@@ -18,7 +18,8 @@ const device: DeviceInfo = {
 };
 
 const CLAIM: DeviceClaim = {
-  schemaVersion: 2,
+  schemaVersion: 3,
+  claimOwnerKind: 'open-session',
   deviceKey: 'local:apple:ios:SIM-1',
   device: { family: 'apple', id: device.id, name: device.name, kind: device.kind },
   session: 'cwd:/w:default',
 
@@ -146,7 +146,8 @@ const unavailable = Object.freeze({
 
 function makeClaim(stateDir: string): DeviceClaim {
   return {
-    schemaVersion: 2,
+    schemaVersion: 3,
+    claimOwnerKind: 'open-session',
     deviceKey: 'local:android:none:emulator-5554',
     device: { family: 'android', id: 'emulator-5554', name: 'Pixel', kind: 'emulator' },
     session: 'claimed-session',
 
@@ -20,7 +20,7 @@ function legacyClaim(overrides: Record<string, unknown> = {}): Record<string, un
   };
 }
 
-function currentClaim(overrides: Record<string, unknown> = {}): Record<string, unknown> {
+function v2Claim(overrides: Record<string, unknown> = {}): Record<string, unknown> {
   return {
     ...legacyClaim(),
     schemaVersion: 2,
@@ -29,24 +29,76 @@ function currentClaim(overrides: Record<string, unknown> = {}): Record<string, u
   };
 }
 
-test('v1 and v2 records decode to the process-owned claim with its process principal intact', () => {
-  for (const raw of [legacyClaim(), currentClaim()]) {
+function currentClaim(overrides: Record<string, unknown> = {}): Record<string, unknown> {
+  return {
+    ...v2Claim(),
+    schemaVersion: 3,
+    claimOwnerKind: 'open-session',
+    ...overrides,
+  };
+}
+
+test('v1, v2, and v3 records decode to the process-owned claim with its process principal intact', () => {
+  for (const raw of [legacyClaim(), v2Claim(), currentClaim()]) {
     const record = decodeStoredDeviceClaim(raw);
     expect(record).not.toBeNull();
     if (!record) throw new Error('expected process-owned');
-    expect(record.schemaVersion).toBe(2);
+    expect(record.schemaVersion).toBe(3);
     expect(record.session).toBe('work');
     expect(record.ownerPid).toBe(4242);
     expect(record.ownerToken).toBe('token');
+    expect(record.transientCommand).toBeUndefined();
+  }
+});
+
+// Released v1/v2 recorded a command-scoped claim and an open session *named* `transient:<command>`
+// as the same record, so no stored field can say which one a legacy record was. Such a record
+// still decodes — clearing, reconciliation, and stale settlement need its principal — but it
+// states no kind, so a migrated record can never cover a command.
+test('a migrated record normalizes to the current schema and states no claim kind', () => {
+  for (const raw of [
+    legacyClaim({ session: 'transient:install' }),
+    v2Claim({ session: 'transient:install' }),
+  ]) {
+    const record = decodeStoredDeviceClaim(raw);
+    expect(record).not.toBeNull();
+    if (!record) throw new Error('expected a decoded claim');
+    expect(record.schemaVersion).toBe(3);
+    expect(record.session).toBe('transient:install');
+    expect(record.claimOwnerKind).toBe('unstated');
+    expect(record.transientCommand).toBeUndefined();
   }
+});
+
+// A current record states its kind, and the kind fields have to agree. An open session may
+// legitimately be named after a command; a malformed kind fails the record closed.
+test('a current-version claim kind comes only from its stored fields', () => {
+  const named = decodeStoredDeviceClaim(currentClaim({ session: 'transient:install' }));
+  expect(named).not.toBeNull();
+  if (!named) throw new Error('expected a decoded claim');
+  expect(named.claimOwnerKind).toBe('open-session');
+  expect(named.transientCommand).toBeUndefined();
+
+  const scoped = decodeStoredDeviceClaim(
+    currentClaim({ claimOwnerKind: 'transient-command', transientCommand: 'install' }),
+  );
+  expect(scoped).not.toBeNull();
+  if (!scoped) throw new Error('expected a decoded claim');
+  expect(scoped.claimOwnerKind).toBe('transient-command');
+  expect(scoped.transientCommand).toBe('install');
+
+  expect(decodeStoredDeviceClaim(currentClaim({ transientCommand: 'install' }))).toBeNull();
   expect(
-    decodeStoredDeviceClaim(legacyClaim({ session: 'transient:install' }))?.schemaVersion,
-  ).toBe(2);
+    decodeStoredDeviceClaim(
+      currentClaim({ claimOwnerKind: 'transient-command', transientCommand: '' }),
+    ),
+  ).toBeNull();
+  expect(decodeStoredDeviceClaim(currentClaim({ claimOwnerKind: 'bogus' }))).toBeNull();
 });
 
 test('a record of an unknown schema version is unreadable', () => {
   // A future-schema record carrying a whole process principal is still not migrated into a claim.
-  for (const schemaVersion of [0, 3, 4]) {
+  for (const schemaVersion of [0, 4, 5]) {
     expect(decodeStoredDeviceClaim(currentClaim({ schemaVersion }))).toBeNull();
   }
   expect(decodeStoredDeviceClaim(null)).toBeNull();
 
