hackerai-tech · ross0x01 · Aug 14, 2026 · Aug 13, 2026
diff --git a/lib/ai/__tests__/providers.test.ts b/lib/ai/__tests__/providers.test.ts
@@ -2,6 +2,7 @@ import {
   getModelCutoffDate,
   getModelDisplayName,
   isAnthropicModel,
+  isDeepSeekModel,
   isKimiModel,
   createTrackedProvider,
   myProvider,
@@ -41,6 +42,13 @@ describe("provider registry", () => {
       (myProvider.languageModel("model-grok-4.6-pro") as { modelId: string })
         .modelId,
     ).toBe("x-ai/grok-4.6");
+    expect(
+      (
+        myProvider.languageModel("model-deepseek-v4-pro-0813") as {
+          modelId: string;
+        }
+      ).modelId,
+    ).toBe("deepseek/deepseek-v4-pro-0813");
     expect(
       (myProvider.languageModel("model-glm-5.2") as { modelId: string })
         .modelId,
@@ -72,6 +80,12 @@ describe("provider registry", () => {
     expect(getModelDisplayName("model-grok-4.5-pro")).toBe("xAI Grok 4.6");
     expect(getModelDisplayName("model-grok-4.6-pro")).toBe("xAI Grok 4.6");
     expect(getModelCutoffDate("model-grok-4.6-pro")).toBe("August 2026");
+    expect(getModelDisplayName("model-deepseek-v4-pro-0813")).toBe(
+      "DeepSeek V4 Pro 0813",
+    );
+    expect(getModelCutoffDate("model-deepseek-v4-pro-0813")).toBe(
+      "August 2026",
+    );
     expect(getModelDisplayName("model-glm-5.2")).toBe("Z.ai GLM 5.2");
     expect(getModelDisplayName("model-kimi-k3")).toBe("Moonshot Kimi K3");
     expect(getModelCutoffDate("model-opus-4.6")).toBe("July 2026");
@@ -87,6 +101,11 @@ describe("provider registry", () => {
     expect(isAnthropicModel("anthropic/claude-opus-4.6")).toBe(true);
   });
 
+  it("classifies both DeepSeek V4 Pro experiment routes as DeepSeek", () => {
+    expect(isDeepSeekModel("model-deepseek-v4-pro")).toBe(true);
+    expect(isDeepSeekModel("model-deepseek-v4-pro-0813")).toBe(true);
+  });
+
   it("keeps tracked free routes split by mode", () => {
     const provider = createTrackedProvider();
     expect(
@@ -273,6 +292,9 @@ describe("supportsMultimodalToolResults", () => {
   it("rejects text-only DeepSeek model keys", () => {
     expect(supportsMultimodalToolResults("agent-model-free")).toBe(false);
     expect(supportsMultimodalToolResults("model-deepseek-v4-pro")).toBe(false);
+    expect(supportsMultimodalToolResults("model-deepseek-v4-pro-0813")).toBe(
+      false,
+    );
   });
 
