> ## Documentation Index
> Fetch the complete documentation index at: https://docs.turen.io/llms.txt
> Use this file to discover all available pages before exploring further.

# Agents and models

> Choose instructions, tools, providers, models, and reasoning variants

## Agents

An agent combines a role, system instructions, tool access, permissions, model preferences, and turn limits. Primary agents run interactive sessions; specialized subagents perform bounded delegated work.

Common built-in roles include a normal implementation agent, planning mode, read-only exploration, research, scoped implementation, qualification, and adversarial review. Hidden maintenance agents handle titles, summaries, and context compaction.

## Models

The model picker is populated from connected providers. A model reference uses:

```text theme={null}
provider/model
```

Providers can expose variants such as reasoning effort, context limits, or provider-specific options. TurenOS records the resolved provider and model with each assistant turn.

## Resolution

Agent defaults, session selections, and command-line overrides are resolved at the location that owns the session. If a provider disconnects or a model disappears, select an available model before continuing.

## Model safety

Models receive only the context selected for a turn, but that context can include repository files, prompts, tool results, and attachments. Treat remote model providers as external data processors and review their retention policy.

See [Connect providers](/get-started/providers) and [Subagents](/orchestration/subagents).