diff --git a/changelog.d/features/6636-codex-session-import.md b/changelog.d/features/6636-codex-session-import.md
new file mode 100644
index 0000000000..17d794f787
--- /dev/null
+++ b/changelog.d/features/6636-codex-session-import.md
@@ -0,0 +1 @@
+- feat(oauth): accept the full ChatGPT session JSON (not just a bare access token) when pasting Codex credentials manually or via `POST /api/oauth/codex/import-token` (#6636)
diff --git a/config/quality/file-size-baseline.json b/config/quality/file-size-baseline.json
index 57e16cf512..5586cc71ba 100644
--- a/config/quality/file-size-baseline.json
+++ b/config/quality/file-size-baseline.json
@@ -263,7 +263,8 @@
     "src/lib/usage/usageHistory.ts": 988,
     "_rebaseline_2026_06_27_5193_5203_antigravity_oauthmodal": "Antigravity remote-login own growth: OAuthModal.tsx 960->969 (gate units). #5193 (+~4: remote paste instruction shown for all remote incl. Google + its rationale comment) and #5203 (+~5: handleManualSubmit credential-blob branch + button guard; submit logic extracted to oauthBlobSubmit.ts to minimize). Frozen set to the SUM so either merge order passes. Cohesive at the existing manual-submit chokepoint.",
     "_rebaseline_2026_07_18_7399_xai_oauth_modal": "PR #7399 (xAI OAuth PKCE) own growth: OAuthModal.tsx 993->998 (+5 = provider entry + PKCE flow branch wiring at the existing provider-switch chokepoint; the provider logic itself lives in src/lib/oauth/providers/xai-oauth.ts, new leaf). Third irreducible wiring bump on this modal (969->989->993->998); structural shrink tracked in #3501.",
-    "src/shared/components/OAuthModal.tsx": 998,
+    "_rebaseline_2026_07_19_6636_codex_session_json": "#6636 own growth: OAuthModal.tsx 998->1030 (gate units, split(\"\\n\").length incl. trailing newline; +32 = session-JSON paste branch for handleManualSubmit plus a shared submitCodexAccessToken() helper extracted from the pre-existing bare-JWT branch, mirroring the #5203 oauthBlobSubmit.ts extraction precedent; the normalizer logic itself lives in the new src/lib/oauth/utils/codexSessionImport.ts leaf module, not here). Fourth irreducible wiring bump on this modal (969->989->993->998->1030); structural shrink tracked in #3501.",
+    "src/shared/components/OAuthModal.tsx": 1030,
     "src/shared/components/RequestLoggerV2.tsx": 1629,
     "src/shared/components/analytics/charts.tsx": 1558,
     "_rebaseline_2026_07_10_6318_omp_letta": "PR #6318 (@hamsa0x7, omp+letta CLI integrations) own growth: cliTools.ts (+53 = 2 registry entries incl. omp docsUrl) and cliRuntime.ts (+18 = runtime-detection wiring for the 2 new tools). Cohesive registry/wiring growth at the existing chokepoints; scope reduced from the original 5 tools (pi/codewhale/jcode shipped separately).",
diff --git a/src/app/api/oauth/codex/import-token/route.ts b/src/app/api/oauth/codex/import-token/route.ts
index 6706f2b5a5..4601b2ae2d 100644
--- a/src/app/api/oauth/codex/import-token/route.ts
+++ b/src/app/api/oauth/codex/import-token/route.ts
@@ -1,6 +1,7 @@
 import { NextResponse } from "next/server";
 import { z } from "zod";
 import { extractCodexAccountInfo } from "@/lib/oauth/services/codexImport";
+import { parseCodexSessionJson } from "@/lib/oauth/utils/codexSessionImport";
 import { createProviderConnection } from "@/models";
 import { isAuthRequired, isAuthenticated } from "@/shared/utils/apiAuth";
 import { buildErrorBody, sanitizeErrorMessage } from "@omniroute/open-sse/utils/error.ts";
@@ -18,15 +19,79 @@ import { buildErrorBody, sanitizeErrorMessage } from "@omniroute/open-sse/utils/
  * expiry (forcing re-auth) instead of attempting a refresh-token exchange —
  * see open-sse/executors/codex.ts.
  *
- * Body: `{ accessToken: string, name?: string }`
+ * Body: `{ accessToken: string, name?: string }` OR, defense-in-depth for
+ * non-UI/API callers (#6636), the full session JSON object copied from
+ * `chatgpt.com/api/auth/session` under `{ session: {...} }`.
  *
  * Inspired-by: https://github.com/decolua/9router/pull/1290
  */
 
