diff --git a/scripts/test-layout/layout.json b/scripts/test-layout/layout.json
index ef1c68922bb..405bf09de26 100644
--- a/scripts/test-layout/layout.json
+++ b/scripts/test-layout/layout.json
@@ -939,6 +939,7 @@
     "management-provider-proto-override.test.ts": "server",
     "management-provider-synthetic-max.test.ts": "server",
     "management-provider-validation.test.ts": "server",
+    "management-provider-verbosity.test.ts": "server",
     "management-route-registry.test.ts": "server",
     "management-workflow-budget-routes.test.ts": "server",
     "memory-watchdog.test.ts": "server",
diff --git a/src/server/auth-cors.ts b/src/server/auth-cors.ts
index c8f53c861ae..49d6f9e65cd 100644
--- a/src/server/auth-cors.ts
+++ b/src/server/auth-cors.ts
@@ -801,6 +801,8 @@ export function providerManagementConfigError(
   if (reasoningSummariesError) return `provider ${name} ${reasoningSummariesError}`;
   const suppressSyntheticMaxError = booleanRecordConfigError(raw.modelSuppressSyntheticMax, "modelSuppressSyntheticMax");
   if (suppressSyntheticMaxError) return `provider ${name} ${suppressSyntheticMaxError}`;
+  const verbositySupportError = booleanRecordConfigError(raw.modelSupportsVerbosity, "modelSupportsVerbosity");
+  if (verbositySupportError) return `provider ${name} ${verbositySupportError}`;
   const reasoningSummaryDeliveryError = reasoningSummaryDeliveryRecordConfigError(
     raw.modelReasoningSummaryDelivery,
     raw.modelSupportsReasoningSummaries,
diff --git a/tests/fixtures/test-layout-expected.json b/tests/fixtures/test-layout-expected.json
index d8a39f76b8b..da054536441 100644
--- a/tests/fixtures/test-layout-expected.json
+++ b/tests/fixtures/test-layout-expected.json
@@ -765,6 +765,7 @@
   "management-provider-proto-override.test.ts": "server",
   "management-provider-synthetic-max.test.ts": "server",
   "management-provider-validation.test.ts": "server",
+  "management-provider-verbosity.test.ts": "server",
   "management-route-registry.test.ts": "server",
   "management-workflow-budget-routes.test.ts": "server",
   "memory-watchdog.test.ts": "server",
diff --git a/tests/server/management-provider-verbosity.test.ts b/tests/server/management-provider-verbosity.test.ts
new file mode 100644
index 00000000000..75f8e65deea
--- /dev/null
+++ b/tests/server/management-provider-verbosity.test.ts
@@ -0,0 +1,71 @@
+import { expect, test } from "bun:test";
+import { mkdtempSync } from "node:fs";
+import { tmpdir } from "node:os";
+import { join } from "node:path";
+import { loadConfig, saveConfig } from "../../src/config";
+import { startServer } from "../../src/server";
+import { installIsolatedCodexHome } from "../helpers/isolated-codex-home";
+import { managementFetch as fetch } from "../helpers/management-auth";
+import { removeTreeWithRetry } from "../helpers/remove-tree";
+
+test("provider management validates verbosity records without replacing valid config", async () => {
+  const testDir = mkdtempSync(join(tmpdir(), "ocx-provider-verbosity-"));
+  const previousHome = process.env.OPENCODEX_HOME;
+  const previousToken = process.env.OPENCODEX_API_AUTH_TOKEN;
+  const isolatedCodexHome = installIsolatedCodexHome("ocx-provider-verbosity-codex-");
+  process.env.OPENCODEX_HOME = testDir;
+  let server: ReturnType<typeof startServer> | undefined;
+  try {
+    saveConfig({
+      port: 0,
+      defaultProvider: "openai",
+      openaiProviderTierVersion: 2,
+      providers: {
+        openai: {
+          adapter: "openai-responses",
+          baseUrl: "https://chatgpt.com/backend-api/codex",
+          authMode: "forward",
+          codexAccountMode: "direct",
+        },
+      },
+    });
+    server = startServer(0);
+    const acceptedVerbosityCapability = await fetch(new URL("/api/providers", server.url), {
+      method: "POST",
+      headers: { "content-type": "application/json" },
+      body: JSON.stringify({
+        name: "custom-verbosity-capability",
+        provider: {
+          adapter: "openai-responses",
+          baseUrl: "https://api.example.test/v1",
+          modelSupportsVerbosity: { terse: false },
+        },
+      }),
+    });
+    expect(acceptedVerbosityCapability.status).toBe(200);
+    for (const invalid of [[], { terse: "false" }, { "": false }]) {
+      const rejected = await fetch(new URL("/api/providers", server.url), {
+        method: "POST",
+        headers: { "content-type": "application/json" },
+        body: JSON.stringify({
+          name: "custom-verbosity-capability",
+          provider: {
+            adapter: "openai-responses",
+            baseUrl: "https://api.example.test/v1",
+            modelSupportsVerbosity: invalid,
+          },
+        }),
+      });
+      expect(rejected.status).toBe(400);
+    }
+    expect(loadConfig().providers["custom-verbosity-capability"].modelSupportsVerbosity).toEqual({ terse: false });
+  } finally {
+    await server?.stop(true);
+    if (previousHome === undefined) delete process.env.OPENCODEX_HOME;
+    else process.env.OPENCODEX_HOME = previousHome;
+    if (previousToken === undefined) delete process.env.OPENCODEX_API_AUTH_TOKEN;
+    else process.env.OPENCODEX_API_AUTH_TOKEN = previousToken;
+    isolatedCodexHome.restore();
+    removeTreeWithRetry(testDir);
+  }
+}, 60_000);