diff --git a/apps/server/src/provider/ClaudeProvider.ts b/apps/server/src/provider/ClaudeProvider.ts
index 97512d3d621f0..1d33fd50471a8 100644
--- a/apps/server/src/provider/ClaudeProvider.ts
+++ b/apps/server/src/provider/ClaudeProvider.ts
@@ -609,6 +609,17 @@ export const checkClaudeProviderStatus = Effect.fn("checkClaudeProviderStatus")(
   const slashCommands = [COMPACT_SLASH_COMMAND, ...(capabilities?.slashCommands ?? [])];
   const dedupedSlashCommands = dedupeSlashCommands(slashCommands);
 
+  // First-party account fields cannot verify custom endpoint credentials.
+  const baseUrl =
+    (yield* readClaudeSettingsEnv(claudeSettings, cwd, resolvedEnvironment)).ANTHROPIC_BASE_URL ??
+    resolvedEnvironment.ANTHROPIC_BASE_URL;
+  const endpoint = URL.parse(baseUrl?.trim() ?? "");
+  const customApiEndpoint =
+    endpoint !== null &&
+    (endpoint.protocol === "http:" || endpoint.protocol === "https:") &&
+    endpoint.hostname !== "" &&
+    endpoint.hostname !== "api.anthropic.com";
+
   if (!capabilities) {
     return buildServerProvider({
       presentation: CLAUDE_PRESENTATION,
@@ -628,20 +639,13 @@ export const checkClaudeProviderStatus = Effect.fn("checkClaudeProviderStatus")(
             ? `Timed out after ${CAPABILITIES_PROBE_TIMEOUT_MS / 1_000}s while checking Claude account status.`
             : "Claude Agent CLI failed while checking account status."
           : "Could not verify Claude authentication status from initialization result.",
+        ...(customApiEndpoint
+          ? { usageLimits: makeUnavailableUsageLimits({ checkedAt, reason: "unsupported" }) }
+          : {}),
       },
     });
   }
 
-  // First-party account fields cannot verify custom endpoint credentials.
-  const baseUrl =
-    (yield* readClaudeSettingsEnv(claudeSettings, cwd, resolvedEnvironment)).ANTHROPIC_BASE_URL ??
-    resolvedEnvironment.ANTHROPIC_BASE_URL;
-  const endpoint = URL.parse(baseUrl?.trim() ?? "");
-  const customApiEndpoint =
-    endpoint !== null &&
-    (endpoint.protocol === "http:" || endpoint.protocol === "https:") &&
-    endpoint.hostname !== "" &&
-    endpoint.hostname !== "api.anthropic.com";
   if (!customApiEndpoint && claudeAuthStatus(capabilities) === "unauthenticated") {
     return buildServerProvider({
       presentation: CLAUDE_PRESENTATION,
@@ -670,17 +674,20 @@ export const checkClaudeProviderStatus = Effect.fn("checkClaudeProviderStatus")(
       authMethod: capabilities.tokenSource,
     });
   const usageCheckedAt = capabilities.usageCheckedAt ?? checkedAt;
-  const usageLimits = !capabilities.usage
-    ? makeUnavailableUsageLimits({ checkedAt, reason: "probeFailed" })
-    : scopedLimitNames
-      ? yield* recordClaudeUsageResponse(scopedLimitNames, {
-          response: capabilities.usage,
-          checkedAt: usageCheckedAt,
-        })
-      : claudeUsageResponseToLimits({
-          response: capabilities.usage,
-          checkedAt: usageCheckedAt,
-        }).limits;
+  // A custom endpoint answers usage for whichever account it routes to, not this login.
+  const usageLimits = customApiEndpoint
+    ? makeUnavailableUsageLimits({ checkedAt, reason: "unsupported" })
+    : !capabilities.usage
+      ? makeUnavailableUsageLimits({ checkedAt, reason: "probeFailed" })
+      : scopedLimitNames
+        ? yield* recordClaudeUsageResponse(scopedLimitNames, {
+            response: capabilities.usage,
+            checkedAt: usageCheckedAt,
+          })
+        : claudeUsageResponseToLimits({
+            response: capabilities.usage,
+            checkedAt: usageCheckedAt,
+          }).limits;
   const resetCredits =
     resolveResetCredits &&
     capabilities.subscriptionType &&
diff --git a/apps/server/src/provider/ProviderRegistry.test.ts b/apps/server/src/provider/ProviderRegistry.test.ts
index e318a3c79a66e..34b84a92f8e5d 100644
--- a/apps/server/src/provider/ProviderRegistry.test.ts
+++ b/apps/server/src/provider/ProviderRegistry.test.ts
@@ -8,6 +8,7 @@ import * as NodeCrypto from "@effect/platform-node/NodeCrypto";
 import * as NodeServices from "@effect/platform-node/NodeServices";
 import type { ModelInfo } from "@anthropic-ai/claude-agent-sdk";
 import { describe, it, assert, expect } from "@effect/vitest";
+import * as Cause from "effect/Cause";
 import * as DateTime from "effect/DateTime";
 import * as Deferred from "effect/Deferred";
 import * as Effect from "effect/Effect";
@@ -46,7 +47,7 @@ import { applyServerSettingsPatch } from "@t3tools/shared/serverSettings";
 