-const bodySchema = z.object({
-  accessToken: z.string().trim().min(1, "accessToken is required"),
-  name: z.string().trim().min(1).optional(),
-});
+const bodySchema = z.union([
+  z.object({
+    accessToken: z.string().trim().min(1, "accessToken is required"),
+    name: z.string().trim().min(1).optional(),
+  }),
+  z.object({
+    session: z.record(z.string(), z.unknown()),
+    name: z.string().trim().min(1).optional(),
+  }),
+]);
+
+type ResolvedBody = { accessToken: string; name?: string };
+
+/** Resolve either request-body shape to a flat `{ accessToken, name }` pair. */
+function resolveAccessToken(
+  parsed: z.infer<typeof bodySchema>
+): { ok: true; resolved: ResolvedBody } | { ok: false; error: string } {
+  if ("accessToken" in parsed) {
+    return { ok: true, resolved: { accessToken: parsed.accessToken, name: parsed.name } };
+  }
+  const result = parseCodexSessionJson(parsed.session);
+  if (!result.ok) return { ok: false, error: result.error };
+  return { ok: true, resolved: { accessToken: result.session.accessToken, name: parsed.name } };
+}
+
+/**
+ * Parse + validate the request body (JSON parse, Zod schema, then the
+ * accessToken/session-JSON union resolution). Returns either the resolved
+ * `{ accessToken, name }` pair or a ready-to-return 400 error response —
+ * keeps POST's own branch count flat as the accepted body shapes grow (#6636).
+ */
+async function parseRequestBody(
+  request: Request
+): Promise<{ ok: true; resolved: ResolvedBody } | { ok: false; response: NextResponse }> {
+  let rawBody: unknown;
+  try {
+    rawBody = await request.json();
+  } catch {
+    return {
+      ok: false,
+      response: NextResponse.json(buildErrorBody(400, "Invalid or empty JSON body"), {
+        status: 400,
+      }),
+    };
+  }
+
+  const parsed = bodySchema.safeParse(rawBody);
+  if (!parsed.success) {
+    return {
+      ok: false,
+      response: NextResponse.json(
+        buildErrorBody(400, parsed.error.issues[0]?.message ?? "Invalid request body"),
+        { status: 400 }
+      ),
+    };
+  }
+
+  const resolved = resolveAccessToken(parsed.data);
+  if (!resolved.ok) {
+    return {
+      ok: false,
+      response: NextResponse.json(buildErrorBody(400, resolved.error), { status: 400 }),
+    };
+  }
+  return { ok: true, resolved: resolved.resolved };
+}
 
 async function requireAuth(request: Request): Promise<NextResponse | null> {
   if (!(await isAuthRequired(request))) return null;
@@ -38,22 +103,10 @@ export async function POST(request: Request) {
   const authResponse = await requireAuth(request);
   if (authResponse) return authResponse;
 
-  let rawBody: unknown;
-  try {
-    rawBody = await request.json();
-  } catch {
-    return NextResponse.json(buildErrorBody(400, "Invalid or empty JSON body"), { status: 400 });
-  }
+  const body = await parseRequestBody(request);
+  if (!body.ok) return body.response;
 
-  const parsed = bodySchema.safeParse(rawBody);
-  if (!parsed.success) {
-    return NextResponse.json(
-      buildErrorBody(400, parsed.error.issues[0]?.message ?? "Invalid request body"),
-      { status: 400 }
-    );
-  }
-
-  const { accessToken, name } = parsed.data;
+  const { accessToken, name } = body.resolved;
   const info = extractCodexAccountInfo(accessToken);
 
