diff --git a/.changeset/22384-auth-session-api-getsession-input-query.md b/.changeset/22384-auth-session-api-getsession-input-query.md
new file mode 100644
index 00000000000..81abb2c9ab8
--- /dev/null
+++ b/.changeset/22384-auth-session-api-getsession-input-query.md
@@ -0,0 +1,11 @@
+---
+"@objectstack/spec": minor
+---
+
+`AuthSessionApi.getSession` (`@objectstack/spec/contracts`) now declares the optional `query.disableRefresh` that the in-process session readers send
+
+Clause-②: yes (widening)
+
+- **The declaration.** `getSession`'s input is `{ headers: unknown; query?: { disableRefresh?: boolean } }`. It was `{ headers: unknown }`. The return type and the rest of `AuthSessionApi` are unchanged.
+- **Why.** The in-process readers call `api.getSession(inProcessSessionReadInput(headers))` (`@objectstack/types`). For a request that carries a better-auth session cookie, that input is `{ headers, query: { disableRefresh: true } }`, so the session renews only on the `get-session` route, which re-issues the cookie. A bearer-only request is still read with `{ headers }` alone. The declaration said the readers send only `{ headers }`, which stopped being true when the readers moved to the helper.
+- **Nothing to migrate.** The added key is optional. A caller that passes `{ headers }` compiles as before, and so does an implementation of `getSession` that accepts `{ headers }` and ignores the rest. An implementation that reads `input.query?.disableRefresh` now type-checks against the contract instead of needing a cast.
diff --git a/packages/spec/src/contracts/auth-service.ts b/packages/spec/src/contracts/auth-service.ts
index e835e0b70e4..d5a8d35a375 100644
--- a/packages/spec/src/contracts/auth-service.ts
+++ b/packages/spec/src/contracts/auth-service.ts
@@ -169,13 +169,36 @@ export interface IAuthService {
  * The slice of the session API the platform actually uses.
  *
  * [#4127 batch 4] Deliberately NOT a re-declaration of better-auth's handle,
- * which is far wider and belongs to that library. Every dispatcher-side reader
- * calls exactly `getSession({ headers })` and reads exactly the fields below,
- * so that is what is declared. Widening this is for whoever needs more, with
- * the call site to prove it.
+ * which is far wider and belongs to that library. What is declared is exactly
+ * the input the in-process readers send and exactly the fields below that they
+ * read. Widening this is for whoever needs more, with the call site to prove it.
+ *
+ * [#22384] `getSession`'s input has two read forms, decided by what the
+ * request carries:
+ *
+ * - a request carrying a better-auth session cookie (a browser) reads with
+ *   `{ headers, query: { disableRefresh: true } }` — the session then renews
+ *   only on the `get-session` route, which re-issues the cookie, so cookie
+ *   expiry and session expiry cannot split;
+ * - a bearer-only request (the SDK outside a browser, the CLI) reads with
+ *   `{ headers }` alone, renewal included.
+ *
+ * Their one source is `inProcessSessionReadInput(headers)` in
+ * `@objectstack/types` (`packages/types/src/in-process-session-read.ts`):
+ * read with `api.getSession(inProcessSessionReadInput(headers))`, not with a
+ * hand-built input — a hand-built `{ headers }` on a cookie-carrying request
+ * renews the session behind a cookie nobody re-issues. `query` is declared
+ * because readers send it (#22258): `rest-server.ts` in `@objectstack/rest`
+ * (twice); in `@objectstack/runtime`, `http-dispatcher.ts` (twice),
+ * `security/resolve-session-principal.ts` and
+ * `security/resolve-execution-context.ts`; `current-user-endpoints.ts` in
+ * `@objectstack/plugin-hono-server`; and in `@objectstack/cloud-connection`,
+ * `cloud-connection-plugin.ts` and `marketplace-install-local-plugin.ts`
+ * (twice). `packages/types/src/in-process-session-read.contract.test.ts`
+ * holds the helper's return inside this declaration, key for key.
  */
 export interface AuthSessionApi {
-    getSession?(input: { headers: unknown }): Promise<{
+    getSession?(input: { headers: unknown; query?: { disableRefresh?: boolean } }): Promise<{
         user?: { id?: string };
         session?: { userId?: string; activeOrganizationId?: string };
     } | undefined>;
diff --git a/packages/types/src/in-process-session-read.contract.test.ts b/packages/types/src/in-process-session-read.contract.test.ts
new file mode 100644
index 00000000000..f4439ad8b17
--- /dev/null
+++ b/packages/types/src/in-process-session-read.contract.test.ts
@@ -0,0 +1,106 @@
+// Copyright (c) 2026 ObjectStack. Licensed under the Apache-2.0 license.
+
+/**
+ * [#22384] The in-process session-read input stays inside the contract that
+ * declares it.
+ *
+ * Every in-process reader calls `api.getSession(inProcessSessionReadInput(headers))`
+ * with `api` typed by `AuthSessionApi` (`@objectstack/spec/contracts`), so the
+ * helper's return IS what that declaration receives. This file holds the two
+ * together: every key the helper returns is a key the declaration names. It
+ * lives in this package because only here are both visible — the helper is
+ * this package's, the contract is its dependency's, and `@objectstack/spec`
+ * must not import this package.
