fix(agents): avoid duplicate same-provider cooldown probes in fallback runs (#41711)

Merged via squash.

Prepared head SHA: 8be8967bcb4be81f6abc5ff078644ec4efcfe7a0
Co-authored-by: cgdusek <38732970+cgdusek@users.noreply.github.com>
Co-authored-by: altaywtf <9790196+altaywtf@users.noreply.github.com>
Reviewed-by: @altaywtf

CHANGELOG.md

@@ -59,6 +59,7 @@ Docs: https://docs.openclaw.ai
 - Mattermost/plugin send actions: normalize direct `replyTo` fallback handling so threaded plugin sends trim blank IDs and reuse the correct reply target again. (#41176) Thanks @hnykda.
 - MS Teams/allowlist resolution: use the General channel conversation ID as the resolved team key (with Graph GUID fallback) so Bot Framework runtime `channelData.team.id` matching works for team and team/channel allowlist entries. (#41838) Thanks @BradGroux.
 - Mattermost/Markdown formatting: preserve first-line indentation when stripping bot mentions so nested list items and indented code blocks keep their structure, and render Mattermost tables natively by default instead of fenced-code fallback. (#18655) thanks @echo931.
+- Agents/fallback cooldown probing: cap cooldown-bypass probing to one attempt per provider per fallback run so multi-model same-provider cooldown chains can continue to cross-provider fallbacks instead of repeatedly stalling on duplicate cooldown probes. (#41711) Thanks @cgdusek.
 
 ## 2026.3.8
 

src/agents/model-fallback.test.ts

@@ -1318,6 +1318,86 @@ describe("runWithModelFallback", () => {
       }); // Rate limit allows attempt
       expect(run).toHaveBeenNthCalledWith(2, "groq", "llama-3.3-70b-versatile"); // Cross-provider works
     });
+
+    it("limits cooldown probes to one per provider before moving to cross-provider fallback", async () => {
+      const { dir } = await makeAuthStoreWithCooldown("anthropic", "rate_limit");
+      const cfg = makeCfg({
+        agents: {
+          defaults: {
+            model: {
+              primary: "anthropic/claude-opus-4-6",
+              fallbacks: [
+                "anthropic/claude-sonnet-4-5",
+                "anthropic/claude-haiku-3-5",
+                "groq/llama-3.3-70b-versatile",
+              ],
+            },
+          },
+        },
+      });
+
+      const run = vi
+        .fn()
+        .mockRejectedValueOnce(new Error("Still rate limited")) // First same-provider probe fails
+        .mockResolvedValueOnce("groq success"); // Next provider succeeds
+
+      const result = await runWithModelFallback({
+        cfg,
+        provider: "anthropic",
+        model: "claude-opus-4-6",
+        run,
+        agentDir: dir,
+      });
+
+      expect(result.result).toBe("groq success");
+      // Primary is skipped, first same-provider fallback is probed, second same-provider fallback
+      // is skipped (probe already attempted), then cross-provider fallback runs.
+      expect(run).toHaveBeenCalledTimes(2);
+      expect(run).toHaveBeenNthCalledWith(1, "anthropic", "claude-sonnet-4-5", {
+        allowTransientCooldownProbe: true,
+      });
+      expect(run).toHaveBeenNthCalledWith(2, "groq", "llama-3.3-70b-versatile");
+    });
+
+    it("does not consume transient probe slot when first same-provider probe fails with model_not_found", async () => {
+      const { dir } = await makeAuthStoreWithCooldown("anthropic", "rate_limit");
+      const cfg = makeCfg({
+        agents: {
+          defaults: {
+            model: {
+              primary: "anthropic/claude-opus-4-6",
+              fallbacks: [
+                "anthropic/claude-sonnet-4-5",
+                "anthropic/claude-haiku-3-5",
+                "groq/llama-3.3-70b-versatile",
+              ],
+            },
+          },
+        },
+      });
+
+      const run = vi
+        .fn()
+        .mockRejectedValueOnce(new Error("Model not found: anthropic/claude-sonnet-4-5"))
+        .mockResolvedValueOnce("haiku success");
+
+      const result = await runWithModelFallback({
+        cfg,
+        provider: "anthropic",
+        model: "claude-opus-4-6",
+        run,
+        agentDir: dir,
+      });
+
+      expect(result.result).toBe("haiku success");
+      expect(run).toHaveBeenCalledTimes(2);
+      expect(run).toHaveBeenNthCalledWith(1, "anthropic", "claude-sonnet-4-5", {
+        allowTransientCooldownProbe: true,
+      });
+      expect(run).toHaveBeenNthCalledWith(2, "anthropic", "claude-haiku-3-5", {
+        allowTransientCooldownProbe: true,
+      });
+    });
   });
 });
 

