Files
strix/tests/test_hooks.py
Mads Hvelplund 962d4459d9 Add configurable token / cost usage limits (#576)
* fix: resolve pre-commit check failures

- Change RuntimeError to TypeError for type validation in report/writer.py
- Update pyupgrade to v3.21.2 for Python 3.14 compatibility

* feat(cli): add --max-budget-usd flag

Raises BudgetExceededError in ReportUsageHooks after each LLM call when
accumulated cost reaches the limit, with clean "stopped" status and
child-agent cancellation in non-interactive mode.

* test: add budget enforcement unit tests

7 tests covering no-budget, under-budget, at-limit, over-limit, error
message content, None report state, and exception hierarchy.
Also adds pytest/pytest-asyncio to dev deps and a mypy override for tests.

* fix(budget): validate positive budget and check the live cost ledger

Two hardening fixes for --max-budget-usd enforcement:

- Reject non-positive budgets. ReportUsageHooks now raises ValueError for
  max_budget_usd <= 0, and the CLI validates the flag via a custom argparse
  type so '--max-budget-usd 0' fails fast with a friendly message instead of
  silently killing the scan on the first model response.
- Read the live cost. The budget check now reads ReportState.get_total_llm_cost()
  (the live ledger) instead of the persisted run-record snapshot, so it stays
  accurate even when a usage save fails after a model call.

* fix(budget): stop the entire scan deterministically when the limit is hit

Previously a BudgetExceededError was handled per-agent: it was swallowed in
interactive mode (the loop kept waiting), a child's error escaped its detached
task as an unretrieved-exception warning, the parent was never released from
wait_for_message, and the stop was logged at ERROR with a traceback as if the
agent had failed.

Replace that with a single scan-wide signal on the coordinator:

- AgentCoordinator.trigger_budget_stop() sets a flag and wakes every parked
  agent; wait_for_message returns as soon as the flag is set.
- The run loops check coordinator.budget_stopped and raise to exit cleanly,
  marking themselves 'stopped'. The root's exception reaches run_strix_scan's
  handler, which cancels descendants and tears the scan down once; child
  exceptions are swallowed in their detached task.
- The budget stop is logged at INFO, not as a failure.

This is deterministic regardless of tree depth or which agent first sees the
limit, fixing the interactive/TUI hang where a deep agent's stop never reached
a parked root. Also re-raises BudgetExceededError explicitly in the stream
handler so it can't be mistaken for the LiteLLM 'after shutdown' race.

* fix(budget): treat a budget stop as a clean stop in the TUI

Add an explicit BudgetExceededError handler in the TUI scan thread so that, if
the error ever reaches it, the budget stop is logged as a graceful stop rather
than surfaced as a red scan error by the broad 'except Exception'. The runner
normally absorbs the error and returns cleanly, so this is defensive depth for
a money-spending feature.

* docs(cli): document --max-budget-usd behavior and limitations

Clarify that the budget is cumulative across all agents, checked after each
model response, that the scan stops cleanly (not as a failure), that the value
must be > 0, and that spend can slightly overshoot due to in-flight calls and
best-effort cost estimation.

* Apply suggestions from code review

Co-authored-by: greptile-apps[bot] <165735046+greptile-apps[bot]@users.noreply.github.com>

---------

Co-authored-by: greptile-apps[bot] <165735046+greptile-apps[bot]@users.noreply.github.com>
2026-06-22 11:17:08 -04:00

109 lines
3.7 KiB
Python

"""Tests for budget enforcement in ReportUsageHooks."""
from __future__ import annotations
from unittest.mock import MagicMock, patch
import pytest
from strix.core.hooks import BudgetExceededError, ReportUsageHooks
def _make_hooks(max_budget: float | None) -> ReportUsageHooks:
return ReportUsageHooks(model="test-model", max_budget_usd=max_budget)
def _make_report_state(cost: float) -> MagicMock:
state = MagicMock()
state.get_total_llm_cost.return_value = cost
state.record_sdk_usage = MagicMock()
return state
def _make_context(agent_id: str = "test-agent") -> MagicMock:
ctx: MagicMock = MagicMock()
ctx.context = {"agent_id": agent_id}
return ctx
@pytest.mark.asyncio
async def test_no_budget_never_raises() -> None:
hooks = _make_hooks(None)
state = _make_report_state(9999.0)
with patch("strix.core.hooks.get_global_report_state", return_value=state):
await hooks.on_llm_end(_make_context(), MagicMock(), MagicMock())
@pytest.mark.asyncio
async def test_under_budget_does_not_raise() -> None:
hooks = _make_hooks(10.0)
state = _make_report_state(9.99)
with patch("strix.core.hooks.get_global_report_state", return_value=state):
await hooks.on_llm_end(_make_context(), MagicMock(), MagicMock())
@pytest.mark.asyncio
async def test_at_budget_raises() -> None:
hooks = _make_hooks(10.0)
state = _make_report_state(10.0)
with (
patch("strix.core.hooks.get_global_report_state", return_value=state),
pytest.raises(BudgetExceededError),
):
await hooks.on_llm_end(_make_context(), MagicMock(), MagicMock())
@pytest.mark.asyncio
async def test_over_budget_raises() -> None:
hooks = _make_hooks(10.0)
state = _make_report_state(10.01)
with (
patch("strix.core.hooks.get_global_report_state", return_value=state),
pytest.raises(BudgetExceededError),
):
await hooks.on_llm_end(_make_context(), MagicMock(), MagicMock())
@pytest.mark.asyncio
async def test_budget_check_uses_live_cost_accessor() -> None:
# The check must read the live ledger, not the persisted run-record snapshot,
# so it stays accurate even when a save fails after a usage record.
hooks = _make_hooks(5.0)
state = _make_report_state(6.0)
with (
patch("strix.core.hooks.get_global_report_state", return_value=state),
pytest.raises(BudgetExceededError),
):
await hooks.on_llm_end(_make_context(), MagicMock(), MagicMock())
state.get_total_llm_cost.assert_called_once()
state.get_total_llm_usage.assert_not_called()
@pytest.mark.asyncio
async def test_error_message_includes_amounts() -> None:
hooks = _make_hooks(5.0)
state = _make_report_state(7.1234)
with patch("strix.core.hooks.get_global_report_state", return_value=state):
with pytest.raises(BudgetExceededError, match=r"\$5\.00") as exc_info:
await hooks.on_llm_end(_make_context(), MagicMock(), MagicMock())
assert "7.1234" in str(exc_info.value)
@pytest.mark.asyncio
async def test_no_raise_when_report_state_none() -> None:
hooks = _make_hooks(1.0)
with patch("strix.core.hooks.get_global_report_state", return_value=None):
# Should return early without raising, even with budget set
await hooks.on_llm_end(_make_context(), MagicMock(), MagicMock())
@pytest.mark.parametrize("bad_budget", [0.0, -0.01, -5.0])
def test_non_positive_budget_rejected(bad_budget: float) -> None:
with pytest.raises(ValueError, match="greater than 0"):
ReportUsageHooks(model="test-model", max_budget_usd=bad_budget)
def test_budget_exceeded_error_is_runtime_error() -> None:
err = BudgetExceededError("test")
assert isinstance(err, RuntimeError)