@@ -8,15 +8,30 @@ import { isRecord } from '@agent-device/kernel/record';
 
 import { canonicalLocalDeviceKey } from './device-claim-paths.ts';
 
-/** Schema version of a process-owned claim record; v1 records migrate to it on read. */
-export const DEVICE_CLAIM_SCHEMA_VERSION = 2;
+/** Schema version of a process-owned claim record; v1/v2 records normalize to it on read. */
+export const DEVICE_CLAIM_SCHEMA_VERSION = 3;
+
+/**
+ * What a claim's record states about who owns it. A current writer always states one.
+ * `unstated` is what a record migrated from the released v1/v2 schemas decodes to, because those
+ * schemas wrote a command-scoped claim and an open session *named* `transient:<command>`
+ * identically; the session label is never re-read as the discriminant. A claim that states no kind
+ * can hold and fence a device but can never cover a command.
+ */
+export type DeviceClaimOwnerKind = 'open-session' | 'transient-command' | 'unstated';
+
+const DEVICE_CLAIM_OWNER_KINDS: readonly DeviceClaimOwnerKind[] = [
+  'open-session',
+  'transient-command',
+  'unstated',
+];
 
 /**
  * A claim owned by one process: the session or the sessionless command that took it. Its principal
  * is `ownerPid`/`ownerStartTime`/`ownerToken`, which is what every clearing surface matches on.
  */
 export type DeviceClaim = {
-  schemaVersion: 2;
+  schemaVersion: 3;
   deviceKey: string;
   device: DeviceIdentity & { name: string };
   session: string;
@@ -27,6 +42,15 @@ export type DeviceClaim = {
   ownerToken: string;
   createdAtMs: number;
   updatedAtMs: number;
+  /**
+   * The persisted claim-kind discriminant (#3345). Coverage reads this and never the `session`
+   * label: an open session may legitimately be named `transient:<command>`, and any printed
+   * address can be pasted back into `--session`. It is stored rather than derived from the schema
+   * version so a record renewed or abandoned after migration keeps saying the same thing.
+   */
+  claimOwnerKind: DeviceClaimOwnerKind;
+  /** The command a `transient-command` claim is scoped to; present for exactly that kind. */
+  transientCommand?: string;
   /** Set by `abandonDeviceClaim`; absent while the claim still holds the device for its owner. */
   abandonedAtMs?: number;
 };
@@ -52,20 +76,53 @@ export function ownershipFromClaim(claim: DeviceClaim): DeviceClaimSessionOwners
   };
 }
 
+/**
+ * Every stored record normalizes to the current schema so that a renewal or an abandon can write a
+ * decoded claim back without changing its shape. A v1/v2 record has no kind field, and the session
+ * label cannot supply one, so it decodes as `unstated`: it keeps its full principal for clearing,
+ * reconciliation, and stale settlement, and states no ownership kind.
+ */
 export function decodeStoredDeviceClaim(value: unknown): DeviceClaim | null {
   if (!isRecord(value)) return null;
   if (value.schemaVersion === DEVICE_CLAIM_SCHEMA_VERSION) return decodeCurrentClaim(value);
+  if (value.schemaVersion === 2) return decodeClaimBody(value, 'unstated');
   if (value.schemaVersion === 1) return migrateLegacyClaim(value);
   return null;
 }
 
+/**
+ * A current record states its kind, and the two kind fields have to agree: a command claim names
+ * its command, any other kind names none. Anything else fails the record closed rather than
+ * guessing which owner a session label suggests.
+ */
 function decodeCurrentClaim(raw: Record<string, unknown>): DeviceClaim | null {
+  const { claimOwnerKind, transientCommand } = raw;
+  if (!isKnownOwnerKind(claimOwnerKind)) return null;
+  if (claimOwnerKind === 'transient-command') {
+    if (!isNonEmptyString(transientCommand)) return null;
+    const claim = decodeClaimBody(raw, claimOwnerKind);
+    return claim ? { ...claim, transientCommand } : null;
+  }
+  if (transientCommand !== undefined) return null;
+  return decodeClaimBody(raw, claimOwnerKind);
+}
+
+function isKnownOwnerKind(value: unknown): value is DeviceClaimOwnerKind {
+  return (
+    typeof value === 'string' && (DEVICE_CLAIM_OWNER_KINDS as readonly string[]).includes(value)
+  );
+}
+
+function decodeClaimBody(
+  raw: Record<string, unknown>,
+  claimOwnerKind: DeviceClaimOwnerKind,
+): DeviceClaim | null {
   if (!isRecord(raw.device) || !isNonEmptyString(raw.device.name)) return null;
   const identity = decodeDeviceIdentity(raw.device);
-  return identity ? buildDecodedClaim(raw, identity, raw.device.name) : null;
+  return identity ? decodeClaimFields(raw, identity, raw.device.name, claimOwnerKind) : null;
 }
 
