feat(#1756): Add dynamic agent color styling system

pkg/tui/components/message/message.go

@@ -178,7 +178,7 @@ func (mv *messageModel) senderPrefix(sender string) string {
 	if sender == "" {
 		return ""
 	}
-	return styles.AgentBadgeStyle.MarginLeft(2).Render(sender) + "\n\n"
+	return styles.AgentBadgeStyleFor(sender).MarginLeft(2).Render(sender) + "\n\n"
 }
 
 // sameAgentAsPrevious returns true if the previous message was from the same agent

pkg/tui/components/sidebar/sidebar.go

@@ -1091,17 +1091,17 @@ func (m *model) agentInfo(contentWidth int) string {
 }
 
 func (m *model) renderAgentEntry(content *strings.Builder, agent runtime.AgentDetails, isCurrent bool, index, contentWidth int) {
+	agentStyle := styles.AgentAccentStyleFor(agent.Name)
 	var prefix string
 	if isCurrent {
 		if m.workingAgent == agent.Name {
-			// Style the spinner with the same green as the agent name
-			prefix = styles.TabAccentStyle.Render(m.spinner.View()) + " "
+			prefix = agentStyle.Render(m.spinner.View()) + " "
 		} else {
-			prefix = styles.TabAccentStyle.Render("▶") + " "
+			prefix = agentStyle.Render("▶") + " "
 		}
 	}
 	// Agent name
-	agentNameText := prefix + styles.TabAccentStyle.Render(agent.Name)
+	agentNameText := prefix + agentStyle.Render(agent.Name)
 	// Shortcut hint (^1, ^2, etc.) - show for agents 1-9
 	var shortcutHint string
 	if index >= 0 && index < 9 {

pkg/tui/components/tabbar/tab.go

@@ -1,9 +1,7 @@
 package tabbar
 
 import (
-	"fmt"
 	"image/color"
-	"math"
 
 	"charm.land/lipgloss/v2"
 
@@ -26,17 +24,6 @@ const (
 	// attentionIndicator is shown before the title when the tab needs attention,
 	// replacing the running indicator to signal that user action is required.
 	attentionIndicator = "! "
-	// mutedContrastStrength controls how much the muted foreground shifts
-	// away from the background (0.0 = invisible, 1.0 = full black/white).
-	mutedContrastStrength = 0.45
-	// minIndicatorContrast is the minimum WCAG contrast ratio required for
-	// semantic indicator colors (running dot, attention bang). If the themed
-	// color doesn't meet this threshold against the tab background, it is
-	// automatically boosted while preserving its hue.
-	minIndicatorContrast = 4.5
-	// maxBoostSteps limits the blend iterations in ensureContrast to avoid
-	// infinite loops on degenerate inputs.
-	maxBoostSteps = 20
 
 	// dragSourceColorBoost controls how much the drag source tab is blended toward
 	// the active tab colors when it is not the active tab.
@@ -67,106 +54,6 @@ func (t Tab) Width() int { return t.width }
 // and the close-button click area begins.
 func (t Tab) MainZoneEnd() int { return t.mainZoneEnd }
 
