Gateway adds spend budgets shared by a whole group

What

The gateway bundled with Claude Code is a proxy that sits between Claude Code and the model provider and can enforce spending caps. It can now enforce a budget shared by a whole group of users (an RBAC group, a role-based permission group), in addition to each developer's own cap.

• The gateway's database update adds pooled_limit_enabled and pooled_monthly_credit_limit to the spend_limits table, plus a new pooled_spend table.
• The schema for setting limits gains a pooled_budget object.
• On each request the gateway checks the group's shared budget. When it is used up, the request is refused with a 429 billing_error, and the groups involved are logged.
• If the shared-budget check itself fails, the gateway logs "pooled spend check failed, so group budgets are not enforced (developers' own caps are)", at most once a minute. Each developer's own cap still applies.
• After each request the gateway records spending against the pool, and warns if that write has not finished after 30 seconds.
• The retention job now also deletes pooled_spend rows older than the retention window.
• The built-in gateway documentation now explains group-shared budgets: a 429 billing_error can mean the group budget ran out, and the gateway then sends the monthly limit details plus the header anthropic-ratelimit-unified-overage-scope: group_pool. The header is sent when the scope type is group_pool.

Why

Administrators running the bundled gateway can cap spending for a whole group, not only for each person. If you hit a 429 billing_error with the group_pool scope, it is your group's shared budget that ran out, not your own.