diff --git a/static/index.html b/static/index.html
index a19b4389..0f6af92a 100644
--- a/static/index.html
+++ b/static/index.html
@@ -473,7 +473,7 @@
       <div id="queueCard" class="queue-card" role="region" aria-label="Queued messages" aria-live="polite">
         <div id="queueChips" class="queue-card-inner"></div>
       </div>
-      <div class="approval-card" id="approvalCard" role="alertdialog" aria-labelledby="approvalHeading" aria-describedby="approvalDesc">
+      <div class="approval-card" id="approvalCard" role="alertdialog" aria-labelledby="approvalHeading" aria-describedby="approvalDesc" hidden aria-hidden="true" inert>
         <div class="approval-inner">
           <div class="approval-header">
             <svg width="14" height="14" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2"><path d="M10.29 3.86L1.82 18a2 2 0 0 0 1.71 3h16.94a2 2 0 0 0 1.71-3L13.71 3.86a2 2 0 0 0-3.42 0z"/><line x1="12" y1="9" x2="12" y2="13"/><line x1="12" y1="17" x2="12.01" y2="17"/></svg>
@@ -509,7 +509,7 @@
           </div>
         </div>
       </div>
-      <div class="clarify-card" id="clarifyCard" role="dialog" aria-labelledby="clarifyHeading" aria-describedby="clarifyQuestion clarifyHint">
+      <div class="clarify-card" id="clarifyCard" role="dialog" aria-labelledby="clarifyHeading" aria-describedby="clarifyQuestion clarifyHint" hidden aria-hidden="true" inert>
         <div class="clarify-inner">
           <div class="clarify-header">
             <svg width="14" height="14" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2"><path d="M12 17h.01"/><path d="M9.09 9a3 3 0 1 1 5.82 1c0 2-3 2-3 4"/><circle cx="12" cy="12" r="10"/></svg>
diff --git a/static/messages.js b/static/messages.js
index 686b05c2..12369613 100644
--- a/static/messages.js
+++ b/static/messages.js
@@ -6066,6 +6066,26 @@ const APPROVAL_MIN_VISIBLE_MS = 30000;
 
 // showApprovalCard moved above respondApproval
 
+function _setPromptFlyoutHidden(card, hidden) {
+  if (!card) return;
+  if (hidden) {
+    card.setAttribute("aria-hidden", "true");
+    card.setAttribute("inert", "");
+    const markHidden = () => {
+      if (!card.classList || !card.classList.contains("visible")) card.hidden = true;
+    };
+    if (typeof setTimeout === "function") setTimeout(markHidden, 450);
+    else markHidden();
+    return;
+  }
+  card.hidden = false;
+  card.setAttribute("aria-hidden", "false");
+  card.removeAttribute("inert");
+  // Force the unhidden, pre-visible state to be observed so the existing
+  // transform/opacity transition can still animate when `.visible` is added.
+  void card.offsetHeight;
+}
+
 function _clearApprovalHideTimer() {
   if (_approvalHideTimer) {
     clearTimeout(_approvalHideTimer);
@@ -6099,6 +6119,7 @@ function hideApprovalCard(force=false) {
   _resetApprovalCardState();
   card.classList.remove("visible");
   card.classList.remove("collapsed");
+  _setPromptFlyoutHidden(card, true);
   _syncApprovalTranscriptSpace(null);
   $("approvalCmd").textContent = "";
   $("approvalDesc").textContent = "";
@@ -6261,6 +6282,7 @@ function showApprovalCard(pending, pendingCount) {
     responding ? _approvalResponding.choice : null,
     responding,
   );
+  _setPromptFlyoutHidden(card, false);
   card.classList.add("visible");
   _syncApprovalCollapseButton(card);
   _syncApprovalTranscriptSpace(card, {immediate: true});
@@ -7038,6 +7060,7 @@ function _ensureClarifyCardDom() {
