PASH — Protocol for Agentic Semantic Hypermedia

The AI doesn't write markup. It sends intent. The client renders.

PASH is a token-efficient text format for transmitting UI components from LLMs to clients.

Instead of asking the AI to generate HTML:

<div class="product-card"><h3>Смартфон X1</h3><p>AMOLED 120Hz</p>
<span class="price">69 990 ₽</span><button>Купить</button></div>

(52 tokens)

The AI outputs:

1|Смартфон X1|AMOLED 120Hz|69990|Купить

(11 tokens — 79% fewer)

Your client knows 1 = ProductCard, renders it with your CSS, your locale, your design system.

---

Quick Start: 1 minute integration

Step 1 — Get the system prompt

pash-sdk is LLM-agnostic. For prompt generation install @pash/prompt:

npm install pash-sdk @pash/prompt

const { PromptEngine } = require('@pash/prompt');
const { SCHEMAS }      = require('pash-sdk');

const engine = new PromptEngine({ schemas: SCHEMAS });
const system = engine.generate({ lang: 'ru', mode: 'pash' });
// Auto-generated from your component registry. Always in sync.

Step 2 — Decode the AI response

const { decodeStream, renderStream } = require('pash-sdk');

const aiResponse = `
1|Смартфон X1|AMOLED 120Hz, 256GB|69990|Купить
2|warn|Последний в наличии
`;

const decoded = decodeStream(aiResponse);
// { version: null, components: [ ProductCard, Notification ] }

document.getElementById('output').innerHTML = renderStream(decoded);

Step 3 — Streaming (optional)

const { StreamingDecoder, renderComponent } = require('pash-sdk');

const decoder = new StreamingDecoder((component) => {
  document.getElementById('output').innerHTML += renderComponent(component);
});

const response = await fetch('/api/ai');
const reader   = response.body.getReader();
const utf8     = new TextDecoder();

while (true) {
  const { done, value } = await reader.read();
  if (done) { decoder.flush(); break; }
  decoder.push(utf8.decode(value));
}

Non-JS users

Copy a ready-to-use prompt from SYSTEM_PROMPT.md — available in Russian and English, for all three modes.

---

Installation

npm install pash-sdk

Browser (no bundler):

<script src="https://unpkg.com/pash-sdk/dist/pash.browser.js"></script>
<script>
  const { decodeStream } = PASH;
</script>

---

Format

COMP_ID|field1|field2|field3|...

• | — separator (1 BPE token in GPT-4, LLaMA-3)
• \| — escaped pipe inside a value
• # — nested component prefix
• v:1 — optional version header (first line)
• \n — component separator

Token efficiency

Format	Tokens	vs HTML
HTML	~52	—
JSON	~34	−35%
Markdown	~26	−50%
PASH	~11	−79%
PASH+ID	~7	−87%

---

Component Registry

UI Components (ID 1–6)

ID	Component	Fields
1	ProductCard	title* | desc | price[currency] | cta
2	Notification	level*(info|warn|error) | message*
3	List	title | items*
4	Hero	headline* | sub | cta
5	Article	title* | author | date | summary
6	RichBlock	content*[richtext]

PASH-Doc Blocks (ID 20–32)

ID	Block	Fields
20	Heading	level*(1-6) | text*
21	Paragraph	text*[richtext]
22	Code	lang | body*
23	Blockquote	author | text*[richtext]
24	Image	url* | alt | caption
25	Divider	—
26	Table	headers* | rows*
27	OrderedList	title | items*
28	BulletList	title | items*
29	Note	level*(info|tip|warn|danger) | text*
30	Spoiler	title* | body*[richtext]
31	Math	display*(block|inline) | formula*
32	Embed	type*(youtube|...) | url* | title

* = required. ID 40+ available for custom components.

---

What's in the SDK

Module	Description
decodeStream / parseLine	Parse PASH stream
encode / encodeStream	Serialize components to PASH
renderComponent / renderStream	Components → HTML
setRichtextRenderer	Plug in marked/remark for richtext
StreamingDecoder	Byte-by-byte SSE decoder
EventStreamDecoder	Event Stream format decoder
Dictionary	Content Layer for PASH+ID mode
setLocale / addLocale	i18n: ru-RU, en-US, de-DE + custom
validateStream	Validate against schema
registerComponent	Add custom component (ID 40+)
generateSystemPrompt	Moved to @pash/prompt (LLM-agnostic split)
@pash/prompt (separate pkg)	Prompt Engine for any LLM
VERSION	SDK version string

---

Modes

Mode	Example	Tokens
pash	1|Смартфон X1|AMOLED|69990|Купить	~11
pash+id	1|102|45|69990|12	~7
events	COMP_START(1)\nTEXT(Смартфон X1)...	similar

---

CLI

npm install -g pash-sdk

echo "1|Смартфон X1|AMOLED|69990|Купить" | pash decode
echo "1|Смартфон X1|AMOLED|69990|Купить" | pash validate
echo "1|Смартфон X1|AMOLED|69990|Купить" | pash render
pash prompt --lang ru --mode pash

---

Custom component

const { registerComponent } = require('pash-sdk');

registerComponent(40, {
  name: 'UserCard',
  fields: [
    { id: 0, type: 'string', label: 'name',  required: true },
    { id: 1, type: 'string', label: 'email'                 },
  ],
  render: (f) => `<div class="user-card"><b>${f.name}</b><span>${f.email}</span></div>`,
});

// AI can now generate: 40|Иван Петров|ivan@example.com

---

Locale

const { setLocale } = require('pash-sdk');

setLocale('en-US');  // price: 69990 → $69,990
setLocale('de-DE');  // price: 69990 → 69.990 €
setLocale('ru-RU');  // price: 69990 → 69 990 ₽  (default)

---

Links

• Specification
• System Prompts
• Playground
• Contributing
• Changelog

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Community

Good first issues: new components, language ports, React/Vue bindings.
See CONTRIBUTING.md for details.

License

MIT © Сергей Павленко