIBUTING.md

License

MIT / Apache / etc.

### Architecture Doc Structure

```markdown
# Architecture

## Overview
High-level description

## System Context
C4 Context diagram

## Components
C4 Component diagram

## Data Flow
Sequence diagrams

## Technology Stack
| Layer | Technology |
|-------|------------|

## Decisions
Link to ADRs

## Deployment
Infrastructure diagram

Best Practices

Writing Principles

Principle	Description	Example
Scannable	Headers, bullets, tables	Use ## for sections
Task-oriented	Focus on goals, not features	"How to X" not "X feature"
Example-driven	Code before explanation	php example then text
Layered	Quick start → details	README → Guide → Reference
Up-to-date	Doc near code	Update together

Code Examples Principles

✅ Good:
- Minimal complete example
- Copy-paste ready
- Shows expected output
- Uses realistic data

❌ Bad:
- Snippets that don't run
- Foo/Bar/Baz naming
- Missing imports
- Outdated syntax

Example Quality Checklist

// ✅ Good example
use App\Service\PaymentService;

$payment = new PaymentService($gateway);
$result = $payment->charge(
    amount: 99.99,
    currency: 'USD',
    customerId: 'cus_123'
);

echo $result->transactionId; // "txn_abc123"

// ❌ Bad example
$foo = new Foo();
$bar = $foo->doSomething($baz);
// returns something

Common Antipatterns

Documentation Smell Checklist

Smell	Detection	Fix
Stale	Code changed, docs not	Review on PR
Wall of text	No headers, no examples	Structure + code
Jargon soup	Undefined terms	Glossary, links
Dead links	404 errors	Link checker CI
No examples	Pure prose	Add code blocks
Copy-paste broken	Missing imports	Run examples
Version mismatch	Wrong versions	Automate sync

README Antipatterns

❌ No installation instructions
❌ No usage examples
❌ Badges only (no content)
❌ Generated API docs only
❌ Outdated screenshots
❌ Broken links
❌ No clear project description

Architecture Doc Antipatterns

❌ Box-and-arrow without explanation
❌ Outdated diagrams
❌ Missing "why" context
❌ No technology justification
❌ Inconsistent terminology
❌ Too much detail (implementation in arch doc)

Documentation as Code

Principles

1. Version control — docs in git with code
2. Review — PRs include doc updates
3. Test — validate links, examples
4. Automate — generate where possible
5. CI/CD — build and deploy docs

File Organization

project/
├── README.md           # Quick start
├── docs/
│   ├── architecture/
│   │   ├── README.md
│   │   ├── diagrams/
│   │   └── decisions/ (ADRs)
│   ├── api/
│   │   └── README.md
│   ├── guides/
│   │   ├── getting-started.md
│   │   └── deployment.md
│   └── reference/
│       └── configuration.md
├── CHANGELOG.md
├── CONTRIBUTING.md
└── LICENSE

Markdown Best Practices

Formatting Guidelines

Element	Usage
# H1	Document title only
## H2	Main sections
### H3	Subsections
-	Unordered lists
1.	Ordered steps
>	Warnings, notes
\```	Code blocks
|	Data tables

Code Block Languages

```php      # PHP code
```bash     # Shell commands
```yaml     # Configuration
```json     # API responses
```mermaid  # Diagrams
```sql      # Database

References

For detailed information, load these reference files:

• references/readme-patterns.md — README structure and examples
• references/api-documentation.md — API documentation guidelines
• references/architecture-docs.md — Architecture documentation patterns
• references/adr-format.md — ADR structure and examples
• references/diagramming.md — Diagram types and tools