Using Downsizing with Crush

Prerequisites

Install the Downsizing CLI — see the CLI guide if you haven't already.

Link Crush (Recommended)

Link Crush to Downsizing:

ds link crush

This writes a custom downsizing Anthropic-compatible provider into your global Crush config (~/.config/crush/crush.json) and sets it as both the "large" and "small" default model. It's idempotent — safe to run again any time.

Manual Setup

If you prefer to configure manually, edit ~/.config/crush/crush.json (or a project-local crush.json / .crush.json, which Crush prefers over the global file) and add:

{
  "$schema": "https://charm.land/crush.json",
  "providers": {
    "downsizing": {
      "type": "anthropic",
      "base_url": "https://api.downsizing.dev/YOUR_INFERENCE_ID/anthropic/v1",
      "api_key": "dws_YOUR_API_KEY",
      "models": [
        {
          "id": "claude-opus-4-8",
          "name": "Downsizing",
          "context_window": 200000,
          "default_max_tokens": 8192
        }
      ]
    }
  },
  "models": {
    "large": { "model": "claude-opus-4-8", "provider": "downsizing" },
    "small": { "model": "claude-opus-4-8", "provider": "downsizing" }
  }
}

Find your Inference ID and API key on the Inference API page. Note the base URL must end in /anthropic/v1 — Crush'santhropic provider type posts straight to {base_url}/messages without appending a version prefix itself.

Verify

Launch Crush in a project directory and send a quick message to confirm traffic is routing through Downsizing:

crush run "hello"

If Crush responds, Downsizing is set up correctly. You can also check your savings dashboard to see the request appear in your usage metrics.

Unlinking

To remove Downsizing from Crush and restore your original settings:

ds unlink crush