   if (!info.email && !info.chatgptAccountId && !name) {
diff --git a/src/lib/oauth/services/codexImport.ts b/src/lib/oauth/services/codexImport.ts
index 9f5b929d34..aa8a362c44 100644
--- a/src/lib/oauth/services/codexImport.ts
+++ b/src/lib/oauth/services/codexImport.ts
@@ -58,10 +58,7 @@ function decodeJwtPayload(jwt: unknown): Record<string, unknown> | null {
     const missingPadding =
       (BASE64_BLOCK_SIZE - (base64.length % BASE64_BLOCK_SIZE)) % BASE64_BLOCK_SIZE;
     const padded = base64 + "=".repeat(missingPadding);
-    return JSON.parse(Buffer.from(padded, "base64").toString("utf8")) as Record<
-      string,
-      unknown
-    >;
+    return JSON.parse(Buffer.from(padded, "base64").toString("utf8")) as Record<string, unknown>;
   } catch {
     return null;
   }
@@ -82,21 +79,31 @@ export function extractCodexAccountInfo(idToken: string): {
 } {
   const payload = decodeJwtPayload(idToken);
   if (!payload) return {};
-  const chatgpt =
-    (payload["https://api.openai.com/auth"] as Record<string, unknown>) || {};
+  const chatgpt = (payload["https://api.openai.com/auth"] as Record<string, unknown>) || {};
   return {
     email: typeof payload.email === "string" ? payload.email : undefined,
     chatgptAccountId:
-      typeof chatgpt.chatgpt_account_id === "string"
-        ? chatgpt.chatgpt_account_id
-        : undefined,
+      typeof chatgpt.chatgpt_account_id === "string" ? chatgpt.chatgpt_account_id : undefined,
     chatgptPlanType:
-      typeof chatgpt.chatgpt_plan_type === "string"
-        ? chatgpt.chatgpt_plan_type
-        : undefined,
+      typeof chatgpt.chatgpt_plan_type === "string" ? chatgpt.chatgpt_plan_type : undefined,
   };
 }
 
+/**
+ * Decode a JWT's `exp` claim (seconds since epoch, per RFC 7519) without
+ * verifying the signature. Returns `null` when the token isn't a decodable
+ * JWT or carries no numeric `exp`.
+ *
+ * Exported so sibling Codex import paths (e.g. the session-JSON normalizer
+ * at `codexSessionImport.ts`, #6636) can check expiry without duplicating a
+ * 3rd inline JWT decoder.
+ */
+export function decodeJwtExp(jwt: unknown): number | null {
+  const payload = decodeJwtPayload(jwt);
+  const exp = payload && typeof payload.exp === "number" ? payload.exp : null;
+  return exp !== null && Number.isFinite(exp) ? exp : null;
+}
+
 function pickString(...candidates: (string | undefined)[]): string | undefined {
   for (const c of candidates) {
     if (typeof c === "string" && c.trim()) return c.trim();
@@ -146,9 +153,7 @@ function unwrapCodexAuthJson(rec: Record<string, unknown>): Record<string, unkno
  * its camelCase alias when it is absent, so a snake_case or mixed export keeps
  * working unchanged.
  */
-function applyCamelCaseAliases(
-  rec: Record<string, unknown>,
-): Record<string, unknown> {
+function applyCamelCaseAliases(rec: Record<string, unknown>): Record<string, unknown> {
   const out: Record<string, unknown> = { ...rec };
   const fillFrom = (snake: string, value: unknown) => {
     if (out[snake] === undefined && typeof value === "string" && value) {
@@ -181,9 +186,7 @@ export function normalizeCodexImportRecord(input: unknown): NormalizeResult {
     return { ok: false, error: "Record is not an object" };
   }
 
-  const rec = applyCamelCaseAliases(
-    unwrapCodexAuthJson(input as Record<string, unknown>),
-  );
+  const rec = applyCamelCaseAliases(unwrapCodexAuthJson(input as Record<string, unknown>));
 
   // Allow type field to be missing or "codex"; reject anything else explicitly so
   // users don't accidentally import claude/gemini exports through this path.
@@ -211,15 +214,14 @@ export function normalizeCodexImportRecord(input: unknown): NormalizeResult {
 
   const chatgptAccountId = pickString(
     fromJwt.chatgptAccountId,
-    rec.account_id as string | undefined,
+    rec.account_id as string | undefined
   );
   const chatgptPlanType = pickString(
     fromJwt.chatgptPlanType,
-    rec.chatgpt_plan_type as string | undefined,
+    rec.chatgpt_plan_type as string | undefined
   );
 
