Project spending limits
An organization has one credit balance. An optional project budget limits a project's spending; it does not create another wallet.
Ask your agent to read project_budget_get and explain the current limit before changing it. project_budget_set accepts the requested amount and mode using the current tool schema. Read the result back after an authorized change.
Check both reserved credits and posted consumption when a new operation cannot start. Low balance, a project limit and a Paid entitlement are different conditions. The returned error tells the agent which action is needed.