diff --git a/packages/pi-ai/src/utils/overflow.ts b/packages/pi-ai/src/utils/overflow.ts
index ef0bfb467..d288afeeb 100644
--- a/packages/pi-ai/src/utils/overflow.ts
+++ b/packages/pi-ai/src/utils/overflow.ts
@@ -104,6 +104,19 @@ export function isContextOverflow(message: AssistantMessage, contextWindow?: num
 		}
 	}
 
+	// Some providers surface overflow as assistant text while putting a generic
+	// classifier value in errorMessage (e.g. claude-code: errorMessage="success",
+	// text="Prompt is too long"). Check rendered text as a fallback.
+	if (message.stopReason === "error") {
+		const assistantText = message.content
+			.filter((block) => block.type === "text")
+			.map((block) => block.text)
+			.join("\n");
+		if (assistantText && OVERFLOW_PATTERNS.some((p) => p.test(assistantText))) {
+			return true;
+		}
+	}
+
 	// Case 2: Silent overflow (z.ai style) - successful but usage exceeds context
 	if (contextWindow && message.stopReason === "stop") {
 		const inputTokens = message.usage.input + message.usage.cacheRead;
@@ -113,4 +126,4 @@ export function isContextOverflow(message: AssistantMessage, contextWindow?: num
 	}
 
 	return false;
-}
\ No newline at end of file
+}
diff --git a/packages/pi-ai/src/utils/tests/overflow.test.ts b/packages/pi-ai/src/utils/tests/overflow.test.ts
new file mode 100644
index 000000000..068196bcb
--- /dev/null
+++ b/packages/pi-ai/src/utils/tests/overflow.test.ts
@@ -0,0 +1,58 @@
+import { describe, test } from "node:test";
+import assert from "node:assert/strict";
+
+import { isContextOverflow } from "../overflow.js";
+import type { AssistantMessage } from "../../types.js";
+
+function makeAssistantMessage(overrides: Partial<AssistantMessage> = {}): AssistantMessage {
+	return {
+		role: "assistant",
+		content: [],
+		api: "anthropic-messages",
+		provider: "anthropic",
+		model: "claude-sonnet-4-6",
+		usage: {
+			input: 0,
+			output: 0,
+			cacheRead: 0,
+			cacheWrite: 0,
+			totalTokens: 0,
+			cost: { input: 0, output: 0, cacheRead: 0, cacheWrite: 0, total: 0 },
+		},
+		stopReason: "error",
+		timestamp: Date.now(),
+		...overrides,
+	};
+}
+
+describe("isContextOverflow", () => {
+	test("detects overflow from provider errorMessage", () => {
+		const message = makeAssistantMessage({
+			errorMessage: "prompt is too long: 213462 tokens > 200000 maximum",
+		});
+
+		assert.equal(isContextOverflow(message, 200000), true);
+	});
+
+	test("detects claude-code overflow when text contains the error but errorMessage is generic (#3925)", () => {
+		const message = makeAssistantMessage({
+			provider: "claude-code",
+			api: "anthropic-messages",
+			model: "claude-sonnet-4-6",
+			errorMessage: "success",
+			content: [{ type: "text", text: "Prompt is too long" }],
+		});
+
+		assert.equal(isContextOverflow(message, 200000), true);
+	});
+
+	test("does not treat normal non-error text as overflow", () => {
+		const message = makeAssistantMessage({
+			stopReason: "stop",
+			errorMessage: undefined,
+			content: [{ type: "text", text: "Prompt is too long" }],
+		});
+
+		assert.equal(isContextOverflow(message, 200000), false);
+	});
+});