-/** Released schema-v1 advisory claims are normalized into the canonical v2 model on read. */
+/** Released schema-v1 claims differ only in device shape; they state no claim kind. */
 function migrateLegacyClaim(raw: Record<string, unknown>): DeviceClaim | null {
   if (!isRecord(raw.device)) return null;
   const legacy = raw.device;
@@ -87,13 +144,14 @@ function migrateLegacyClaim(raw: Record<string, unknown>): DeviceClaim | null {
       ? {}
       : { iosPhysicalDeviceBackend: legacy.iosPhysicalDeviceBackend }),
   });
-  return identity ? buildDecodedClaim(raw, identity, name) : null;
+  return identity ? decodeClaimFields(raw, identity, name, 'unstated') : null;
 }
 
-function buildDecodedClaim(
+function decodeClaimFields(
   raw: Record<string, unknown>,
   identity: DeviceIdentity,
   name: string,
+  claimOwnerKind: DeviceClaimOwnerKind,
 ): DeviceClaim | null {
   const location = decodeClaimLocation(raw);
   const owner = decodeClaimOwner(raw);
@@ -106,9 +164,20 @@ function buildDecodedClaim(
     device: { ...identity, name },
     ...owner,
     ...timestamps,
+    claimOwnerKind,
   };
 }
 
+/**
+ * The claim `session` recorded for a command-scoped claim. Lives with the record so the label and
+ * its inverse stay one owner; `claimOwnerKind` is what decides a kind, never this shape.
+ */
+export function transientDeviceClaimSession(command: string): string {
+  return `${TRANSIENT_CLAIM_LABEL_PREFIX}${command}`;
+}
+
+const TRANSIENT_CLAIM_LABEL_PREFIX = 'transient:';
+
 function decodeClaimLocation(
   raw: Record<string, unknown>,
 ): Pick<DeviceClaim, 'deviceKey' | 'session' | 'workspace' | 'stateDir'> | null {
 
@@ -22,6 +22,7 @@ import { resolveDeviceClaimPath } from './device-claim-paths.ts';
 import {
   ownershipFromClaim,
   type DeviceClaim,
+  type DeviceClaimOwnerKind,
   type DeviceClaimSessionOwnership,
 } from './device-claim-record.ts';
 import { writeDeviceClaim } from './device-claim-store.ts';
@@ -44,6 +45,13 @@ export type DeviceClaimReconciler = (
   claim: DeviceClaim,
 ) => Promise<DeviceClaimReconciliationResult>;
 
+/**
+ * The acquirer whose ownership `resolveExistingClaim` judges: the kind of claim it could have
+ * written itself — never `unstated`, which no acquirer can be — plus the command a transient
+ * acquirer scopes to.
+ */
+export type DeviceClaimAcquirerKind = Exclude<DeviceClaimOwnerKind, 'unstated'>;
+
 /**
  * Settles the claim file an acquisition found, and decides whether this caller may write its own.
  * The recorded owner's own state answers first — a dead, unreachable, or superseded owner is
@@ -58,6 +66,10 @@ export async function resolveExistingClaim(params: {
   session: string;
   workspace: string;
   stateDir: string;
+  /** The kind of claim this acquirer would write, so `isCurrentClaimOwner` can compare kinds. */
+  claimOwnerKind: DeviceClaimAcquirerKind;
+  /** The command a `transient-command` acquirer scopes to; absent exactly when the kind is. */
+  transientCommand?: string;
   reconcileOrphanedDeviceClaim: DeviceClaimReconciler;
   observeDeviceBoot?: DeviceBootObservationService;
   env: EnvMap;
@@ -192,11 +204,31 @@ function isAbandonedClaimOfThisDaemon(
   return isAbandonedDeviceClaim(claim) && isClaimOwnedByThisDaemon(claim, stateDir, owner);
 }
 
+/**
+ * An acquirer holds an existing claim only when the record states the very kind of claim this
+ * acquirer would write itself — the same `transientCommand` for transient admission — under the
+ * same session, workspace, and daemon. `unstated` matches no acquirer, so a migrated record can
+ * hold and fence the device but can never be adopted at acquisition, however exactly its session
+ * label or copyable `--session` address lines up (#3345).
+ */
 function isCurrentClaimOwner(
   claim: DeviceClaim,
-  params: { session: string; workspace: string; stateDir: string },
+  params: {
+    session: string;
+    workspace: string;
+    stateDir: string;
+    claimOwnerKind: DeviceClaimAcquirerKind;
+    transientCommand?: string;
+  },
   owner: ReturnType<typeof readCurrentOwnerIdentity>,
 ): boolean {
+  if (claim.claimOwnerKind !== params.claimOwnerKind) return false;
+  if (
+    params.claimOwnerKind === 'transient-command' &&
+    claim.transientCommand !== params.transientCommand
+  ) {
+    return false;
+  }
   return (
     claim.session === params.session &&
     claim.workspace === params.workspace &&