compact

Compact context

Changed on Aug 13, 2026

Compress chat history and code context by removing irrelevant lines at 33,000 tok/s. Every surviving line is byte-for-byte identical to the original input. Accepts string input or message arrays.

post/v1/compact

Request

Base URL
https://api.morphllm.com
Auth
HTTP bearer

Request body

inputstring

Text to compact. One of input or messages is required.

querystring

Focus query for relevance-based pruning. Lines relevant to this query are kept.

compression_rationumber

Fraction of input to keep. 0.3 = aggressive, 0.7 = light.

preserve_recentinteger

Keep last N messages uncompressed.

compress_system_messagesboolean

When true, system messages are also compressed. By default they are preserved verbatim.

include_line_rangesboolean

Include compacted_line_ranges in response.

include_markersboolean

Include (filtered N lines) text markers. When false, gaps become empty lines.

modelstring

Model ID.

Example request

{
  "input": "def hello():\n    return 1\n\ndef unused():\n    pass\n\ndef world():\n    return 2",
  "messages": [
    {
      "role": "user",
      "content": "Help me build a Node.js API with JWT auth"
    }
  ],
  "query": "hello function",
  "compression_ratio": 0.5,
  "preserve_recent": 0,
  "compress_system_messages": false,
  "include_line_ranges": true,
  "include_markers": true,
  "model": "morph-compactor"
}

Response

Compact response with compressed output and metadata

idstring required

Unique identifier for the compact request

objectstring required

Object type, always compact

modelstring required

Model used

outputstring required

All compacted messages joined into a single string

Example response

{
  "id": "cmpr-7373faf8af65",
  "object": "compact",
  "model": "morph-compactor",
  "output": "def hello():\n    return 1\n(filtered 3 lines)\ndef world():\n    return 2",
  "messages": [
    {
      "role": "user",
      "content": "def hello():\n    return 1\n(filtered 3 lines)\ndef world():\n    return 2",
      "compacted_line_ranges": [
        {
          "start": 4,
          "end": 6
        }
      ],
      "kept_line_ranges": []
    }
  ],
  "usage": {
    "input_tokens": 101,
    "output_tokens": 65,
    "compression_ratio": 0.644,
    "processing_time_ms": 109
  }
}

Changes

Aug 13, 2026b9a74274b2ab Revision changes
- warning
  removed the optional property / from the response with the status
- warning
  removed the optional property / from the response with the status
- info
  api operation id createCompaction was added
- info
  the endpoint scheme security bearerAuth was added to the API
- info
  api tag compact added
- info
  added the non-success response with the status
- info
  added the non-success response with the status
- info
  removed the non-success response with the status
- info
  removed the non-success response with the status
- info
  the response property / became required for the status
- info
  the response property / became required for the status
- info
  the response property / became required for the status
- info
  the response property / became required for the status
- info
  the response property //// became required for the status
- info
  the response property //// became required for the status
- info
  the response property // became required for the status
- info
  the response property //// became required for the status
- info
  the response property //// became required for the status
- info
  the response property // became required for the status
- info
  the response property / became required for the status
- info
  the response property / became required for the status
- info
  the response property / became required for the status
- info
  the response property / became required for the status

Operation history