diff --git a/ui/litellm-dashboard/src/components/add_model/ClassificationMethodConfig.tsx b/ui/litellm-dashboard/src/components/add_model/ClassificationMethodConfig.tsx
index 8a982556a51..4eaab3f3af9 100644
--- a/ui/litellm-dashboard/src/components/add_model/ClassificationMethodConfig.tsx
+++ b/ui/litellm-dashboard/src/components/add_model/ClassificationMethodConfig.tsx
@@ -10,6 +10,8 @@ import { RadioGroup, RadioGroupItem } from "@/components/ui/radio-group";
 import { Switch } from "@/components/ui/switch";
 import React from "react";
 import ClassifierPromptEditor from "./ClassifierPromptEditor";
+import ClassificationPromptEditor from "./ClassificationPromptEditor";
+import { Restricted, restrictedBy } from "./TierRestrictions";
 import HeuristicScoringConfig from "./HeuristicScoringConfig";
 import { useComplexityScorerDefaults } from "@/app/(dashboard)/hooks/autoRouter/useComplexityScorerDefaults";
 import {
@@ -32,9 +34,6 @@ import {
   DEFAULT_HEURISTIC_FIRST_MAX_TIER,
   HEURISTIC_FIRST_MAX_TIER_KEYS,
   effectiveClassifierType,
-  heuristicScoringRole,
-  restrictedBy,
-  Restricted,
 } from "./ComplexityRouterConfig";
 
 const DEFAULT_SCORING_EXPLANATION =
@@ -202,6 +201,10 @@ const ClassificationMethodConfig: React.FC<ClassificationMethodConfigProps> = ({
     onChange({ ...value, heuristic_first_max_tier: tier });
   };
 
+  const handleClassificationPromptChange = (classificationPrompt: string | undefined) => {
+    onChange({ ...value, classification_prompt: classificationPrompt });
+  };
+
   const handleClassifierModelChange = (model: string) => {
     onChange({
       ...value,
@@ -414,7 +417,13 @@ const ClassificationMethodConfig: React.FC<ClassificationMethodConfigProps> = ({
           </div>
           <div>
             <strong className="block mb-1 font-semibold">Classifier Prompt</strong>
-            <Restricted by={restrictedBy(value, "classifierPrompt")}>
+            {value.custom_tier_set ? (
+              <ClassificationPromptEditor
+                classificationPrompt={value.classification_prompt}
+                onChange={handleClassificationPromptChange}
+                tierRows={value.custom_tier_set.tiers}
+              />
+            ) : (
               <ClassifierPromptEditor
                 systemPrompt={value.classifier_llm_config?.system_prompt}
                 onChange={handleClassifierSystemPromptChange}
@@ -422,7 +431,7 @@ const ClassificationMethodConfig: React.FC<ClassificationMethodConfigProps> = ({
                 tierLabels={value.tier_labels}
                 classificationRubric={classificationRubric}
               />
-            </Restricted>
+            )}
           </div>
           <div>
             <strong className="block mb-1 font-semibold">If the classifier fails</strong>
diff --git a/ui/litellm-dashboard/src/components/add_model/ClassificationPromptEditor.tsx b/ui/litellm-dashboard/src/components/add_model/ClassificationPromptEditor.tsx
new file mode 100644
index 00000000000..1840eaea13c
--- /dev/null
+++ b/ui/litellm-dashboard/src/components/add_model/ClassificationPromptEditor.tsx
@@ -0,0 +1,101 @@
+import React, { useState } from "react";
+import { Button } from "@/components/ui/button";
+import { Dialog, DialogContent, DialogFooter, DialogHeader, DialogTitle } from "@/components/ui/dialog";
+import { Textarea } from "@/components/ui/textarea";
+import { TierRow, activeTierName } from "./tier_rows";
+
+interface ClassificationPromptEditorProps {
+  classificationPrompt: string | undefined;
+  onChange: (classificationPrompt: string | undefined) => void;
+  tierRows: readonly TierRow[];
+}
+
+const PLACEHOLDER = `Classify the request into exactly one tier for a payments engineering team.
