Synthetic Provider Setup for OpenClaw

Synthetic offers endpoints that work with Anthropic. OpenClaw delivers access to them via the official @openclaw/synthetic-provider plugin, and it relies on the Anthropic Messages API.

Property	Value
Provider	`synthetic`
Auth	`SYNTHETIC_API_KEY`
API	Anthropic Messages
Base URL	`https://api.synthetic.new/anthropic`

Getting started

Install the plugin

openclaw plugins install @openclaw/synthetic-provider

If a Gateway is already running, the installation is applied to it automatically. Otherwise it takes effect the next time it starts. See Apply changes and inspect.

Get an API key

Obtain a SYNTHETIC_API_KEY from your Synthetic account, or let onboarding ask you for one.

Run onboarding

openclaw onboard --auth-choice synthetic-api-key

Verify the default model

Onboarding registers synthetic/hf:MiniMaxAI/MiniMax-M3 as the default model. To confirm it is registered:

openclaw models list --provider synthetic

Warning

OpenClaw's Anthropic client adds /v1 to the base URL on its own, so supply https://api.synthetic.new/anthropic (not /anthropic/v1). Should Synthetic change its base URL, override models.providers.synthetic.baseUrl.

Config example

{
  env: { vars: { SYNTHETIC_API_KEY: "sk-..." } },
  agents: {
    defaults: {
      model: { primary: "synthetic/hf:MiniMaxAI/MiniMax-M3" },
      models: { "synthetic/hf:MiniMaxAI/MiniMax-M3": { alias: "MiniMax M3" } },
    },
  },
  models: {
    mode: "merge",
    providers: {
      synthetic: {
        baseUrl: "https://api.synthetic.new/anthropic",
        apiKey: "${SYNTHETIC_API_KEY}",
        api: "anthropic-messages",
        models: [
          {
            id: "hf:MiniMaxAI/MiniMax-M3",
            name: "MiniMax M3",
            reasoning: true,
            input: ["text", "image"],
            cost: { input: 0, output: 0, cacheRead: 0, cacheWrite: 0 },
            contextWindow: 262144,
            maxTokens: 65536,
          },
        ],
      },
    },
  },
}

Model discovery

When a Synthetic credential is present, OpenClaw pulls the current text models from Synthetic's /openai/v1/models API. Inference continues to go through the Anthropic Messages API. Models that appear later, small models and syn: aliases included, require no catalog update in OpenClaw.

Context and output limits, image input, reasoning, tool support, and usage-based token prices all come from the live catalog. Those prices are estimates rather than a subscription bill. Consult Synthetic's current model list for availability and for its recommended aliases.

When catalog generation runs offline, or when discovery responses are missing or unusable, the bundled seed models are used. The model you selected is never switched automatically. If you override the inference base URL, OpenClaw bypasses Synthetic's fixed discovery URL, which keeps a proxy credential from being sent to Synthetic.

Tip

Model refs take the form synthetic/<modelId>. To inspect your configured models, use openclaw models list --provider synthetic.

Model allowlist

When a model allowlist is enabled (agents.defaults.modelPolicy.allow), every Synthetic model you intend to use must be added to it. Any model left out of the allowlist is hidden from the agent.

Base URL override

If Synthetic changes its API endpoint, override the base URL:

{
  models: {
    providers: {
      synthetic: {
        baseUrl: "https://new-api.synthetic.new/anthropic",
      },
    },
  },
}

OpenClaw continues to add /v1 automatically.

Model providers, Provider rules, model refs, and failover behavior.
Configuration reference, Full config schema including provider settings.
Synthetic, Synthetic dashboard and API docs.