feat(ui): add context meter indicator

Replace duplicated Used/Avail pills with a shared ContextMeter component and add a small filled context usage indicator for quick scanning.

packages/ui/src/components/context-meter.tsx

@@ -0,0 +1,123 @@
+import type { Component } from "solid-js"
+
+interface ContextMeterProps {
+  usedTokens: number
+  availableTokens: number | null
+  formatTokens: (value: number) => string
+  usedLabel: string
+  availableLabel: string
+  class?: string
+}
+
+const LABEL_CLASS = "uppercase text-[10px] tracking-wide text-muted"
+
+function clamp(value: number, min: number, max: number) {
+  return Math.min(Math.max(value, min), max)
+}
+
+function resolveFillColor(percent: number): string {
+  if (percent >= 0.8) return "var(--status-error)"
+  if (percent >= 0.6) return "var(--status-warning)"
+  return "var(--status-success)"
+}
+
+export const ContextMeter: Component<ContextMeterProps> = (props) => {
+  const hasAvailable = () => typeof props.availableTokens === "number" && props.availableTokens > 0
+  const used = () => (typeof props.usedTokens === "number" && props.usedTokens > 0 ? props.usedTokens : 0)
+  const available = () => (hasAvailable() ? (props.availableTokens as number) : null)
+
+  const percent = () => {
+    const usedValue = used()
+    const availableValue = available()
+    if (availableValue === null || availableValue <= 0) return null
+
+    // Heuristic: if available >= used, treat it like a capacity/limit.
+    // Otherwise treat it like remaining tokens.
+    const ratio = availableValue >= usedValue ? usedValue / availableValue : usedValue / (usedValue + availableValue)
+    return clamp(ratio, 0, 1)
+  }
+
+  const fillColor = () => {
+    const value = percent()
+    if (value === null) return "var(--border-base)"
+    return resolveFillColor(value)
+  }
+
+  const percentLabel = () => {
+    const value = percent()
+    if (value === null) return "--"
+    return `${Math.round(value * 100)}%`
+  }
+
+  const containerClass =
+    `inline-flex items-center gap-2 rounded-full border border-base px-2 py-0.5 text-xs text-primary ${props.class ?? ""}`
+
+  function polarToCartesian(cx: number, cy: number, r: number, angleDeg: number) {
+    const rad = (angleDeg * Math.PI) / 180
+    return {
+      x: cx + r * Math.cos(rad),
+      y: cy + r * Math.sin(rad),
+    }
+  }
+
+  function describeSectorPath(cx: number, cy: number, r: number, startAngle: number, endAngle: number) {
+    const start = polarToCartesian(cx, cy, r, startAngle)
+    const end = polarToCartesian(cx, cy, r, endAngle)
+    const delta = ((endAngle - startAngle) % 360 + 360) % 360
+    const largeArc = delta > 180 ? 1 : 0
+
+    return `M ${cx} ${cy} L ${start.x} ${start.y} A ${r} ${r} 0 ${largeArc} 1 ${end.x} ${end.y} Z`
+  }
+
+  const circle = () => {
+    const value = percent()
+    const size = 22
+    const r = 9
+    const cx = 11
+    const cy = 11
+    const progress = value === null ? 0 : value
+    const startAngle = -90
+    const endAngle = startAngle + progress * 360
+    const isFull = progress >= 0.999
+    const hasFill = progress > 0.001
+
+    const sectorPath = hasFill && !isFull ? describeSectorPath(cx, cy, r, startAngle, endAngle) : null
+
+    return (
+      <svg
+        width={size}
+        height={size}
+        viewBox="0 0 22 22"
+        aria-hidden="true"
+        style={{ flex: "0 0 auto" }}
+      >
+        <circle cx={String(cx)} cy={String(cy)} r={String(r)} fill="var(--surface-secondary)" />
+        <circle cx={String(cx)} cy={String(cy)} r={String(r)} fill="none" stroke="var(--border-base)" stroke-width="1" />
+        {isFull ? (
+          <circle cx={String(cx)} cy={String(cy)} r={String(r)} fill={fillColor()} opacity="0.95" />
+        ) : sectorPath ? (
+          <path d={sectorPath} fill={fillColor()} opacity="0.95" />
+        ) : null}
+      </svg>
+    )
+  }
+
+  const tooltipText = () => `Context Used: ${percentLabel()}`
+
+  return (
+    <div class="inline-flex items-center gap-2" title={tooltipText()}>
+      {circle()}
+      <div class={containerClass}>
+        <span class={LABEL_CLASS}>{props.usedLabel}</span>
+        <span class="font-semibold text-primary tabular-nums">{props.formatTokens(used())}</span>
+        <span class="text-muted">/</span>
+        <span class={LABEL_CLASS}>{props.availableLabel}</span>
+        <span class="font-semibold text-primary tabular-nums">
+          {available() !== null ? props.formatTokens(available() as number) : "--"}
+        </span>
+      </div>
+    </div>
+  )
+}
+
+export default ContextMeter

packages/ui/src/components/instance/instance-shell2.tsx

@@ -29,6 +29,7 @@ import PermissionNotificationBanner from "../permission-notification-banner"
 import PermissionApprovalModal from "../permission-approval-modal"
 import SessionView from "../session/session-view"
 import { formatTokenTotal } from "../../lib/formatters"
+import ContextMeter from "../context-meter"
 import { sseManager } from "../../lib/sse-manager"
 import { getLogger } from "../../lib/logger"
 import { serverApi } from "../../lib/api-client"
@@ -349,16 +350,6 @@ const InstanceShell2: Component<InstanceShellProps> = (props) => {
     measureDrawerHost,
   })
 