-  const expiresAt =
-    parseExpiry(rec.expired) ?? parseAccessTokenExp(accessToken);
+  const expiresAt = parseExpiry(rec.expired) ?? parseAccessTokenExp(accessToken);
 
   const providerSpecificData: CodexImportPayload["providerSpecificData"] = {};
   if (chatgptAccountId) providerSpecificData.chatgptAccountId = chatgptAccountId;
diff --git a/src/lib/oauth/utils/codexSessionImport.ts b/src/lib/oauth/utils/codexSessionImport.ts
new file mode 100644
index 0000000000..ec63de0973
--- /dev/null
+++ b/src/lib/oauth/utils/codexSessionImport.ts
@@ -0,0 +1,125 @@
+/**
+ * Codex (OpenAI) session-JSON normalizer
+ *
+ * Accepts the raw JSON object copied straight from
+ * `https://chatgpt.com/api/auth/session` (`{ user: {...}, accessToken, expires }`,
+ * NextAuth's session-endpoint shape) and extracts a bare access token + optional
+ * email, the same credential type already accepted by the bare-token import path
+ * (`POST /api/oauth/codex/import-token`, #1290) — this module only widens what
+ * shapes of pasted input can reach that endpoint.
+ *
+ * Pure: no I/O, no network, no DB import. Safe to unit-test. Mirrors the style
+ * of `codexAuthImport.ts` / `codexImport.ts`, deliberately kept separate from
+ * both: the bulk `auth.json` import requires a `refresh_token`; this path is
+ * for a bare access token and deliberately does not.
+ *
+ * Ref: #6636
+ */
+
+import { decodeJwtExp } from "@/lib/oauth/services/codexImport";
+
+// ── Types ─────────────────────────────────────────────────────────────────────
+
+export type ParsedCodexSession = { accessToken: string; email?: string };
+export type ParseResult = { ok: true; session: ParsedCodexSession } | { ok: false; error: string };
+
+// ── Internal helpers ──────────────────────────────────────────────────────────
+
+function toRecord(value: unknown): Record<string, unknown> | null {
+  return value && typeof value === "object" && !Array.isArray(value)
+    ? (value as Record<string, unknown>)
+    : null;
+}
+
+function toNonEmptyString(value: unknown): string | undefined {
+  return typeof value === "string" && value.trim() ? value.trim() : undefined;
+}
+
+/** Looks like a JWT (3 dot-separated segments) — a loose shape check only. */
+function looksLikeJwt(value: string): boolean {
+  return value.split(".").length === 3;
+}
+
+/**
+ * Field-name aliases for the access token across known Codex/ChatGPT session
+ * export shapes: the literal `accessToken` returned by `chatgpt.com/api/auth/session`
+ * first, then snake_case and alternate names, then the same aliases nested one
+ * level under `tokens` (mirrors `unwrapCodexAuthJson` in `codexAuthImport.ts`).
+ */
+function findAccessToken(rec: Record<string, unknown>): string | undefined {
+  const direct =
+    toNonEmptyString(rec.accessToken) ||
+    toNonEmptyString(rec.access_token) ||
+    toNonEmptyString(rec.sessionToken) ||
+    toNonEmptyString(rec.session_token);
+  if (direct) return direct;
+
+  const nested = toRecord(rec.tokens);
+  if (!nested) return undefined;
+  return toNonEmptyString(nested.access_token) || toNonEmptyString(nested.accessToken);
+}
+
+/** True when either expiry signal (top-level `expires` ISO string, or JWT `exp`) is in the past. */
+function isExpired(rec: Record<string, unknown>, accessToken: string): boolean {
+  const expiresField = toNonEmptyString(rec.expires);
+  if (expiresField) {
+    const ms = Date.parse(expiresField);
+    if (Number.isFinite(ms) && ms <= Date.now()) return true;
+  }
+  const exp = decodeJwtExp(accessToken);
+  return exp !== null && exp * 1000 <= Date.now();
+}
+
+// ── Public API ──────────────────────────────────────────────────────────────
+
+/**
+ * True if the pasted text looks like a JSON object (vs a bare JWT or an OAuth
+ * callback URL/code) — a cheap guard so the modal only attempts the JSON
+ * normalizer on plausible input and every other paste shape falls through to
+ * the existing parsers unchanged.
+ */
+export function looksLikeCodexSessionJson(value: string): boolean {
+  const trimmed = typeof value === "string" ? value.trim() : "";
+  if (!trimmed.startsWith("{")) return false;
+  try {
+    return toRecord(JSON.parse(trimmed)) !== null;
+  } catch {
+    return false;
+  }
+}
+
+/**
+ * Extract a bare access token (+ optional email) from a parsed
+ * `chatgpt.com/api/auth/session`-shaped JSON value. Returns a typed error
+ * (never throws) for malformed, tokenless, or expired input.
+ */
+export function parseCodexSessionJson(raw: unknown): ParseResult {
+  const rec = toRecord(raw);
+  if (!rec) {
+    return { ok: false, error: "Pasted session data is not a JSON object" };
+  }
+
+  const accessToken = findAccessToken(rec);
+  if (!accessToken) {
+    return {
+      ok: false,
+      error:
+        "Could not find an access token field in the pasted session JSON (expected accessToken, access_token, sessionToken, or tokens.access_token)",
+    };
+  }
+  if (!looksLikeJwt(accessToken)) {
+    return { ok: false, error: "The access token field does not look like a valid JWT" };
+  }
+
+  if (isExpired(rec, accessToken)) {
+    return {
+      ok: false,
+      error: "Session is expired — sign in to chatgpt.com again and re-copy the session JSON",
+    };
+  }
+
+  const user = toRecord(rec.user);
+  const email = (user && toNonEmptyString(user.email)) || undefined;
+
+  return { ok: true, session: { accessToken, email } };
+}
diff --git a/src/shared/components/OAuthModal.tsx b/src/shared/components/OAuthModal.tsx
index 07bb0a34ad..7d079724b2 100644
--- a/src/shared/components/OAuthModal.tsx
+++ b/src/shared/components/OAuthModal.tsx
@@ -9,6 +9,10 @@ import LinkifiedText from "./LinkifiedText";
 import { useCopyToClipboard } from "@/shared/hooks/useCopyToClipboard";
 import { parseResponseBody, getErrorMessage } from "@/shared/utils/api";
 import { isCredentialBlob, submitCredentialBlob } from "@/shared/components/oauthBlobSubmit";
+import {
+  looksLikeCodexSessionJson,
+  parseCodexSessionJson,
+} from "@/lib/oauth/utils/codexSessionImport";
 
