yaab.limits¶

Usage limits and run control.

yaab.limits ¶

Usage limits and run cancellation — bounded, interruptible runs.

Two small, composable controls the ecosystem repeatedly asks for:

:class:UsageLimits — hard caps on requests, input/output/total tokens, tool calls (overall and per-tool), and wall-clock seconds. Checked by the Runner between steps and before each tool call; breaching one raises :class:~yaab.exceptions.UsageLimitExceeded.
:class:CancellationToken — a cooperative stop signal. Call :meth:CancellationToken.cancel (from a signal handler, a timeout, another task, an API endpoint) and the Runner stops at the next checkpoint with :class:~yaab.exceptions.RunCancelled. A timeout on the run wires an automatic deadline to the same mechanism.

Both are optional; with neither set, runs behave exactly as before.

UsageLimits ¶

Declarative caps enforced across an agent run.

Any limit left None is unbounded. per_tool_calls maps a tool name to its own maximum call count (e.g. {"charge": 1}).

check_usage ¶

check_usage(usage: Usage) -> None

Raise if the accumulated token/request usage breaches a cap.

check_wall_clock ¶

check_wall_clock(started_at: float) -> None

Raise if the run has exceeded its wall-clock budget.

started_at is a time.monotonic() timestamp from the run's start.

check_tool_call ¶

check_tool_call(tool_name: str, counts: dict[str, int]) -> None

Raise if invoking tool_name would breach an overall/per-tool cap.

counts is the running tally of calls per tool including this one.

CancellationToken ¶

A cooperative cancellation signal shared with a run.

The Runner checks :meth:raise_if_cancelled between supersteps and before each tool call. A token can carry a wall-clock deadline so timeouts and explicit cancels flow through one path.