Custom LLMs

Junie CLI supports custom models defined via JSON profiles. This feature allows you to integrate with local providers (e.g., Ollama), enterprise proxies, or any LLM endpoint that follows the supported API formats.

Configuration

Location and discovery

By default, custom models are discovered from JSON files located in:

User-scope: $JUNIE_HOME/models/*.json.
Project-scope: .junie/models/*.json.

The filename (without the .json extension) is used as the profile identifier.

You can control where Junie searches for custom models using the following command-line options:

Option	Default	Description
`--model-default-locations`	`true`	Enable or disable adding custom models from default locations (per user / per project).
`--model-location <path>`	—	Additional folders where custom models should be found. Can be specified multiple times.

You can also set these values in the config.json file. For details, see Junie CLI configuration files.

Profile structure

A custom model profile consists of a top-level configuration and two optional model roles:

Top-level properties: Serve as the default configuration (base URL, API key, API type, and extra headers) for the models in the profile.
primaryModel: The model used for main reasoning and code generation tasks.
fasterModel: The model used for internal helper tasks like summarizing context or classifying tasks.

If primaryModel or fasterModel is not explicitly defined, they inherit the top-level properties.

Top-level parameters

These parameters appear at the root of the JSON profile and define the defaults shared by both model roles.

Parameter	Type	Required	Description
`id`	String	Yes	The model identifier as expected by the API endpoint (for example, `gpt-4o` or `qwen3-coder:latest`).
`baseUrl`	String	Yes	The full URL of the LLM API endpoint (for example, `http://localhost:11434/v1/responses`).
`apiType`	String	Yes	The API format to use when communicating with the endpoint. See Supported API types for the list of accepted values.
`apiKey`	String	No	The API key for authenticating with the endpoint. If omitted, requests are sent without an `Authorization` header.
`extraHeaders`	Object	No	A key-value map of additional HTTP headers to include in every request to the endpoint.
`temperature`	Number	No	The sampling temperature to use for requests. If omitted, the provider's default temperature is used. See Temperature.
`primaryModel`	Object	No	Role-specific overrides for the primary model. See Role-specific parameters.
`fasterModel`	Object	No	Role-specific overrides for the faster model. See Role-specific parameters.

Role-specific parameters

primaryModel and fasterModel accept the same set of parameters. Any parameter specified here overrides the corresponding top-level value for that model role. Omitted parameters fall back to the top-level defaults.

Parameter	Type	Description
`id`	String	Override for the model identifier used for this role.
`baseUrl`	String	Override for the API endpoint URL used for this role.
`apiType`	String	Override for the API format used for this role.
`apiKey`	String	Override for the API key used for this role.
`extraHeaders`	Object	Additional headers for this role. Merged with (not replaced by) the top-level `extraHeaders`.
`temperature`	Number	Override for the sampling temperature used for this role.

Merging logic

Overrides in primaryModel or fasterModel are merged with the top-level defaults:

Simple fields (id, baseUrl, apiKey, apiType, temperature) are replaced by the override value when present.
Headers (extraHeaders) are merged: headers defined in the override are added to the top-level headers. If the same header key appears in both, the role-level value takes precedence.

Supported API types

The apiType field controls which request format Junie uses when calling the endpoint.

Value	Description
`OpenAICompletion`	OpenAI Chat Completions API (`/v1/chat/completions`). Compatible with most self-hosted and third-party OpenAI-compatible endpoints.
`OpenAIResponses`	OpenAI Responses API (`/v1/responses`). Use this for endpoints that implement the newer Responses API format.
`Google`	Google Gemini API format. Use this for Google AI Studio or Vertex AI endpoints.
`Anthropic`	Anthropic Messages API format. Use this for Anthropic Claude endpoints.

Temperature

By default, Junie does not send a temperature value for custom models, allowing the provider to use its own default. You can set a specific temperature at the top level (shared by both model roles) or override it per role.

Recommended temperature values vary by model. For example:

Model	Recommended temperature
DeepSeek	0
Gemini	1
Kimi	0.6–1
GLM	0.7
Qwen	0.6
MiMo	0.3

Example profiles

Basic profile

Below is an example of a profile named local-ollama.json:

{
  "baseUrl": "http://localhost:11434/v1/responses",
  "id": "qwen3-coder:latest",
  "apiType": "OpenAIResponses",
  "extraHeaders": {
    "X-Custom-Source": "Junie"
  },
  "fasterModel": {
    "id": "qwen2.5-coder:1.5b"
  }
}

In this example, the primary model will be qwen3-coder:latest, and the faster model will be qwen2.5-coder:1.5b. Both will use the same base URL, API type, and extra headers.

Profile with temperature

Below is an example that sets a default temperature and overrides it for the primary model:

{
  "baseUrl": "http://localhost:11434/v1/responses",
  "id": "qwen3-coder:latest",
  "apiType": "OpenAIResponses",
  "temperature": 0.6,
  "primaryModel": {
    "id": "qwen3-coder:latest",
    "temperature": 0.3
  },
  "fasterModel": {
    "id": "qwen2.5-coder:1.5b"
  }
}

In this example, the primary model uses temperature 0.3 (overridden), while the faster model inherits the top-level temperature 0.6.

Using custom models

Once a profile is created, you can select it using the /model command or the --model flag. Custom models are identified by a custom: prefix followed by the profile ID:

junie --model custom:local-ollama

In the interactive TUI, custom models appear in the model selection list after the built-in providers.

08 June 2026