feat(tui): style bg subagent footer (#1288)

src/cli/components/BlinkingSpinner.tsx

@@ -0,0 +1,95 @@
+import { memo, useEffect, useState } from "react";
+import stringWidth from "string-width";
+import { useAnimation } from "../contexts/AnimationContext.js";
+import { colors } from "./colors.js";
+import { Text } from "./Text";
+
+export const BRAILLE_SPINNER_FRAMES = [
+  "⠋",
+  "⠙",
+  "⠹",
+  "⠸",
+  "⠼",
+  "⠴",
+  "⠦",
+  "⠧",
+  "⠇",
+  "⠏",
+] as const;
+
+/**
+ * Frame-based spinner for lightweight status indicators in the TUI.
+ */
+export const BlinkingSpinner = memo(
+  ({
+    color = colors.tool.pending,
+    frames = BRAILLE_SPINNER_FRAMES,
+    intervalMs = 90,
+    pulse = true,
+    pulseIntervalMs = 300,
+    width = 1,
+    marginRight = 0,
+    shouldAnimate: shouldAnimateProp,
+  }: {
+    color?: string;
+    frames?: readonly string[];
+    intervalMs?: number;
+    pulse?: boolean;
+    pulseIntervalMs?: number;
+    width?: number;
+    marginRight?: number;
+    shouldAnimate?: boolean;
+  }) => {
+    const { shouldAnimate: shouldAnimateContext } = useAnimation();
+    const shouldAnimate =
+      shouldAnimateProp === false ? false : shouldAnimateContext;
+
+    const [frameIndex, setFrameIndex] = useState(0);
+    const [blinkOn, setBlinkOn] = useState(true);
+
+    useEffect(() => {
+      if (!shouldAnimate || frames.length === 0) return;
+
+      const timer = setInterval(() => {
+        setFrameIndex((v) => (v + 1) % frames.length);
+      }, intervalMs);
+
+      return () => clearInterval(timer);
+    }, [shouldAnimate, frames, intervalMs]);
+
+    useEffect(() => {
+      if (!shouldAnimate || !pulse) return;
+
+      const timer = setInterval(() => {
+        setBlinkOn((v) => !v);
+      }, pulseIntervalMs);
+
+      return () => clearInterval(timer);
+    }, [shouldAnimate, pulse, pulseIntervalMs]);
+
+    const frame =
+      frames.length > 0
+        ? shouldAnimate
+          ? (frames[frameIndex] ?? frames[0] ?? "·")
+          : (frames[0] ?? "·")
+        : "·";
+
+    const frameWidth = stringWidth(frame);
+    const targetWidth = Math.max(1, width);
+    const totalPadding = Math.max(0, targetWidth - frameWidth);
+    const leftPadding = Math.floor(totalPadding / 2);
+    const rightPadding = totalPadding - leftPadding;
+    const paddedFrame =
+      " ".repeat(leftPadding) + frame + " ".repeat(rightPadding);
+
+    const output = paddedFrame + " ".repeat(Math.max(0, marginRight));
+
+    return (
+      <Text color={color} dimColor={pulse && !blinkOn}>
+        {output}
+      </Text>
+    );
+  },
+);
+
+BlinkingSpinner.displayName = "BlinkingSpinner";

src/cli/components/InputRich.tsx

@@ -37,7 +37,7 @@ import {
   getSnapshot as getSubagentSnapshot,
   subscribe as subscribeToSubagents,
 } from "../helpers/subagentState.js";
-import { BlinkDot } from "./BlinkDot.js";
+import { BlinkingSpinner } from "./BlinkingSpinner.js";
 import { colors } from "./colors";
 import { InputAssist } from "./InputAssist";
 import { PasteAwareTextInput } from "./PasteAwareTextInput";
@@ -267,7 +267,23 @@ const InputFooter = memo(function InputFooter({
 
   // Subscribe to subagent state for background agent indicators
   useSyncExternalStore(subscribeToSubagents, getSubagentSnapshot);
-  const backgroundAgents = [...getActiveBackgroundAgents()];
+  const backgroundAgents = [
+    ...getActiveBackgroundAgents(),
+    // DEBUG: hardcoded agent for local footer testing
+    {
+      id: "debug-bg-agent",
+      type: "Reflection",
+      description: "Debug background agent",
+      status: "running" as const,
+      agentURL: "https://app.letta.com/chat/agent-debug-link",
+      toolCalls: [],
+      totalTokens: 0,
+      durationMs: 0,
+      startTime: Date.now() - 12_000,
+      isBackground: true,
+      silent: true,
+    },
+  ];
 
   // Tick counter for elapsed time display (only active when background agents exist)
   const [, setTick] = useState(0);
@@ -306,10 +322,10 @@ const InputFooter = memo(function InputFooter({
   const rightPrefixSpaces = Math.max(0, rightColumnWidth - rightTextLength);
 
   // When bg agents are active, widen the right column to fit the indicator + label
-  // "· " (2) + parts text + " │ " (3)
+  // spinner slot (3) + parts text + " │ " (3)
   const bgIndicatorWidth =
     backgroundAgents.length > 0
-      ? 2 +
+      ? 3 +
         bgAgentParts.reduce(
           (acc, p, i) =>
             acc +
@@ -416,21 +432,30 @@ const InputFooter = memo(function InputFooter({
           ))
         ) : backgroundAgents.length > 0 ? (
           <Text>
-            <BlinkDot color={colors.tool.pending} symbol="·" />
-            <Text dimColor> </Text>
+            <BlinkingSpinner
+              color={colors.bgSubagent.spinner}
+              width={2}
+              marginRight={0}
+              pulseIntervalMs={400}
+            />
             {bgAgentParts.map((part, i) => (
               <Text key={`bg-agent-${part}`}>
                 {i > 0 && (
-                  <Text key={`bg-agent-indicator-${part}`} dimColor>
+                  <Text
+                    key={`bg-agent-indicator-${part}`}
+                    color={colors.bgSubagent.label}
+                  >
                     {" · "}
                   </Text>
                 )}
                 {part.chatUrl ? (
-                  <Link url={part.chatUrl}>
-                    <Text dimColor>{part.typeLabel}</Text>
+                  <Link url={part.chatUrl} fallback={false}>
+                    <Text color={colors.bgSubagent.label}>
+                      {part.typeLabel}
+                    </Text>
                   </Link>
                 ) : (
-                  <Text dimColor>{part.typeLabel}</Text>
+                  <Text color={colors.bgSubagent.label}>{part.typeLabel}</Text>
                 )}
                 <Text dimColor> ({part.elapsed})</Text>
               </Text>

src/cli/components/colors.ts

@@ -161,6 +161,12 @@ const _colors = {
     hint: "#808080", // Grey to match Ink's dimColor
   },
 
+  // Background subagent
+  bgSubagent: {
+    label: "#87af87",
+    spinner: "#5faf5f",
+  },
+
   // Info/modal views
   info: {
     border: brandColors.primaryAccent,