 import { checkCodexProviderStatus, type CodexAppServerProviderSnapshot } from "./CodexProvider.ts";
 import { BUNDLED_CLAUDE_MODEL_CATALOG } from "./ClaudeModelCatalog.ts";
-import { checkClaudeProviderStatus } from "./ClaudeProvider.ts";
+import { checkClaudeProviderStatus, type ClaudeCapabilitiesProbe } from "./ClaudeProvider.ts";
 import * as BackgroundPolicy from "../background/BackgroundPolicy.ts";
 import * as AntigravityInstallation from "./AntigravityInstallation.ts";
 import * as ModelManifest from "./ModelManifest.ts";
@@ -177,6 +178,7 @@ type TestClaudeCapabilities = {
   readonly apiKeySource: string | undefined;
   readonly apiProvider: string | undefined;
   readonly slashCommands: ReadonlyArray<ServerProviderSlashCommand>;
+  readonly usage?: NonNullable<ClaudeCapabilitiesProbe["usage"]>;
   readonly models?: ReadonlyArray<ModelInfo>;
 };
 
@@ -3167,6 +3169,32 @@ it.layer(
       ),
     );
 
+    it.effect.each([
+      { baseUrl: "https://proxy.example/api", reason: "unsupported" },
+      { baseUrl: "https://api.anthropic.com", reason: undefined },
+    ])(
+      "preserves quota classification when the Claude probe fails: $baseUrl",
+      ({ baseUrl, reason }) =>
+        Effect.gen(function* () {
+          const status = yield* checkClaudeProviderStatus(
+            defaultClaudeSettings,
+            () => Effect.fail(new Cause.UnknownError("probe failed")),
+            { ANTHROPIC_BASE_URL: baseUrl },
+          );
+          assert.strictEqual(status.status, "warning");
+          assert.strictEqual(status.auth.status, "unknown");
+          assert.strictEqual(status.usageLimits?.unavailable?.reason, reason);
+          if (reason) assert.deepStrictEqual(status.usageLimits?.windows, []);
+        }).pipe(
+          Effect.provide(
+            layerMockSpawner((args) => {
+              if (args.join(" ") === "--version") return { stdout: "1.0.0\n", stderr: "", code: 0 };
+              throw new Error("Unexpected command");
+            }),
+          ),
+        ),
+    );
+
     it.effect.each([
       { source: "inherited HTTPS endpoint", baseUrl: "https://proxy.example/api", overrides: [] },
       {
@@ -3187,6 +3215,10 @@ it.layer(
             tokenSource: "none",
             apiKeySource: "none",
             apiProvider: "firstParty",
+            usage: {
+              rate_limits_available: true,
+              rate_limits: { five_hour: { utilization: 1, resets_at: null } },
+            },
           }),
           environment,
         );
@@ -3194,6 +3226,8 @@ it.layer(
         assert.strictEqual(status.auth.status, "authenticated");
         assert.strictEqual(status.auth.type, "customEndpoint");
         assert.strictEqual(status.auth.label, "Custom API endpoint");
+        assert.strictEqual(status.usageLimits?.unavailable?.reason, "unsupported");
+        assert.deepStrictEqual(status.usageLimits?.windows, []);
       }).pipe(
         Effect.provide(
           layerMockSpawner((args) => {