diff --git a/open-sse/executors/codex.ts b/open-sse/executors/codex.ts
index 12af8ae216..274158873d 100644
--- a/open-sse/executors/codex.ts
+++ b/open-sse/executors/codex.ts
@@ -37,6 +37,14 @@ import { CORS_HEADERS } from "../utils/cors.ts";
 import { normalizeCodexResponsesInput } from "../utils/responsesInputNormalization.ts";
 import * as prl from "../utils/providerRequestLogging.ts";
 import { createRequire } from "module";
+// Quota parsing/scheduling extracted to a pure leaf; re-exported for external
+// importers (handlers/chatCore/codexQuota.ts + tests).
+export {
+  type CodexQuotaSnapshot,
+  parseCodexQuotaHeaders,
+  getCodexResetTime,
+  getCodexDualWindowCooldownMs,
+} from "./codex/quota.ts";
 
 // ─── wreq-js lazy loader ───────────────────────────────────────────────────
 // wreq-js is a Rust-native module that requires platform-specific .node binaries.
@@ -104,119 +112,6 @@ function codexWebSocketUnavailableResponse(): Response {
 // Ref: sub2api PR #1129 (feat(openai): split codex spark rate limiting from codex)
 export { getCodexModelScope, getCodexRateLimitKey, type CodexQuotaScope };
 
-/**
- * T03: Parsed quota snapshot from Codex response headers.
- * Codex includes per-account usage windows that allow precise reset scheduling.
- * Ref: sub2api PR #357 (feat(oauth): persist usage snapshots and window cooldown)
- */
-export interface CodexQuotaSnapshot {
-  usage5h: number; // tokens used in 5h window
-  limit5h: number; // token limit for 5h window
-  resetAt5h: string | null; // ISO timestamp when 5h window resets
-  usage7d: number; // tokens used in 7d window
-  limit7d: number; // token limit for 7d window
-  resetAt7d: string | null; // ISO timestamp when 7d window resets
-}
-
-/**
- * T03: Parse Codex-specific quota headers from a provider response.
- * Returns null if none of the relevant headers are present.
- *
- * Extracts:
- *   x-codex-5h-usage / x-codex-5h-limit / x-codex-5h-reset-at
- *   x-codex-7d-usage / x-codex-7d-limit / x-codex-7d-reset-at
- */
-export function parseCodexQuotaHeaders(headers: Record<string, string>): CodexQuotaSnapshot | null {
-  const usage5h = headers["x-codex-5h-usage"] ?? null;
-  const limit5h = headers["x-codex-5h-limit"] ?? null;
-  const resetAt5h = headers["x-codex-5h-reset-at"] ?? null;
-  const usage7d = headers["x-codex-7d-usage"] ?? null;
-  const limit7d = headers["x-codex-7d-limit"] ?? null;
-  const resetAt7d = headers["x-codex-7d-reset-at"] ?? null;
-
-  // Return null if none of the quota headers are present (not a quota-aware response)
-  if (!usage5h && !limit5h && !resetAt5h && !usage7d && !limit7d && !resetAt7d) {
-    return null;
-  }
-
-  return {
-    usage5h: usage5h ? parseFloat(usage5h) : 0,
-    limit5h: limit5h ? parseFloat(limit5h) : Infinity,
-    resetAt5h: resetAt5h ?? null,
-    usage7d: usage7d ? parseFloat(usage7d) : 0,
-    limit7d: limit7d ? parseFloat(limit7d) : Infinity,
-    resetAt7d: resetAt7d ?? null,
-  };
-}
-
-/**
- * T03: Get the soonest quota reset time from a CodexQuotaSnapshot.
- * 7d window takes priority (wider window, harder limit) but we use whichever
- * is further in the future to avoid releasing the block too early.
- *
- * @returns Unix timestamp (ms) of the soonest effective reset, or null
- */
-export function getCodexResetTime(quota: CodexQuotaSnapshot): number | null {
-  const times: number[] = [];
-  if (quota.resetAt7d) {
-    const t = new Date(quota.resetAt7d).getTime();
-    if (!isNaN(t) && t > Date.now()) times.push(t);
-  }
-  if (quota.resetAt5h) {
-    const t = new Date(quota.resetAt5h).getTime();
-    if (!isNaN(t) && t > Date.now()) times.push(t);
-  }
-  if (times.length === 0) return null;
-  return Math.max(...times); // Use furthest-out reset to avoid premature unblock
-}
-
-/**
- * T03 (Item 3): Compute the minimum-necessary cooldown based on which window
- * is actually exhausted. Prevents over-blocking the account:
- *
- * - If 7d window >= threshold: cooldown until 7d reset (weekly window exhausted)
- * - If 5h window >= threshold: cooldown until 5h reset only (short-term limit)
- * - Otherwise: 0 (account is healthy, no cooldown needed)
- *
- * Called after parsing quota headers from a successful/429 response to
- * mark the account accordingly without overly long cooldowns.
