OpenCode

Guide to configuring OpenCode — a TUI coding assistant — to call a model via GreenNode MaaS through the @ai-sdk/openai-compatible provider, billed via internal credit-tokens.

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Prerequisites

• Prepare your API key, Base URL, and model following Getting Started with AI Coding

• Node.js installed

The GLM 5.2 model via OpenCode uses the OpenAI standard — the Base URL includes /v1: https://maas-llm-aiplatform-hcm.api.vngcloud.vn/v1.

Using a Token Plan (subscription package) key instead of a pay-as-you-go API key? Use https://tokenplan.api.greennode.ai/v1 as the Base URL instead. See Token Plan for details.

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Step 1 — Install OpenCode

npm install -g opencode-ai

Or via Homebrew (macOS):

brew install opencode

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Step 2 — Get an API key from AI Platform

1. Log in to the AI Platform Console

2. Go to API Keys → Create API Key

3. Name the key (5–50 characters, lowercase letters + numbers + hyphens)

4. Copy the API key (vn-...) you just created

A newly created API key starts in pending status. Wait until status = ACTIVE before using it.

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Step 3 — Create the opencode.json config file

Create an opencode.json file at your project root:

{
  "$schema": "https://opencode.ai/config.json",
  "model": "MAAS-chat/openai/gpt-oss-120b",
  "provider": {
    "MAAS-chat": {
      "npm": "@ai-sdk/openai-compatible",
      "name": "MAAS chat",
      "options": {
        "baseURL": "https://maas-llm-aiplatform-hcm.api.vngcloud.vn/v1",
        "apiKey": "{env:MAAS_API_KEY}"
      },
      "models": {
        "openai/gpt-oss-120b": {
          "name": "openai/gpt-oss-120b"
        }
      }
    }
  }
}

Field explanations:

Field	Purpose
$schema	Enables autocomplete/validation in your editor
model	Default model — format <provider-key>/<model-id>
provider.MAAS-chat	Provider key — must exactly match the part before / in model
npm	Adapter package — @ai-sdk/openai-compatible works for any OpenAI-style endpoint
options.baseURL	MaaS endpoint, ending with /v1
options.apiKey	MaaS token — use {env:MAAS_API_KEY} instead of hardcoding
models	List of models exposed from this provider

Common mistake: setting "model" to a name that doesn't match a registered provider key. OpenCode splits on the first / to find the provider — if it doesn't match, the model won't load. Always use MAAS-chat/openai/gpt-oss-120b.

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Step 4 — Provide the API key

Since the config uses {env:MAAS_API_KEY}, the key isn't in the file but is read from an environment variable at runtime. There are two ways:

Option A — Export an environment variable (recommended)

Export the key in your shell, then run OpenCode in the same session:

export MAAS_API_KEY="vn-xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx"
opencode

To do this automatically every time you open a terminal, add it to ~/.zshrc or ~/.bashrc:

echo 'export MAAS_API_KEY="vn-xxxx..."' >> ~/.zshrc
source ~/.zshrc

Or set it inline for a single run:

MAAS_API_KEY="vn-xxxx..." opencode

Option B — Use a gitignored .env file in your project

Create a .env file (add it to .gitignore):

export MAAS_API_KEY="vn-xxxx..."

Run OpenCode by loading the .env file first:

source .env && opencode

Don't hardcode your API key directly in opencode.json if that file gets committed. If a key has already been committed, rotate it immediately in the MAAS Console since it must be treated as leaked.

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Step 5 — Run OpenCode and select a model

1. Navigate to your project directory and run:

   opencode

   OpenCode starts with MAAS-chat/openai/gpt-oss-120b as the default model.

2. Switch models within the session with the /models command, then choose MAAS chat → openai/gpt-oss-120b from the list.

OpenCode running with the openai/gpt-oss-120b model via GreenNode MaaS

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Adding other MaaS models

To expose more models from the same MaaS endpoint, add entries to models:

"models": {
  "openai/gpt-oss-120b": { "name": "openai/gpt-oss-120b" },
  "openai/gpt-oss-20b":  { "name": "openai/gpt-oss-20b" }
}

Then select via /models, or change the top-level model to the new MAAS-chat/<model-id>.

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Troubleshooting

Symptom	Cause	Fix
provider not found / model won't load	model value doesn't match the provider key	Use MAAS-chat/openai/gpt-oss-120b
401 Unauthorized	Wrong, expired, or not-yet-ACTIVE API key	Re-export MAAS_API_KEY; rotate the token in the MAAS Console
404 when sending a request	Wrong Base URL or missing /v1	Check baseURL ends with /v1
Connection timeout	Endpoint unreachable from the current network	Check VPN / connection to *.api.vngcloud.vn
Model errors but auth is correct	Wrong model ID	Use the exact ID published by MaaS (openai/gpt-oss-120b)

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Result

Once done, OpenCode routes all requests through GreenNode MaaS. Usage is logged on the AI Platform Console → Usage.

I want to next...	Go to
Use Codex with Minimax via MaaS	Use Codex with Minimax via GreenNode MaaS
Connect Claude Code to MaaS	Connect Claude Code to GreenNode MaaS
View usage and billing	AI Platform Console

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Need help?

If you've followed the steps and it's still not working, feel free to contact GreenNode Customer Support:

• Email: [e-mail]

• Hotline: [phone]

• Help center: helpdesk.greennode.ai

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