+
+Examples:
+- "bump the copy on the checkout button" -> TRIAGE
+- "why is our webhook signature check failing" -> SECURITY_REVIEW`;
+
+const appendedTierBullets = (tierRows: readonly TierRow[]): string =>
+  tierRows.map((row) => `- ${activeTierName(row)}: ${row.definition}`).join("\n");
+
+const ClassificationPromptEditor: React.FC<ClassificationPromptEditorProps> = ({
+  classificationPrompt,
+  onChange,
+  tierRows,
+}) => {
+  const [isOpen, setIsOpen] = useState(false);
+  const [draft, setDraft] = useState("");
+  const isOverridden = Boolean(classificationPrompt?.trim());
+
+  const openEditor = () => {
+    setDraft(classificationPrompt ?? "");
+    setIsOpen(true);
+  };
+
+  const handleSave = () => {
+    onChange(draft.trim() || undefined);
+    setIsOpen(false);
+  };
+
+  return (
+    <div>
+      <div className="flex items-center gap-2">
+        <Button type="button" size="sm" variant="outline" onClick={openEditor}>
+          {isOverridden ? "Edit opening instructions" : "Change default prompt"}
+        </Button>
+        {isOverridden && (
+          <Button type="button" size="sm" variant="link" onClick={() => onChange(undefined)}>
+            Reset to default
+          </Button>
+        )}
+      </div>
+      <p className="mt-1 text-xs text-muted-foreground">
+        {isOverridden
+          ? "This router opens its classifier prompt with your own instructions."
+          : "Replace the opening instructions, and write calibration examples of your own. Your tier definitions and the injection guard are always appended below them."}
+      </p>
+
+      <Dialog open={isOpen} onOpenChange={setIsOpen}>
+        <DialogContent className="sm:max-w-3xl max-h-[90vh] overflow-y-auto">
+          <DialogHeader>
+            <DialogTitle>Classifier prompt</DialogTitle>
+          </DialogHeader>
+
+          <p className="text-sm text-muted-foreground">
+            Your text is the opening of the classifier prompt, so it is where calibration examples of your own belong.
+            The router appends your tier definitions and its injection guard underneath, and neither can be edited or
+            removed from here. Edit the definitions themselves with Edit tiers above.
+          </p>
+
+          <Textarea
+            value={draft}
+            onChange={(e) => setDraft(e.target.value)}
+            rows={12}
+            placeholder={PLACEHOLDER}
+            aria-label="Classifier opening instructions"
+            className="mt-3 font-mono text-xs"
+          />
+
+          <div className="mt-3">
+            <p className="text-xs font-medium">Always appended below your text</p>
+            <pre className="mt-1 overflow-x-auto rounded-md bg-muted p-3 font-mono text-xs text-muted-foreground">
+              {`Tiers:\n${appendedTierBullets(tierRows)}\n\n<injection guard and closing line>`}
+            </pre>
+          </div>
+
+          <DialogFooter className="mt-4">
+            <Button type="button" variant="outline" onClick={() => setIsOpen(false)}>
+              Cancel
+            </Button>
+            <Button type="button" onClick={handleSave}>
+              Save prompt
+            </Button>
+          </DialogFooter>
+        </DialogContent>
+      </Dialog>
+    </div>
+  );
+};
+
+export default ClassificationPromptEditor;
diff --git a/ui/litellm-dashboard/src/components/add_model/ComplexityRouterConfig.test.tsx b/ui/litellm-dashboard/src/components/add_model/ComplexityRouterConfig.test.tsx
