@@ -0,0 +1,30 @@
+---
+'@objectstack/spec': minor
+'@objectstack/plugin-auth': minor
+---
+
+feat(spec,plugin-auth): a short-lived principal-session mint, `IAuthService.mintPrincipalSession`, implemented by `AuthManager`
+
+Clause-②: yes (widening)
+
+An in-process service can now act as the requesting user through a door that only accepts a session, such as a headless browser rendering a page the user may see, under the user's own principal and never a system one. Nothing is removed and no HTTP route is added.
+
+- **`@objectstack/spec`** (`contracts`): an optional `IAuthService` member, `mintPrincipalSession(context, options?)`, its types `PrincipalSession`, `PrincipalSessionCookie` and `PrincipalSessionMintOptions`, and the constant `PRINCIPAL_SESSION_MAX_TTL_SECONDS` (`120`). The member is optional, so every existing `IAuthService` implementation compiles unchanged.
+- **`@objectstack/plugin-auth`**: `AuthManager.mintPrincipalSession(context, options?)`.
+
+What the mint guarantees:
+
+- **Human principals only, refused before anything is minted.** A context with no user, a system context, or a `principalKind` other than `human` gets `PERMISSION_DENIED` / `403`. So does a user row that is missing, the system user or banned. A user an authentication policy holds gets `403` with the policy's own code (`MFA_REQUIRED`, `PASSWORD_EXPIRED`, `PASSWORD_RESET_REQUIRED`), whether the posture rides on the context or is computed at the call. A `ttlSeconds` outside 1 to 120 gets `VALIDATION_ERROR` / `400`: it is refused, never clamped.
+- **Short and never renewed.** The session lives at most 120 seconds. Reading it never extends it, on the cookie lane, the bearer lane or the in-process session read alike.
+- **Revocable.** `revoke()` ends the session. Afterwards neither the token nor the cookie resolves one. It is bound to that session alone and safe to call twice, so call it in a `finally`.
+- **The deployment's own cookie.** The cookie carries the name and attributes of the plugin's session cookie, the cookie prefix and, on a secure deployment, `__Secure-` included. The session's active organization is the context's `tenantId`.
+
+```ts
+const auth = ctx.getService<IAuthService>('auth');
+const session = await auth.mintPrincipalSession?.(context, { ttlSeconds: 60 });
+try {
+  // send session.token as `Authorization: Bearer`, or set session.cookie in a browser
+} finally {
+  await session?.revoke();
+}
+```
@@ -191,6 +191,7 @@ One of the largest consumers of the flag;
 | 59 | Email-template organization door passes; webhook provenance stamp skipped | plugin-email, plugin-webhooks | Get (`sys_email_template`): a create or update of a template row. The door refuses every other write that names a caller, `403 PERMISSION_DENIED` (ADR-0131 D6); the plugin itself no longer writes the table (templates resolve from the registry), so the v18 migration ceremony's promotion is the one remaining writer. Lose (`sys_webhook`): the row is not marked as an admin customization | `packages/plugins/plugin-email/src/email-template-door.ts#isOrganizationWrite`, `packages/plugins/plugin-webhooks/src/webhook-provenance.ts#bindWebhookProvenanceStamp` |
 | 60 | **Automation flow data nodes re-add the `owner_id` stamp** (the one place row 2's gap is compensated inline) | service-automation | Get: a flow-authored INSERT under system elevation still lands owned, when the run resolved a user. Fill-only — flow-authored values win | `packages/services/service-automation/src/runtime-identity.ts#stampSystemInsertOwner`, called from `packages/services/service-automation/src/builtin/crud-nodes.ts#registerCrudNodes` |
 | 61 | Inbox caller refusal names `isSystem` as what was carried | service-messaging | Get: nothing — the refusal still fires. The flag only shapes the diagnostic, because privilege is not an authorization subject | `packages/services/service-messaging/src/inbox-caller.ts#resolveInboxRecipient` |
+| 61b | **The principal-session mint refuses a system context** | plugin-auth | Get: nothing — `mintPrincipalSession` answers `PERMISSION_DENIED` / `403` before anything is minted. A principal session acts as the requesting user and never as the system, so a render or any other in-process act that needs a session must carry the user's own context | `packages/plugins/plugin-auth/src/principal-session-mint.ts#refuseUpFront` |