 const GOOGLE_OAUTH_PROVIDERS = new Set(["antigravity", "agy"]);
 
@@ -23,6 +27,27 @@ const PKCE_CALLBACK_SERVER_PROVIDERS = new Set(["codex", "xai-oauth"]);
  */
 const IMPORT_TOKEN_ONLY_PROVIDERS = new Set(["windsurf", "devin-cli", "grok-cli"]);
 
+// POST a bare Codex access token to the access-token-only import endpoint
+// (#1290); shared by the bare-JWT and session-JSON paste branches (#6636).
+async function submitCodexAccessToken(
+  accessToken: string,
+  name: string | undefined,
+  setStep: (s: string) => void,
+  onSuccess?: () => void
+): Promise<void> {
+  const res = await fetch("/api/oauth/codex/import-token", {
+    method: "POST",
+    headers: { "Content-Type": "application/json" },
+    body: JSON.stringify({ accessToken, name }),
+  });
+  const data = (await parseResponseBody(res)) as Record<string, unknown>;
+  if (!res.ok) {
+    throw new Error(getErrorMessage(data, res.status, "Failed to import access token"));
+  }
+  setStep("success");
+  onSuccess?.();
+}
+
 type OAuthModalProps = {
   isOpen: boolean;
   provider?: string;
@@ -672,17 +697,24 @@ export default function OAuthModal({
       // raw-token paste pattern. Routed through the access-token-only import
       // endpoint (#1290) instead of the authorization-code exchange below.
       if (provider === "codex" && /^eyJ/.test(callbackUrl.trim())) {
-        const res = await fetch("/api/oauth/codex/import-token", {
-          method: "POST",
-          headers: { "Content-Type": "application/json" },
-          body: JSON.stringify({ accessToken: callbackUrl.trim() }),
-        });
-        const data = (await parseResponseBody(res)) as Record<string, unknown>;
-        if (!res.ok) {
-          throw new Error(getErrorMessage(data, res.status, "Failed to import access token"));
+        await submitCodexAccessToken(callbackUrl.trim(), undefined, setStep, onSuccess);
+        return;
+      }
+
+      // Codex: full session JSON from chatgpt.com/api/auth/session
+      // (`{user, accessToken, expires}`), not just the bare token (#6636).
+      if (provider === "codex" && looksLikeCodexSessionJson(callbackUrl)) {
+        const result = parseCodexSessionJson(JSON.parse(callbackUrl.trim()));
+        if (!result.ok) {
+          setError(result.error);
+          return;
         }
-        setStep("success");
-        onSuccess?.();
+        await submitCodexAccessToken(
+          result.session.accessToken,
+          result.session.email,
+          setStep,
+          onSuccess
+        );
         return;
       }
 