index f9572371b17..b517f27cdf6 100644
--- a/ui/litellm-dashboard/src/components/add_model/ComplexityRouterConfig.test.tsx
+++ b/ui/litellm-dashboard/src/components/add_model/ComplexityRouterConfig.test.tsx
@@ -1298,6 +1298,26 @@ describe("ComplexityRouterConfig tier editing", () => {
     ).toBeInTheDocument();
   });
 
+  it("lets an edited tier set write its own opening instructions instead of refusing a prompt outright", () => {
+    renderWithProviders(<ComplexityRouterConfig {...baseProps} value={customValue} onEditingTiersChange={vi.fn()} />);
+    fireEvent.click(screen.getByText("Advanced: Classification Method"));
+    expect(screen.getByText("write calibration examples of your own", { exact: false })).toBeInTheDocument();
+    expect(screen.queryByText("A replacement prompt drops the tier bullets", { exact: false })).not.toBeInTheDocument();
+  });
+
+  it("keeps the whole-prompt replacement editor on built-in routers, which the backend still accepts there", () => {
+    renderWithProviders(
+      <ComplexityRouterConfig
+        {...baseProps}
+        value={{ ...defaultValue, classifier_type: "llm", classifier_llm_config: { model: "gpt-4", timeout_ms: 3000 } }}
+        onEditingTiersChange={vi.fn()}
+      />,
+    );
+    fireEvent.click(screen.getByText("Advanced: Classification Method"));
+    expect(screen.getByText("Replace the built-in complexity rubric", { exact: false })).toBeInTheDocument();
+    expect(screen.queryByText("write calibration examples of your own", { exact: false })).not.toBeInTheDocument();
+  });
+
   it("leaves built-in routers with their display-name inputs and no restriction copy", () => {
     renderWithProviders(<ComplexityRouterConfig {...baseProps} onEditingTiersChange={vi.fn()} />);
     expect(screen.getByLabelText("Display name for the Simple tier")).toBeInTheDocument();
diff --git a/ui/litellm-dashboard/src/components/add_model/ComplexityRouterConfig.tsx b/ui/litellm-dashboard/src/components/add_model/ComplexityRouterConfig.tsx
index 5091d722ab7..0dc576d6ddd 100644
--- a/ui/litellm-dashboard/src/components/add_model/ComplexityRouterConfig.tsx
+++ b/ui/litellm-dashboard/src/components/add_model/ComplexityRouterConfig.tsx
@@ -13,11 +13,9 @@ import { Input } from "@/components/ui/input";
 import { Textarea } from "@/components/ui/textarea";
 import {
   type CustomTierSet,
-  type TierRestriction,
   type ActiveTierRow,
   type TierRow,
   rowParamsByTier,
-  CUSTOM_TIER_RESTRICTIONS,
   MAX_TIER_COUNT,
   MAX_TIER_DEFINITION_CHARS,
   MAX_TIER_NAME_CHARS,
@@ -37,6 +35,7 @@ import React from "react";
 import { ModelGroup } from "@/components/llm_calls/fetch_models";
 import AdaptiveRoutingConfig from "./AdaptiveRoutingConfig";
 import ClassificationMethodConfig from "./ClassificationMethodConfig";
+import { Restricted, restrictedBy } from "./TierRestrictions";
 import {
   REASONING_EFFORT_OPTIONS,
   ReasoningEffort,
@@ -166,16 +165,6 @@ export const effectiveClassifierType = (
   value: Pick<ComplexityRouterConfigValue, "custom_tier_set" | "classifier_type">,
 ): ClassifierType => (value.custom_tier_set ? "llm" : value.classifier_type);
 
-export const restrictedBy = (
-  value: Pick<ComplexityRouterConfigValue, "custom_tier_set">,
-  key: keyof typeof CUSTOM_TIER_RESTRICTIONS,
-): TierRestriction | undefined => (value.custom_tier_set ? CUSTOM_TIER_RESTRICTIONS[key] : undefined);
-