 | 62 | **`organization_id` is not auto-stamped on INSERT** — the organization-axis twin of the `owner_id` gap above | organizations | Get: an elevated write may name another organization deliberately, which is what the per-organization seed replay, the orphan-row claim, imports and migrations all rely on. Lose: the fill-only stamp, so an elevated insert that names no organization lands `organization_id = NULL` and the wall hides it. ⛔ Neither path rewrites a supplied `organization_id`: the non-elevated path fills only an absent one, and a supplied value meets the Layer 0 write wall, which refuses a forged one `403 PERMISSION_DENIED` exactly as it refuses an update re-pointing a row. Elevation skips the stamp and the wall alike, which is why it is the seam the legitimate cross-organization writers use | `packages/plugins/organizations/src/organizations-plugin.ts#start` |
 
 ### 6. Reads that only carry the flag onward
 
@@ -51,7 +51,14 @@ import {
   resolveUserAuthzGrants,
 } from '@objectstack/core';
 import type { AuthGate } from '@objectstack/core';
-import type { ApiKeyLifecyclePolicy, IEmailService, ISmsService } from '@objectstack/spec/contracts';
+import type { ExecutionContext } from '@objectstack/spec/kernel';
+import type {
+  ApiKeyLifecyclePolicy,
+  IEmailService,
+  ISmsService,
+  PrincipalSession,
+  PrincipalSessionMintOptions,
+} from '@objectstack/spec/contracts';
 import {
   readEnvWithDeprecation,
   resolveTenancyPosture,
@@ -95,6 +102,11 @@ import {
   VENDOR_ROLE_SCALAR_ADMIN_PATHS,
 } from './admin-impersonate-endpoint.js';
 import { judgeHeldSession } from './platform-admin-gate.js';
+import {
+  holdPrincipalSessionExpiry,
+  mintPrincipalSession,
+  type PrincipalSessionAuthContext,
+} from './principal-session-mint.js';
 import {
   applyDeclaredInvitationVerificationToListing,
 } from './list-user-invitations-verification.js';
@@ -7837,6 +7849,31 @@ export class AuthManager {
       );
       return result;
     };
+    // [#23772] A minted principal session is NEVER renewed. better-auth's
+    // `get-session` renews any session past `updateAge` to `now + expiresIn`,
+    // a short session from its first read, and on the bearer lane nothing
+    // client-side can stop it (no dont-remember cookie rides a bearer). Every
+    // renewal is one `internalAdapter.updateSession`, so the guard sits on
+    // that write — the cookie lane, the bearer lane and the in-process
+    // `getSession` alike, under secondary storage too
+    // (`principal-session-mint.ts`, `holdPrincipalSessionExpiry`). A host
+    // hook chains FIRST and its `false` (abort) is honoured; the guard then
+    // judges what the host left.
+    const hostSessionUpdateBefore = (host as any)?.session?.update?.before;
+    const sessionUpdateBefore = async (update: any, ctx: any) => {
+      let draft = update;
+      if (hostSessionUpdateBefore) {
+        const hostResult = await hostSessionUpdateBefore(update, ctx);
+        if (hostResult === false) return false;
+        if (hostResult && typeof hostResult === 'object' && 'data' in hostResult) {
+          draft = { ...draft, ...(hostResult as any).data };
+        }
+      }
+      const held = holdPrincipalSessionExpiry(draft, ctx);
+      if (held) return { data: held };
+      return draft === update ? undefined : { data: draft };
+    };
+
     const hostSessionDeleteAfter = (host as any)?.session?.delete?.after;
     const sessionDeleteAfter = async (session: any, ctx: any) => {
       const result = hostSessionDeleteAfter ? await hostSessionDeleteAfter(session, ctx) : undefined;
@@ -7938,6 +7975,10 @@ export class AuthManager {
           ...(sessionBefore ? { before: sessionBefore } : {}),
           after: sessionCreateAfter,
         },
+        update: {
+          ...((host as any)?.session?.update ?? {}),
+          before: sessionUpdateBefore,
+        },
         delete: {
           ...((host as any)?.session?.delete ?? {}),
           after: sessionDeleteAfter,
@@ -8289,6 +8330,28 @@ export class AuthManager {
     };
   }
 
+  /**
+   * [#23772] `IAuthService.mintPrincipalSession`: a short-lived session for
+   * the requesting user's own principal, in-process only (no route reaches
+   * it). Human principals only, refused before anything is minted; at most
+   * `PRINCIPAL_SESSION_MAX_TTL_SECONDS`; never renewed by a read on either
+   * lane (the `session.update.before` guard in `composeDatabaseHooks`); ended
+   * by the returned `revoke`. `principal-session-mint.ts` owns all of it.
+   */
+  public async mintPrincipalSession(
+    context: ExecutionContext,
+    options?: PrincipalSessionMintOptions,
+  ): Promise<PrincipalSession> {
+    return mintPrincipalSession(
+      {
+        authContext: async () => (await this.getAuthContext()) as PrincipalSessionAuthContext,
+        resolveUserAuthGates: (userId, opts) => this.resolveUserAuthGates(userId, opts),
+      },
+      context,
+      options,
+    );
+  }
+
   public async resolveUserAuthGates(
     userId: string,
     options: { organizationId?: string } = {},
 
@@ -0,0 +1,93 @@
+// Copyright (c) 2026 ObjectStack. Licensed under the Apache-2.0 license.
