Explanation
What a mode is, and why a tool belongs to one
Why Turret scopes a session's tools, panes and prompt together as a single mode, fixed for its life.
A mode decides three things about a session: which tools it can call, which panes it can draw into, and what its system prompt adds. Turret treats those three as a single fixed bundle, chosen when a session starts and never split apart.
Why every session in a mode shares the same tool list
A repository a session opens can carry its own tool configuration for Claude, adding servers of its own. Turret refuses that addition for every session, so a mode's tool list never depends on which repository a session happens to be open on. Without that refusal, two sessions in the same mode could show different tools, and mode would stop meaning a fixed set of tools at all.
Why a mode's own tool list stays small
A mode's prompt fragment is what tells the model how to use its own tools, and that fragment has a cost every turn pays. Only a small number of a mode's own tools sit in the model's default view. Everything past that has to be found by search before it can be called.
A reader might expect a mode that wants more of its tools in that default view to raise its own cap. Turret reads that instead as a sign the mode's prompt fragment is not saying enough on its own.
Why some tools wait to be found
Spawning another session, sending it a message and reading what it did are not any single mode's own tools. Turret gives every session that ability itself, whatever mode it runs under, and keeps those particular tools out of the model's default view on purpose.
A tool the model has to search for gets reached for less casually than a tool already sitting in the model's default view. A reader might take that deferral as a safeguard. It changes how readily the model reaches for the tool, not whether it is allowed to use it.
See Modes for what each of Turret's seven modes actually gives a session.