   card.setAttribute("role", "dialog");
   card.setAttribute("aria-labelledby", "clarifyHeading");
   card.setAttribute("aria-describedby", "clarifyQuestion clarifyHint");
+  _setPromptFlyoutHidden(card, true);
   card.innerHTML = `
     <div class="clarify-inner">
       <div class="clarify-header">
@@ -7250,6 +7273,7 @@ function hideClarifyCard(force=false, reason="dismissed") {
   _clarifySessionId = null;
   _resetClarifyCardState();
   card.classList.remove("visible");
+  _setPromptFlyoutHidden(card, true);
   _syncClarifyTranscriptSpace(null);
   if (typeof unlockComposerForClarify === "function") unlockComposerForClarify();
   $("clarifyQuestion").textContent = "";
@@ -7368,6 +7392,7 @@ function showClarifyCard(pending) {
   }
   _clarifySetControlsDisabled(false, false);
   _ensureClarifyResizeListener();
+  _setPromptFlyoutHidden(card, false);
   card.classList.add("visible");
   _syncClarifyCollapseButton(card);
   _syncClarifyTranscriptSpace(card, {immediate: true});
diff --git a/static/style.css b/static/style.css
index 410e2f2c..73de7060 100644
--- a/static/style.css
+++ b/static/style.css
@@ -1947,6 +1947,7 @@
   .composer-flyout{position:relative;height:0;z-index:1;}
   .composer-wrap.terminal-dock-visible .composer-flyout{z-index:4;}
   /* ── Approval card ── */
+  .approval-card[hidden],.clarify-card[hidden]{display:none!important;}
   .approval-card{position:absolute;left:0;right:0;bottom:-24px;max-width:var(--msg-max);margin:0 auto;padding:0 20px;box-sizing:border-box;width:100%;overflow:hidden;pointer-events:none;}
   .approval-card.visible{pointer-events:auto;z-index:3;}
   .approval-inner{background:var(--surface);backdrop-filter:blur(8px);border:1px solid var(--accent-bg-strong);border-radius:14px;padding:16px 18px 40px;transform:translateY(100%);opacity:0;transition:transform .4s cubic-bezier(.32,.72,.16,1),opacity .25s ease;}
diff --git a/tests/test_a11y_prompt_flyout_hidden_state.py b/tests/test_a11y_prompt_flyout_hidden_state.py
new file mode 100644
index 00000000..5cb2a1f1
--- /dev/null
+++ b/tests/test_a11y_prompt_flyout_hidden_state.py
@@ -0,0 +1,70 @@
+from pathlib import Path
+
+ROOT = Path(__file__).resolve().parent.parent
+INDEX = (ROOT / "static" / "index.html").read_text(encoding="utf-8")
+MESSAGES_JS = (ROOT / "static" / "messages.js").read_text(encoding="utf-8")
+STYLE = (ROOT / "static" / "style.css").read_text(encoding="utf-8")
+
+
+def _function_body(name: str, *, limit: int = 5000) -> str:
+    start = MESSAGES_JS.index(f"function {name}")
+    return MESSAGES_JS[start : start + limit]
+
+
+def test_inactive_prompt_flyouts_are_hidden_from_accessibility_tree_initially():
+    """Approval/clarify flyouts are not persistent dialogs when no prompt is pending."""
+    approval_start = INDEX.index('id="approvalCard"')
+    approval_tag = INDEX[INDEX.rfind("<div", 0, approval_start) : INDEX.index(">", approval_start) + 1]
+    clarify_start = INDEX.index('id="clarifyCard"')
+    clarify_tag = INDEX[INDEX.rfind("<div", 0, clarify_start) : INDEX.index(">", clarify_start) + 1]
+
+    for tag in (approval_tag, clarify_tag):
+        assert " hidden" in tag
+        assert 'aria-hidden="true"' in tag
+        assert " inert" in tag
+
+    assert 'role="alertdialog"' in approval_tag
+    assert 'role="dialog"' in clarify_tag
+
+
+def test_prompt_flyout_hidden_css_guard_keeps_hidden_flyouts_display_none():
+    """Future display rules must not override hidden prompt flyouts."""