- *
- * @param quota - Parsed quota snapshot from response headers
- * @param threshold - Fraction (0-1) that triggers cooldown (default: 0.95)
- * @returns Cooldown duration in milliseconds (0 = no cooldown needed)
- */
-export function getCodexDualWindowCooldownMs(
-  quota: CodexQuotaSnapshot,
-  threshold = 0.95
-): { cooldownMs: number; window: "7d" | "5h" | "none" } {
-  const now = Date.now();
-
-  // Compute per-window usage ratios (0..1)
-  const ratio7d =
-    quota.limit7d > 0 && Number.isFinite(quota.limit7d) ? quota.usage7d / quota.limit7d : 0;
-  const ratio5h =
-    quota.limit5h > 0 && Number.isFinite(quota.limit5h) ? quota.usage5h / quota.limit5h : 0;
-
-  // 7d window takes priority — if the weekly budget is near-exhausted,
-  // we must wait until the weekly reset (not just 5h).
-  if (ratio7d >= threshold && quota.resetAt7d) {
-    const resetTime = new Date(quota.resetAt7d).getTime();
-    if (resetTime > now) {
-      return { cooldownMs: resetTime - now, window: "7d" };
-    }
-  }
-
-  // 5h window (primary short-term rate limit)
-  if (ratio5h >= threshold && quota.resetAt5h) {
-    const resetTime = new Date(quota.resetAt5h).getTime();
-    if (resetTime > now) {
-      return { cooldownMs: resetTime - now, window: "5h" };
-    }
-  }
-
-  return { cooldownMs: 0, window: "none" };
-}
-
 // Ordered list of effort levels from lowest to highest
 const EFFORT_ORDER = ["none", "low", "medium", "high", "xhigh"] as const;
 type EffortLevel = (typeof EFFORT_ORDER)[number];
@@ -1159,9 +1054,7 @@ export class CodexExecutor extends BaseExecutor {
       headers["chatgpt-account-id"] = workspaceId;
     }
     const clientIdentity = credentials?.providerSpecificData?.codexClientIdentity as
-      | CodexClientIdentity
-      | null
-      | undefined;
+      CodexClientIdentity | null | undefined;
 
     // Originator header — identifies the client type to the Codex backend.
     // Ref: openai/codex login/src/auth/default_client.rs DEFAULT_ORIGINATOR = "codex_cli_rs"
@@ -1481,9 +1374,7 @@ export class CodexExecutor extends BaseExecutor {
       applyCodexClientMetadata(
         body,
         credentials?.providerSpecificData?.codexClientIdentity as
-          | CodexClientIdentity
-          | null
-          | undefined
+          CodexClientIdentity | null | undefined
       );
     }
 
diff --git a/open-sse/executors/codex/quota.ts b/open-sse/executors/codex/quota.ts
new file mode 100644
index 0000000000..977f794dde
--- /dev/null
+++ b/open-sse/executors/codex/quota.ts
@@ -0,0 +1,114 @@
+// Codex quota-snapshot parsing + reset/cooldown scheduling (pure). Verbatim from codex.ts.
+
+/**
+ * T03: Parsed quota snapshot from Codex response headers.
+ * Codex includes per-account usage windows that allow precise reset scheduling.
+ * Ref: sub2api PR #357 (feat(oauth): persist usage snapshots and window cooldown)
+ */
+export interface CodexQuotaSnapshot {
+  usage5h: number; // tokens used in 5h window
+  limit5h: number; // token limit for 5h window
+  resetAt5h: string | null; // ISO timestamp when 5h window resets
+  usage7d: number; // tokens used in 7d window
+  limit7d: number; // token limit for 7d window
+  resetAt7d: string | null; // ISO timestamp when 7d window resets
+}
+
+/**
+ * T03: Parse Codex-specific quota headers from a provider response.
+ * Returns null if none of the relevant headers are present.
+ *
+ * Extracts:
+ *   x-codex-5h-usage / x-codex-5h-limit / x-codex-5h-reset-at
+ *   x-codex-7d-usage / x-codex-7d-limit / x-codex-7d-reset-at
+ */
+export function parseCodexQuotaHeaders(headers: Record<string, string>): CodexQuotaSnapshot | null {
+  const usage5h = headers["x-codex-5h-usage"] ?? null;
+  const limit5h = headers["x-codex-5h-limit"] ?? null;
+  const resetAt5h = headers["x-codex-5h-reset-at"] ?? null;
+  const usage7d = headers["x-codex-7d-usage"] ?? null;
+  const limit7d = headers["x-codex-7d-limit"] ?? null;
+  const resetAt7d = headers["x-codex-7d-reset-at"] ?? null;
+
+  // Return null if none of the quota headers are present (not a quota-aware response)
+  if (!usage5h && !limit5h && !resetAt5h && !usage7d && !limit7d && !resetAt7d) {
+    return null;
+  }
+
+  return {
+    usage5h: usage5h ? parseFloat(usage5h) : 0,
+    limit5h: limit5h ? parseFloat(limit5h) : Infinity,
+    resetAt5h: resetAt5h ?? null,
+    usage7d: usage7d ? parseFloat(usage7d) : 0,
+    limit7d: limit7d ? parseFloat(limit7d) : Infinity,
+    resetAt7d: resetAt7d ?? null,
+  };
+}
+
+/**
+ * T03: Get the soonest quota reset time from a CodexQuotaSnapshot.