-export const Restricted: React.FC<{ by: TierRestriction | undefined; children: React.ReactNode }> = ({
-  by,
-  children,
-}) => (by ? <span className="block text-sm text-muted-foreground">{by.reason}</span> : <>{children}</>);
-
 const rowOrigin = (row: TierRow, editing: boolean): string => {
   if (!editing) return row.id;
   return isBuiltInTierName(row.name) ? "built-in" : "custom";
@@ -219,6 +208,8 @@ export interface ComplexityRouterConfigValue {
   classifier_context_per_turn_chars?: number;
   classifier_context_include_assistant_turns?: boolean;
   classifier_fallback?: ClassifierFallback;
+  /** Opening instructions only; the router appends the tier bullets and the injection guard after them. */
+  classification_prompt?: string;
   /** Highest tier the scorer may decide alone under heuristic_first. Required by that type, rejected by the others. */
   heuristic_first_max_tier?: string;
   session_affinity?: boolean;
diff --git a/ui/litellm-dashboard/src/components/add_model/TierRestrictions.tsx b/ui/litellm-dashboard/src/components/add_model/TierRestrictions.tsx
new file mode 100644
index 00000000000..764be82ba77
--- /dev/null
+++ b/ui/litellm-dashboard/src/components/add_model/TierRestrictions.tsx
@@ -0,0 +1,12 @@
+import React from "react";
+import { CUSTOM_TIER_RESTRICTIONS, CustomTierSet, TierRestriction } from "./tier_rows";
+
+export const restrictedBy = (
+  value: { custom_tier_set?: CustomTierSet },
+  key: keyof typeof CUSTOM_TIER_RESTRICTIONS,
+): TierRestriction | undefined => (value.custom_tier_set ? CUSTOM_TIER_RESTRICTIONS[key] : undefined);
+
+export const Restricted: React.FC<{ by: TierRestriction | undefined; children: React.ReactNode }> = ({
+  by,
+  children,
+}) => (by ? <span className="block text-sm text-muted-foreground">{by.reason}</span> : <>{children}</>);
diff --git a/ui/litellm-dashboard/src/components/add_model/add_auto_router_tab.tsx b/ui/litellm-dashboard/src/components/add_model/add_auto_router_tab.tsx
index 0ed27b3a34a..96894b079c4 100644
--- a/ui/litellm-dashboard/src/components/add_model/add_auto_router_tab.tsx
+++ b/ui/litellm-dashboard/src/components/add_model/add_auto_router_tab.tsx
@@ -339,6 +339,7 @@ const AddAutoRouterTab: React.FC<AddAutoRouterTabProps> = ({
     customTierSet: complexityRouterConfig.custom_tier_set,
     defaultModel: complexityRouterConfig.default_model,
     planModeMinTier: complexityRouterConfig.plan_mode_min_tier,
+    classificationPrompt: complexityRouterConfig.classification_prompt,
     heuristicFirstMaxTier: complexityRouterConfig.heuristic_first_max_tier,
     tierLabels: complexityRouterConfig.tier_labels,
     classifierType: complexityRouterConfig.classifier_type,
diff --git a/ui/litellm-dashboard/src/components/add_model/build_complexity_router_config.test.ts b/ui/litellm-dashboard/src/components/add_model/build_complexity_router_config.test.ts
index 290729ec2be..cffc3aa7e5d 100644
--- a/ui/litellm-dashboard/src/components/add_model/build_complexity_router_config.test.ts
+++ b/ui/litellm-dashboard/src/components/add_model/build_complexity_router_config.test.ts
@@ -28,6 +28,7 @@ const baseParams: BuildComplexityRouterConfigParams = {
   classifierContextWindowSize: undefined,
   classifierContextBudgetChars: undefined,
   classifierContextIncludeAssistantTurns: undefined,
+  classificationPrompt: undefined,
   classifierFallback: undefined,
   sessionAffinity: false,
   deploymentAffinity: true,
