diff --git a/src/server/responses/input-admission.ts b/src/server/responses/input-admission.ts
index 219c3b6f89..a2a06e5b73 100644
--- a/src/server/responses/input-admission.ts
+++ b/src/server/responses/input-admission.ts
@@ -13,6 +13,7 @@
 import { nativeOpenAiContextWindow, nativeOpenAiMaxInputTokens, type NativeContextLimitsInput } from "../../codex/catalog/metadata";
 import { estimateTokens } from "../../lib/token-estimate";
 import { isCanonicalOpenAiForwardProvider, OPENAI_CODEX_PROVIDER_ID } from "../../providers/openai-tiers";
+import { modelRecordValue } from "../../reasoning-effort";
 import type { OcxContentPart, OcxParsedRequest, OcxProviderConfig } from "../../types";
 
 /**
@@ -133,7 +134,11 @@ export function resolveInputCeiling(
   // config here so this stays pure: no filesystem, no catalog, no registry scan.
   nativeContextCap?: NativeContextLimitsInput,
 ): number | null {
-  const configured = positive(provider.modelContextWindows?.[modelId]) ?? positive(provider.contextWindow);
+  // `modelRecordValue`, not a bare lookup: the catalog resolves these same two maps that
+  // way, so a `gpt-oss` entry covers `gpt-oss:120b`. Reading raw here made the gate fall
+  // back to the provider-wide window and refuse turns the model can plainly hold.
+  const configured = positive(modelRecordValue(provider.modelContextWindows, modelId))
+    ?? positive(provider.contextWindow);
 
   // The canonical `openai` registry entry declares no context fields, so without this the
   // gate would be inert on the default Codex route. All three clauses are load-bearing: a
@@ -156,7 +161,7 @@ export function resolveInputCeiling(
 
   const window = canonicalNativeBare ? native : configured;
   // modelMaxInputTokens is an input-only cap, so it can only tighten the window.
-  const configuredMaxInput = positive(provider.modelMaxInputTokens?.[modelId]);
+  const configuredMaxInput = positive(modelRecordValue(provider.modelMaxInputTokens, modelId));
   const limits = [window, configuredMaxInput, nativeMaxInput].filter((v): v is number => v !== null);
   return limits.length === 0 ? null : Math.min(...limits);
 }
diff --git a/tests/input-admission.test.ts b/tests/input-admission.test.ts
index 44422d502c..d97e0fe82e 100644
--- a/tests/input-admission.test.ts
+++ b/tests/input-admission.test.ts
@@ -5,6 +5,7 @@ import {
   estimateInputTokens,
   resolveInputCeiling,
 } from "../src/server/responses/input-admission";
+import { modelRecordValue } from "../src/reasoning-effort";
 import type { OcxMessage, OcxParsedRequest, OcxProviderConfig, OcxTool } from "../src/types";
 
 const CANONICAL_NATIVE: OcxProviderConfig = {
@@ -91,6 +92,42 @@ describe("resolveInputCeiling", () => {
     const pinned: OcxProviderConfig = { ...CANONICAL_NATIVE, modelContextWindows: { "gpt-5.6-sol": 50_000 } };
     expect(resolveInputCeiling(pinned, "openai", "gpt-5.6-sol")).toBe(50_000);
   });
+
+  test("a family entry covers its tagged siblings, like the catalog", () => {
+    // The catalog resolves modelContextWindows through modelRecordValue, so it advertises
+    // 131_072 for gpt-oss:120b off this config. A bare lookup here resolved nothing and
+    // fell back to contextWindow, leaving the gate refusing turns the model can hold.
+    const provider: OcxProviderConfig = {
+      adapter: "openai-chat",
+      baseUrl: "https://example.test/v1",
+      contextWindow: 8_000,
+      modelContextWindows: { "gpt-oss": 131_072 },
+    };
+    expect(modelRecordValue(provider.modelContextWindows, "gpt-oss:120b")).toBe(131_072);
+    expect(resolveInputCeiling(provider, "custom", "gpt-oss:120b")).toBe(131_072);
+    // An id with no tag and no entry still falls back to the provider-wide window.
+    expect(resolveInputCeiling(provider, "custom", "other")).toBe(8_000);
+  });
+
+  test("an exact entry still beats the family entry", () => {
+    const provider: OcxProviderConfig = {
+      adapter: "openai-chat",
+      baseUrl: "https://example.test/v1",
+      modelContextWindows: { "gpt-oss": 131_072, "gpt-oss:20b": 32_000 },
+    };
+    expect(resolveInputCeiling(provider, "custom", "gpt-oss:20b")).toBe(32_000);
+    expect(resolveInputCeiling(provider, "custom", "gpt-oss:120b")).toBe(131_072);
+  });
+
+  test("a family modelMaxInputTokens tightens its tagged siblings", () => {
+    const provider: OcxProviderConfig = {
+      adapter: "openai-chat",
+      baseUrl: "https://example.test/v1",
+      modelContextWindows: { "gpt-oss": 131_072 },
+      modelMaxInputTokens: { "gpt-oss": 40_000 },
+    };
+    expect(resolveInputCeiling(provider, "custom", "gpt-oss:120b")).toBe(40_000);
+  });
 });
 
 describe("estimateInputTokens", () => {