fix: use display name in runtime-fallback retry

src/hooks/runtime-fallback/auto-retry.ts

@@ -9,6 +9,7 @@ import { SessionCategoryRegistry } from "../../shared/session-category-registry"
 import { buildRetryModelPayload } from "./retry-model-payload"
 import { getLastUserRetryParts } from "./last-user-retry-parts"
 import { extractSessionMessages } from "./session-messages"
+import { getAgentDisplayName } from "../../shared/agent-display-names"
 
 const SESSION_TTL_MS = 30 * 60 * 1000
 
@@ -126,13 +127,14 @@ export function createAutoRetryHelpers(deps: HookDeps) {
         })
 
         const retryAgent = resolvedAgent ?? getSessionAgent(sessionID)
+        const retryAgentDisplayName = retryAgent ? getAgentDisplayName(retryAgent) : undefined
         sessionAwaitingFallbackResult.add(sessionID)
         scheduleSessionFallbackTimeout(sessionID, retryAgent)
 
         await ctx.client.session.promptAsync({
           path: { id: sessionID },
           body: {
-            ...(retryAgent ? { agent: retryAgent } : {}),
+            ...(retryAgentDisplayName ? { agent: retryAgentDisplayName } : {}),
             ...retryModelPayload,
             parts: retryParts,
           },

src/hooks/runtime-fallback/index.test.ts

@@ -2404,7 +2404,7 @@ describe("runtime-fallback", () => {
 
       expect(promptCalls.length).toBe(1)
       const callBody = promptCalls[0]?.body as Record<string, unknown>
-      expect(callBody?.agent).toBe("prometheus")
+      expect(callBody?.agent).toBe("Prometheus (Plan Builder)")
       expect(callBody?.model).toEqual({ providerID: "github-copilot", modelID: "claude-opus-4.6" })
     })
   })