+    compact_style = STYLE.replace(" ", "")
+
+    assert ".approval-card[hidden],.clarify-card[hidden]{display:none!important;}" in compact_style
+
+
+def test_prompt_flyout_hidden_helper_toggles_hidden_aria_and_inert():
+    body = _function_body("_setPromptFlyoutHidden", limit=800)
+
+    assert 'card.setAttribute("aria-hidden", "true")' in body
+    assert 'card.setAttribute("aria-hidden", "false")' in body
+    assert 'card.setAttribute("inert", "")' in body
+    assert 'card.removeAttribute("inert")' in body
+    assert "card.hidden = true" in body
+    assert "card.hidden = false" in body
+    assert "void card.offsetHeight" in body
+
+
+def test_approval_show_and_hide_toggle_accessibility_visibility():
+    hide_body = _function_body("hideApprovalCard")
+    show_body = _function_body("showApprovalCard")
+
+    assert 'card.classList.remove("visible")' in hide_body
+    assert "_setPromptFlyoutHidden(card, true)" in hide_body
+    assert "_setPromptFlyoutHidden(card, false)" in show_body
+    assert 'card.classList.add("visible")' in show_body
+    assert show_body.index("_setPromptFlyoutHidden(card, false)") < show_body.index('card.classList.add("visible")')
+
+
+def test_clarify_show_and_hide_toggle_accessibility_visibility():
+    ensure_body = _function_body("_ensureClarifyCardDom")
+    hide_body = _function_body("hideClarifyCard")
+    show_body = _function_body("showClarifyCard")
+
+    assert "_setPromptFlyoutHidden(card, true)" in ensure_body
+    assert 'card.classList.remove("visible")' in hide_body
+    assert "_setPromptFlyoutHidden(card, true)" in hide_body
+    assert "_setPromptFlyoutHidden(card, false)" in show_body
+    assert 'card.classList.add("visible")' in show_body
+    assert show_body.index("_setPromptFlyoutHidden(card, false)") < show_body.index('card.classList.add("visible")')
diff --git a/tests/test_issue4771_gateway_approval_failure_ui.py b/tests/test_issue4771_gateway_approval_failure_ui.py
index b7fcbe2d..b47f537e 100644
--- a/tests/test_issue4771_gateway_approval_failure_ui.py
+++ b/tests/test_issue4771_gateway_approval_failure_ui.py
@@ -62,6 +62,7 @@ def _run_failure_case(api_js: str) -> dict:
             _extract_fn(MESSAGES_JS, "_renderPendingApprovalForActiveSession"),
             _extract_fn(MESSAGES_JS, "_approvalResponseMatches"),
             _extract_fn(MESSAGES_JS, "_setApprovalControlsDisabled"),
+            _extract_fn(MESSAGES_JS, "_setPromptFlyoutHidden"),
             _extract_fn(MESSAGES_JS, "showApprovalCard"),
             _extract_fn(MESSAGES_JS, "_restoreFailedApprovalResponse"),
             _extract_fn(MESSAGES_JS, "respondApproval", prefix="async function "),
@@ -117,6 +118,10 @@ const card = {{
       else this.values.delete(value);
     }},
   }},
+  hidden: false,
+  attributes: {{}},
+  setAttribute(name, value) {{ this.attributes[name] = String(value); }},
+  removeAttribute(name) {{ delete this.attributes[name]; }},
   querySelector() {{ return null; }},
 }};
 const approvalDesc = {{ textContent: '' }};
@@ -239,6 +244,7 @@ def test_poll_rerender_keeps_inflight_buttons_disabled_and_blocks_duplicates():
             _extract_fn(MESSAGES_JS, "_renderPendingApprovalForActiveSession"),
             _extract_fn(MESSAGES_JS, "_approvalResponseMatches"),
             _extract_fn(MESSAGES_JS, "_setApprovalControlsDisabled"),
+            _extract_fn(MESSAGES_JS, "_setPromptFlyoutHidden"),
             _extract_fn(MESSAGES_JS, "showApprovalCard"),
             _extract_fn(MESSAGES_JS, "_restoreFailedApprovalResponse"),
             _extract_fn(MESSAGES_JS, "respondApproval", prefix="async function "),
@@ -291,6 +297,10 @@ const card = {{
       else this.values.delete(value);
     }},
   }},
+  hidden: false,
+  attributes: {{}},
+  setAttribute(name, value) {{ this.attributes[name] = String(value); }},
+  removeAttribute(name) {{ delete this.attributes[name]; }},
   querySelector() {{ return null; }},
 }};
 const approvalDesc = {{ textContent: '' }};