Update contributing, deduplicate more functions

src/agents/model-fallback.ts

@@ -35,10 +35,10 @@ type FallbackAttempt = {
 };
 
 /**
- * Strict abort check for model fallback. Only treats explicit AbortError names as user aborts.
+ * Fallback abort check. Only treats explicit AbortError names as user aborts.
  * Message-based checks (e.g., "aborted") can mask timeouts and skip fallback.
  */
-function isStrictAbortError(err: unknown): boolean {
+function isFallbackAbortError(err: unknown): boolean {
   if (!err || typeof err !== "object") {
     return false;
   }
@@ -50,7 +50,7 @@ function isStrictAbortError(err: unknown): boolean {
 }
 
 function shouldRethrowAbort(err: unknown): boolean {
-  return isStrictAbortError(err) && !isTimeoutError(err);
+  return isFallbackAbortError(err) && !isTimeoutError(err);
 }
 
 function resolveImageFallbackCandidates(params: {

src/agents/pi-embedded-runner/abort.ts

@@ -1 +1,17 @@
-export { isAbortError } from "../../infra/unhandled-rejections.js";
+/**
+ * Runner abort check. Catches any abort-related message for embedded runners.
+ * More permissive than the core isAbortError since runners need to catch
+ * various abort signals from different sources.
+ */
+export function isRunnerAbortError(err: unknown): boolean {
+  if (!err || typeof err !== "object") {
+    return false;
+  }
+  const name = "name" in err ? String(err.name) : "";
+  if (name === "AbortError") {
+    return true;
+  }
+  const message =
+    "message" in err && typeof err.message === "string" ? err.message.toLowerCase() : "";
+  return message.includes("aborted");
+}

src/agents/pi-embedded-runner/run/attempt.ts

@@ -60,7 +60,7 @@ import { buildSystemPromptParams } from "../../system-prompt-params.js";
 import { buildSystemPromptReport } from "../../system-prompt-report.js";
 import { resolveTranscriptPolicy } from "../../transcript-policy.js";
 import { DEFAULT_BOOTSTRAP_FILENAME } from "../../workspace.js";
-import { isAbortError } from "../abort.js";
+import { isRunnerAbortError } from "../abort.js";
 import { appendCacheTtlTimestamp, isCacheTtlEligibleProvider } from "../cache-ttl.js";
 import { buildEmbeddedExtensionPaths } from "../extensions.js";
 import { applyExtraParamsToAgent } from "../extra-params.js";
@@ -832,7 +832,7 @@ export async function runEmbeddedAttempt(
         try {
           await waitForCompactionRetry();
         } catch (err) {
-          if (isAbortError(err)) {
+          if (isRunnerAbortError(err)) {
             if (!promptError) {
               promptError = err;
             }

src/commands/onboard-helpers.ts

@@ -11,7 +11,7 @@ import { CONFIG_PATH } from "../config/config.js";
 import { resolveSessionTranscriptsDirForAgent } from "../config/sessions.js";
 import { callGateway } from "../gateway/call.js";
 import { normalizeControlUiBasePath } from "../gateway/control-ui-shared.js";
-import { pickPrimaryLanIPv4 } from "../gateway/net.js";
+import { pickPrimaryLanIPv4, isValidIPv4 } from "../gateway/net.js";
 import { isSafeExecutableValue } from "../infra/exec-safety.js";
 import { pickPrimaryTailnetIPv4 } from "../infra/tailnet.js";
 import { isWSL } from "../infra/wsl.js";
@@ -464,14 +464,3 @@ export function resolveControlUiLinks(params: {
     wsUrl: `ws://${host}:${port}${wsPath}`,
   };
 }
-
-function isValidIPv4(host: string): boolean {
-  const parts = host.split(".");
-  if (parts.length !== 4) {
-    return false;
-  }
-  return parts.every((part) => {
-    const n = Number.parseInt(part, 10);
-    return !Number.isNaN(n) && n >= 0 && n <= 255 && part === String(n);
-  });
-}

src/gateway/net.ts

@@ -244,7 +244,7 @@ export async function resolveGatewayListenHosts(
  * @param host - The string to validate
  * @returns True if valid IPv4 format
  */
-function isValidIPv4(host: string): boolean {
+export function isValidIPv4(host: string): boolean {
   const parts = host.split(".");
   if (parts.length !== 4) {
     return false;

src/infra/unhandled-rejections.ts

@@ -62,10 +62,12 @@ export function isAbortError(err: unknown): boolean {
   if (name === "AbortError") {
     return true;
   }
-  // Check for abort messages from Node's undici and other sources
-  const message =
-    "message" in err && typeof err.message === "string" ? err.message.toLowerCase() : "";
-  return message.includes("aborted");
+  // Check for "This operation was aborted" message from Node's undici
+  const message = "message" in err && typeof err.message === "string" ? err.message : "";
+  if (message === "This operation was aborted") {
+    return true;
+  }
+  return false;
 }
 
 function isFatalError(err: unknown): boolean {

src/infra/wsl.ts

@@ -1,3 +1,4 @@
+import { readFileSync } from "node:fs";
 import fs from "node:fs/promises";
 
 let wslCached: boolean | null = null;
@@ -9,6 +10,40 @@ export function isWSLEnv(): boolean {
   return false;
 }
 
+/**
+ * Synchronously check if running in WSL.
+ * Checks env vars first, then /proc/version.
+ */
+export function isWSLSync(): boolean {
+  if (process.platform !== "linux") {
+    return false;
+  }
+  if (isWSLEnv()) {
+    return true;
+  }
+  try {
+    const release = readFileSync("/proc/version", "utf8").toLowerCase();
+    return release.includes("microsoft") || release.includes("wsl");
+  } catch {
+    return false;
+  }
+}
+
+/**
+ * Synchronously check if running in WSL2.
+ */
+export function isWSL2Sync(): boolean {
+  if (!isWSLSync()) {
+    return false;
+  }
+  try {
+    const version = readFileSync("/proc/version", "utf8").toLowerCase();
+    return version.includes("wsl2") || version.includes("microsoft-standard");
+  } catch {
+    return false;
+  }
+}
+
 export async function isWSL(): Promise<boolean> {
   if (wslCached !== null) {
     return wslCached;

src/plugin-sdk/index.ts

@@ -136,6 +136,8 @@ export {
   rejectDevicePairing,
 } from "../infra/device-pairing.js";
 export { formatErrorMessage } from "../infra/errors.js";
+export { isWSLSync, isWSL2Sync, isWSLEnv } from "../infra/wsl.js";
+export { isTruthyEnvValue } from "../infra/env.js";
 export { resolveToolsBySender } from "../config/group-policy.js";
 export {
   buildPendingHistoryContextFromMap,