+
+/**
+ * [#23772] The shared fixture of the principal-session mint pins: a REAL
+ * `AuthManager` (the installed better-auth) over the in-memory engine the
+ * impersonation pins use, one signed-up human user, and readers for what a
+ * pin judges — the `sys_session` row straight off the engine's table, and
+ * `GET /get-session` through the manager's real request seam on each lane.
+ * Test-only; nothing in the package imports it.
+ */
+
+import { AuthManager } from './auth-manager.js';
+import { inviteForAudienceGate } from './audience-gate-test-support.js';
+import type { PrincipalSession } from '@objectstack/spec/contracts';
+import type { ExecutionContext } from '@objectstack/spec/kernel';
+
+export const MINT_SECRET = 'test-secret-at-least-32-chars-long!!';
+export const MINT_BASE = '/api/v1/auth';
+const PASSWORD = 'S3cure!Passw0rd-23772';
+
+/** The in-memory engine of `impersonation-bearer-rotation.test.ts`, as far as these pins read it. */
+export interface MintFixtureEngine {
+  tables: Map<string, Array<Record<string, unknown>>>;
+}
+
+export interface MintFixture {
+  manager: AuthManager;
+  engine: MintFixtureEngine;
+  origin: string;
+  userId: string;
+  /** The user's own context, as the HTTP entry assembles it for a session. */
+  human(extra?: Partial<ExecutionContext>): ExecutionContext;
+  /** The `sys_session` row whose token is `token`, or `undefined`. */
+  row(token: string): Record<string, unknown> | undefined;
+  /** `GET /get-session` carrying `headers`, answered by the real request seam. */
+  getSession(headers: Record<string, string>): Promise<{ status: number; body: any }>;
+}
+
+export async function bootMintFixture(
+  createEngine: () => MintFixtureEngine,
+  options: { origin?: string; advanced?: Record<string, unknown> } = {},
+): Promise<MintFixture> {
+  const origin = options.origin ?? 'http://localhost:3000';
+  const engine = createEngine();
+  const manager = new AuthManager({
+    secret: MINT_SECRET,
+    baseUrl: origin,
+    dataEngine: engine,
+    plugins: { admin: true },
+    ...(options.advanced ? { advanced: options.advanced } : {}),
+  } as any);
+
+  const email = 'mint.23772@example.com';
+  await inviteForAudienceGate(manager, email);
+  const res = await manager.handleRequest(
+    new Request(`${origin}${MINT_BASE}/sign-up/email`, {
+      method: 'POST',
+      headers: { 'content-type': 'application/json', origin },
+      body: JSON.stringify({ email, password: PASSWORD, name: 'Mint Human' }),
+    }),
+  );
+  if (res.status !== 200) throw new Error(`fixture sign-up answered ${res.status}: ${await res.text()}`);
+  const user = (engine.tables.get('sys_user') ?? []).find((r) => r.email === email);
+  if (!user) throw new Error('fixture sign-up wrote no sys_user row');
+  const userId = String(user.id);
+
+  return {
+    manager,
+    engine,
+    origin,
+    userId,
+    human: (extra = {}) => ({ userId, positions: [], permissions: [], isSystem: false, ...extra }),
+    row: (token) => (engine.tables.get('sys_session') ?? []).find((r) => r.token === token),
+    getSession: async (headers) => {
+      const r = await manager.handleRequest(
+        new Request(`${origin}${MINT_BASE}/get-session`, { method: 'GET', headers: { origin, ...headers } }),
+      );
+      const text = await r.text();
+      return { status: r.status, body: text ? JSON.parse(text) : null };
+    },
+  };
+}
+
+/** The raw token of a minted session, read back out of its signed value. */
+export function rawTokenOf(minted: PrincipalSession): string {
+  return decodeURIComponent(minted.token).split('.')[0];
+}
+
+/** The stored `expires_at` of a row, in ms. */
+export function expiresAtMs(row: Record<string, unknown> | undefined): number {
+  if (!row) throw new Error('pin: the session row is gone');
+  return new Date(row.expires_at as string | Date).getTime();
+}
@@ -0,0 +1,95 @@
+// Copyright (c) 2026 ObjectStack. Licensed under the Apache-2.0 license.
+
+/**
+ * [#23772] The principal-session mint on the BEARER lane: a client sending
+ * the minted token as `Authorization: Bearer`, over HTTP and through the
+ * in-process session read every transport makes for a bearer-only request
+ * (`inProcessSessionReadInput`, `@objectstack/types`, which reads WITH
+ * renewal on that lane).
