aiti-ctx-meter

❝ How much context is left — one glance at the battery tells you. ❞

Input-area context ratio-bar indicator: on desktop the compactLead vertical bar (immediately left of the compact button) shows context %, and the host's new small-screen slot modelInfoLead (the leading position of the ModelSelector in both the expanded input row and the InfoSheet model row) has it too. A pure client extension (vite-free, pure mjs + host render primitives); it works as soon as it is installed.

Capabilities

• Four-tier urgency color scale: the scale is driven by the host contextUrgency()'s CtxUrgency object (the extension holds zero display logic and only consumes it) — calm (<70 gray) / warn (70–90 yellow) / urgent (90–97 red) / critical (>97 deep red + breathing animation, disabled under prefers-reduced-motion)
• Compact three states: compact.isCompacting / compactQueued (the compact subset seam of streamingActions proposals) adds a tooltip note "compacting… / compact queued"
• Click: openSessionInfo() opens the host session stats panel (token detail + compact button) — slot extra callback first → pi-web.composer client service as fallback → when both are absent it degrades to not clickable
• Small screens (v0.1.4): shows only the bar itself without the number (the number stays in title/aria-label, so accessibility loses no information) — making room for the right-side buttons on the bottom row
• Pure-function kernel (barFillHeight/barPercentLabel/formatWindow/shouldShowPercentLabel/barTitleText) pinned by 5 groups of tests; no polling — percent arrives straight through the slot extra, driven by host state events

Contract and degradation

• Host slots: compactLead (hard) + modelInfoLead (soft) — when the host is too old and lacks the new slot, safeRegister console.warns and nothing is rendered; no throw, no blank screen
• Since v0.1.3 the sessionStats balance section is retired: balance/quota is unified under the host provider-usage panel (dedup), and this extension no longer takes over that slot

Origin

Launched 2026-09-13 (implemented; host passes through contextUsage/onSessionStatsPanelOpen + the lib/ext/types.ts contract).