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|[email protected]

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

Community

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

License

MIT — Copyright (c) 2026 Sergei