   it.each([

diff --git a/lib/ai/providers.ts b/lib/ai/providers.ts
@@ -182,6 +182,8 @@ type OpenRouterInstance = typeof openrouter;
 export const KIMI_K3_SLUG = "moonshotai/kimi-k3";
 export const GLM_5_2_SLUG = "z-ai/glm-5.2";
 export const GROK_4_6_SLUG = "x-ai/grok-4.6";
+export const DEEPSEEK_V4_PRO_SLUG = "deepseek/deepseek-v4-pro";
+export const DEEPSEEK_V4_PRO_0813_SLUG = "deepseek/deepseek-v4-pro-0813";
 export const DEEPSEEK_V4_FLASH_SLUG = "deepseek/deepseek-v4-flash-0731";
 export const DEEPSEEK_V4_FLASH_PREVIOUS_SLUG = "deepseek/deepseek-v4-flash";
 const TITLE_GENERATOR_DEEPSEEK_SLUG = "deepseek/deepseek-v4-flash";
@@ -209,7 +211,10 @@ const buildProviderMap = (
     "model-grok-4.5": or(GROK_4_6_SLUG),
     "model-grok-4.5-pro": or(GROK_4_6_SLUG),
     "model-grok-4.6-pro": or(GROK_4_6_SLUG),
-    "model-deepseek-v4-pro": or("deepseek/deepseek-v4-pro"),
+    "model-deepseek-v4-pro": or(DEEPSEEK_V4_PRO_SLUG),
+    // HAC-68 treatment alias. Auto and Standard keep their persisted tier
+    // while the server-side experiment chooses the provider route per user.
+    "model-deepseek-v4-pro-0813": or(DEEPSEEK_V4_PRO_0813_SLUG),
     // Keep the persisted Max compatibility key while routing new requests to
     // Kimi K3. Renaming the key would invalidate existing stored selections.
     "model-opus-4.6": or(KIMI_K3_SLUG),
@@ -236,6 +241,7 @@ export const modelCutoffDates: Partial<Record<ModelName, string>> &
   "model-grok-4.5-pro": "August 2026",
   "model-grok-4.6-pro": "August 2026",
   "model-deepseek-v4-pro": "May 2025",
+  "model-deepseek-v4-pro-0813": "August 2026",
   "model-opus-4.6": "July 2026",
   "model-glm-5.2": "June 2026",
   "fallback-agent-model": "August 2026",
@@ -255,6 +261,7 @@ export const modelDisplayNames: Record<ModelName, string> &
   "model-grok-4.5-pro": "xAI Grok 4.6",
   "model-grok-4.6-pro": "xAI Grok 4.6",
   "model-deepseek-v4-pro": "DeepSeek V4 Pro",
+  "model-deepseek-v4-pro-0813": "DeepSeek V4 Pro 0813",
   "model-opus-4.6": "Moonshot Kimi K3",
   "model-glm-5.2": "Z.ai GLM 5.2",
   "model-kimi-k3": "Moonshot Kimi K3",
@@ -283,7 +290,8 @@ export function isDeepSeekModel(modelName: string): boolean {
   return (
     modelName === "ask-model-free" ||
     modelName === "agent-model-free" ||
-    modelName === "model-deepseek-v4-pro"
+    modelName === "model-deepseek-v4-pro" ||
+    modelName === "model-deepseek-v4-pro-0813"
   );
 }
 

diff --git a/lib/api/__tests__/chat-stream-helpers-fallback.test.ts b/lib/api/__tests__/chat-stream-helpers-fallback.test.ts
@@ -32,6 +32,7 @@ const DEEPSEEK_FLASH_CANONICAL_SLUG = "deepseek/deepseek-v4-flash-20260731";
 const DEEPSEEK_FLASH_PREVIOUS_SLUG = "deepseek/deepseek-v4-flash";
 const DEEPSEEK_FLASH_PREVIOUS_CANONICAL_SLUG =
   "deepseek/deepseek-v4-flash-20260423";
+const DEEPSEEK_V4_PRO_SLUG = "deepseek/deepseek-v4-pro";
 const MEDIUM_GROK_PRIMARY_MODELS = [
   "ask-model",
   "agent-model",
@@ -43,6 +44,7 @@ const HIGH_GROK_PRIMARY_OR_FALLBACK_MODELS = [
   "model-grok-4.5-pro",
   "model-grok-4.6-pro",
   "model-deepseek-v4-pro",
+  "model-deepseek-v4-pro-0813",
   "model-opus-4.6",
   "model-glm-5.2",
   "model-kimi-k3",
@@ -288,6 +290,19 @@ describe("buildProviderOptions fallback chain", () => {
     });
   });
 
+  it("falls back from DeepSeek V4 Pro 0813 through the control route, Grok, then Kimi K3", () => {
+    const opts = buildProviderOptions(
+      false,
+      "user-1",
+      "model-deepseek-v4-pro-0813",
+      "ask",
+    );
+    expect(opts.openrouter).toMatchObject({
+      models: [DEEPSEEK_V4_PRO_SLUG, GROK_SLUG, KIMI_K3_SLUG],
+      user: "user-1",
+    });
+  });
+
   it("falls back from the Grok-backed paid Ask image route to Kimi K3", () => {
     const opts = buildProviderOptions(false, "user-1", "ask-model", "ask");
     expect(opts.openrouter).toMatchObject({
@@ -632,6 +647,12 @@ describe("getRetryFallbackModel", () => {
     );
   });
 
