Statusline: expose per-model weekly rate limit in the payload (rate_limits only carries account-wide five_hour/seven_day)

Feature request

Expose a model-scoped weekly rate limit in the statusline stdin payload. Today rate_limits carries only the two account-wide windows:

"rate_limits": {
  "five_hour": { "used_percentage": 33, "resets_at": 1786506600 },
  "seven_day": { "used_percentage": 13, "resets_at": 1786874400 }
}

(measured live on 2.1.228, Windows 11, Team plan)

Why

/usage now displays a per-model weekly bar in addition to the overall weekly — e.g. on Team plans where Fable 5 is capped at a share of the weekly limit (promotional access article), /usage shows "Fable 5 — 24%" while the payload's seven_day.used_percentage is 13%. The two numbers differ in both scope (one model vs. account-wide) and denominator (the model cap vs. the full weekly limit), and only the account-wide one reaches statusline scripts.

Practical consequence: a custom statusline cannot render the number users actually compare against /usage's per-model bar. We shipped an org statusline that displayed the weekly next to the model name on Fable sessions; users read it as the Fable-scoped figure, it diverged from /usage (13% vs 24%), and we had to revert the feature because the payload has no honest source for the per-model value.

Proposal

Add per-model (or per-tier) weekly usage to rate_limits when the plan has a model-scoped cap, following the existing absent-key convention (key absent when the plan has no per-model cap), e.g.:

"rate_limits": {
  "five_hour":  { "used_percentage": 33, "resets_at": 1786506600 },
  "seven_day":  { "used_percentage": 13, "resets_at": 1786874400 },
  "seven_day_by_model": {
    "claude-fable-5": { "used_percentage": 24, "resets_at": 1786874400 }
  }
}

A single key scoped to the session's current model would also cover the main use case (rendering the current model's own weekly next to the model name).

Environment

• Claude Code 2.1.228
• Windows 11 (also relevant on macOS/Linux — the payload is platform-independent)
• Team plan (Standard + Premium seats), Fable 5 weekly cap active