diff --git a/packages/coding-agent/src/tools/bash-interactive.ts b/packages/coding-agent/src/tools/bash-interactive.ts
index b65e90851..761cd7cdc 100644
--- a/packages/coding-agent/src/tools/bash-interactive.ts
+++ b/packages/coding-agent/src/tools/bash-interactive.ts
@@ -151,9 +151,23 @@ class BashInteractiveOverlayComponent implements Component {
 	}
 
 	#trimWriteQueue(): void {
-		const firstPending = this.#writing ? this.#writeOffset + 1 : this.#writeOffset;
-		while (this.#writeQueue.length - firstPending > MAX_LIVE_WRITE_QUEUE_CHUNKS) {
-			this.#writeQueue.splice(firstPending, 1);
+		// Compact the consumed prefix first: the queue only self-resets on a
+		// full drain, which never happens while a fast producer keeps a
+		// backlog alive, so already-written chunks must be released here to
+		// keep the retained array itself bounded.
+		if (this.#writeOffset > 0) {
+			this.#writeQueue.splice(0, this.#writeOffset);
+			this.#writeOffset = 0;
+		}
+		const firstPending = this.#writing ? 1 : 0;
+		const overflow = this.#writeQueue.length - firstPending - MAX_LIVE_WRITE_QUEUE_CHUNKS;
+		if (overflow > 0) {
+			this.#writeQueue.splice(firstPending, overflow);
+			// Dropped chunks can split an in-flight DCS/OSC/APC string (e.g. a
+			// sixel payload) across the gap; a stray string terminator is a
+			// no-op in the ground state but resynchronizes the parser if the
+			// terminator was dropped.
+			this.#writeQueue[firstPending] = `\u001b\\${this.#writeQueue[firstPending]}`;
 		}
 	}