diff --git a/docs-site/src/content/docs/reference/adapters.md b/docs-site/src/content/docs/reference/adapters.md
index 970557956..dd6224d6c 100644
--- a/docs-site/src/content/docs/reference/adapters.md
+++ b/docs-site/src/content/docs/reference/adapters.md
@@ -181,8 +181,9 @@ advertised effort control on those models as proof of upstream-native reasoning
 - Exposes Cursor Router as `cursor/auto` plus explicit `cursor/auto-cost`,
   `cursor/auto-balance`, and `cursor/auto-intelligence` entries. Explicit levels are encoded in
   `requested_model.parameters` while the legacy `cursor/auto` entry retains the account/team default.
-- Keeps `cursor/grok-4.5-fast` as a selectable model while sending Cursor's canonical `grok-4.5`
-  model with separate `effort` and `fast=true` parameters.
+- Sends regular `cursor/grok-4.5` tiers with Cursor's exact live-discovery wire ids
+  (`cursor-grok-4.5-low`, `-medium`, or `-high`). Keeps `cursor/grok-4.5-fast` selectable while
+  sending the canonical `grok-4.5` model with separate `effort` and `fast=true` parameters.
 - Cursor-native local filesystem/shell/network execution is denied by default. Explicit `mcpServers`
   and `desktopExecutor` integrations have separate opt-ins; `nativeLocalExec: "on"` enables the
   broader built-in executor and bypasses Codex approval/sandbox semantics, and legacy
diff --git a/src/adapters/cursor/effort-map.ts b/src/adapters/cursor/effort-map.ts
index a7c0b76e4..1e937b310 100644
--- a/src/adapters/cursor/effort-map.ts
+++ b/src/adapters/cursor/effort-map.ts
@@ -126,3 +126,14 @@ export function cursorWireModelIdWithEffort(baseModelId: string, effortSuffix: s
   }
   return `${baseModelId}-${effortSuffix}`;
 }
+
+/**
+ * Compose the exact flattened id sent by AgentService/Run. Discovery normalizes Cursor's optional
+ * `cursor-` prefix only for catalog matching, but regular Grok 4.5 requests require that prefix on
+ * the wire. Keep this separate from {@link cursorWireModelIdWithEffort} so discovery can continue
+ * comparing canonical, prefix-free ids. Grok Fast uses requested_model parameters instead.
+ */
+export function cursorRequestWireModelIdWithEffort(baseModelId: string, effortSuffix: string): string {
+  const flattened = cursorWireModelIdWithEffort(baseModelId, effortSuffix);
+  return baseModelId === "grok-4.5" ? `cursor-${flattened}` : flattened;
+}
diff --git a/src/adapters/cursor/request-builder.ts b/src/adapters/cursor/request-builder.ts
index e550c6910..9c7e91e64 100644
--- a/src/adapters/cursor/request-builder.ts
+++ b/src/adapters/cursor/request-builder.ts
@@ -10,7 +10,7 @@ import type {
 import { isAllowedToolChoice, namespacedToolName, toolChoiceAliases, type OcxTool, type OcxToolChoice } from "../../types";
 import type { CursorRequestMessage, CursorRequestedModelParameter, CursorRunRequest } from "./types";
 import { cursorWireModelSelection, type CursorRoutingLevel } from "./discovery";
-import { cursorEffortSuffix, cursorWireModelIdWithEffort } from "./effort-map";
+import { cursorEffortSuffix, cursorRequestWireModelIdWithEffort } from "./effort-map";
 import {
   cursorMcpToolEncodedSize,
   cursorMcpToolsEncodedSize,
@@ -140,7 +140,7 @@ function normalizeCursorModelId(modelId: string, reasoning?: string): {
       ],
     };
   }
-  return { ...selection, modelId: suffix ? cursorWireModelIdWithEffort(id, suffix) : id };
+  return { ...selection, modelId: suffix ? cursorRequestWireModelIdWithEffort(id, suffix) : id };
 }
 
 function contentPartToText(part: OcxContentPart | OcxAssistantContentPart): string | undefined {
diff --git a/tests/cursor-effort-suffix.test.ts b/tests/cursor-effort-suffix.test.ts
index 218a06eef..2d4c627f0 100644
--- a/tests/cursor-effort-suffix.test.ts
+++ b/tests/cursor-effort-suffix.test.ts
@@ -3,6 +3,15 @@ import { createCursorRequest } from "../src/adapters/cursor/request-builder";
 import { cursorEffortSuffix, cursorModelEffortLadder } from "../src/adapters/cursor/effort-map";
 import type { OcxParsedRequest } from "../src/types";
 
+// Static fixture recorded from Cursor GetUsableModels on 2026-08-06. This pins the
+// exact wire ids observed during the incident; live availability normalization is
+// covered separately in cursor-discovery.test.ts.
+const RECORDED_CURSOR_GROK_45_DISCOVERY_IDS = [
+  "cursor-grok-4.5-low",
+  "cursor-grok-4.5-medium",
+  "cursor-grok-4.5-high",
+] as const;
+
 function modelIdFor(modelId: string, reasoning?: string): string {
   const parsed: OcxParsedRequest = {
     modelId,
@@ -84,13 +93,13 @@ describe("Cursor per-model reasoning-effort suffix", () => {
   });
 
   test("grok-4.5 uses current tiers and sends Fast as a separate model parameter", () => {
-    expect(modelIdFor("cursor/grok-4.5", "low")).toBe("grok-4.5-low");
-    expect(modelIdFor("cursor/grok-4.5", "medium")).toBe("grok-4.5-medium");
-    expect(modelIdFor("cursor/grok-4.5", "high")).toBe("grok-4.5-high");
-    expect(modelIdFor("cursor/grok-4.5", "xhigh")).toBe("grok-4.5-high");
-    expect(modelIdFor("cursor/grok-4.5")).toBe("grok-4.5-high");
+    expect(modelIdFor("cursor/grok-4.5", "low")).toBe("cursor-grok-4.5-low");
+    expect(modelIdFor("cursor/grok-4.5", "medium")).toBe("cursor-grok-4.5-medium");
+    expect(modelIdFor("cursor/grok-4.5", "high")).toBe("cursor-grok-4.5-high");
+    expect(modelIdFor("cursor/grok-4.5", "xhigh")).toBe("cursor-grok-4.5-high");
+    expect(modelIdFor("cursor/grok-4.5")).toBe("cursor-grok-4.5-high");
     expect(selectionFor("cursor/grok-4.5", "high")).toEqual({
-      modelId: "grok-4.5-high",
+      modelId: "cursor-grok-4.5-high",
       parameters: undefined,
     });
     expect(selectionFor("cursor/grok-4.5-fast", "low")).toEqual({
@@ -118,6 +127,14 @@ describe("Cursor per-model reasoning-effort suffix", () => {
     expect(cursorModelEffortLadder("grok-4.5-fast")).toEqual(["low", "medium", "high"]);
   });
 
+  test("regular grok-4.5 request ids match the recorded discovery fixture", () => {
+    for (const effort of ["low", "medium", "high"] as const) {
+      const requestModelId = modelIdFor("cursor/grok-4.5", effort);
+      expect(requestModelId).toBe(`cursor-grok-4.5-${effort}`);
+      expect(RECORDED_CURSOR_GROK_45_DISCOVERY_IDS).toContain(requestModelId);
+    }
+  });
+
   test("kimi-k3 maps to its live effort-suffixed variants", () => {
     expect(modelIdFor("cursor/kimi-k3", "low")).toBe("kimi-k3-low");
     expect(modelIdFor("cursor/kimi-k3", "medium")).toBe("kimi-k3-high");