@@ -811,6 +812,25 @@ describe("buildComplexityRouterConfig with an edited tier set", () => {
     expect(build({ sessionAffinity: true }).session_affinity).toBe(false);
   });
 
+  it("writes the operator's opening instructions, trimmed, as classification_prompt", () => {
+    expect(build({ classificationPrompt: "  Route for a payments team.\n\nExamples:\n- x -> CASUAL  " })).toMatchObject(
+      { classification_prompt: "Route for a payments team.\n\nExamples:\n- x -> CASUAL" },
+    );
+  });
+
+  it("keeps classification_prompt out of the payload when the operator wrote only whitespace", () => {
+    expect(build({ classificationPrompt: "   \n  " })).not.toHaveProperty("classification_prompt");
+  });
+
+  it("never writes classification_prompt on a built-in router, which the backend rejects without tier_definitions", () => {
+    const payload = buildComplexityRouterConfig({
+      ...baseParams,
+      classifierType: "llm",
+      classificationPrompt: "opening instructions",
+    });
+    expect(payload).not.toHaveProperty("classification_prompt");
+  });
+
   it("omits a definition on a built-in name, letting the backend rubric supply it", () => {
     const payload = build({
       customTierSet: {
diff --git a/ui/litellm-dashboard/src/components/add_model/build_complexity_router_config.ts b/ui/litellm-dashboard/src/components/add_model/build_complexity_router_config.ts
index 16fb37ec33d..04e6e16f81e 100644
--- a/ui/litellm-dashboard/src/components/add_model/build_complexity_router_config.ts
+++ b/ui/litellm-dashboard/src/components/add_model/build_complexity_router_config.ts
@@ -102,6 +102,7 @@ export interface BuildComplexityRouterConfigParams {
   classifierContextBudgetChars: number | undefined;
   classifierContextIncludeAssistantTurns: boolean | undefined;
   classifierFallback: ClassifierFallback | undefined;
+  classificationPrompt: string | undefined;
   heuristicFirstMaxTier: string | undefined;
   sessionAffinity: boolean;
   deploymentAffinity: boolean;
@@ -142,6 +143,7 @@ export interface ComplexityRouterConfigPayload {
   classifier_context_per_turn_chars?: number;
   classifier_context_include_assistant_turns?: boolean;
   classifier_fallback?: ClassifierFallback;
+  classification_prompt?: string;
   heuristic_first_max_tier?: string;
   session_affinity: boolean;
   deployment_affinity: boolean;
@@ -257,6 +259,7 @@ export const customTierWireFields = (
   customTierSet: CustomTierSet,
   classifierLlmConfig: ClassifierLLMConfig | undefined,
   planModeMinTierId: string | undefined,
+  classificationPrompt: string | undefined,
 ): Partial<ComplexityRouterConfigPayload> => {
   const rows = customTierSet.tiers;
   const fallback = tierRowById(rows, customTierSet.fallback_tier_id);
@@ -269,13 +272,14 @@ export const customTierWireFields = (
     })),
     ...(fallback && { fallback_tier: activeTierName(fallback) }),
     classifier_type: "llm",
-    // Rebuilt from the two fields an edited tier set allows: system_prompt and
-    // classification_rubric are the classifierPrompt and classificationRubric restrictions, and
-    // both live inside this object rather than at the top level the omit list covers.
+    // Rebuilt from the two fields an edited tier set allows. The backend rejects system_prompt and
+    // classification_rubric beside tier_definitions, and both live inside this object rather than at
+    // the top level the omit list covers. The opening instructions ride classification_prompt below.
