AI CLIENT GUIDES

Use the Nexbion API with Codex

Configure Nexbion at user level so the Codex CLI and hosts that run Codex can share the same provider settings.

Prerequisites

Codex CLI runs from your terminal
The API key is stored in an environment variable or local secret file
You can edit ~/.codex/config.toml

Configuration steps

1
Store the API key in a local secret file that Git does not track.
2
Add the Nexbion provider and oc/big-pickle model to ~/.codex/config.toml.
3
Validate the model list and Responses API.
4
Run codex exec as the final smoke test.

Visual walkthrough

01Configure the Nexbion provider for Codex

02Codex and Nexbion API smoke-test evidence

~/.codex/config.toml

model = "oc/big-pickle"
model_provider = "Nexbion"
model_reasoning_effort = "high"

[model_providers.Nexbion]
name = "Nexbion"
base_url = "https://api.nexbion.com/v1"
wire_api = "responses"

[model_providers.Nexbion.auth]
command = "powershell.exe"
args = ["-NoProfile", "-ExecutionPolicy", "Bypass", "-Command", "Get-Content -LiteralPath '<PATH_TO_NEXBION_API_KEY_FILE>' -Raw"]
timeout_ms = 5000

A model catalog warning can appear when local metadata does not recognize the model. Execution can still work through fallback metadata after the provider and endpoint are validated.

Validate the connection

PowerShell: GET /v1/models

$headers = @{ Authorization = "Bearer $env:NEXBION_API_KEY" }
Invoke-RestMethod -Uri "https://api.nexbion.com/v1/models" -Headers $headers

Linux/macOS: curl POST /v1/responses

curl https://api.nexbion.com/v1/responses \
  -H "Authorization: Bearer YOUR_API_KEY_HERE" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "gpt-5.5",
    "input": [
      {
        "role": "user",
        "content": "Reply with exactly pong"
      }
    ],
    "max_output_tokens": 20
  }'

Windows PowerShell: curl.exe POST /v1/responses

$body = @'
{
  "model": "gpt-5.5",
  "input": [
    {
      "role": "user",
      "content": "Reply with exactly pong"
    }
  ],
  "max_output_tokens": 20
}
'@

curl.exe "https://api.nexbion.com/v1/responses" `
  -H "Authorization: Bearer YOUR_API_KEY_HERE" `
  -H "Content-Type: application/json" `
  -d $body

PowerShell: POST /v1/responses

$headers = @{ Authorization = "Bearer $env:NEXBION_API_KEY" }
$body = @{
  model = "oc/big-pickle"
  input = @(@{ role = "user"; content = @(@{
    type = "input_text"; text = "Reply only with OK."
  }) })
} | ConvertTo-Json -Depth 8 -Compress

Invoke-WebRequest -Uri "https://api.nexbion.com/v1/responses" `
  -Method Post -Headers $headers -ContentType "application/json" -Body $body

Codex smoke test

codex exec --json --skip-git-repo-check --sandbox read-only `
  --config approval_policy='never' "Reply only with OK." | Select-String 'agent_message'

Keep your API key in a local secret or environment variable. Never place it in a repository, screenshot, workspace setting, or application code.