diff --git a/tests/unit/codex-import-token-route.test.ts b/tests/unit/codex-import-token-route.test.ts
index 83f2c8ad3f..bff8c49b83 100644
--- a/tests/unit/codex-import-token-route.test.ts
+++ b/tests/unit/codex-import-token-route.test.ts
@@ -141,3 +141,42 @@ test("import-token: error responses never leak a stack trace", async () => {
   assert.ok(!JSON.stringify(body).includes("at /"), "must not leak a stack trace");
   assert.ok(!JSON.stringify(body).includes(".ts:"), "must not leak a source location");
 });
+
+// #6636 — defense-in-depth: the route also accepts the full session JSON
+// object copied from chatgpt.com/api/auth/session under `{ session: {...} }`.
+test("import-token: accepts a full session-JSON body and creates a connection identical to the bare-accessToken path", async () => {
+  const accessToken = makeJwt({
+    email: "session-json@example.com",
+    "https://api.openai.com/auth": { chatgpt_account_id: "acct-session" },
+  });
+
+  const { status, body } = await postImportToken({
+    session: {
+      user: { email: "session-json@example.com" },
+      accessToken,
+      expires: new Date(Date.now() + 60_000).toISOString(),
+    },
+  });
+
+  assert.equal(status, 200);
+  assert.equal(body.success, true);
+  assert.equal(body.connection.provider, "codex");
+  assert.equal(body.connection.email, "session-json@example.com");
+
+  const rows = await providersDb.getProviderConnections({ provider: "codex" });
+  const created = rows.find((r) => r.id === body.connection.id);
+  assert.equal(created?.authType, "access_token");
+  assert.equal(created?.accessToken, accessToken);
+});
+
+test("import-token: session-JSON body with an expired session is rejected with an actionable 400", async () => {
+  const accessToken = makeJwt({ email: "expired@example.com" });
+  const { status, body } = await postImportToken({
+    session: {
+      accessToken,
+      expires: new Date(Date.now() - 60_000).toISOString(),
+    },
+  });
+  assert.equal(status, 400);
+  assert.match(body.error.message, /expired/i);
+});
diff --git a/tests/unit/codex-session-json-import-6636.test.ts b/tests/unit/codex-session-json-import-6636.test.ts
new file mode 100644
index 0000000000..301ad2b7d1
--- /dev/null
+++ b/tests/unit/codex-session-json-import-6636.test.ts
@@ -0,0 +1,118 @@
+// Unit tests for the Codex session-JSON normalizer (#6636).
+//
+// Reproduces the bug: pasting the full JSON object copied from
+// `https://chatgpt.com/api/auth/session` (`{user, accessToken, expires}`)
+// into the Codex OAuth modal used to fall through to the OAuth-code parser
+// and error out — only a bare JWT (`/^eyJ/`) was recognized. These tests
+// exercise the pure normalizer in isolation (no DB, no fetch).
+
+import test from "node:test";
+import assert from "node:assert/strict";
+import {
+  looksLikeCodexSessionJson,
+  parseCodexSessionJson,
+} from "../../src/lib/oauth/utils/codexSessionImport.ts";
+
+function b64url(obj: unknown): string {
+  return Buffer.from(JSON.stringify(obj))
+    .toString("base64")
+    .replace(/=+$/, "")
+    .replace(/\+/g, "-")
+    .replace(/\//g, "_");
+}
+
+function makeJwt(payload: Record<string, unknown>): string {
+  const header = b64url({ alg: "RS256", typ: "JWT" });
+  const body = b64url(payload);
+  return `${header}.${body}.signature`;
+}
+
+test("parseCodexSessionJson: extracts accessToken from the exact chatgpt.com/api/auth/session shape", () => {
+  const accessToken = makeJwt({ email: "session@example.com" });
+  const result = parseCodexSessionJson({
+    user: { email: "session@example.com" },
+    accessToken,
