Quickstart

Make your first Muse Spark call in minutes. The fastest path is Muse Code, Meta's coding agent for the terminal. Prefer your own stack? Model API is drop-in compatible with the OpenAI SDK, the Anthropic SDK, and OpenAI-compatible agent CLIs, so most stacks work with a base-URL and key change. This page uses the Responses API for direct calls; if your code already speaks Chat Completions or Anthropic Messages, see Choosing an API.

Start with Muse Code

Muse Code is Meta's coding agent for the terminal and CI, built on Muse Spark. Install it, sign in through your browser, and start building. No API key or provider config to wire up.

Install the CLI on macOS or Linux:

bash
curl -fsSL https://dev.meta.ai/install.sh | sh

Start building:

bash
muse   # start Muse Code; on first run, choose a browser sign-in or paste an API key

On first run, muse prompts you to sign in, so you can skip Set your API key below unless you're also calling the API directly. For headless CI runs, first run, and permissions, see the Muse Code overview.

Use with your coding agent

Any harness that supports an OpenAI-compatible or custom provider plugs into Model API via Responses or Chat Completions. Anthropic-format harnesses like Claude Code plug in via the Messages API instead, pointed at https://api.meta.ai with your MODEL_API_KEY. Most tools ask for three values: the base URL https://api.meta.ai/v1, your MODEL_API_KEY, and the model ID muse-spark-1.3.

Two-step setup

Step 1: Get an API key. Grab one from the Model API dashboard and export it as MODEL_API_KEY (see Set your API key).

Step 2: Paste this into your coding agent. OpenCode and other self-configuring agents (Goose, Roo, and more) register a provider straight from a prompt. In a session running on your current model, paste:

text
Add a new provider to my config for Meta Model API:
- Provider key: "meta", display name "Meta Model API"
- npm adapter: "@ai-sdk/openai" (targets the Responses API)
- Base URL: https://api.meta.ai/v1
- Model: "muse-spark-1.3"
- Reasoning: true, with reasoningEffort "high", reasoningSummary "auto", and include ["reasoning.encrypted_content"]
- Limits: context 1048576, output 131072
- Modalities: input ["text", "image", "pdf", "video"], output ["text"]
- Read the key from the MODEL_API_KEY environment variable

Select muse-spark-1.3 and start coding. That's it. For Codex, Claude Code, or hand-written config, see the full coding agents guide.

OpenCode config

Prefer to edit the config yourself? Manual setup follows the same shape everywhere: register a provider, point it at the base URL, and select muse-spark-1.3. Here's the complete block for OpenCode, a popular coding CLI.

Add to your opencode.json (global at ~/.config/opencode/opencode.json or per-project). Use the @ai-sdk/openai adapter, which drives Muse Spark over the Responses API — this enables native multimodal input (images and PDFs) and replays encrypted reasoning across turns, so the model retains its prior reasoning during tool loops:

json
{
  "provider": {
    "meta": {
      "name": "Meta Model API",
      "npm": "@ai-sdk/openai",
      "options": {
        "baseURL": "https://api.meta.ai/v1"
      },
      "models": {
        "muse-spark-1.3": {
          "name": "muse-spark-1.3",
          "reasoning": true,
          "limit": {
            "context": 1048576,
            "output": 131072
          },
          "modalities": {
            "input": ["text", "image", "pdf", "video"],
            "output": ["text"]
          },
          "options": {
            "reasoningEffort": "high",
            "reasoningSummary": "auto",
            "include": ["reasoning.encrypted_content"]
          }
        }
      }
    }
  }
}

Run /connect, select the meta provider, and enter your API key when prompted. Restart OpenCode and select Muse Spark.

Any OpenAI-compatible tool

If your tool has a "base URL" or "API base" field, set it to https://api.meta.ai/v1 and use muse-spark-1.3 as the model. This works for LangChain, LlamaIndex, Vercel AI SDK, Continue, and most agentic frameworks.

Make your first API call

Want to call the API directly? Set your key, then send a request. You'll need a Model API account and either curl, Python 3.9+, or Node.js 18+.

Set your API key

Get a key from the Model API dashboard → API keys → Create API key. Store it as an environment variable so it stays out of your code:

macOS / Linux:

shell
export MODEL_API_KEY="your-api-key-here"

Windows (PowerShell):

powershell
$env:MODEL_API_KEY = "your-api-key-here"

To persist it across sessions, add the export line to your ~/.bashrc or ~/.zshrc (macOS/Linux), or set it through System > Environment Variables (Windows).

Call the API

With your key set, send your first request:

curl

shell
curl -X POST "https://api.meta.ai/v1/responses" \
  -H "Authorization: Bearer $MODEL_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
  "model": "muse-spark-1.3",
  "input": "What is the capital of France?"
}'

Python (OpenAI SDK)

shell
pip install openai

python
import os
​
from openai import OpenAI
​
client = OpenAI(
    base_url="https://api.meta.ai/v1",
    api_key=os.environ["MODEL_API_KEY"],
)
​
response = client.responses.create(
    model="muse-spark-1.3",
    input="What is the capital of France?",
)
​
print(response.model_dump_json(indent=2))

TypeScript (OpenAI SDK)

shell
npm install openai

typescript
import OpenAI from 'openai';
​
const apiKey = process.env.MODEL_API_KEY;
if (!apiKey) {
  throw new Error('MODEL_API_KEY is not set');
}
​
const client = new OpenAI({
  baseURL: 'https://api.meta.ai/v1',
  apiKey,
});
​
const response = await client.responses.create({
  model: 'muse-spark-1.3',
  input: 'What is the capital of France?',
});
​
console.log(JSON.stringify(response, null, 2));

A successful call returns generated text plus usage, status, and other response metadata.

Troubleshooting

• 401 authentication_error: your key isn't set or isn't valid. Check echo $MODEL_API_KEY and confirm it matches a key in the dashboard.
• 404 model_not_found: use a valid model ID such as muse-spark-1.3 (the default in these examples) or muse-spark-1.1 exactly.

For other status codes, retries, and error shapes, see the error handling guide.

Next steps

• Automate coding tasks from your terminal or CI with Muse Code.
• Configure OpenCode and other harnesses in the full coding agents guide.
• Add live web access with cited answers using search grounding.
• Copy a runnable starter from the Cookbook, or verify params in the API reference.