What
The data behind the /usage command (which shows session cost, plan usage limits, and activity stats) now has a formally defined structure covering:
- session cost, duration, and lines-of-code totals
- rate-limit rows, each with kind, group, percent used, reset time, scope, severity, and whether it's currently active, exactly as sent by the server
- extra-usage (overage) spend details: whether it's enabled, the monthly limit, credits used, utilization, and currency
This is explicitly marked as experimental, meaning the shape may still change.
Why
A well-defined structure for usage data makes it easier for tools built on top of Claude Code, such as the SDK, to reliably read cost and rate-limit information, though it isn't finalized yet.
Names in the bundle/usage
The entry above is what we published on the day. These lines were added later, as Anthropic's own pages caught up, and they sit beside the original rather than replacing it.
Added since
A small documentation edit on First request touched a line naming /usage after this was published.
For complete parameter details and response schemas, see the [Claude Code Analytics API reference](https://platform.claude.com/docs/en/api/beta/organization/usage_report/retrieve_claude_code).manage-claude/claude-code-analytics-api see the edit
Confirmed since
Anthropic's documentation has since written up /usage, on Claude Code changelog.
* Fixed error hints in Claude Desktop sessions to suggest slash commands like `/usage-credits` instead of CLI flags that cannot be used therechangelog see the edit
One source agreesOne thing we can check says the same as this entry.
Anthropic's documentation agrees
Anthropic's documentation has since written up /usage, on Claude Code changelog.