fix(coding-agent): retry connection lost errors

closes #3317

packages/coding-agent/CHANGELOG.md

@@ -4,6 +4,7 @@
 
 ### Fixed
 
+- Fixed auto-retry transient error detection to treat `Network connection lost.` as retryable, so dropped provider connections retry instead of terminating the agent ([#3317](https://github.com/badlogic/pi-mono/issues/3317))
 - Fixed compact interactive extension startup summaries to disambiguate package extensions and repeated local `index.ts` entries by using package-aware labels and the minimal parent path needed to make local entries unique ([#3308](https://github.com/badlogic/pi-mono/issues/3308))
 - Fixed git package dependency installation to use production installs (`npm install --omit=dev`) during both install and update flows, so extension runtime dependencies must come from `dependencies` and not `devDependencies` ([#3009](https://github.com/badlogic/pi-mono/issues/3009))
 - Fixed `tool_result` / `afterToolCall` extension handling for error results by forwarding `details` and `isError` overrides through `AgentSession` instead of dropping them when `isError` was already true ([#3051](https://github.com/badlogic/pi-mono/issues/3051))

packages/coding-agent/src/core/agent-session.ts

@@ -2404,8 +2404,8 @@ export class AgentSession {
 		if (isContextOverflow(message, contextWindow)) return false;
 
 		const err = message.errorMessage;
-		// Match: overloaded_error, provider returned error, rate limit, 429, 500, 502, 503, 504, service unavailable, network/connection errors, fetch failed, request ended without sending chunks, terminated, retry delay exceeded
-		return /overloaded|provider.?returned.?error|rate.?limit|too many requests|429|500|502|503|504|service.?unavailable|server.?error|internal.?error|network.?error|connection.?error|connection.?refused|other side closed|fetch failed|upstream.?connect|reset before headers|socket hang up|ended without|timed? out|timeout|terminated|retry delay/i.test(
+		// Match: overloaded_error, provider returned error, rate limit, 429, 500, 502, 503, 504, service unavailable, network/connection errors (including connection lost), fetch failed, request ended without sending chunks, terminated, retry delay exceeded
+		return /overloaded|provider.?returned.?error|rate.?limit|too many requests|429|500|502|503|504|service.?unavailable|server.?error|internal.?error|network.?error|connection.?error|connection.?refused|connection.?lost|other side closed|fetch failed|upstream.?connect|reset before headers|socket hang up|ended without|timed? out|timeout|terminated|retry delay/i.test(
 			err,
 		);
 	}

packages/coding-agent/test/suite/regressions/3317-network-connection-lost-retry.test.ts

@@ -0,0 +1,33 @@
+import { fauxAssistantMessage } from "@mariozechner/pi-ai";
+import { afterEach, describe, expect, it } from "vitest";
+import { createHarness, getAssistantTexts, type Harness } from "../harness.js";
+
+describe("issue #3317 network connection lost retry", () => {
+	const harnesses: Harness[] = [];
+
+	afterEach(() => {
+		while (harnesses.length > 0) {
+			harnesses.pop()?.cleanup();
+		}
+	});
+
+	it('retries transient "Network connection lost." failures', async () => {
+		const harness = await createHarness({
+			settings: { retry: { enabled: true, maxRetries: 3, baseDelayMs: 1 } },
+		});
+		harnesses.push(harness);
+		harness.setResponses([
+			fauxAssistantMessage("", { stopReason: "error", errorMessage: "Network connection lost." }),
+			fauxAssistantMessage("recovered after reconnect"),
+		]);
+
+		await harness.session.prompt("test");
+
+		expect(harness.faux.state.callCount).toBe(2);
+		expect(harness.eventsOfType("auto_retry_start").map((event) => event.errorMessage)).toEqual([
+			"Network connection lost.",
+		]);
+		expect(harness.eventsOfType("auto_retry_end").map((event) => event.success)).toEqual([true]);
+		expect(getAssistantTexts(harness)).toContain("recovered after reconnect");
+	});
+});