---
title: "Generate LLM completion"
method: POST
path: "/llm/completions"
tags: ["llm"]
---

# Generate LLM completion

`POST /llm/completions`

Generate completion from the specified LLM provider.
Supports OpenAI, Claude, and Bedrock-backed models with multiple response formats (chat, notebook, auto).

## Request body

- object
  - `language` 'en' | 'ja' — Response language (en or ja)
  - `messages` object[], required
    - `content` string, required
    - `role` 'system' | 'user' | 'assistant', required
  - `metadata` object
    - `request_id` string
    - `tags` string[]
  - `model` string, required — Model identifier (e.g., gpt-4o, claude-sonnet-4-5, claude-sonnet-4-5-20250929)
  - `parameters` object
    - `max_tokens` integer
    - `stop` string[]
    - `temperature` number
    - `top_p` number
  - `provider` 'openai' | 'claude' | 'bedrock', required — LLM provider to use
  - `response_format` 'chat' | 'notebook' | 'auto', required — Response format

## Response `200`

Completion generated successfully

- union
  - object
    - `content` object, required
      - `message` object, required
        - `content` string, required
        - `role` 'assistant', required
    - `metadata` object, required
      - `created_at` string, date-time
      - `finish_reason` string
      - `request_id` string
    - `model` string, required
    - `provider` string, required
    - `response_format` 'chat', required
    - `usage` object, required
      - `completion_tokens` integer
      - `prompt_tokens` integer
      - `total_tokens` integer
  - object
    - `content` object, required
      - `notebook` object, required — Complete .ipynb format JSON
      - `validation` object, required
        - `cell_count` integer, required
        - `code_cell_count` integer, required
        - `is_valid` boolean, required
        - `markdown_cell_count` integer, required
    - `metadata` object, required
      - `created_at` string, date-time
      - `finish_reason` string
      - `request_id` string
    - `model` string, required
    - `provider` string, required
    - `response_format` 'notebook', required
    - `usage` object, required
      - `completion_tokens` integer
      - `prompt_tokens` integer
      - `total_tokens` integer

## Other responses

- `400` — Bad request
- `503` — Service unavailable
- `default` — Other error

---

[API](https://skmtc.dev/matlantis/apis/matlantis-web-ui-backend-api.md) · [All operations](https://skmtc.dev/matlantis/apis/matlantis-web-ui-backend-api/llms.txt) · [OpenAPI document](https://skmtc-service-production.skmtc.workers.dev/v1/apis/matlantis/matlantis-web-ui-backend-api/revisions/b155f3a32673/schema)