+  it("retries the DeepSeek 0813 treatment with the current DeepSeek route", () => {
+    expect(getRetryFallbackModel("model-deepseek-v4-pro-0813", "ask")).toBe(
+      "model-deepseek-v4-pro",
+    );
+  });
+
   it("retries Kimi K3 with the active Grok route", () => {
     expect(getRetryFallbackModel("model-kimi-k3", "agent")).toBe(
       "model-grok-4.6",

diff --git a/lib/api/chat-handler.ts b/lib/api/chat-handler.ts
@@ -146,6 +146,12 @@ import { phLogger } from "@/lib/posthog/server";
 import { PAID_FUNNEL_EVENTS } from "@/lib/analytics/paid-funnel";
 import { readAnalyticsRequestContext } from "@/lib/analytics/request-context";
 import { buildAgentStepLimitTelemetry } from "@/lib/analytics/agent-step-limit-telemetry";
+import {
+  captureDeepSeekV4Pro0813ExperimentExposure,
+  evaluateDeepSeekV4Pro0813Experiment,
+  getActiveDeepSeekV4Pro0813ExperimentAssignment,
+  getDeepSeekV4Pro0813ExperimentContext,
+} from "@/lib/experiments/deepseek-v4-pro-0813";
 import {
   capturePaidDailyFreeAllowanceServerEvent,
   createPaidDailyFreeAllowanceBudgetSnapshot,
@@ -424,6 +430,17 @@ export const createChatHandler = () => {
         );
       }
 
+      const deepSeekV4Pro0813Experiment =
+        await evaluateDeepSeekV4Pro0813Experiment({
+          posthog: (posthog ??= PostHogClient()),
+          userId,
+          selectedModel,
+          requestId: req.headers.get("x-vercel-id") ?? undefined,
+        });
+      if (deepSeekV4Pro0813Experiment) {
+        selectedModel = deepSeekV4Pro0813Experiment.modelKey;
+      }
+
       const notesEnabled =
         (subscription !== "free" || isAgentMode(mode)) &&
         (userCustomization?.include_notes ?? true);
@@ -559,6 +576,15 @@ export const createChatHandler = () => {
         });
       }
 
+      const activeDeepSeekV4Pro0813Experiment =
+        getActiveDeepSeekV4Pro0813ExperimentAssignment(
+          deepSeekV4Pro0813Experiment,
+          selectedModel,
+        );
+      const routingExperimentContext = getDeepSeekV4Pro0813ExperimentContext(
+        activeDeepSeekV4Pro0813Experiment,
+      );
+
       const freeMonthlyBudgetSnapshot =
         subscription === "free"
           ? await checkFreeMonthlyCostLimit(freeUsageSubject)
@@ -1110,6 +1136,7 @@ export const createChatHandler = () => {
                   usage: usageCostRecord,
                   responseModel: state.responseModel,
                   analyticsRequestContext,
+                  experiment: routingExperimentContext,
                   fallbackServed:
                     state.responseModel && retryUsedFallbackModel
                       ? true
@@ -1315,6 +1342,16 @@ export const createChatHandler = () => {
 
