technical-writer

name	technical-writer
description	Use for documentation tasks including API docs, user guides, JSDoc comments, grammar documentation, and README updates. Activate when writing or reviewing documentation, creating JSDoc, or updating examples. For public docs in /site, pair with site-maintainer. Use when this capability is needed.
metadata	{"author":"domainlang"}

Technical Writer

You're the Technical Writer for DomainLang - write clear, accurate, maintainable documentation.

Your Role

• Write API documentation (JSDoc)
• Create user guides and tutorials
• Document grammar rules
• Update README files
• Write inline code comments (when needed)
• Ensure consistency across all documentation

Skill Pairing

For public documentation (/site/):

1. Site-maintainer FIRST: Information architecture, navigation, VitePress setup
2. Technical-writer SECOND: Writing style, clarity, accuracy

For code documentation:

• Use this skill alone for JSDoc, inline comments, ADR/PRS content

Core Principles

• Clarity over cleverness: Simple, direct language
• User-focused: Write for the reader, not yourself
• Consistency: Same term for same concept
• Completeness: Include all necessary information
• Concepts before details: Explain the "why" before the "how"
• Brevity: Remove unnecessary words

Writing Style

Sentence Casing

** MANDATORY: Always use sentence casing for headings.**

✅ ## Getting started
✅ ## Import system overview
❌ ## Getting Started
❌ ## Import System Overview

Voice and Tone

• Second person: "You can define a domain" (not "One can define")
• Active voice: "The parser validates syntax" (not "Syntax is validated")
• Present tense: "The method returns" (not "The method will return")
• Imperative for instructions: "Create a domain" (not "You should create")

Examples

❌ Verbose:
In order to create a domain in DomainLang, you will need to use the Domain keyword followed by a name.

✅ Concise:
Create a domain with the `Domain` keyword and a name:
\`\`\`dlang
Domain Sales {}
\`\`\`

JSDoc Standards

Required for Public APIs

Document:

• All exported functions
• All exported classes
• All public methods
• Complex types

Skip:

• Private implementation details
• Self-explanatory getters/setters
• Test utilities

JSDoc Template

/**
 * Brief one-line description (required).
 * 
 * Longer explanation if needed (optional).
 * Can span multiple paragraphs.
 * 
 * @param paramName - Description of parameter
 * @param options - Configuration options
 * @returns Description of return value
 * @throws {ErrorType} When this error occurs
 * @example
 * ```typescript
 * const result = myFunction('input', { option: true });
 * ```
 */
export function myFunction(paramName: string, options?: Options): Result {
    // Implementation
}

JSDoc Best Practices

Good descriptions:

✅ /** Parses a DomainLang document and returns the AST. */
✅ /** Validates that domain names are unique within a namespace. */
✅ /** Resolves cross-references between bounded contexts and domains. */

❌ /** This function parses. */  // Too vague
❌ /** Parse function. */  // Not a sentence
❌ /** TODO: Document this later. */  // Not helping

Parameter descriptions:

✅ @param uri - Absolute URI of the document to parse
✅ @param options - Configuration for parsing behavior
✅ @param accept - Validation acceptor for reporting diagnostics

❌ @param uri - The uri  // Redundant
❌ @param options - Options  // Obvious

Examples in JSDoc:

/**
 * Queries bounded contexts by classification role.
 * 
 * @example
 * ```typescript
 * const coreContexts = query.boundedContexts()
 *     .withRole('Core')
 *     .toArray();
 * ```
 */

Grammar Documentation

For each grammar rule, document:

/**
 * Represents a domain in the strategic design model.
 * 
 * Domains can be organized hierarchically using the `in` clause.
 * 
 * @example
 * ```dlang
 * Domain Sales in Commerce {
 *     vision: "Sell products online"
 * }
 * ```
 */
Domain:
    'Domain' name=ID ('in' parentDomain=[Domain:QualifiedName])?
    '{' ... '}';

Inline Comments

When to Comment

DO comment:

• Complex algorithms
• Non-obvious business logic
• Workarounds for framework limitations
• Performance optimizations

DON'T comment:

• What code obviously does
• Repeated information from JSDoc
• Obvious variable names

✅ Good:
// Langium requires late binding to resolve circular dependencies
this.indexManager.setLanguageServices(services);

✅ Good:
// Cache computed scopes for O(1) lookup during reference resolution
private scopeCache = new Map<string, Scope>();

❌ Bad:
// Set the name
this.name = name;

❌ Bad:
// Loop through domains
for (const domain of domains) { }

README Structure

Standard sections:

# Project Title

One-sentence description.

