Anthropic spend limits and the Default Workspace

The rule

Anthropic's workspaces documentation says: “You cannot set spend limits on the Default Workspace.” Every organization has a Default Workspace that cannot be renamed, archived or deleted, and it is where keys end up if you never created another workspace. Organization-wide limits still apply, but there is no separate cap for the Default Workspace.

Why it matters

Agent loops are expensive with frontier models: one builder described a $14,800 Anthropic bill from an agent stuck in a recursive grep loop for 9 hours, and another burnt $4,200 in credits overnight.

How to cap it

1. In the Claude Console, open Workspaces and click Create workspace (only organization admins can).
2. Select the new workspace and click Spend limits to set a monthly cap and alerts. Workspace limits can be lower than, but not higher than, your organization's limits.
3. Optionally set rate limits for the workspace under Rate limits.
4. Create new API keys in that workspace, switch your agents to them, and disable the old Default Workspace keys.

Monitoring: mind the lag

The Usage and Cost Admin API reports costs in USD (as decimal strings in cents) and says data typically appears within 5 minutes of a request. Costs for the Default Workspace show null as the workspace_id. The Admin API needs an Admin API key and is unavailable for individual accounts; you need an organization set up in the Console.

KeyBark uses this cost report with your Admin key to alert on daily and monthly thresholds and spikes, including Default Workspace spend, and (if you opt in) can set a named API key to inactive when a threshold is crossed.