diff --git a/test/unit/webview/mode-icons.test.ts b/test/unit/webview/mode-icons.test.ts
new file mode 100644
index 0000000..2ccaa81
--- /dev/null
+++ b/test/unit/webview/mode-icons.test.ts
@@ -0,0 +1,38 @@
+import { describe, it, expect } from "vitest";
+import { readFileSync } from "node:fs";
+import path from "node:path";
+
+/**
+ * The chat UI's mode picker (agent / ask / manual / plan / composer) must
+ * use standard VS Code codicon glyphs, not emoji. Emoji render differently
+ * across platforms and never match the editor theme's icon font.
+ */
+const ROOT = path.resolve(__dirname, "../../..");
+const MAIN_JS = readFileSync(
+  path.join(ROOT, "webview-ui/static/main.js"),
+  "utf8",
+);
+
+const MODE_SECTION = MAIN_JS.slice(
+  MAIN_JS.indexOf("const modeIcons"),
+  MAIN_JS.indexOf("const modeDescs"),
+);
+
+describe("mode picker icons use standard codicons", () => {
+  it("maps every mode to a codicon name (no emoji)", () => {
+    const names = ["agent", "ask", "manual", "plan", "composer"];
+    for (const mode of names) {
+      expect(MODE_SECTION, `mode '${mode}' must have a codicon entry`).toMatch(
+        new RegExp(`${mode}:\\s*'[a-z-]+'`),
+      );
+    }
+  });
+
+  it("does not use emoji glyphs in the mode icon map", () => {
+    expect(MODE_SECTION).not.toMatch(/[\u{1F300}-\u{1FAFF}]/u);
+  });
+
+  it("renders mode icons through the codicon() helper", () => {
+    expect(MAIN_JS).toMatch(/codicon\(modeIcons\[m\] \|\| 'circuit-board'\)/);
+  });
+});
diff --git a/webview-ui/static/main.js b/webview-ui/static/main.js
index e437efd..7fc1334 100644
--- a/webview-ui/static/main.js
+++ b/webview-ui/static/main.js
@@ -673,15 +673,30 @@
   const bottomBar = el('div', { class: 'bottom-bar' });
 
   // Mode picker — styled popup replacing native <select>.
-  const modeIcons = { agent: '⚙', ask: '💬', manual: '🛡', plan: '📋', composer: '🎼' };
+  // Standard VS Code codicons (not emoji) so they match the theme's icon font.
+  const modeIcons = {
+    agent: 'circuit-board',
+    ask: 'comment-discussion',
+    manual: 'shield',
+    plan: 'list-unordered',
+    composer: 'multiple-windows',
+  };
   const modeDescs = {
-    agent:    '🔴 Autonomous — reads & edits files, runs commands',
-    ask:      '🟢 Read-only — answers questions, never edits files',
-    manual:   '🟡 Step-by-step — asks approval before every action',
-    plan:     '🟡 Plan only — researches and proposes, no file changes',
-    composer: '🔴 Multi-file — edits multiple files with diff review',
+    agent:    'Autonomous — reads & edits files, runs commands',
+    ask:      'Read-only — answers questions, never edits files',
+    manual:   'Step-by-step — asks approval before every action',
+    plan:     'Plan only — researches and proposes, no file changes',
+    composer: 'Multi-file — edits multiple files with diff review',
   };
-  const modePickerBtn = el('button', { class: 'mode-picker-btn' }, [`${modeIcons[state.mode] || '⚙'} ${state.mode.charAt(0).toUpperCase() + state.mode.slice(1)} ▾`]);
+  /** Label for a mode: codicon glyph + capitalized name + caret. */
+  function modeLabel(m) {
+    const span = el('span', { class: 'mode-btn-label' });
+    span.append(codicon(modeIcons[m] || 'circuit-board'));
+    span.append(document.createTextNode(` ${m.charAt(0).toUpperCase() + m.slice(1)} ▾`));
+    return span;
+  }
+  const modePickerBtn = el('button', { class: 'mode-picker-btn' });
+  modePickerBtn.append(modeLabel(state.mode));
   const modePickerPopup = el('div', { class: 'mode-picker-popup', hidden: 'true' });
   modePickerBtn.addEventListener('click', (ev) => {
     ev.stopPropagation();
@@ -693,7 +708,7 @@
         modeTooltipShown = true;
         sessionStorage.setItem('champ-mode-tip', 'true');
         const tip = el('div', { class: 'mode-tip' }, [
-          '🟢 Ask = read-only safe   🟡 Plan/Manual = supervised   🔴 Agent/Composer = edits files'
+          'Ask = read-only safe   Plan/Manual = supervised   Agent/Composer = edits files'
         ]);
         modePickerPopup.insertBefore(tip, modePickerPopup.firstChild);
       }
@@ -709,7 +724,8 @@
     modePickerPopup.innerHTML = '';
     for (const m of ['agent', 'ask', 'manual', 'plan', 'composer']) {
       const row = el('div', { class: `mode-row${m === state.mode ? ' active' : ''}` });
-      const icon = el('span', { class: 'mode-icon' }, [modeIcons[m] || '']);
+      const icon = el('span', { class: 'mode-icon' });
+      icon.append(codicon(modeIcons[m] || 'circuit-board'));
       const textCol = el('div', { class: 'mode-text' });
       const nameEl = el('span', { class: 'mode-name' }, [m.charAt(0).toUpperCase() + m.slice(1)]);
       const descEl = el('span', { class: 'mode-desc' }, [modeDescs[m] || '']);
@@ -723,7 +739,8 @@
       row.addEventListener('click', () => {
         state.mode = m;
         vscode.postMessage({ type: 'setMode', mode: m });
-        modePickerBtn.textContent = `${modeIcons[m]} ${m.charAt(0).toUpperCase() + m.slice(1)} ▾`;
+        modePickerBtn.textContent = '';
+        modePickerBtn.append(modeLabel(m));
         modePickerPopup.setAttribute('hidden', 'true');
         if (state.messages.length === 0) renderEmptyState();
       });