+    expires: new Date(Date.now() + 60_000).toISOString(),
+  });
+  assert.equal(result.ok, true);
+  if (result.ok) {
+    assert.equal(result.session.accessToken, accessToken);
+    assert.equal(result.session.email, "session@example.com");
+  }
+});
+
+test("parseCodexSessionJson: accepts access_token, sessionToken, and nested tokens.access_token aliases", () => {
+  const jwt = makeJwt({});
+  const snakeCase = parseCodexSessionJson({ access_token: jwt });
+  assert.equal(snakeCase.ok, true);
+
+  const sessionToken = parseCodexSessionJson({ sessionToken: jwt });
+  assert.equal(sessionToken.ok, true);
+
+  const nested = parseCodexSessionJson({ tokens: { access_token: jwt } });
+  assert.equal(nested.ok, true);
+  if (nested.ok) assert.equal(nested.session.accessToken, jwt);
+});
+
+test("parseCodexSessionJson: rejects malformed / non-object input with a typed error, not a throw", () => {
+  assert.equal(parseCodexSessionJson(null).ok, false);
+  assert.equal(parseCodexSessionJson("just a string").ok, false);
+  assert.equal(parseCodexSessionJson(42).ok, false);
+  assert.equal(parseCodexSessionJson([]).ok, false);
+
+  const result = parseCodexSessionJson("just a string");
+  assert.equal(result.ok, false);
+  if (!result.ok) assert.match(result.error, /not a JSON object/i);
+});
+
+test("parseCodexSessionJson: rejects an object with no recognizable token field", () => {
+  const result = parseCodexSessionJson({ user: { email: "no-token@example.com" } });
+  assert.equal(result.ok, false);
+  if (!result.ok) assert.match(result.error, /access token/i);
+});
+
+test("parseCodexSessionJson: rejects an expired session via the top-level `expires` field", () => {
+  const accessToken = makeJwt({});
+  const result = parseCodexSessionJson({
+    accessToken,
+    expires: new Date(Date.now() - 60_000).toISOString(),
+  });
+  assert.equal(result.ok, false);
+  if (!result.ok) assert.match(result.error, /expired/i);
+});
+
+test("parseCodexSessionJson: rejects an expired session via the JWT `exp` claim", () => {
+  const pastExpSeconds = Math.floor((Date.now() - 60_000) / 1000);
+  const accessToken = makeJwt({ exp: pastExpSeconds });
+  const result = parseCodexSessionJson({ accessToken });
+  assert.equal(result.ok, false);
+  if (!result.ok) assert.match(result.error, /expired/i);
+});
+
+test("parseCodexSessionJson: accepts a non-expired session with a future JWT `exp` claim", () => {
+  const futureExpSeconds = Math.floor((Date.now() + 60_000) / 1000);
+  const accessToken = makeJwt({ exp: futureExpSeconds });
+  const result = parseCodexSessionJson({ accessToken });
+  assert.equal(result.ok, true);
+});
+
+test("parseCodexSessionJson: rejects a token field that does not look like a JWT", () => {
+  const result = parseCodexSessionJson({ accessToken: "not-a-jwt" });
+  assert.equal(result.ok, false);
+  if (!result.ok) assert.match(result.error, /JWT/i);
+});
+
+test("looksLikeCodexSessionJson: true for a JSON object string", () => {
+  assert.equal(looksLikeCodexSessionJson('{"accessToken":"eyJ.eyJ.sig"}'), true);
+  assert.equal(looksLikeCodexSessionJson('  {"user":{}}  '), true);
+});
+
+test("looksLikeCodexSessionJson: false for a bare JWT, an OAuth callback URL, and malformed JSON", () => {
+  assert.equal(looksLikeCodexSessionJson("eyJhbGciOiJSUzI1NiJ9.eyJzdWIiOiIxIn0.sig"), false);
+  assert.equal(
+    looksLikeCodexSessionJson("https://example.com/callback?code=abc&state=xyz"),
+    false
+  );
+  assert.equal(looksLikeCodexSessionJson("{not valid json"), false);
+  assert.equal(looksLikeCodexSessionJson(""), false);
+});