-  const formattedUsedTokens = () => formatTokenTotal(tokenStats().used)
-
-
-  const formattedAvailableTokens = () => {
-    const avail = tokenStats().avail
-    if (typeof avail === "number") {
-      return formatTokenTotal(avail)
-    }
-    return "--"
-  }
 
   const renderLeftPanel = () => {
     if (leftPinned()) {
@@ -661,20 +652,15 @@ const InstanceShell2: Component<InstanceShellProps> = (props) => {
                     </Show>
                   </div>
 
-                  <div class="flex flex-wrap items-center justify-center gap-2 pb-1">
-                    <div class="inline-flex items-center gap-1 rounded-full border border-base px-2 py-0.5 text-xs text-primary">
-                      <span class="uppercase text-[10px] tracking-wide text-muted">
-                        {t("instanceShell.metrics.usedLabel")}
-                      </span>
-                      <span class="font-semibold text-primary">{formattedUsedTokens()}</span>
+                    <div class="flex flex-wrap items-center justify-center gap-2 pb-1">
+                      <ContextMeter
+                        usedTokens={tokenStats().used}
+                        availableTokens={tokenStats().avail}
+                        formatTokens={formatTokenTotal}
+                        usedLabel={t("instanceShell.metrics.usedLabel")}
+                        availableLabel={t("instanceShell.metrics.availableLabel")}
+                      />
                     </div>
-                    <div class="inline-flex items-center gap-1 rounded-full border border-base px-2 py-0.5 text-xs text-primary">
-                      <span class="uppercase text-[10px] tracking-wide text-muted">
-                        {t("instanceShell.metrics.availableLabel")}
-                      </span>
-                      <span class="font-semibold text-primary">{formattedAvailableTokens()}</span>
-                    </div>
-                  </div>
                 </div>
               }
             >
@@ -693,18 +679,13 @@ const InstanceShell2: Component<InstanceShellProps> = (props) => {
                 </Show>
 
                 <Show when={!showingInfoView()}>
-                  <div class="inline-flex items-center gap-1 rounded-full border border-base px-2 py-0.5 text-xs text-primary">
-                    <span class="uppercase text-[10px] tracking-wide text-muted">
-                      {t("instanceShell.metrics.usedLabel")}
-                    </span>
-                    <span class="font-semibold text-primary">{formattedUsedTokens()}</span>
-                  </div>
-                  <div class="inline-flex items-center gap-1 rounded-full border border-base px-2 py-0.5 text-xs text-primary">
-                    <span class="uppercase text-[10px] tracking-wide text-muted">
-                      {t("instanceShell.metrics.availableLabel")}
-                    </span>
-                    <span class="font-semibold text-primary">{formattedAvailableTokens()}</span>
-                  </div>
+                  <ContextMeter
+                    usedTokens={tokenStats().used}
+                    availableTokens={tokenStats().avail}
+                    formatTokens={formatTokenTotal}
+                    usedLabel={t("instanceShell.metrics.usedLabel")}
+                    availableLabel={t("instanceShell.metrics.availableLabel")}
+                  />
                 </Show>
 
                 <div class="ml-auto flex items-center session-header-hints">

packages/ui/src/components/message-list-header.tsx

@@ -1,10 +1,8 @@
 import { Show } from "solid-js"
 import Kbd from "./kbd"
+import ContextMeter from "./context-meter"
 import { useI18n } from "../lib/i18n"
 
-const METRIC_CHIP_CLASS = "inline-flex items-center gap-1 rounded-full border border-base px-2 py-0.5 text-xs text-primary"
-const METRIC_LABEL_CLASS = "uppercase text-[10px] tracking-wide text-muted"
-
 interface MessageListHeaderProps {
   usedTokens: number
 
@@ -21,7 +19,6 @@ export default function MessageListHeader(props: MessageListHeaderProps) {
   const { t } = useI18n()
 
   const hasAvailableTokens = () => typeof props.availableTokens === "number"
-  const availableDisplay = () => (hasAvailableTokens() ? props.formatTokens(props.availableTokens as number) : "--")
 
   return (
     <div class={props.forceCompactStatusLayout ? "connection-status connection-status--compact" : "connection-status"}>
@@ -40,14 +37,13 @@ export default function MessageListHeader(props: MessageListHeaderProps) {
 
       <div class="connection-status-text connection-status-info">
         <div class="connection-status-usage">
-          <div class={METRIC_CHIP_CLASS}>
-            <span class={METRIC_LABEL_CLASS}>{t("messageListHeader.metrics.usedLabel")}</span>
-            <span class="font-semibold text-primary">{props.formatTokens(props.usedTokens)}</span>
-          </div>
-          <div class={METRIC_CHIP_CLASS}>
-            <span class={METRIC_LABEL_CLASS}>{t("messageListHeader.metrics.availableLabel")}</span>
-            <span class="font-semibold text-primary">{hasAvailableTokens() ? availableDisplay() : "--"}</span>
-          </div>
+          <ContextMeter
+            usedTokens={props.usedTokens}
+            availableTokens={hasAvailableTokens() ? (props.availableTokens as number) : null}
+            formatTokens={props.formatTokens}
+            usedLabel={t("messageListHeader.metrics.usedLabel")}
+            availableLabel={t("messageListHeader.metrics.availableLabel")}
+          />
         </div>
       </div>