# Agents and models

Source: https://cohalen.com/docs/agents



Each workspace has one coding agent at a time, picked from a roster of ten. The
agent is how you get access, not the thing doing the thinking.

It decides which models you can reach through your subscription for that agent.
The model is what actually runs. You pick both from the prompt input.

## Models and reasoning effort [#models-and-reasoning-effort]

Switch agent and Cohalen re-lists its models, landing on that agent's flagship
default. Each model brings its own capabilities.

* **Reasoning effort** is how much thinking you're paying for on this model, set
  from a small gauge in the prompt input. The steps are the model's own. The gauge
  hides for a model that has no such setting.
* **Fast mode** is faster output at the same level of thinking. It shows up only on
  models that support it.

Some agents give you no model choice at all. There the control is missing, not
empty.

## Turns [#turns]

One prompt, the agent's work, and the reply that streams back make a turn. The
workspace is busy from the moment you send until the reply finishes. You can cancel
a turn that's running.

Turns carry on from each other. Each one picks the workspace's session back up, so
the agent keeps its context across turns and across app restarts.

The reply arrives in parts, in the order the agent produced them. Prose, a
collapsible **Thinking** trace, and each tool call inline with its status and what
it returned.

Everything the agent does shows up in the chat. Nothing about a running agent hides
in the **Terminal**.

## Skills [#skills]

A skill is a reusable `SKILL.md` playbook each agent loads from its own directories.
Cohalen keeps its hands off what's in them. It never stores or injects one, because
re-injecting a skill the agent already loads would put it in the context twice.

What Cohalen adds is the `/` picker in the prompt input. It autocompletes skill
names from the active agent's own roots, and the agent takes it from there.

Skills aside, a custom instruction in **Settings** is text Cohalen owns and carries
into every turn. Use it for preferences every agent on this machine should follow.

## Prompting for a clean changeset [#prompting-for-a-clean-changeset]

Keep the prompt to one task, and say in it what done looks like: what to build,
what to test. The changeset you read afterwards is everything that workspace
changed, so a prompt that wandered gives you a diff that wandered.

When the reply needs fixing, leave a [note](/docs/review) on the diff line rather
than writing a fresh prose prompt.