diff --git a/components/terminal/runtime/createXTermRuntime.ts b/components/terminal/runtime/createXTermRuntime.ts
index fdd84eb440..3386de1038 100644
--- a/components/terminal/runtime/createXTermRuntime.ts
+++ b/components/terminal/runtime/createXTermRuntime.ts
@@ -1662,6 +1662,13 @@ export const createXTermRuntime = (ctx: CreateXTermRuntimeContext): XTermRuntime
       return false;
     }
 
+    if (e.type === "keypress" && broadcastForwardedKeys.has(kittyKeyIdentity(e))) {
+      // Space and uppercase letters can emit xterm data from keypress, after
+      // keydown's zero-delay cleanup. Rejoin that physical broadcast instead
+      // of sending the same character a second time as unpaired raw text.
+      markBroadcastLegacyDataPending(kittyKeyIdentity(e));
+    }
+
     if (e.type !== "keydown") {
       return true;
     }
@@ -2423,6 +2430,10 @@ export const createXTermRuntime = (ctx: CreateXTermRuntimeContext): XTermRuntime
       });
       return;
     }
+    // insertText can follow an already-delivered keypress. Its fallback marker
+    // must not classify the next physical key as a second composition commit.
+    // Actual composition/input handlers clear the physical-key pairing first.
+    if (broadcastLegacyDataPending) kittyCompositionPending = false;
     if (kittyCompositionPending && !data.startsWith("\u001b")) {
       kittyCompositionPending = false;
       if (kittyCompositionClearTimer !== undefined) {
diff --git a/components/terminal/runtime/terminalBroadcastKeypress.test.ts b/components/terminal/runtime/terminalBroadcastKeypress.test.ts
new file mode 100644
index 0000000000..28f53f95e9
--- /dev/null
+++ b/components/terminal/runtime/terminalBroadcastKeypress.test.ts
@@ -0,0 +1,169 @@
+import assert from "node:assert/strict";
+import { readFileSync } from "node:fs";
+import test from "node:test";
+import { runInNewContext } from "node:vm";
+import ts from "typescript";
+import { resolveKittyKeyboardBroadcastInput, type KittyKeyboardBroadcastInput } from "./kittyKeyboardBroadcast";
+import { createKittyKeyboardModeState, setKittyKeyboardModeFlags, shouldEncodeKittyCompositionText, shouldMarkKittyTextInputEvent, encodeKittyCompositionText } from "./kittyKeyboardProtocol";
+import { shouldBlockKeyPressForImeTextInput, shouldCommitDeferredImeTextInput } from "./terminalImeTextInput";
+import { sanitizeTerminalInput } from "./terminalInputSanitize";
+
+// Execute the actual registered key/data callbacks, without constructing the
+// renderer and its WebGL/addon stack. In particular, retain their real timer
+// cleanup and raw-broadcast suppression rather than reproducing that logic here.
+const source = readFileSync(new URL("./createXTermRuntime.ts", import.meta.url), "utf8");
+function section(start: string, end: string): string {
+  const from = source.indexOf(start);
+  const to = source.indexOf(end, from);
+  assert.ok(from >= 0 && to > from, `runtime section missing: ${start}`);
+  return source.slice(from, to);
+}
+const declarations = section("  let suppressNextTerminalDataBroadcast =", "  const broadcastKittyInput =");
+const keyboardCallback = section("  term.attachCustomKeyEventHandler((e: KeyboardEvent) => {", "  const handleMiddleClick =");
+const dataCallback = section("  term.onData((data) => {", "  const handleKittyKeyboardBroadcast =");
+const compositionMarker = section("  const markKittyCompositionPending =", "  const finishKittyComposition =");
+const textInputMarker = section("  const markKittyTextInput =", '  textarea?.addEventListener("compositionstart"');
+const suppression = section("    const suppressTerminalBroadcast =", "    // skipBroadcast");
+const callbackCode = ts.transpileModule(`
+  ${declarations}
+  let win32InputModePendingEvent = null;
+  let kittyCompositionPending = false;
+  let kittyCompositionClearTimer;
+  const handleTerminalInputData = (data) => {
+    const inputSource = "terminal";
+    ${suppression}
+    if (!suppressTerminalBroadcast) raw(data);
+  };
+  const textarea = null;
+  ${compositionMarker}
+  ${textInputMarker}
+  ${keyboardCallback}
+  ${dataCallback}
+  globalThis.controls = { mark: markBroadcastLegacyDataPending, clear: clearBroadcastLegacyDataPending, input: markKittyTextInput };
+`, { compilerOptions: { target: ts.ScriptTarget.ES2022 } }).outputText;
+
+function setup(flags = 0) {
+  const writes: string[] = [];
+  const timers = new Map<number, () => void>();
+  let timerId = 0;
+  let receive!: (data: string) => void;
+  let keyboard!: (event: Partial<KeyboardEvent>) => boolean;
+  const forwarded = new Map<string, { targetSessionIds: string[] }>();
+  const mode = createKittyKeyboardModeState();
+  setKittyKeyboardModeFlags(mode, flags);
+  const options = {
+    kittyProtocolEnabled: flags !== 0, kittyMode: mode, applicationCursorMode: false,
