Compact API - Morph Documentation

Overview

Compact compresses chat history and code context at 33,000 tok/s by removing irrelevant lines. Every surviving line is byte-for-byte identical to the original input. 100K tokens compresses in under 2 seconds. Pass query to tell the model what matters for the next LLM call. Without it, the model auto-detects from the last user message.

Usage Examples

import { MorphClient } from '@morphllm/morphsdk';

const morph = new MorphClient({ apiKey: "YOUR_API_KEY" });

const result = await morph.compact({
  input: chatHistory,
  query: "How do I validate JWT tokens?",
  compressionRatio: 0.5,
  preserveRecent: 3,
});

// result.output is the compressed text — pass it to your LLM

from openai import OpenAI

client = OpenAI(
    api_key="YOUR_API_KEY",
    base_url="https://api.morphllm.com/v1",
)

response = client.chat.completions.create(
    model="morph-compactor",
    messages=[{"role": "user", "content": chat_history}],
)

compressed = response.choices[0].message.content

import requests

response = requests.post(
    "https://api.morphllm.com/v1/compact",
    headers={"Authorization": "Bearer YOUR_API_KEY"},
    json={
        "input": source_code,
        "query": "authentication",
        "compression_ratio": 0.5,
        "preserve_recent": 0,
    },
)

data = response.json()
print(data["output"])

for r in data["messages"][0]["compacted_line_ranges"]:
    print(f"  lines {r['start']}-{r['end']} removed")

curl -X POST "https://api.morphllm.com/v1/compact" \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "input": "def hello():\n    return 1\n\ndef unused():\n    pass\n\ndef world():\n    return 2",
    "query": "hello function",
    "compression_ratio": 0.5,
    "preserve_recent": 0
  }'

keepContext Tags

Wrap sections you never want compressed in <keepContext> / </keepContext> tags. Tagged content survives compression verbatim regardless of the compression ratio.

<keepContext>
// CRITICAL: Auth middleware — do not compress
function authenticate(req, res, next) {
  const token = req.headers.authorization?.split(' ')[1];
  if (!token) return res.status(401).json({ error: 'No token' });
  req.user = jwt.verify(token, process.env.JWT_SECRET);
  next();
}
</keepContext>

The response includes kept_line_ranges showing which lines were force-preserved.

Compatible Endpoints

Compact also works through OpenAI-compatible endpoints with model: "morph-compactor":

Endpoint	Format	Use with
`POST /v1/compact`	Native Morph format	Direct HTTP, Morph SDK
`POST /v1/responses`	OpenAI Responses API	Any OpenAI SDK (`client.responses.create()`)
`POST /v1/chat/completions`	OpenAI Chat Completions	Any OpenAI-compatible client

See the full Compact documentation for SDK reference, best practices, and advanced usage.