-// --- Color helpers ---
-
-// sRGBLuminance returns the relative luminance of an sRGB color using the
-// WCAG 2.x formula (linearized channel values, ITU-R BT.709 coefficients).
-func sRGBLuminance(r, g, b float64) float64 {
-	linearize := func(c float64) float64 {
-		if c <= 0.03928 {
-			return c / 12.92
-		}
-		return math.Pow((c+0.055)/1.055, 2.4)
-	}
-	return 0.2126*linearize(r) + 0.7152*linearize(g) + 0.0722*linearize(b)
-}
-
-// colorToLinear extracts normalized [0,1] sRGB components from a color.Color.
-func colorToLinear(c color.Color) (float64, float64, float64) {
-	r, g, b, _ := c.RGBA()
-	return float64(r) / 65535, float64(g) / 65535, float64(b) / 65535
-}
-
-// contrastRatio returns the WCAG 2.x contrast ratio between two colors.
-func contrastRatio(fg, bg color.Color) float64 {
-	r1, g1, b1 := colorToLinear(fg)
-	r2, g2, b2 := colorToLinear(bg)
-	l1 := sRGBLuminance(r1, g1, b1)
-	l2 := sRGBLuminance(r2, g2, b2)
-	lighter := max(l1, l2)
-	darker := min(l1, l2)
-	return (lighter + 0.05) / (darker + 0.05)
-}
-
-// toHexColor formats normalized [0,1] RGB components as a lipgloss color.
-func toHexColor(r, g, b float64) color.Color {
-	clamp := func(v float64) int {
-		if v < 0 {
-			return 0
-		}
-		if v > 1 {
-			return 255
-		}
-		return int(v * 255)
-	}
-	return lipgloss.Color(fmt.Sprintf("#%02x%02x%02x", clamp(r), clamp(g), clamp(b)))
-}
-
-// mutedContrastFg returns a foreground color that is visible but subtle against
-// the given background. It blends the background toward white (for dark bg) or
-// black (for light bg) by mutedContrastStrength.
-func mutedContrastFg(bg color.Color) color.Color {
-	rf, gf, bf := colorToLinear(bg)
-
-	// Perceived luminance for direction decision (BT.601 for perceptual balance).
-	lum := 0.299*rf + 0.587*gf + 0.114*bf
-
-	var tgt float64
-	if lum > 0.5 {
-		tgt = 0.0
-	} else {
-		tgt = 1.0
-	}
-
-	s := mutedContrastStrength
-	return toHexColor(rf+(tgt-rf)*s, gf+(tgt-gf)*s, bf+(tgt-bf)*s)
-}
-
-// ensureContrast returns fg unchanged if it already meets minIndicatorContrast
-// against bg. Otherwise it progressively blends fg toward white (on dark bg) or
-// black (on light bg) until the threshold is met, preserving the original hue.
-func ensureContrast(fg, bg color.Color) color.Color {
-	if contrastRatio(fg, bg) >= minIndicatorContrast {
-		return fg
-	}
-
-	rf, gf, bf := colorToLinear(fg)
-	bgR, bgG, bgB := colorToLinear(bg)
-	bgLum := sRGBLuminance(bgR, bgG, bgB)
-
-	// Blend toward white on dark backgrounds, toward black on light ones.
-	var tR, tG, tB float64
-	if bgLum > 0.5 {
-		tR, tG, tB = 0, 0, 0
-	} else {
-		tR, tG, tB = 1, 1, 1
-	}
-
-	for step := 1; step <= maxBoostSteps; step++ {
-		t := float64(step) / float64(maxBoostSteps)
-		nr := rf + (tR-rf)*t
-		ng := gf + (tG-gf)*t
-		nb := bf + (tB-bf)*t
-		candidate := toHexColor(nr, ng, nb)
-		if contrastRatio(candidate, bg) >= minIndicatorContrast {
-			return candidate
-		}
-	}
-
-	// Fallback: full contrast direction (should always meet the threshold).
-	return toHexColor(tR, tG, tB)
-}
-
 // dragRole describes a tab's role during a drag-and-drop operation.
 type dragRole int
 
@@ -178,9 +65,9 @@ const (
 
 // blendColors mixes two colors by the given ratio (0 = a, 1 = b).
 func blendColors(a, b color.Color, ratio float64) color.Color {
-	ar, ag, ab := colorToLinear(a)
-	br, bg, bb := colorToLinear(b)
-	return toHexColor(
+	ar, ag, ab := styles.ColorToRGB(a)
+	br, bg, bb := styles.ColorToRGB(b)
+	return styles.RGBToColor(
 		ar+(br-ar)*ratio,
 		ag+(bg-ag)*ratio,
 		ab+(bb-ab)*ratio,
@@ -225,7 +112,7 @@ func renderTab(info messages.TabInfo, maxTitleLen, animFrame int, role dragRole)
 	}
 
 	// Close button color derived from this tab's background.
-	closeFg := mutedContrastFg(bgColor)
+	closeFg := styles.MutedContrastFg(bgColor)
 
