[FEATURE]: Public API for Go plan usage/limits

[TiceWise]

• I have checked that this feature hasn't been suggested before

Problem

OpenCode Go plan users can only check their usage limits (rolling 5h, weekly, monthly) via the interactive web console at https://opencode.ai. There's no programmatic way to monitor usage from the CLI.

Use case

• CLI tools/dashboards that show Go usage alongside other metrics
• Automated alerts when approaching limits
• Local dashboard integration (like the opencode-sessions project)

Current alternatives

• opencode stats shows session-level costs from the local DB, but can't match server-side sliding windows (especially the 5h rolling window which is tied to the server's timeUpdated, not "last 5 hours")
• Browser automation to scrape the workspace page (brittle, requires session cookies)

Suggested API

A simple endpoint accessible with the existing Go API key:

GET https://opencode.ai/zen/go/v1/usage
Authorization: Bearer sk-...

{
  "rolling5h": { "usageDollars": 2.34, "limitDollars": 12, "usagePercent": 19.5, "resetInSec": 7200 },
  "weekly":    { "usageDollars": 8.91, "limitDollars": 30, "usagePercent": 29.7, "resetInSec": 345600 },
  "monthly":   { "usageDollars": 15.00, "limitDollars": 60, "usagePercent": 25.0, "resetInSec": 1414800 },
  "subscribedAt": "2026-05-22T14:30:00Z"
}

The server already computes this via Subscription.analyzeRollingUsage / analyzeWeeklyUsage / analyzeMonthlyUsage — it's just not exposed outside the console SPA.

Would be a small but high-value addition. Thanks!

[github-actions]

This issue doesn't fully meet our contributing guidelines.

What needs to be fixed:

• Feature requests must use the [FEATURE]: prefix in the title (e.g., [FEATURE]: Public API for Go plan usage/limits)
• The feature request template requires checking the verification checkbox confirming the feature hasn't been suggested before

Please edit this issue to address the above within 2 hours, or it will be automatically closed.

---

This issue might be a duplicate of existing issues. Please check:

• [FEATURE]: Add Go plan usage/balance API endpoint (rolling/weekly/monthly windows) #16017: Add Go plan usage/balance API endpoint (rolling/weekly/monthly windows) — nearly identical request for a programmatic API to query Go plan rolling/weekly/monthly usage windows

If you believe this was flagged incorrectly, please let a maintainer know.

[github-actions]

Thanks for updating the issue! It now meets our contributing guidelines. We appreciate the clear description and well-structured feature request.

[TiceWise]

Duplicate of #16017 — adding my support there.