refactor(subagent): centralize finalize status values

index.ts

@@ -37,8 +37,13 @@ interface SubagentStatus {
   recentToolCalls: SubagentToolActivity[];
 }
 
+enum FinalizeStatus {
+  SUCCESS = "SUCCESS",
+  ERROR = "ERROR",
+}
+
 interface SubagentFinalizePayload {
-  status: "SUCCESS" | "ERROR";
+  status: FinalizeStatus;
   result?: string;
   error?: string;
 }
@@ -85,7 +90,7 @@ function getSubagentMarkdownTheme(theme: Theme): MarkdownTheme {
 
 // Format Tool Content - Some clients hide structured details from the model.
 function formatSubagentContent(
-  status: "SUCCESS" | "ERROR",
+  status: FinalizeStatus,
   sessionId: string,
   result?: string,
   error?: string,
@@ -178,7 +183,7 @@ function buildSubagentPrompt(agent: PromptConfig): string {
     "You are running as a subagent.",
     `When the task is complete, call ${FINALIZE_TOOL_NAME} as your final action.`,
     "Do not provide the final answer as normal assistant text.",
-    `${FINALIZE_TOOL_NAME} requires status SUCCESS with result, or status ERROR with error and optional result.`,
+    `${FINALIZE_TOOL_NAME} requires status ${FinalizeStatus.SUCCESS} with result, or status ${FinalizeStatus.ERROR} with error and optional result.`,
   ].join("\n");
 
   return [agent.systemPrompt, finalizePrompt].filter(Boolean).join("\n\n");
@@ -208,16 +213,16 @@ function validateFinalizePayload(
 ): SubagentFinalizePayload | null {
   if (!value || typeof value !== "object") return null;
   const payload = value as Record<string, unknown>;
-  if (payload.status === "SUCCESS") {
+  if (payload.status === FinalizeStatus.SUCCESS) {
     return typeof payload.result === "string" && payload.result.trim()
-      ? { status: "SUCCESS", result: payload.result }
+      ? { status: FinalizeStatus.SUCCESS, result: payload.result }
       : null;
   }
-  if (payload.status === "ERROR") {
+  if (payload.status === FinalizeStatus.ERROR) {
     const result =
       typeof payload.result === "string" ? payload.result : undefined;
     return typeof payload.error === "string" && payload.error.trim()
-      ? { status: "ERROR", error: payload.error, result }
+      ? { status: FinalizeStatus.ERROR, error: payload.error, result }
       : null;
   }
   return null;
@@ -592,7 +597,7 @@ export default function (pi: ExtensionAPI) {
       promptSnippet:
         "Call subagent_finalize as your final action when subagent work is complete.",
       parameters: Type.Object({
-        status: Type.Union([Type.Literal("SUCCESS"), Type.Literal("ERROR")]),
+        status: Type.Enum(FinalizeStatus),
         result: Type.Optional(Type.String()),
         error: Type.Optional(Type.String()),
       }),
@@ -709,7 +714,7 @@ export default function (pi: ExtensionAPI) {
             {
               type: "text",
               text: formatSubagentContent(
-                "ERROR",
+                FinalizeStatus.ERROR,
                 sessionId,
                 undefined,
                 "Subagent did not run.",
@@ -731,7 +736,7 @@ export default function (pi: ExtensionAPI) {
             {
               type: "text",
               text: formatSubagentContent(
-                "ERROR",
+                FinalizeStatus.ERROR,
                 sessionId,
                 undefined,
                 fallback,
@@ -743,13 +748,13 @@ export default function (pi: ExtensionAPI) {
         };
       }
 
-      if (result.finalized.status === "ERROR") {
+      if (result.finalized.status === FinalizeStatus.ERROR) {
         return {
           content: [
             {
               type: "text",
               text: formatSubagentContent(
-                "ERROR",
+                FinalizeStatus.ERROR,
                 sessionId,
                 result.finalized.result,
                 result.finalized.error ?? "Subagent failed.",
@@ -766,7 +771,7 @@ export default function (pi: ExtensionAPI) {
           {
             type: "text",
             text: formatSubagentContent(
-              "SUCCESS",
+              FinalizeStatus.SUCCESS,
               sessionId,
               result.finalized.result,
             ),