Cherry-pick 4 critical recovery fixes from pi-mono upstream

- agent-loop: wrap afterToolCall in try/catch so hook throws don't crash
  parallel tool batches (#3084)
- retry-handler: add "connection lost" to retryable error patterns (#3317)
- rpc-mode: redirect console.log to stderr to protect JSON stdout (#2388)
- openai-completions: ignore null/non-object chunks in stream (#2466)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

packages/pi-agent-core/src/agent-loop.ts

@@ -753,6 +753,7 @@ async function finalizeExecutedToolCall(
 	let isError = executed.isError;
 
 	if (config.afterToolCall) {
+		try {
 			const afterResult = await config.afterToolCall(
 				{
 					assistantMessage,
@@ -771,6 +772,10 @@ async function finalizeExecutedToolCall(
 				};
 				isError = afterResult.isError !== undefined ? afterResult.isError : isError;
 			}
+		} catch (error) {
+			result = createErrorToolResult(error instanceof Error ? error.message : String(error));
+			isError = true;
+		}
 	}
 
 	return emitToolCallOutcome(prepared.toolCall, result, isError, stream);

packages/pi-ai/src/providers/openai-completions.ts

@@ -123,6 +123,8 @@ export const streamOpenAICompletions: StreamFunction<"openai-completions", OpenA
 			};
 
 			for await (const chunk of openaiStream) {
+				if (!chunk || typeof chunk !== "object") continue;
+
 				if (chunk.usage) {
 					const cachedTokens = chunk.usage.prompt_tokens_details?.cached_tokens || 0;
 					const reasoningTokens = chunk.usage.completion_tokens_details?.reasoning_tokens || 0;
@@ -148,7 +150,7 @@ export const streamOpenAICompletions: StreamFunction<"openai-completions", OpenA
 					calculateCost(model, output.usage);
 				}
 
-				const choice = chunk.choices?.[0];
+				const choice = Array.isArray(chunk.choices) ? chunk.choices[0] : undefined;
 				if (!choice) continue;
 
 				if (choice.finish_reason) {

packages/pi-coding-agent/src/core/retry-handler.ts

@@ -116,7 +116,7 @@ export class RetryHandler {
 		// generated error from getApiKey() when credentials are in a backoff window.
 		// Re-entering the retry handler for that message creates a cascade of empty
 		// error entries in the session file, breaking resume (#3429).
-		return /overloaded|rate.?limit|too many requests|402|429|500|502|503|504|service.?unavailable|server.?error|internal.?error|connection.?error|connection.?refused|other side closed|fetch failed|upstream.?connect|reset before headers|terminated|retry delay|network.?(?:is\s+)?unavailable|credentials.*expired|requires more credits|can only afford|insufficient credits|not enough credits|extra usage is required|(?:out of|no) extra usage|third.party.*draw from extra|third.party.*not.*available/i.test(
+		return /overloaded|rate.?limit|too many requests|402|429|500|502|503|504|service.?unavailable|server.?error|internal.?error|connection.?error|connection.?refused|connection.?lost|other side closed|fetch failed|upstream.?connect|reset before headers|terminated|retry delay|network.?(?:is\s+)?unavailable|credentials.*expired|requires more credits|can only afford|insufficient credits|not enough credits|extra usage is required|(?:out of|no) extra usage|third.party.*draw from extra|third.party.*not.*available/i.test(
 			err,
 		);
 	}

packages/pi-coding-agent/src/modes/rpc/rpc-mode.ts

@@ -50,8 +50,15 @@ export type {
  * Listens for JSON commands on stdin, outputs events and responses on stdout.
  */
 export async function runRpcMode(session: AgentSession): Promise<never> {
+	const rawStdoutWrite = process.stdout.write.bind(process.stdout);
+	const rawStderrWrite = process.stderr.write.bind(process.stderr);
+
+	process.stdout.write = ((
+		...args: Parameters<typeof process.stdout.write>
+	): ReturnType<typeof process.stdout.write> => rawStderrWrite(...args)) as typeof process.stdout.write;
+
 	const output = (obj: RpcResponse | RpcExtensionUIRequest | object) => {
-		process.stdout.write(serializeJsonLine(obj));
+		rawStdoutWrite(serializeJsonLine(obj));
 	};
 
 	const success = <T extends RpcCommand["type"]>(