     ...(classifierLlmConfig && {
       classifier_llm_config: { model: classifierLlmConfig.model, timeout_ms: classifierLlmConfig.timeout_ms },
     }),
     session_affinity: false,
+    ...(classificationPrompt?.trim() && { classification_prompt: classificationPrompt.trim() }),
     ...(floor && { plan_mode_min_tier: activeTierName(floor) }),
   };
 };
@@ -335,6 +339,7 @@ export const buildComplexityRouterConfig = ({
   classifierContextBudgetChars,
   classifierContextIncludeAssistantTurns,
   classifierFallback,
+  classificationPrompt,
   heuristicFirstMaxTier,
   sessionAffinity,
   deploymentAffinity,
@@ -425,5 +430,8 @@ export const buildComplexityRouterConfig = ({
   const kept = Object.fromEntries(
     Object.entries(payload).filter(([key]) => !CUSTOM_TIER_STRIPPED_KEYS.includes(key)),
   ) as ComplexityRouterConfigPayload;
-  return { ...kept, ...customTierWireFields(customTierSet, classifierLlmConfig, planModeMinTier) };
+  return {
+    ...kept,
+    ...customTierWireFields(customTierSet, classifierLlmConfig, planModeMinTier, classificationPrompt),
+  };
 };
diff --git a/ui/litellm-dashboard/src/components/add_model/tier_rows.ts b/ui/litellm-dashboard/src/components/add_model/tier_rows.ts
index 32a5bb122d6..67eaf37c79d 100644
--- a/ui/litellm-dashboard/src/components/add_model/tier_rows.ts
+++ b/ui/litellm-dashboard/src/components/add_model/tier_rows.ts
@@ -143,10 +143,6 @@ export const CUSTOM_TIER_RESTRICTIONS = {
     ],
     reason: "The heuristic scorer never runs under an edited tier set, so its inputs have no effect",
   },
-  classifierPrompt: {
-    omit: [],
-    reason: "A replacement prompt drops the tier bullets and the injection guard. Your definitions are the rubric",
-  },
   classificationRubric: {
     omit: [],
     reason: "The preset calibration examples are written against the built-in tiers, which your tier set replaces",
diff --git a/ui/litellm-dashboard/src/components/edit_auto_router/build_updated_complexity_router_config.test.ts b/ui/litellm-dashboard/src/components/edit_auto_router/build_updated_complexity_router_config.test.ts
index 3822dba0d90..02629edcf57 100644
--- a/ui/litellm-dashboard/src/components/edit_auto_router/build_updated_complexity_router_config.test.ts
+++ b/ui/litellm-dashboard/src/components/edit_auto_router/build_updated_complexity_router_config.test.ts
@@ -476,9 +476,10 @@ describe("managed keys survive an untouched open-and-save", () => {
     reasoning_override_min_score: 0.3,
   };
 
-  // tier_definitions and fallback_tier cannot sit beside heuristic_first, which this fixture uses, so
-  // no single stored config can hold every managed key. They get their own round trip below.
-  const CUSTOM_TIER_ONLY_KEYS = new Set(["tier_definitions", "fallback_tier"]);
+  // tier_definitions, fallback_tier and classification_prompt cannot sit beside heuristic_first, which
+  // this fixture uses, so no single stored config can hold every managed key. They get their own round
+  // trip below.