+    encodedKeys: new Set<string>(), legacySuppressedKeys: new Set<string>(),
+  };
+  const normalized = (input: KittyKeyboardBroadcastInput) => {
+    const result = resolveKittyKeyboardBroadcastInput(input, options);
+    if (result) writes.push(result.data);
+  };
+  const context = {
+    controls: undefined as unknown as { mark: (identity: string) => void; clear: () => void; input: (event: { data: string; inputType: string }) => void },
+    window: {
+      setTimeout(fn: () => void) { const id = ++timerId; timers.set(id, fn); return id; },
+      clearTimeout(id: number) { timers.delete(id); },
+    },
+    term: {
+      modes: { win32InputMode: false },
+      onData(fn: typeof receive) { receive = fn; },
+      attachCustomKeyEventHandler(fn: typeof keyboard) { keyboard = fn; },
+    },
+    ctx: { terminalSettingsRef: { current: {} }, isBroadcastEnabledRef: { current: true }, onBroadcastInputRef: { current: () => undefined } },
+    imeTextInputDeferredKey: null, imeTextInputDeferredKittyEvent: null,
+    shouldBlockKeyPressForImeTextInput, shouldCommitDeferredImeTextInput, shouldMarkKittyTextInputEvent, shouldEncodeKittyCompositionText, encodeKittyCompositionText,
+    kittyKeyboardMode: createKittyKeyboardModeState(), shouldSplitImeTextInputForWire: () => false,
+    kittyKeyIdentity: (event: Partial<KeyboardEvent>) => event.code || event.key,
+    broadcastForwardedKeys: forwarded,
+    broadcastKittyInput: normalized,
+    sanitizeTerminalInput,
+    shouldSplitRawPasteInputForWire: () => false,
+    raw: (data: string) => writes.push(data),
+  };
+  runInNewContext(callbackCode, context);
+  return {
+    writes, receive: (data: string) => receive(data), controls: context.controls,
+    keypress: (key: string, code: string) => keyboard({ type: "keypress", key, code }),
+    press(key: string, code: string) {
+      normalized({ kind: "key", event: { type: "keydown", key, code }, fallbackToLegacy: true });
+      forwarded.set(code, { targetSessionIds: ["target"] });
+      context.controls.mark(code);
+    },
+    flushTimers() { for (const [id, fn] of timers) { timers.delete(id); fn(); } },
+    release(key: string, code: string) {
+      normalized({ kind: "key", event: { type: "keyup", key, code }, fallbackToLegacy: true });
+      forwarded.delete(code);
+      context.controls.clear();
+    },
+  };
+}
+
+for (const flags of [0, 8]) {
+  for (const [key, code] of [["A", "KeyA"], [" ", "Space"]]) {
+    test(`broadcast pairs delayed ${code} keypress once with target flags ${flags}`, () => {
+      const runtime = setup(flags);
+      runtime.press(key, code);
+      const firstWrite = runtime.writes.join("");
+      assert.ok(firstWrite);
+      runtime.flushTimers();
+      assert.equal(runtime.keypress(key, code), true);
+      runtime.receive(key);
+      assert.equal(runtime.writes.join(""), firstWrite, "the source's later text must not duplicate its physical key broadcast");
+    });
+  }
+}
+
+test("repeated physical presses each reach the broadcast target once", () => {
+  const runtime = setup();
+  for (let i = 0; i < 3; i++) {
+    runtime.press("A", "KeyA");
+    runtime.flushTimers();
+    runtime.keypress("A", "KeyA");
+    runtime.receive("A");
+  }
+  assert.equal(runtime.writes.join(""), "AAA");
+});
+
+test("keypress without an earlier broadcast and text after release are not swallowed", () => {
+  const runtime = setup();
+  runtime.keypress("B", "KeyB");
+  runtime.receive("B");
+  runtime.press("A", "KeyA");
+  runtime.flushTimers();
+  runtime.keypress("A", "KeyA");
+  runtime.receive("A");
+  runtime.release("A", "KeyA");
+  runtime.receive("paste");
+  assert.equal(runtime.writes.join(""), "BApaste");
+});
+
+test("unmatched keypress cleanup still permits a later paste", () => {
+  const runtime = setup();
+  runtime.press("A", "KeyA");
+  runtime.flushTimers();
+  runtime.keypress("A", "KeyA");
+  runtime.flushTimers();
+  runtime.receive("paste");
+  assert.equal(runtime.writes.join(""), "Apaste");
+});
+
+test("trailing insertText for Space does not turn the next physical key into duplicate composition text", () => {
+  const runtime = setup();
+  for (const [key, code] of [[" ", "Space"], ["A", "KeyA"], ["B", "KeyB"], ["C", "KeyC"]]) {
+    runtime.press(key, code);
+    runtime.keypress(key, code);
+    runtime.receive(key);
+    runtime.controls.input({ data: key, inputType: "insertText" });
+    runtime.release(key, code);
+    // Real trace: the next key can arrive before insertText's zero-delay timer.
+  }
+  assert.equal(runtime.writes.join(""), " ABC");
+});
+
+test("keyless insertText is still broadcast as actual text", () => {
+  const runtime = setup();
+  runtime.controls.input({ data: "中文", inputType: "insertText" });
+  runtime.receive("中文");
+  assert.equal(runtime.writes.join(""), "中文");
+});