 	// Fade all foreground elements when this tab is a bystander during drag.
 	if role == dragRoleBystander {
@@ -250,13 +137,13 @@ func renderTab(info messages.TabInfo, maxTitleLen, animFrame int, role dragRole)
 	case info.NeedsAttention:
 		// Attention takes priority over running: replace the streaming dot
 		// with a warning-colored indicator so it's obvious the tab needs action.
-		attnFg := ensureContrast(styles.Warning, bgColor)
+		attnFg := styles.EnsureContrast(styles.Warning, bgColor)
 		if role == dragRoleBystander {
 			attnFg = blendColors(attnFg, bgColor, dragBystanderDimAmount)
 		}
 		content += lipgloss.NewStyle().Foreground(attnFg).Background(bgColor).Bold(true).Render(attentionIndicator)
 	case info.IsRunning && !info.IsActive:
-		runFg := ensureContrast(styles.TabAccentFg, bgColor)
+		runFg := styles.EnsureContrast(styles.TabAccentFg, bgColor)
 		if role == dragRoleBystander {
 			runFg = blendColors(runFg, bgColor, dragBystanderDimAmount)
 		}

pkg/tui/components/tabbar/tabbar.go

@@ -408,11 +408,11 @@ func (t *TabBar) View() string {
 	}
 
 	// Compute "+" and arrow colors dynamically from the terminal background.
-	chromeFg := mutedContrastFg(styles.Background)
+	chromeFg := styles.MutedContrastFg(styles.Background)
 	plusStyle := lipgloss.NewStyle().Foreground(chromeFg)
 	arrowStyle := lipgloss.NewStyle().Foreground(chromeFg)
 	// Attention arrow style: warning-colored and bold so off-screen attention tabs are obvious.
-	attnArrowStyle := lipgloss.NewStyle().Foreground(ensureContrast(styles.Warning, styles.Background)).Bold(true)
+	attnArrowStyle := lipgloss.NewStyle().Foreground(styles.EnsureContrast(styles.Warning, styles.Background)).Bold(true)
 
 	var line string
 	var cursor int
@@ -436,7 +436,7 @@ func (t *TabBar) View() string {
 	var dropLine string
 	visualDrop := noTab
 	if t.drag.active && !t.drag.isNoOp() {
-		dropFg := ensureContrast(styles.TabAccentFg, styles.Background)
+		dropFg := styles.EnsureContrast(styles.TabAccentFg, styles.Background)
 		dropLine = lipgloss.NewStyle().Foreground(dropFg).Render(dropIndicator)
 		visualDrop = t.drag.dropIdx
 	}

pkg/tui/components/tool/handoff/handoff.go

@@ -22,5 +22,5 @@ func render(msg *types.Message, _ spinner.Spinner, _ service.SessionStateReader,
 		return ""
 	}
 
-	return styles.AgentBadgeStyle.MarginLeft(2).Render(msg.Sender) + " ─► " + styles.AgentBadgeStyle.Render(params.Agent)
+	return styles.AgentBadgeStyleFor(msg.Sender).MarginLeft(2).Render(msg.Sender) + " ─► " + styles.AgentBadgeStyleFor(params.Agent).Render(params.Agent)
 }

pkg/tui/components/tool/transfertask/transfertask.go

@@ -25,9 +25,9 @@ func render(msg *types.Message, _ spinner.Spinner, _ service.SessionStateReader,
 		return ""
 	}
 
-	header := styles.AgentBadgeStyle.MarginLeft(2).Render(msg.Sender) +
+	header := styles.AgentBadgeStyleFor(msg.Sender).MarginLeft(2).Render(msg.Sender) +
 		" calls " +
-		styles.AgentBadgeStyle.Render(params.Agent)
+		styles.AgentBadgeStyleFor(params.Agent).Render(params.Agent)
 
 	// Calculate the icon with its margin
 	icon := styles.ToolCompletedIcon.Render("✓")

pkg/tui/service/sessionstate.go

@@ -3,6 +3,7 @@ package service
 import (
 	"github.com/docker/cagent/pkg/runtime"
 	"github.com/docker/cagent/pkg/session"
+	"github.com/docker/cagent/pkg/tui/styles"
 	"github.com/docker/cagent/pkg/tui/types"
 	"github.com/docker/cagent/pkg/userconfig"
 )
@@ -116,6 +117,12 @@ func (s *SessionState) AvailableAgents() []runtime.AgentDetails {
 
 func (s *SessionState) SetAvailableAgents(availableAgents []runtime.AgentDetails) {
 	s.availableAgents = availableAgents
+
+	names := make([]string, len(availableAgents))
+	for i, a := range availableAgents {
+		names[i] = a.Name
+	}
+	styles.SetAgentOrder(names)
 }
 
 func (s *SessionState) GetCurrentAgent() runtime.AgentDetails {