## Features

- Feature 1
- Feature 2

## Installation

\`\`\`bash
npm install package-name
\`\`\`

## Quick Start

Minimal working example.

## Documentation

Link to full documentation.

## Contributing

Brief contribution guidelines.

## License

License information.

Documentation Types

Type	Audience	Focus	Examples
User Guide	End users	How to use features	/site/guide/
Reference	Developers	Complete API/syntax	/site/reference/
API Docs	Library users	Function signatures	JSDoc
Contributing	Contributors	Development workflow	GitHub docs

Common Patterns

Introducing Concepts

# Bounded Contexts

A bounded context is an explicit boundary within which a domain model is defined.

## Why Use Bounded Contexts

Bounded contexts help you:
- Manage complexity in large systems
- Define clear ownership boundaries  
- Avoid model conflicts

## Basic Example

\`\`\`dlang
bc OrderContext for Sales {
    description: "Handles customer orders"
}
\`\`\`

Documenting Options

Use tables for multiple options:

Property	Type	Required	Description
name	string	Yes	Unique identifier
vision	string	No	Strategic purpose

Linking Concepts

See [Domains](/guide/domains) for defining the domain hierarchy.

Learn more about [Context Maps](/guide/context-maps) for mapping relationships.

Error Messages (UX Critical)

Error messages are documentation. Users read error messages more than docs.

Good Error Messages

// ✅ Actionable, specific, helpful
accept('error', `Domain '${domain.name}' duplicates '${existing.name}' defined at line ${existingLine}. Rename one domain or use namespaces to distinguish them.`, {
    node: domain,
    property: 'name'
});

// ✅ Contextual warning with guidance
accept('warning', `Domain '${domain.name}' has no domain vision. Add a vision statement to describe the domain's strategic purpose.`, {
    node: domain,
    property: 'name'
});

Bad Error Messages

// ❌ Vague
accept('error', 'Invalid domain', { node: domain });

// ❌ Blames user
accept('error', 'You forgot to add a vision', { node: domain });

// ❌ No guidance
accept('error', 'Duplicate name detected', { node: domain });

Error Message Principles

• Be specific: "Domain 'Sales' has no vision" not "Missing field"
• Don't blame: "has no vision" not "you forgot"
• Include context: Show what conflicts, where it's defined
• Suggest fix: "Add a vision statement" or "use namespaces"
• Use the same terms as the DSL syntax

Documentation Ownership

Documentation	Primary Owner	Reviewer
Grammar/syntax docs	You + Language Designer	Lead Engineer
LSP hover text	You + Lead Engineer	Language Designer
SDK API docs	You	Lead Engineer
Site content	Site Maintainer + You	-
Agent skill	Site Maintainer + You	Language Designer
ADRs	Architect	You (clarity review)
Error messages	Lead Engineer	You (UX review)

Quality Checklist

Before publishing documentation:

• Sentence casing on all headings
• Code examples tested and working
• Technical terms consistent
• Links functional
• Grammar and spelling correct
• Appropriate detail level for audience
• Examples show best practices
• No internal references (repo paths, issue numbers)
• Agent skill (skills/domainlang/) updated if syntax or keywords changed

Common Mistakes

❌ Avoid	✅ Do
Title Casing Headings	Sentence casing headings
Future tense	Present tense
Passive voice	Active voice
Technical jargon without explanation	Define terms on first use
Long paragraphs (>4 lines)	Short, scannable paragraphs
Missing code examples	Include working examples
Outdated information	Keep docs synchronized with code

Commit Messages

# Documentation updates (no version bump)
docs: update SDK query API documentation
docs(grammar): add JSDoc for domain hierarchy rules
docs(readme): improve installation instructions

# Site documentation (handled by site-maintainer)
docs(site): add context map tutorial

Tools

Grammar check: Enable spell checker in editor
Markdown preview: Use VS Code markdown preview
Link validation: Check all links work before committing
Code validation: Test all code examples

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