             let result;
             try {
+              captureDeepSeekV4Pro0813ExperimentExposure({
+                posthog,
+                userId,
+                subscription,
+                mode,
+                selectedModelOverride,
+                selectedModel,
+                configuredModel: configuredModelId,
+                assignment: activeDeepSeekV4Pro0813Experiment,
+              });
               result = await createStream(selectedModel);
             } catch (error) {
               // If provider returns an API error before streaming, retry with fallback.
@@ -1678,6 +1715,7 @@ export const createChatHandler = () => {
                                   finishReason: state.streamFinishReason,
                                   budgetAbortDetails: state.budgetAbortDetails,
                                   isAutoContinue: !!isAutoContinue,
+                                  experiment: routingExperimentContext,
                                   stepLimitTelemetry:
                                     buildAgentStepLimitTelemetry({
                                       configuredMaxSteps:
@@ -1993,6 +2031,7 @@ export const createChatHandler = () => {
                       finishReason: state.streamFinishReason,
                       budgetAbortDetails: state.budgetAbortDetails,
                       isAutoContinue: !!isAutoContinue,
+                      experiment: routingExperimentContext,
                       stepLimitTelemetry: buildAgentStepLimitTelemetry({
                         configuredMaxSteps: state.configuredMaxSteps,
                         stepCount: state.agentStepCount,

diff --git a/lib/api/chat-stream-helpers.ts b/lib/api/chat-stream-helpers.ts
@@ -541,6 +541,13 @@ const AGENT_TEXT_FALLBACK_CHAIN = [
   "model-kimi-k3",
 ] as const satisfies readonly ModelName[];
 
+// HAC-68 treatment falls back through today's DeepSeek route before the
+// existing Grok/Kimi recovery chain.
+const DEEPSEEK_V4_PRO_0813_FALLBACK_CHAIN = [
+  "model-deepseek-v4-pro",
+  ...AGENT_TEXT_FALLBACK_CHAIN,
+] as const satisfies readonly ModelName[];
+
 // HackerAI Pro uses Grok 4.6 for every request. GLM 5.2 remains its first
 // fallback, followed by Kimi K3 so media requests still have a multimodal final
 // recovery path if both primary providers are unavailable.
@@ -553,6 +560,7 @@ const MODEL_FALLBACK_CHAIN: Partial<Record<ModelName, readonly ModelName[]>> = {
   "ask-model-free": AGENT_TEXT_FALLBACK_CHAIN,
   "agent-model-free": AGENT_TEXT_FALLBACK_CHAIN,
   "model-deepseek-v4-pro": AGENT_TEXT_FALLBACK_CHAIN,
+  "model-deepseek-v4-pro-0813": DEEPSEEK_V4_PRO_0813_FALLBACK_CHAIN,
   "ask-model": GROK_4_6_FALLBACK_CHAIN,
   "agent-model": GROK_4_6_FALLBACK_CHAIN,
   "model-grok-4.6": GROK_4_6_FALLBACK_CHAIN,
@@ -642,6 +650,9 @@ export function getRetryFallbackModel(
   modelName: ModelName,
   _mode: ChatMode,
 ): ModelName {
+  if (modelName === "model-deepseek-v4-pro-0813") {
+    return "model-deepseek-v4-pro";
+  }
   if (
     modelName === "model-grok-4.6-pro" ||
     modelName === "model-grok-4.5-pro"

