Writing Style Library

A composable catalog of writing instructions. Pick one value from each axis - Voice, Tone, Style, Format - and the compose-instruction skill assembles a prompt prefix that steers any LLM toward a precise register, reasoning pattern, and layout. Mix and match to get exactly the writing you need.

The catalog ships 60 curated entries (15 per axis), each with worked examples on three anchor topics, side-by-side diff-pairs that isolate a single axis, recipes that bundle common combinations, and copyable format templates.

The four axes

Voice and Tone are distinct dimensions of one conceptual axis: Voice is who is speaking (persistent identity), Tone is how they sound right now (situational register). Style and Format are independent. Any value from any axis composes with any other.

Axis	What it controls	Example entries
Voice	Persistent writer identity: worldview, characteristic concerns, professional archetype	pragmatic-architect, pastoral, journalist, coach
Tone	Situational register layered on top of voice	candid, warm, reverent, urgent
Style	Cognitive and rhetorical pattern: how ideas are sequenced	problem-solution, layered-disclosure, socratic-inquiry, dialectic
Format	Visual and structural container: headings, sections, layout	adr, daily-standup, slack-message, devotional-entry

Quick start

The library is packaged as a Claude Code plugin, published in the Product on Purpose marketplace. Install it from inside Claude Code:

/plugin marketplace add product-on-purpose/agent-plugins
/plugin install writing-style-catalog@product-on-purpose

Already installed? Run /plugin update writing-style-catalog. For the direct-from-repo and Claude.ai / Claude Desktop paths, see the installation guide.

Then compose an instruction from any combination of axes:

/writing-style-catalog:compose-instruction voice=pragmatic-architect tone=candid style=problem-solution format=adr

The skill outputs a structured prompt prefix. Copy it into your system prompt or prepend it to your writing task.

How to read this site

Browse the catalog

Every entry has its own page with language patterns, when-to-use guidance, cross-references to compatible and confusable neighbors, and worked examples across three anchor topics.

See the difference

Diff-pairs put two near-neighbor entries side by side on the same topic, varying one axis, so you can see exactly what each value changes.

Start from a recipe

Recipes are named four-axis combinations for common writing tasks, so you do not have to compose from scratch.

Grab a template

Templates give you the canonical structure for each format, ready to copy.

Learn the model

Install the plugin - marketplace, direct-from-repo, and ZIP paths
Three-Axis Model - the design behind the catalog
Composition - how axis values combine
Compose an Instruction - step-by-step guide
Add an Entry - contribute to the catalog

This project is early and experimental. The catalog, schema, and skill interface may change. See the repository README for current status.