fix: permanently resolve agent name duplication yo-yo bug

src/shared/agent-display-names.test.ts

@@ -187,10 +187,13 @@ describe("AGENT_DISPLAY_NAMES", () => {
       "sisyphus-junior": "Sisyphus-Junior",
       metis: "Metis (Plan Consultant)",
       momus: "Momus (Plan Critic)",
+      athena: "Athena (Council)",
+      "athena-junior": "Athena-Junior (Council)",
       oracle: "oracle",
       librarian: "librarian",
       explore: "explore",
       "multimodal-looker": "multimodal-looker",
+      "council-member": "council-member",
     }
 
     // when checking the constant

src/shared/agent-display-names.ts

@@ -11,10 +11,13 @@ export const AGENT_DISPLAY_NAMES: Record<string, string> = {
   "sisyphus-junior": "Sisyphus-Junior",
   metis: "Metis (Plan Consultant)",
   momus: "Momus (Plan Critic)",
+  athena: "Athena (Council)",
+  "athena-junior": "Athena-Junior (Council)",
   oracle: "oracle",
   librarian: "librarian",
   explore: "explore",
   "multimodal-looker": "multimodal-looker",
+  "council-member": "council-member",
 }
 
 /**
@@ -51,4 +54,32 @@ export function getAgentConfigKey(agentName: string): string {
   if (reversed !== undefined) return reversed
   if (AGENT_DISPLAY_NAMES[lower] !== undefined) return lower
   return lower
-}
+}
+
+/**
+ * Normalize an agent name for prompt APIs.
+ * - Known display names -> canonical display names
+ * - Known config keys (any case) -> canonical display names
+ * - Unknown/custom names -> preserved as-is (trimmed)
+ */
+export function normalizeAgentForPrompt(agentName: string | undefined): string | undefined {
+  if (typeof agentName !== "string") {
+    return undefined
+  }
+
+  const trimmed = agentName.trim()
+  if (!trimmed) {
+    return undefined
+  }
+
+  const lower = trimmed.toLowerCase()
+  const reversed = REVERSE_DISPLAY_NAMES[lower]
+  if (reversed !== undefined) {
+    return AGENT_DISPLAY_NAMES[reversed] ?? trimmed
+  }
+  if (AGENT_DISPLAY_NAMES[lower] !== undefined) {
+    return AGENT_DISPLAY_NAMES[lower]
+  }
+
+  return trimmed
+}