Use OpenCode with onomeo

What to fill in

Step by step

Screenshots and dated measurements show earlier tests. Their model names and costs are historical; use the current model and pricing shown above.

1. 1

   Install OpenCode

   On Windows, press the Windows key, type PowerShell and press Enter. On macOS, open Terminal. Paste the line below and press Enter.

   Copy

   npm install -g opencode-ai

   If npm is not found, install Node.js (the LTS version) from nodejs.org first, then close PowerShell and open it again.

2. 2

   Save the configuration

   Press Copy, paste the command into the same window and press Enter. It writes this site's address, your key and a few models into OpenCode's configuration file.

   WindowsmacOS / Linux

   Copy

   $f = "$HOME\.config\opencode\opencode.json"
   if (-not (Test-Path $f)) {
   New-Item -ItemType Directory -Force -Path (Split-Path $f) | Out-Null
   [IO.File]::WriteAllText($f, @'
   {
     "$schema": "https://opencode.ai/config.json",
     "model": "onomeo/MODEL_ID",
     "provider": {
       "onomeo": {
         "npm": "@ai-sdk/openai-compatible",
         "name": "onomeo",
         "options": {
           "baseURL": "https://onomeo.com/v1",
           "apiKey": "YOUR_API_KEY"
         },
         "models": {
           "MODEL_ID": { "name": "MODEL_ID" }
         }
       }
     }
   }
   '@)
   Write-Host "Saved: $f" -ForegroundColor Green
   } else { Write-Host "Config file already exists, left unchanged: $f" -ForegroundColor Yellow }

   Replace YOUR_API_KEY in the command with your key. Once you create a key in this browser, it is filled in here.

   

   If the yellow line "Config file already exists, left unchanged" appears, OpenCode has been set up on this computer before. To keep your settings, the command wrote nothing: open the file it names in Notepad and add the "onomeo" block above under "provider".

3. 3

   Start OpenCode

   Go to your project folder first (for example, type cd D:\my-project and press Enter), then type the word below and press Enter.

   Copy

   opencode

   

4. 4

   Give it a task

   Type what you want done in the input box and press Enter. OpenCode reads files, writes files and runs commands on its own until the job is done.

   

   OpenCode sends the model its long working instructions and its list of tools at every step; each step counts as one call, and a long step as several. Measured on 27 September 2026: the task above took three steps, 3 calls with auto, and nothing charged.

5. 5

   Switch modelsOptional

   Type /models in the input box and press Enter, use the arrow keys to pick a model under "onomeo", then press Enter.

   

If it will not connect

• 401: the key is wrong. Copy the command in step 2 again; if it said the file already exists, check the apiKey line in that file.
• 402: insufficient balance. Claude, GPT and other big models are charged by usage; top up on the Pricing page, or choose a lower-cost model and try again.
• No onomeo models in the list: the configuration was not saved. Run step 2 again, make sure the last line is the green Saved, then quit OpenCode completely and start it again.
• OpenCode sends the files it has read with every request. Longer sessions can increase input usage and charges; start a new session for each new task.