fix: short-circuit live model switch fallback redirects (#72375)

docs/concepts/model-failover.md

@@ -265,6 +265,7 @@ That means fallback retries have to coordinate with live model switching:
 - System-driven model changes such as fallback rotation, heartbeat overrides, or compaction never mark a pending live switch on their own.
 - Before a fallback retry starts, the reply runner persists the selected fallback override fields to the session entry.
 - Live-session reconciliation prefers persisted session overrides over stale runtime model fields.
+- If a live-switch error points at a later candidate in the active fallback chain, OpenClaw jumps directly to that selected model instead of walking unrelated candidates first.
 - If the fallback attempt fails, the runner rolls back only the override fields it wrote, and only if they still match that failed candidate.
 
 This prevents the classic race:

src/agents/model-fallback.test.ts

@@ -663,7 +663,7 @@ describe("runWithModelFallback", () => {
     expect(run).toHaveBeenCalledTimes(1);
   });
 
-  it("treats LiveSessionModelSwitchError as failover on last candidate (#58466)", async () => {
+  it("treats LiveSessionModelSwitchError as failover on last candidate (#58496 family)", async () => {
     const cfg = makeCfg();
     const switchError = new LiveSessionModelSwitchError({
       provider: "anthropic",
@@ -689,7 +689,7 @@ describe("runWithModelFallback", () => {
     expect(run).toHaveBeenCalledTimes(1);
   });
 
-  it("continues fallback chain past LiveSessionModelSwitchError to next candidate (#58466)", async () => {
+  it("continues fallback chain past LiveSessionModelSwitchError to next candidate (#58496 family)", async () => {
     const cfg = makeCfg();
     const switchError = new LiveSessionModelSwitchError({
       provider: "anthropic",
@@ -756,6 +756,30 @@ describe("runWithModelFallback", () => {
     ]);
   });
 
+  it("does not redirect stale live-session switch errors back to the current candidate (#58496 family)", async () => {
+    const cfg = makeCfg();
+    const switchError = new LiveSessionModelSwitchError({
+      provider: "openai",
+      model: "gpt-4.1-mini",
+    });
+    const run = vi.fn().mockRejectedValueOnce(switchError).mockResolvedValueOnce("ok");
+
+    const result = await runWithModelFallback({
+      cfg,
+      provider: "openai",
+      model: "gpt-4.1-mini",
+      run,
+    });
+
+    expect(result.result).toBe("ok");
+    expect(result.provider).toBe("anthropic");
+    expect(result.model).toBe("claude-haiku-3-5");
+    expect(run.mock.calls).toEqual([
+      ["openai", "gpt-4.1-mini"],
+      ["anthropic", "claude-haiku-3-5"],
+    ]);
+  });
+
   it("falls back on auth errors", async () => {
     await expectFallsBackToHaiku({
       provider: "openai",

src/agents/model-fallback.ts

@@ -326,16 +326,19 @@ function recordFailedCandidateAttempt(params: {
   });
 }
 
-function findLaterLiveSessionModelSwitchCandidateIndex(params: {
+function findLiveSessionModelSwitchRedirectIndex(params: {
   error: LiveSessionModelSwitchError;
   candidates: ModelCandidate[];
   currentIndex: number;
 }): number | null {
   const targetKey = modelKey(params.error.provider, params.error.model);
-  const targetIndex = params.candidates.findIndex(
-    (candidate) => modelKey(candidate.provider, candidate.model) === targetKey,
-  );
-  return targetIndex > params.currentIndex ? targetIndex : null;
+  for (let i = params.currentIndex + 1; i < params.candidates.length; i += 1) {
+    const candidate = params.candidates[i];
+    if (modelKey(candidate.provider, candidate.model) === targetKey) {
+      return i;
+    }
+  }
+  return null;
 }
 
 function throwFallbackFailureSummary(params: {
@@ -930,13 +933,12 @@ export async function runWithModelFallback<T>(params: {
           model: candidate.model,
         }) ?? err;
 
-      // LiveSessionModelSwitchError during fallback means the session's
-      // persisted model conflicts with this fallback candidate.  Treat it
-      // as a known failover so the chain continues to the next candidate
-      // instead of re-throwing and triggering infinite retry loops in the
-      // outer runner.  (#58466)
+      // LiveSessionModelSwitchError during fallback may point at a later
+      // candidate that is already the active live-session selection.  Jump
+      // there directly.  Stale same/earlier targets remain a known failover
+      // so the outer runner cannot loop on the conflicting model.
       if (err instanceof LiveSessionModelSwitchError) {
-        const liveSwitchTargetIndex = findLaterLiveSessionModelSwitchCandidateIndex({
+        const liveSwitchTargetIndex = findLiveSessionModelSwitchRedirectIndex({
           error: err,
           candidates,
           currentIndex: i,