pi-prose

Make every model write the way you want, with consistent prose rules and styles you can switch instantly without restarting Pi.

Two layers:

1. Named output styles -- switchable live, mid-session, with /style. Includes Claude Code's built-in styles, a matter-of-fact style mined from my own day-to-day usage, and ASD-STE100 Simplified Technical English.
2. Prose contract -- an optional contract.md appended to the system prompt on every turn, regardless of the selected style. Cycle from Claude to GPT to GLM and the register stays put.

Unlike Claude Code's output styles (which require /clear or a new session), style changes here apply on the next prompt: the system prompt is rebuilt every turn via before_agent_start.

Install

pi install npm:pi-prose

Use

Command	Effect
/style	Picker; shows the active style
/style <name>	Activate for this session
/style <name> --save	Also save as your user default
/style <name> --project	Also save as the project default
/style off	Back to default for this session
/style off --save	Clear the saved user default
pi --style <name>	Start with a style

The footer shows the active style when it is not default. The session's style choice persists in the session file and survives resume and fork.

Precedence for the active style: session choice > project default > user default > default.

Built-in styles

Style	What it does
default	No-op; the model's normal behavior
matter-of-fact	BLUF ledes, length matched to the question, sentences over bullet-splatter, -- never em dash, value before mechanism, caveats stated once, no sycophancy or closing recaps
proactive	Executes immediately, minimizes interruptions, prefers action over planning. Never overrides explicit safety rules from project instructions
concise	Terse responses: leads with the result, cuts preamble and narration, 1-3 sentences for simple questions, never trades correctness for brevity
explanatory	Adds short "Insight:" notes explaining implementation choices and codebase patterns
learning	Collaborative learn-by-doing; asks you to write small, strategic pieces of code via TODO(human) markers
ste	ASD-STE100 Simplified Technical English: active voice, short sentences, one instruction per sentence, one word per meaning

default, proactive, concise, explanatory, and learning mirror Claude Code's built-in output styles. matter-of-fact was distilled from ~10k of my own coding-agent prompts: the style corrections I kept repeating across models, collected over months of daily work, turned into a standing instruction set.

Custom styles

Drop a Markdown file in either location (filename becomes the style name unless name is set in frontmatter):

• User: ~/.pi/agent/prose/<name>.md
• Project: .pi/prose/<name>.md (loaded only after the project is trusted; wins over user styles with the same name)

---
name: diagrams-first
description: Lead every explanation with a diagram
---
When explaining code, architecture, or data flow, start with a Mermaid
diagram, then explain in prose.

The body is appended to the system prompt while the style is active. Custom styles can override built-ins by using the same name. /style re-reads the directories on every invocation, so edits apply without /reload.

Prose contract

Create contract.md in the same directories to append instructions on every turn, independent of the selected style (project wins over user):

• User: ~/.pi/agent/prose/contract.md
• Project: .pi/prose/contract.md

Use it for the rules you never want to relitigate per style or per model: banned punctuation, lede discipline, formatting invariants. A good starting point is the matter-of-fact style body -- copy it into contract.md and keep /style free for task-shaped modes like explanatory or ste.

Comparison

	Claude Code output styles	pi-prose
Switch takes effect	After /clear / new session	Next prompt
Baseline layer	None	contract.md, always on
Scope	Replaces system prompt sections	Append-only
Custom styles	Markdown + frontmatter	Markdown + frontmatter
Saved defaults	outputStyle in settings	--save (user) / --project

Related

• Claude Code's output styles -- the origin of the style concept and of the built-in set pi-prose mirrors.
• pi-output-styles -- another take on named styles for Pi/OMP, with its own style set. pi-prose differs in the always-on contract layer and the Claude Code-parity styles.

License

MIT