+  const CUSTOM_TIER_ONLY_KEYS = new Set(["tier_definitions", "fallback_tier", "classification_prompt"]);
 
   it("carries every managed key a built-in router can hold through hydrate then save", () => {
     const hydrated = hydrateComplexityRouterConfig(STORED_ALL_MANAGED, undefined);
@@ -528,6 +529,44 @@ describe("managed keys survive an untouched open-and-save", () => {
     expect(saved.tiers).toEqual(storedCustom.tiers);
   });
 
+  it("clears a stored classification_prompt when the operator resets it, rather than preserving it as an unowned key", () => {
+    const storedCustom = {
+      tiers: { CASUAL: ["gpt-4o-mini"], AUDIT: ["o1"] },
+      tier_definitions: [
+        { name: "CASUAL", description: "small talk" },
+        { name: "AUDIT", description: "security review" },
+      ],
+      fallback_tier: "CASUAL",
+      classifier_type: "llm",
+      classifier_llm_config: { model: "gpt-4o-mini", timeout_ms: 3000 },
+      classification_prompt: "Route for a payments team.",
+    };
+    const hydrated = hydrateComplexityRouterConfig(storedCustom, undefined);
+    const reset = { ...hydrated, classification_prompt: undefined };
+
+    expect(buildUpdatedComplexityRouterConfig(storedCustom, reset)).not.toHaveProperty("classification_prompt");
+  });
+
+  it("round-trips a stored classification_prompt, which an untouched open-and-save must not clear", () => {
+    const storedCustom = {
+      tiers: { CASUAL: ["gpt-4o-mini"], AUDIT: ["o1"] },
+      tier_definitions: [
+        { name: "CASUAL", description: "small talk" },
+        { name: "AUDIT", description: "security review" },
+      ],
+      fallback_tier: "CASUAL",
+      classifier_type: "llm",
+      classifier_llm_config: { model: "gpt-4o-mini", timeout_ms: 3000 },
+      classification_prompt: "Route for a payments team.\n\nExamples:\n- refund status -> CASUAL",
+    };
+    const hydrated = hydrateComplexityRouterConfig(storedCustom, undefined);
+
+    expect(hydrated.classification_prompt).toBe(storedCustom.classification_prompt);
+    expect(buildUpdatedComplexityRouterConfig(storedCustom, hydrated).classification_prompt).toBe(
+      storedCustom.classification_prompt,
+    );
+  });
+
   it("round-trips the heuristic_first threshold, which save requires and the backend rejects without", () => {
     const hydrated = hydrateComplexityRouterConfig(STORED_ALL_MANAGED, undefined);
     expect(hydrated.heuristic_first_max_tier).toBe("SIMPLE");
diff --git a/ui/litellm-dashboard/src/components/edit_auto_router/edit_auto_router_modal.tsx b/ui/litellm-dashboard/src/components/edit_auto_router/edit_auto_router_modal.tsx
index dd390f00209..354d85a3cc9 100644
--- a/ui/litellm-dashboard/src/components/edit_auto_router/edit_auto_router_modal.tsx
+++ b/ui/litellm-dashboard/src/components/edit_auto_router/edit_auto_router_modal.tsx
@@ -86,6 +86,7 @@ export interface StoredComplexityRouterConfig {
   tier_model_configs?: unknown;
   default_model?: string | null;
   plan_mode_min_tier?: unknown;
+  classification_prompt?: unknown;
   heuristic_first_max_tier?: unknown;
   tier_labels?: unknown;
   classifier_type?: ClassifierType;
@@ -153,6 +154,10 @@ export const hydrateComplexityRouterConfig = (
       parsedConfig.classifier_fallback === "default_model" || parsedConfig.classifier_fallback === "heuristic"
         ? parsedConfig.classifier_fallback
         : undefined,
+    classification_prompt:
+      typeof parsedConfig.classification_prompt === "string" && parsedConfig.classification_prompt.trim() !== ""
+        ? parsedConfig.classification_prompt
+        : undefined,
     heuristic_first_max_tier:
       typeof parsedConfig.heuristic_first_max_tier === "string" && parsedConfig.heuristic_first_max_tier.trim() !== ""
         ? parsedConfig.heuristic_first_max_tier
@@ -189,6 +194,7 @@ export const MANAGED_COMPLEXITY_ROUTER_KEYS = new Set([
   "classifier_context_budget_chars",
   "classifier_context_include_assistant_turns",
   "classifier_fallback",
+  "classification_prompt",
   "heuristic_first_max_tier",
   "session_affinity",
   "deployment_affinity",
@@ -269,6 +275,7 @@ export const buildUpdatedComplexityRouterConfig = (
     customTierSet: value.custom_tier_set,
     defaultModel: value.default_model,
     planModeMinTier: value.plan_mode_min_tier,
+    classificationPrompt: value.classification_prompt,
     heuristicFirstMaxTier: value.heuristic_first_max_tier,
     tierLabels: value.tier_labels,
     classifierType: value.classifier_type,