diff --git a/packages/local-config-updater/src/config-agent.ts b/packages/local-config-updater/src/config-agent.ts
index f8a1bc20d..0f69cd0ce 100644
--- a/packages/local-config-updater/src/config-agent.ts
+++ b/packages/local-config-updater/src/config-agent.ts
@@ -35,6 +35,20 @@ export type RunClaudeAgentResult = {
   resultText: string,
 };
 
+export class ClaudeAgentTimeoutError extends Error {
+  constructor(timeoutMs?: number) {
+    super(`Claude agent timed out${timeoutMs == null ? "" : ` after ${timeoutMs}ms`}.`);
+    this.name = "ClaudeAgentTimeoutError";
+  }
+}
+
+export class ClaudeAgentFailureError extends Error {
+  constructor(subtype: string) {
+    super(`Claude agent failed (${subtype}).`);
+    this.name = "ClaudeAgentFailureError";
+  }
+}
+
 function isAbortError(error: unknown): boolean {
   return error instanceof Error && error.name === "AbortError";
 }
@@ -91,13 +105,13 @@ export async function runHeadlessClaudeAgent(options: RunClaudeAgentOptions): Pr
           sawResult = true;
           resultText = message.result;
         } else {
-          throw new Error(`Claude agent failed (${message.subtype}).`);
+          throw new ClaudeAgentFailureError(message.subtype);
         }
       }
     }
   } catch (error) {
     if (abortController.signal.aborted && isAbortError(error)) {
-      throw new Error(`Claude agent timed out${options.timeoutMs == null ? "" : ` after ${options.timeoutMs}ms`}.`);
+      throw new ClaudeAgentTimeoutError(options.timeoutMs ?? undefined);
     }
     throw error;
   } finally {
diff --git a/packages/local-config-updater/src/index.ts b/packages/local-config-updater/src/index.ts
index 51ee9ed32..9bce863ad 100644
--- a/packages/local-config-updater/src/index.ts
+++ b/packages/local-config-updater/src/index.ts
@@ -7,7 +7,7 @@ import { createHash } from "crypto";
 import { existsSync, mkdirSync, readFileSync, renameSync, rmSync, writeFileSync } from "fs";
 import { createJiti } from "jiti";
 import path from "path";
-import { getToolWriteTargetPath, isPathInsideDir, runHeadlessClaudeAgent } from "./config-agent";
+import { ClaudeAgentFailureError, ClaudeAgentTimeoutError, getToolWriteTargetPath, isPathInsideDir, runHeadlessClaudeAgent } from "./config-agent";
 
 const jiti = createJiti(import.meta.url, { moduleCache: false });
 
@@ -190,10 +190,10 @@ async function runConfigUpdateAgent(options: {
       },
     });
   } catch (error) {
-    if (error instanceof Error && error.message.startsWith("Claude agent timed out")) {
+    if (error instanceof ClaudeAgentTimeoutError) {
       throw new Error(`Config update agent timed out after ${timeoutMs}ms. It was unable to apply the config changes to the file.`);
     }
-    if (error instanceof Error && error.message.startsWith("Claude agent failed")) {
+    if (error instanceof ClaudeAgentFailureError) {
       throw new Error(`${error.message} It was unable to apply the config changes to the file.`);
     }
     throw error;