fix: preserve chained fallback origin

src/auto-reply/reply/agent-runner-execution.test.ts

@@ -3658,4 +3658,39 @@ describe("runAgentTurnWithFallback", () => {
       authProfileOverrideSource: "user",
     });
   });
+
+  it("preserves original auto-fallback origin across chained fallbacks", async () => {
+    const applyFallbackCandidateSelectionToEntry =
+      await getApplyFallbackCandidateSelectionToEntry();
+    const entry = {
+      sessionId: "session",
+      updatedAt: 1,
+      providerOverride: "openrouter",
+      modelOverride: "fallback-b",
+      modelOverrideSource: "auto" as const,
+      modelOverrideFallbackOriginProvider: "anthropic",
+      modelOverrideFallbackOriginModel: "claude-opus",
+    } as SessionEntry;
+
+    const { updated } = applyFallbackCandidateSelectionToEntry({
+      entry,
+      run: {
+        provider: "openrouter",
+        model: "fallback-b",
+      } as FollowupRun["run"],
+      provider: "openrouter",
+      model: "fallback-c",
+      now: 123,
+    });
+
+    expect(updated).toBe(true);
+    expect(entry).toMatchObject({
+      updatedAt: 123,
+      providerOverride: "openrouter",
+      modelOverride: "fallback-c",
+      modelOverrideSource: "auto",
+      modelOverrideFallbackOriginProvider: "anthropic",
+      modelOverrideFallbackOriginModel: "claude-opus",
+    });
+  });
 });

src/auto-reply/reply/agent-runner-execution.ts

@@ -242,6 +242,24 @@ function buildFallbackSelectionState(params: {
   };
 }
 
+function resolveFallbackSelectionOrigin(params: { entry: SessionEntry; run: FollowupRun["run"] }): {
+  provider: string;
+  model: string;
+} {
+  if (params.entry.modelOverrideSource === "auto") {
+    const persistedOriginProvider = normalizeOptionalString(
+      params.entry.modelOverrideFallbackOriginProvider,
+    );
+    const persistedOriginModel = normalizeOptionalString(
+      params.entry.modelOverrideFallbackOriginModel,
+    );
+    if (persistedOriginProvider && persistedOriginModel) {
+      return { provider: persistedOriginProvider, model: persistedOriginModel };
+    }
+  }
+  return { provider: params.run.provider, model: params.run.model };
+}
+
 export function applyFallbackCandidateSelectionToEntry(params: {
   entry: SessionEntry;
   run: FollowupRun["run"];
@@ -253,11 +271,12 @@ export function applyFallbackCandidateSelectionToEntry(params: {
     return { updated: false };
   }
   const scopedAuthProfile = resolveRunAuthProfile(params.run, params.provider);
+  const origin = resolveFallbackSelectionOrigin({ entry: params.entry, run: params.run });
   const nextState = buildFallbackSelectionState({
     provider: params.provider,
     model: params.model,
-    originProvider: params.run.provider,
-    originModel: params.run.model,
+    originProvider: origin.provider,
+    originModel: origin.model,
     authProfileId: scopedAuthProfile.authProfileId,
     authProfileIdSource: scopedAuthProfile.authProfileIdSource,
   });