+ *
+ * This is the lane a client-side defence cannot reach: better-auth's
+ * `bearer()` turns the token into the session cookie and no dont-remember
+ * cookie rides along, so `get-session` renews a short session to
+ * `now + expiresIn` on its first read — the control proves it on a session
+ * minted the same way without the brand. The pin is that the minted one does
+ * not move on either reader, and that after revoke the token resolves nothing.
+ */
+
+import { describe, it, expect, vi, beforeAll, afterAll } from 'vitest';
+import { inProcessSessionReadInput } from '@objectstack/types';
+import { createMemoryEngine } from './impersonation-bearer-rotation.test';
+import { bootMintFixture, expiresAtMs, rawTokenOf, type MintFixture } from './principal-session-mint-test-support';
+
+let fx: MintFixture;
+let expiresInSec: number;
+
+beforeAll(async () => {
+  vi.spyOn(console, 'warn').mockImplementation(() => {});
+  vi.spyOn(console, 'error').mockImplementation(() => {});
+  fx = await bootMintFixture(createMemoryEngine as any);
+  expiresInSec = Number((await fx.manager.getAuthContext()).sessionConfig.expiresIn);
+});
+
+afterAll(() => vi.restoreAllMocks());
+
+const inProcessRead = async (token: string) => {
+  const api: any = await fx.manager.getApi();
+  return api.getSession(inProcessSessionReadInput(new Headers({ authorization: `Bearer ${token}` })));
+};
+
+describe('[#23772] bearer lane — a minted session is never renewed', () => {
+  it('control: a short session WITHOUT the brand is renewed by a bearer get-session', async () => {
+    const ctx: any = await fx.manager.getAuthContext();
+    const plain = await ctx.internalAdapter.createSession(
+      fx.userId, false, { expiresAt: new Date(Date.now() + 120_000) }, true,
+    );
+    const before = expiresAtMs(fx.row(plain.token));
+
+    const res = await fx.getSession({ authorization: `Bearer ${plain.token}` });
+
+    expect(res.body?.user?.id, 'the control bearer did not authenticate').toBe(fx.userId);
+    expect(expiresAtMs(fx.row(plain.token)) - before, 'the fixture does not renew — the pins below would pass vacuously')
+      .toBeGreaterThan((expiresInSec - 3600) * 1000);
+  });
+
+  it('over HTTP: the minted token authenticates as the user and its expiry does not move', async () => {
+    const minted = await fx.manager.mintPrincipalSession(fx.human());
+    const token = rawTokenOf(minted);
+    const mintedAt = expiresAtMs(fx.row(token));
+
+    for (let i = 0; i < 3; i++) {
+      const res = await fx.getSession({ authorization: `Bearer ${minted.token}` });
+      expect(res.status).toBe(200);
+      expect(res.body?.user?.id, 'the minted bearer did not authenticate').toBe(fx.userId);
+      expect(new Date(res.body.session.expiresAt).getTime(), 'get-session answered a renewed expiry').toBe(mintedAt);
+      expect(expiresAtMs(fx.row(token)), `read ${i + 1} renewed the minted session row`).toBe(mintedAt);
+    }
+    await minted.revoke();
+  });
+
+  it('in-process (the bearer-only read that renews): the expiry does not move', async () => {
+    const minted = await fx.manager.mintPrincipalSession(fx.human());
+    const token = rawTokenOf(minted);
+    const mintedAt = expiresAtMs(fx.row(token));
+
+    const read = await inProcessRead(minted.token);
+
+    expect(read?.user?.id, 'the in-process bearer read did not resolve the user').toBe(fx.userId);
+    expect(expiresAtMs(fx.row(token)), 'the in-process read renewed the minted session row').toBe(mintedAt);
+    await minted.revoke();
+  });
+
+  it('after revoke the token resolves no session, over HTTP and in-process', async () => {
+    const minted = await fx.manager.mintPrincipalSession(fx.human());
+    expect((await fx.getSession({ authorization: `Bearer ${minted.token}` })).body?.user?.id).toBe(fx.userId);
+
+    await minted.revoke();
+
+    expect(fx.row(rawTokenOf(minted)), 'revoke left the session row').toBeUndefined();
+    // The platform's answer for "no session" on this route (anonymous-session-refusal.ts).
+    const res = await fx.getSession({ authorization: `Bearer ${minted.token}` });
+    expect({ status: res.status, code: res.body?.error?.code }, 'a revoked token still resolved a session')
+      .toEqual({ status: 401, code: 'UNAUTHENTICATED' });
+    expect(await inProcessRead(minted.token)).toBeNull();
+  });
+});