Tools & How They're Exposed

A tool is one concrete action the agent can take. Which tools an agent has is
decided by its abilities. What this page is about is how each tool is
presented to the agent — its exposure mode — because showing every tool's full
instructions on every message would waste the agent's limited attention.

There are three modes:

• Core — always fully available, can't be turned off. These are the few tools the

agent literally needs to function, including the one that loads other tools on demand.

• Always — the tool's full instructions are sent every turn. This is the default,

so existing agents behave exactly as before.

• Discoverable — only the tool's name and one-line description are listed; the

full instructions are withheld until the agent decides it needs the tool and loads
it. Once loaded, it stays available for the rest of the conversation.

The agent sees a generated index of tools each turn, built from the tools it
actually has — so it can never be told about a tool it lacks. When you switch a new
ability on, its tools start as discoverable (so they don't clutter things until
used), while everything already present stays always.

You control this per agent in the Tools panel (a Sent / Discover toggle per tool,
grouped by ability). Behavioural guidance — how to use tools well — comes from
skills, not from tool definitions.