Feature: add a dedicated /usage command in Codex CLI

Problem

Claude Code exposes a dedicated /usage command, which makes it very discoverable to check quota / session usage from within the terminal.

Codex currently has related usage information spread across /status, rate-limit warnings, and the web usage page. There are already requests to expand /status, but there does not appear to be a dedicated issue specifically asking for a first-class /usage command.

For users switching from Claude Code to Codex, /usage is a natural command to try. Right now that expectation fails, even though the underlying need clearly exists.

Feature request

Add a dedicated /usage command in the Codex CLI / TUI.

This could be implemented as either:

1. A standalone /usage panel focused only on usage and limits
2. A thin alias to an enhanced usage section of /status

Either approach would be fine, but having the explicit /usage entry point matters for discoverability and parity with established CLI expectations.

Expected output

At minimum, it should show the most important limits and reset times clearly:

• current plan / account context
• 5-hour usage remaining, with reset time
• weekly usage remaining, with reset time
• whether the displayed values are live, cached, or estimated

If available, it would also help to show:

• current model / reasoning mode that affects rate-limit consumption
• session-level token usage or message usage
• a short pointer to the web dashboard when the CLI cannot fetch exact values

Why this is useful

• Improves discoverability for a common need
• Reduces surprise when users hit limits
• Avoids forcing users to open the browser just to inspect remaining quota
• Matches an expectation many users already have from Claude Code

Related issues

This is adjacent to, but slightly different from, the existing request to expose fuller usage data in /status:

• #15281

That issue is about expanding /status. This request is specifically about adding a dedicated /usage command, even if it is internally backed by the same data source.

Environment

• Codex CLI
• macOS
• ChatGPT-authenticated usage / rate limits