Factory Droid

Factory Droid supports custom models in the Droid CLI through ~/.factory/settings.json. Point a Factory custom model at Merge Gateway and Droid can use Gateway models with one API key, while Gateway keeps routing policies, cost governance, and request observability in the Gateway dashboard.

Before you start

Install the Factory Droid CLI from the Factory quickstart
Grab an API key from gateway.merge.dev/settings/api-keys and export it:
```
$ export MERGE_GATEWAY_API_KEY="mg_your_key"
```
Pick the Gateway models you want Droid to use. Gateway model names take the form provider/model, for example anthropic/claude-sonnet-4-6 or openai/gpt-5.2. Browse the full catalog with GET /v1/models or in the dashboard.

Configure Factory Droid

Open your Factory settings

Open ~/.factory/settings.json (create it if it does not exist).

Add Gateway as a custom model

Add a customModels entry that points Factory’s OpenAI provider at Gateway’s OpenAI-compatible endpoint.

~/.factory/settings.json

1 {
2   "customModels": [
3     {
4       "model": "anthropic/claude-sonnet-4-6",
5       "displayName": "Claude Sonnet 4.6 [Merge Gateway]",
6       "baseUrl": "https://api-gateway.merge.dev/v1/openai",
7       "apiKey": "${MERGE_GATEWAY_API_KEY}",
8       "provider": "openai",
9       "maxOutputTokens": 16384
10     }
11   ]
12 }

Use provider: "openai" so Factory sends OpenAI Responses API requests. Gateway translates those requests through /v1/openai/responses.

Select the model in Droid

Start Droid in your project, run /model, and select the custom model from the Custom models section.

Send a test message

Ask Droid a small coding question or request a small edit. The request will show up in your Gateway dashboard within a few seconds.

Caveats

Use the OpenAI provider

Set provider to "openai", not "generic-chat-completion-api". Factory’s OpenAI provider uses the Responses API, which matches Gateway’s /v1/openai/responses compatibility path.

Custom models are CLI-only in Factory

Factory’s BYOK documentation says custom models are available in the Droid CLI and do not appear in Factory web or mobile. Configure this in ~/.factory/settings.json on the machine running Droid.

Which models can I use?

Any model Gateway supports. Use GET /v1/models to list them, or open the Gateway dashboard and copy the model identifier.

Let Gateway choose the model

Instead of picking one model per Factory custom model entry, point the request at a routing policy and let Gateway choose the vendor and model based on your rules.

Next steps

Routing policies

Let Gateway pick the best vendor for each Droid request

Projects

Use a project-scoped key so Droid usage is tracked separately

Cost governance

Cap spend and restrict which models Droid can hit