diff --git a/changelog.d/maintenance/0000-basered-autocombo-providercandidate.md b/changelog.d/maintenance/0000-basered-autocombo-providercandidate.md
new file mode 100644
index 0000000000..11a9ad3b6d
--- /dev/null
+++ b/changelog.d/maintenance/0000-basered-autocombo-providercandidate.md
@@ -0,0 +1 @@
+- Clear the `release/v3.8.51` typecheck base-red from #12731: the new `Mode pack ranking gates` candidates in `open-sse/services/autoCombo/__tests__/autoCombo.test.ts` omitted the required `provider`, `model` and `errorRate` fields of `ProviderCandidate`, failing `check:open-sse-typecheck` (and with it `Fast Quality Gates`) on every open PR.
diff --git a/open-sse/services/autoCombo/__tests__/autoCombo.test.ts b/open-sse/services/autoCombo/__tests__/autoCombo.test.ts
index e1821c002f..40eab61e00 100644
--- a/open-sse/services/autoCombo/__tests__/autoCombo.test.ts
+++ b/open-sse/services/autoCombo/__tests__/autoCombo.test.ts
@@ -261,8 +261,11 @@ describe("Mode pack ranking gates (cold/warm/health)", () => {
   }
   it("cold pool ranking unchanged (reliability 1, quality 0.5 neutrals)", () => {
     const a: ProviderCandidate = {
+      provider: "test-provider",
+      model: "test-model",
       circuitBreakerState: "CLOSED",
       failureRate: undefined,
+      errorRate: 0,
       quality: undefined,
       quotaRemaining: 50,
       quotaTotal: 100,
@@ -272,8 +275,11 @@ describe("Mode pack ranking gates (cold/warm/health)", () => {
       latencyStdDev: 10,
     };
     const b: ProviderCandidate = {
+      provider: "test-provider",
+      model: "test-model",
       circuitBreakerState: "CLOSED",
       failureRate: undefined,
+      errorRate: 0,
       quality: undefined,
       quotaRemaining: 50,
       quotaTotal: 100,
@@ -287,8 +293,11 @@ describe("Mode pack ranking gates (cold/warm/health)", () => {
   });
   it("warm reliability 0.01 vs 0.4 flips winner at health tie", () => {
     const highFail: ProviderCandidate = {
+      provider: "test-provider",
+      model: "test-model",
       circuitBreakerState: "CLOSED",
       failureRate: 0.4,
+      errorRate: 0,
       quality: 0.5,
       quotaRemaining: 50,
       quotaTotal: 100,
@@ -298,8 +307,11 @@ describe("Mode pack ranking gates (cold/warm/health)", () => {
       latencyStdDev: 10,
     };
     const lowFail: ProviderCandidate = {
+      provider: "test-provider",
+      model: "test-model",
       circuitBreakerState: "CLOSED",
       failureRate: 0.01,
+      errorRate: 0,
       quality: 0.5,
       quotaRemaining: 50,
       quotaTotal: 100,
@@ -313,8 +325,11 @@ describe("Mode pack ranking gates (cold/warm/health)", () => {
   });
   it("boundedRate NaN yields reliability 1", () => {
     const c: ProviderCandidate = {
+      provider: "test-provider",
+      model: "test-model",
       circuitBreakerState: "CLOSED",
       failureRate: NaN,
+      errorRate: 0,
       quotaRemaining: 50,
       quotaTotal: 100,
       costPer1MTokens: 1,
@@ -327,8 +342,11 @@ describe("Mode pack ranking gates (cold/warm/health)", () => {
   });
   it("health CLOSED vs HALF_OPEN still outweighs reliability gap", () => {
     const healthyHighFail: ProviderCandidate = {
+      provider: "test-provider",
+      model: "test-model",
       circuitBreakerState: "CLOSED",
       failureRate: 0.4,
+      errorRate: 0,
       quality: 0.5,
       quotaRemaining: 50,
       quotaTotal: 100,
@@ -338,8 +356,11 @@ describe("Mode pack ranking gates (cold/warm/health)", () => {
       latencyStdDev: 10,
     };
     const halfOpenLowFail: ProviderCandidate = {
+      provider: "test-provider",
+      model: "test-model",
       circuitBreakerState: "HALF_OPEN",
       failureRate: 0.01,
+      errorRate: 0,
       quality: 0.5,
       quotaRemaining: 50,
       quotaTotal: 100,