+ *
+ * ## Why plain assignability is not the check
+ *
+ * TypeScript refuses an undeclared key only on an object LITERAL. A
+ * non-literal carrying an extra optional key is assignable to a type that
+ * omits it, so `const input: DeclaredInput = inProcessSessionReadInput(headers)`
+ * compiles against a declaration of `{ headers: unknown }` alone — which is how
+ * the readers compiled while the declaration did not describe what they sent.
+ * `FitsDeclared` applies the literal's rule to a type: assignable, and no key
+ * the declaration does not name, at every depth where the declaration names a
+ * shape (`headers` is declared `unknown`, so it is not looked into).
+ *
+ * ## Where it bites
+ *
+ * At compile time. This package's `typecheck` (`tsc --noEmit`) compiles this
+ * file, reading the contract from `@objectstack/spec`'s BUILT `.d.ts`. A
+ * declaration that stops naming `query` or `disableRefresh`, or a helper that
+ * starts sending a key the declaration does not name, turns a `holds` below
+ * into TS2344, and reading `query` off the declared input in the runtime case
+ * into TS2339. The `@ts-expect-error` controls prove the instrument can fail at
+ * all: if `FitsDeclared` went vacuous, each directive would stop matching an
+ * error and tsc would report TS2578.
+ */
+
+import { expect, it } from 'vitest';
+import type { AuthSessionApi } from '@objectstack/spec/contracts';
+import { inProcessSessionReadInput } from './in-process-session-read.js';
+
+/** What `AuthSessionApi.getSession` declares it accepts. */
+type DeclaredInput = Parameters<NonNullable<AuthSessionApi['getSession']>>[0];
+
+/** What the helper returns for a reader's headers of type `H`. */
+type HelperInput<H> = ReturnType<typeof inProcessSessionReadInput<H>>;
+
+/** `Out` fits `In` the way an object literal must; `true` or `false`, never both. */
+type FitsDeclared<Out, In> = [Fits<Out, In>] extends [true] ? true : false;
+
+/**
+ * One verdict per union member of `Out` — a union is judged member by member,
+ * never by its common keys — and per declared key below it. The verdicts union
+ * together, and `FitsDeclared` reads a single `false` among them as a miss.
+ */
+type Fits<Out, In> = Out extends unknown
+    ? [Out] extends [In]
+        ? unknown extends In
+            ? true
+            : [Out] extends [object]
+                ? [Exclude<keyof Out, keyof In>] extends [never]
+                    ? { [K in keyof Out & keyof In]-?: Fits<Exclude<Out[K], undefined>, Exclude<In[K], undefined>> }[keyof Out & keyof In]
+                    : false
+                : true
+        : false
+    : never;
+
+/** Compiles only when its type argument is `true`. */
+function holds<T extends true>(verdict: T): T {
+    return verdict;
+}
+
+// The pin, for each header shape the readers hand the helper: a Web `Headers`
+// (`c.req.raw.headers`, the dispatcher's), a Node header record (`req.headers`
+// on the Node adapters), and an untyped one.
+holds<FitsDeclared<HelperInput<Headers>, DeclaredInput>>(true);
+holds<FitsDeclared<HelperInput<Record<string, string | string[] | undefined>>, DeclaredInput>>(true);
+holds<FitsDeclared<HelperInput<unknown>, DeclaredInput>>(true);
+
+// The instrument's controls: each of these MUST fail to compile.
+// @ts-expect-error a top-level key the declaration does not name
+holds<FitsDeclared<{ headers: unknown; cookie: string }, DeclaredInput>>(true);
+// @ts-expect-error a key under `query` the declaration does not name
+holds<FitsDeclared<{ headers: unknown; query: { disableRefresh: true; notDeclared: true } }, DeclaredInput>>(true);
+// @ts-expect-error a union member with an undeclared key, beside one without
+holds<FitsDeclared<{ headers: unknown } | { headers: unknown; cookie: string }, DeclaredInput>>(true);
+// @ts-expect-error a declared key with a value the declaration does not accept
+holds<FitsDeclared<{ headers: unknown; query: { disableRefresh: 'yes' } }, DeclaredInput>>(true);
+
+it('[#22384] an implementer typed by the contract reads the renewal decision the helper made', async () => {
+    const renews: boolean[] = [];
+    const api: AuthSessionApi = {
+        async getSession(input) {
+            // `input` is the DECLARED input: on a declaration without `query`
+            // this read is a compile error, not an `undefined`.
+            renews.push(input.query?.disableRefresh !== true);
+            return undefined;
+        },
+    };
+
+    await api.getSession?.(inProcessSessionReadInput(new Headers({ cookie: 'better-auth.session_token=tok3n.c2ln' })));
+    await api.getSession?.(inProcessSessionReadInput(new Headers({ authorization: 'Bearer tok3n.c2ln' })));
+
+    // A browser's read does not renew; a bearer-only read renews as before.
+    expect(renews).toEqual([false, true]);
+});