+ * 7d window takes priority (wider window, harder limit) but we use whichever
+ * is further in the future to avoid releasing the block too early.
+ *
+ * @returns Unix timestamp (ms) of the soonest effective reset, or null
+ */
+export function getCodexResetTime(quota: CodexQuotaSnapshot): number | null {
+  const times: number[] = [];
+  if (quota.resetAt7d) {
+    const t = new Date(quota.resetAt7d).getTime();
+    if (!isNaN(t) && t > Date.now()) times.push(t);
+  }
+  if (quota.resetAt5h) {
+    const t = new Date(quota.resetAt5h).getTime();
+    if (!isNaN(t) && t > Date.now()) times.push(t);
+  }
+  if (times.length === 0) return null;
+  return Math.max(...times); // Use furthest-out reset to avoid premature unblock
+}
+
+/**
+ * T03 (Item 3): Compute the minimum-necessary cooldown based on which window
+ * is actually exhausted. Prevents over-blocking the account:
+ *
+ * - If 7d window >= threshold: cooldown until 7d reset (weekly window exhausted)
+ * - If 5h window >= threshold: cooldown until 5h reset only (short-term limit)
+ * - Otherwise: 0 (account is healthy, no cooldown needed)
+ *
+ * Called after parsing quota headers from a successful/429 response to
+ * mark the account accordingly without overly long cooldowns.
+ *
+ * @param quota - Parsed quota snapshot from response headers
+ * @param threshold - Fraction (0-1) that triggers cooldown (default: 0.95)
+ * @returns Cooldown duration in milliseconds (0 = no cooldown needed)
+ */
+export function getCodexDualWindowCooldownMs(
+  quota: CodexQuotaSnapshot,
+  threshold = 0.95
+): { cooldownMs: number; window: "7d" | "5h" | "none" } {
+  const now = Date.now();
+
+  // Compute per-window usage ratios (0..1)
+  const ratio7d =
+    quota.limit7d > 0 && Number.isFinite(quota.limit7d) ? quota.usage7d / quota.limit7d : 0;
+  const ratio5h =
+    quota.limit5h > 0 && Number.isFinite(quota.limit5h) ? quota.usage5h / quota.limit5h : 0;
+
+  // 7d window takes priority — if the weekly budget is near-exhausted,
+  // we must wait until the weekly reset (not just 5h).
+  if (ratio7d >= threshold && quota.resetAt7d) {
+    const resetTime = new Date(quota.resetAt7d).getTime();
+    if (resetTime > now) {
+      return { cooldownMs: resetTime - now, window: "7d" };
+    }
+  }
+
+  // 5h window (primary short-term rate limit)
+  if (ratio5h >= threshold && quota.resetAt5h) {
+    const resetTime = new Date(quota.resetAt5h).getTime();
+    if (resetTime > now) {
+      return { cooldownMs: resetTime - now, window: "5h" };
+    }
+  }
+
+  return { cooldownMs: 0, window: "none" };
+}
diff --git a/tests/unit/codex-executor-split.test.ts b/tests/unit/codex-executor-split.test.ts
new file mode 100644
index 0000000000..eac6b2eea0
--- /dev/null
+++ b/tests/unit/codex-executor-split.test.ts
@@ -0,0 +1,36 @@
+import { test } from "node:test";
+import assert from "node:assert/strict";
+import { readFileSync } from "node:fs";
+import { fileURLToPath } from "node:url";
+import { dirname, join } from "node:path";
+
+// Split-guard for the codex executor quota extraction.
+// The pure quota-snapshot parsing + reset/cooldown scheduling lives in codex/quota.ts.
+// Host re-exports the 4 public symbols (chatCore/codexQuota.ts + tests import them).
+const HERE = dirname(fileURLToPath(import.meta.url));
+const EXE = join(HERE, "../../open-sse/executors");
+const HOST = join(EXE, "codex.ts");
+const LEAF = join(EXE, "codex/quota.ts");
+
+test("leaf hosts the quota helpers and does not import the host", () => {
+  const src = readFileSync(LEAF, "utf8");
+  for (const sym of [
+    "parseCodexQuotaHeaders",
+    "getCodexResetTime",
+    "getCodexDualWindowCooldownMs",
+    "CodexQuotaSnapshot",
+  ]) {
+    assert.match(src, new RegExp(`export (function|interface) ${sym}\\b`));
+  }
+  assert.doesNotMatch(src, /from "\.\.\/codex\.ts"/);
+});
+
+test("host re-exports the quota symbols for external importers", () => {
+  const host = readFileSync(HOST, "utf8");
+  assert.match(host, /from "\.\/codex\/quota\.ts"/);
+});
+
+test("parseCodexQuotaHeaders returns null without quota headers", async () => {
+  const { parseCodexQuotaHeaders } = await import("../../open-sse/executors/codex/quota.ts");
+  assert.equal(parseCodexQuotaHeaders({}), null);
+});