src/agents/model-fallback.ts

@@ -521,6 +521,7 @@ export async function runWithModelFallback<T>(params: {
     : null;
   const attempts: FallbackAttempt[] = [];
   let lastError: unknown;
+  const cooldownProbeUsedProviders = new Set<string>();
 
   const hasFallbackCandidates = candidates.length > 1;
 
@@ -531,6 +532,7 @@ export async function runWithModelFallback<T>(params: {
       params.provider === candidate.provider && params.model === candidate.model;
     let runOptions: ModelFallbackRunOptions | undefined;
     let attemptedDuringCooldown = false;
+    let transientProbeProviderForAttempt: string | null = null;
     if (authStore) {
       const profileIds = resolveAuthProfileOrder({
         cfg: params.cfg,
@@ -588,7 +590,41 @@ export async function runWithModelFallback<T>(params: {
           decision.reason === "overloaded" ||
           decision.reason === "billing"
         ) {
+          // Probe at most once per provider per fallback run when all profiles
+          // are cooldowned. Re-probing every same-provider candidate can stall
+          // cross-provider fallback on providers with long internal retries.
+          const isTransientCooldownReason =
+            decision.reason === "rate_limit" || decision.reason === "overloaded";
+          if (isTransientCooldownReason && cooldownProbeUsedProviders.has(candidate.provider)) {
+            const error = `Provider ${candidate.provider} is in cooldown (probe already attempted this run)`;
+            attempts.push({
+              provider: candidate.provider,
+              model: candidate.model,
+              error,
+              reason: decision.reason,
+            });
+            logModelFallbackDecision({
+              decision: "skip_candidate",
+              runId: params.runId,
+              requestedProvider: params.provider,
+              requestedModel: params.model,
+              candidate,
+              attempt: i + 1,
+              total: candidates.length,
+              reason: decision.reason,
+              error,
+              nextCandidate: candidates[i + 1],
+              isPrimary,
+              requestedModelMatched: requestedModel,
+              fallbackConfigured: hasFallbackCandidates,
+              profileCount: profileIds.length,
+            });
+            continue;
+          }
           runOptions = { allowTransientCooldownProbe: true };
+          if (isTransientCooldownReason) {
+            transientProbeProviderForAttempt = candidate.provider;
+          }
         }
         attemptedDuringCooldown = true;
         logModelFallbackDecision({
@@ -643,6 +679,18 @@ export async function runWithModelFallback<T>(params: {
     }
     const err = attemptRun.error;
     {
+      if (transientProbeProviderForAttempt) {
+        const probeFailureReason = describeFailoverError(err).reason;
+        const shouldPreserveTransientProbeSlot =
+          probeFailureReason === "model_not_found" ||
+          probeFailureReason === "format" ||
+          probeFailureReason === "auth" ||
+          probeFailureReason === "auth_permanent" ||
+          probeFailureReason === "session_expired";
+        if (!shouldPreserveTransientProbeSlot) {
+          cooldownProbeUsedProviders.add(transientProbeProviderForAttempt);
+        }
+      }
       // Context overflow errors should be handled by the inner runner's
       // compaction/retry logic, not by model fallback.  If one escapes as a
       // throw, rethrow it immediately rather than trying a different model