# Runtime Flags and Modes

This page documents the runtime flags and modes that affect DeerFlow Harness and agent runtime behavior.

## Per-request configurable options

These options are passed via `config.configurable` (for programmatic use) or selected in the web UI (for application use):

| Flag                       | Type          | Default                | Description                                      |
| -------------------------- | ------------- | ---------------------- | ------------------------------------------------ |
| `model_name`               | `str \| None` | First configured model | Model to use for the request                     |
| `agent_name`               | `str \| None` | `None`                 | Load a custom agent configuration                |
| `thinking_enabled`         | `bool`        | `True`                 | Enable extended thinking (model must support it) |
| `reasoning_effort`         | `str \| None` | `None`                 | Reasoning effort level (model-specific)          |
| `is_plan_mode`             | `bool`        | `False`                | Enable TodoList middleware                       |
| `subagent_enabled`         | `bool`        | `False`                | Allow subagent delegation                        |
| `max_concurrent_subagents` | `int`         | `3`                    | Maximum parallel subagent calls per turn         |

## Environment variables

| Variable                | Default         | Description                                      |
| ----------------------- | --------------- | ------------------------------------------------ |
| `DEER_FLOW_CONFIG_PATH` | Auto-discovered | Absolute path to `config.yaml`                   |
| `LOG_LEVEL`             | `info`          | Log level override                               |
| `DEER_FLOW_ROOT`        | Repo root       | Base path for Docker bind mounts                 |
| `BETTER_AUTH_SECRET`    | —               | Frontend session secret (required in production) |
| `BETTER_AUTH_URL`       | —               | Public URL (for callbacks and CORS)              |

## Model capability flags

Set in the model configuration in `config.yaml`:

| Flag                | Type   | Description                           |
| ------------------- | ------ | ------------------------------------- |
| `supports_vision`   | `bool` | Model accepts image inputs            |
| `supports_thinking` | `bool` | Model supports extended thinking mode |
