Quick start

Start the gateway

cmx start

This launches the background daemon: gateway on http://127.0.0.1:17322, web dashboard on http://127.0.0.1:17323.

Point your harness at it

For OpenCode, add to ~/.config/opencode/opencode.jsonc for each provider you want routed through cmx:

{
  "provider": {
    "my-provider": {
      "options": {
        "baseURL": "http://127.0.0.1:17322",
        "headers": {
          "cmx-provider": "my-provider",
          "cmx-harness": "opencode"
        }
      }
    }
  }
}

cmx-provider must match a key under providers in ~/.config/cmx/config.json. Well-known names (openai, anthropic, openrouter, groq, deepseek, moonshot, zai) are preconfigured with their public base URLs — your harness still supplies its own API key and cmx forwards it unchanged.

Use your agent normally

Work in a long session. When the model decides earlier history is stale it calls compress; cmx swaps those spans for summaries on the next turn.

Watch the savings

cmx stats

sessions: 12   requests: 340
input tokens (reported): 4.2M   output: 61k
estimated context: 1.9M sent -> 890k   saved: 1.0M (54.1%)
cache: read 3.1M / write 240k

…or open the dashboard at http://127.0.0.1:17323, or just run cmx for the terminal GUI.