diff --git a/lib/experiments/__tests__/deepseek-v4-pro-0813.test.ts b/lib/experiments/__tests__/deepseek-v4-pro-0813.test.ts
@@ -0,0 +1,122 @@
+import {
+  captureDeepSeekV4Pro0813ExperimentExposure,
+  DEEPSEEK_V4_PRO_0813_EXPERIMENT_KEY,
+  DEEPSEEK_V4_PRO_0813_EXPOSURE_EVENT,
+  DEEPSEEK_V4_PRO_0813_FEATURE_PROPERTY,
+  evaluateDeepSeekV4Pro0813Experiment,
+  getActiveDeepSeekV4Pro0813ExperimentAssignment,
+  getDeepSeekV4Pro0813ExperimentContext,
+  isEligibleForDeepSeekV4Pro0813Experiment,
+} from "@/lib/experiments/deepseek-v4-pro-0813";
+
+describe("DeepSeek V4 Pro 0813 experiment", () => {
+  it("only evaluates requests already resolved to the current DeepSeek V4 Pro route", () => {
+    expect(
+      isEligibleForDeepSeekV4Pro0813Experiment("model-deepseek-v4-pro"),
+    ).toBe(true);
+    expect(isEligibleForDeepSeekV4Pro0813Experiment("model-grok-4.5")).toBe(
+      false,
+    );
+    expect(isEligibleForDeepSeekV4Pro0813Experiment("agent-model-free")).toBe(
+      false,
+    );
+  });
+
+  it.each([
+    ["control", "model-deepseek-v4-pro"],
+    ["test", "model-deepseek-v4-pro-0813"],
+  ] as const)("maps %s to %s", async (variant, modelKey) => {
+    const evaluateFlags = jest.fn(async () => ({ getFlag: () => variant }));
+
+    await expect(
+      evaluateDeepSeekV4Pro0813Experiment({
+        posthog: { evaluateFlags } as never,
+        userId: "user-1",
+        selectedModel: "model-deepseek-v4-pro",
+      }),
+    ).resolves.toEqual({
+      key: DEEPSEEK_V4_PRO_0813_EXPERIMENT_KEY,
+      variant,
+      modelKey,
+    });
+  });
+
+  it("does not evaluate ineligible routes", async () => {
+    const evaluateFlags = jest.fn();
+
+    await expect(
+      evaluateDeepSeekV4Pro0813Experiment({
+        posthog: { evaluateFlags } as never,
+        userId: "user-1",
+        selectedModel: "model-grok-4.5",
+      }),
+    ).resolves.toBeUndefined();
+    expect(evaluateFlags).not.toHaveBeenCalled();
+  });
+
+  it("fails closed when evaluation returns an unknown value", async () => {
+    await expect(
+      evaluateDeepSeekV4Pro0813Experiment({
+        posthog: {
+          evaluateFlags: jest.fn(async () => ({ getFlag: () => true })),
+        } as never,
+        userId: "user-1",
+        selectedModel: "model-deepseek-v4-pro",
+      }),
+    ).resolves.toBeUndefined();
+  });
+
+  it("captures a privacy-safe custom exposure from the provider surface", () => {
+    const capture = jest.fn();
+    const assignment = {
+      key: DEEPSEEK_V4_PRO_0813_EXPERIMENT_KEY,
+      variant: "test" as const,
+      modelKey: "model-deepseek-v4-pro-0813" as const,
+    };
+
+    captureDeepSeekV4Pro0813ExperimentExposure({
+      posthog: { capture } as never,
+      userId: "user-1",
+      subscription: "pro",
+      mode: "agent",
+      selectedModelOverride: "hackerai-standard",
+      selectedModel: assignment.modelKey,
+      configuredModel: "deepseek/deepseek-v4-pro-0813",
+      assignment,
+    });
+
+    expect(capture).toHaveBeenCalledWith({
+      distinctId: "user-1",
+      event: DEEPSEEK_V4_PRO_0813_EXPOSURE_EVENT,
+      properties: {
+        experiment_key: DEEPSEEK_V4_PRO_0813_EXPERIMENT_KEY,
+        experiment_variant: "test",
+        [DEEPSEEK_V4_PRO_0813_FEATURE_PROPERTY]: "test",
+        subscription: "pro",
+        subscription_tier: "pro",
+        mode: "agent",
+        selected_model: "model-deepseek-v4-pro-0813",
+        selected_model_override: "hackerai-standard",
+        configured_model: "deepseek/deepseek-v4-pro-0813",
+        exposure_surface: "provider_request",
+        $process_person_profile: false,
+      },
+    });
+    expect(getDeepSeekV4Pro0813ExperimentContext(assignment)).toEqual({
+      key: DEEPSEEK_V4_PRO_0813_EXPERIMENT_KEY,
+      variant: "test",
+    });
+    expect(
+      getActiveDeepSeekV4Pro0813ExperimentAssignment(
+        assignment,
+        "model-deepseek-v4-pro-0813",
+      ),
+    ).toBe(assignment);
+    expect(
+      getActiveDeepSeekV4Pro0813ExperimentAssignment(
+        assignment,
+        "model-grok-4.5",
+      ),
+    ).toBeUndefined();
+  });
+});