diff --git a/packages/dashboard/app/components/TaskChatTab.css b/packages/dashboard/app/components/TaskChatTab.css
index 15f5632942..69df5a020d 100644
--- a/packages/dashboard/app/components/TaskChatTab.css
+++ b/packages/dashboard/app/components/TaskChatTab.css
@@ -377,6 +377,9 @@ FN-6604 corrects the FN-6507 no-op where var(--space-lg) resolved to the same 16
 
 FNXC:TaskDetailChat 2026-06-18-06:36:
 FN-6639 corrects the FN-6604 sizing because var(--space-xl) rendered a 24px glyph that filled only about 60% of the 40px button and still looked too small on mobile. Use var(--space-2xl) so Send and Loader2 render at 32px, about 80% fill, on desktop and mobile while preserving the tap box alignment.
+
+FNXC:TaskDetailChat 2026-06-18-12:00:
+FN-6660 corrects the repeated mobile sizing misses from FN-6507, FN-6604, and FN-6639: those passes only grew the glyph token inside a fixed 40px box, so the mobile affordance was never larger than desktop and still felt too small. Grow only the mobile box to calc(var(--space-2xl) + var(--space-lg)) and the mobile glyph to calc(var(--space-2xl) + var(--space-sm)), roughly 83% fill, while raising the mobile composer textarea min-height to the same 48px token sum for bottom alignment. Desktop stays intentionally unchanged.
 */
 .task-chat-send {
   --btn-icon-size: var(--space-2xl);
@@ -479,9 +482,15 @@ FN-6639 corrects the FN-6604 sizing because var(--space-xl) rendered a 24px glyp
     gap: var(--space-xs);
   }
 
+  .task-chat-input {
+    min-height: calc(var(--space-2xl) + var(--space-lg));
+  }
+
   .task-chat-send {
-    --btn-icon-size: var(--space-2xl);
-    inline-size: calc(var(--space-2xl) + var(--space-sm));
-    min-inline-size: calc(var(--space-2xl) + var(--space-sm));
+    --btn-icon-size: calc(var(--space-2xl) + var(--space-sm));
+    inline-size: calc(var(--space-2xl) + var(--space-lg));
+    min-inline-size: calc(var(--space-2xl) + var(--space-lg));
+    block-size: calc(var(--space-2xl) + var(--space-lg));
+    min-block-size: calc(var(--space-2xl) + var(--space-lg));
   }
 }
diff --git a/packages/dashboard/app/components/__tests__/TaskChatTab.test.tsx b/packages/dashboard/app/components/__tests__/TaskChatTab.test.tsx
index 7f305c66c1..35e87a0c24 100644
--- a/packages/dashboard/app/components/__tests__/TaskChatTab.test.tsx
+++ b/packages/dashboard/app/components/__tests__/TaskChatTab.test.tsx
@@ -2072,24 +2072,32 @@ describe("TaskChatTab", () => {
     const sendRule = getCssRuleBlock(css, ".task-chat-send");
     const mobileCss = getCssAfter(css, "@media (max-width: 768px)");
     const mobileSendRule = getCssRuleBlock(mobileCss, ".task-chat-send");
+    const mobileInputRule = getCssRuleBlock(mobileCss, ".task-chat-input");
     const tokenValues = getRootTokenPxValues(sharedStyles);
     const defaultIconSizePx = tokenValues["--icon-size-md"];
     const desktopIconSizePx = resolveCssPxToken(getCssDeclaration(sendRule, "--btn-icon-size"), tokenValues);
-    const mobileIconSizePx = resolveCssPxToken(getCssDeclaration(mobileSendRule, "--btn-icon-size"), tokenValues);
+    const mobileIconSizePx = resolveCssCalcSumPx(getCssDeclaration(mobileSendRule, "--btn-icon-size"), tokenValues);
     const desktopBoxSizePx = resolveCssCalcSumPx(getCssDeclaration(sendRule, "inline-size"), tokenValues);
     const mobileBoxSizePx = resolveCssCalcSumPx(getCssDeclaration(mobileSendRule, "inline-size"), tokenValues);
+    const mobileInputMinHeightPx = resolveCssCalcSumPx(getCssDeclaration(mobileInputRule, "min-height"), tokenValues);
 
     expect(defaultIconSizePx).toBe(16);
     expect(desktopIconSizePx).toBeGreaterThan(defaultIconSizePx);
     expect(mobileIconSizePx).toBeGreaterThan(defaultIconSizePx);
+    expect(mobileBoxSizePx).toBeGreaterThan(desktopBoxSizePx);
+    expect(mobileIconSizePx).toBeGreaterThan(desktopIconSizePx);
     expect(desktopIconSizePx / desktopBoxSizePx).toBeGreaterThanOrEqual(0.75);
-    expect(mobileIconSizePx / mobileBoxSizePx).toBeGreaterThanOrEqual(0.75);
+    expect(mobileIconSizePx / mobileBoxSizePx).toBeGreaterThanOrEqual(0.8);
+    expect(mobileInputMinHeightPx).toBe(mobileBoxSizePx);
     expect(sendRule).toContain("inline-size: calc(var(--space-2xl) + var(--space-sm))");
     expect(sendRule).toContain("min-inline-size: calc(var(--space-2xl) + var(--space-sm))");
     expect(sendRule).toContain("block-size: calc(var(--space-2xl) + var(--space-sm))");
     expect(sendRule).toContain("min-block-size: calc(var(--space-2xl) + var(--space-sm))");
-    expect(mobileSendRule).toContain("inline-size: calc(var(--space-2xl) + var(--space-sm))");
-    expect(mobileSendRule).toContain("min-inline-size: calc(var(--space-2xl) + var(--space-sm))");
+    expect(mobileSendRule).toContain("inline-size: calc(var(--space-2xl) + var(--space-lg))");
+    expect(mobileSendRule).toContain("min-inline-size: calc(var(--space-2xl) + var(--space-lg))");
+    expect(mobileSendRule).toContain("block-size: calc(var(--space-2xl) + var(--space-lg))");
+    expect(mobileSendRule).toContain("min-block-size: calc(var(--space-2xl) + var(--space-lg))");
+    expect(mobileInputRule).toContain("min-height: calc(var(--space-2xl) + var(--space-lg))");
   });
 
   it("keeps task chat timestamp styling tokenized and mobile-safe", () => {
@@ -2132,8 +2140,8 @@ describe("TaskChatTab", () => {
     expect(mobileComposerRule).toContain("align-items: flex-end");
     expect(mobileComposerRule).not.toContain("flex-direction: column");
     expect(mobileComposerRule).not.toContain("align-items: stretch");
-    expect(mobileSendRule).toContain("--btn-icon-size: var(--space-2xl)");
-    expect(mobileSendRule).toContain("inline-size: calc(var(--space-2xl) + var(--space-sm))");
+    expect(mobileSendRule).toContain("--btn-icon-size: calc(var(--space-2xl) + var(--space-sm))");
+    expect(mobileSendRule).toContain("inline-size: calc(var(--space-2xl) + var(--space-lg))");
     expect(css).toContain(".task-chat-tool-group-summary");
     expect(css).toContain(".task-chat-tool-group-names");
     expect(css).toContain(".task-chat-tool-group-error-count");