polish(policies): tighten comments on the team-scope/authority code

Trim verbose/history-framing comments to concise, timeless descriptions. No behaviour change.

app/proprietary/src/main/java/stirling/software/proprietary/policy/config/AdminPolicyManagementAuthority.java

@@ -0,0 +1,37 @@
+package stirling.software.proprietary.policy.config;
+
+import org.springframework.context.annotation.Profile;
+import org.springframework.stereotype.Component;
+
+import lombok.RequiredArgsConstructor;
+
+import stirling.software.proprietary.model.Team;
+import stirling.software.proprietary.security.model.User;
+import stirling.software.proprietary.security.service.UserService;
+
+/** Self-hosted policy authority: a global admin may edit; scoping uses the current user's team. */
+@Component
+@Profile("!saas")
+@RequiredArgsConstructor
+public class AdminPolicyManagementAuthority implements PolicyManagementAuthority {
+
+    private final UserService userService;
+
+    @Override
+    public boolean canEditPolicies() {
+        return userService.isCurrentUserAdmin();
+    }
+
+    @Override
+    public Long currentUserTeamId() {
+        String username = userService.getCurrentUsername();
+        if (username == null) {
+            return null;
+        }
+        return userService
+                .findByUsername(username)
+                .map(User::getTeam)
+                .map(Team::getId)
+                .orElse(null);
+    }
+}

app/proprietary/src/main/java/stirling/software/proprietary/policy/config/PolicyAccessGuard.java

@@ -1,6 +1,7 @@
 package stirling.software.proprietary.policy.config;
 
 import java.util.List;
+import java.util.Objects;
 
 import org.springframework.stereotype.Component;
 
@@ -11,10 +12,9 @@ import stirling.software.common.service.UserServiceInterface;
 import stirling.software.proprietary.policy.model.Policy;
 
 /**
- * Policies are org-wide: every user may view and run any stored policy, so reads and runs are open
- * to all. Creating, editing, and deleting is gated to admins at the controller (see {@code
- * PolicyController#requirePolicyEditingAllowed}). The owner is still recorded server-side (for run
- * / usage attribution) but no longer restricts visibility or access.
+ * Scopes policy access to the caller's team: every user — admins included — may view, run, edit, or
+ * delete only policies stamped with their own team. Whether a user may edit at all is a separate
+ * check at the controller. Applies only when login is enabled; single-user deployments pass.
  */
 @Component
 @RequiredArgsConstructor
@@ -22,15 +22,33 @@ public class PolicyAccessGuard {
 
     private final UserServiceInterface userService;
     private final ApplicationProperties applicationProperties;
+    private final PolicyManagementAuthority policyManagementAuthority;
 
     /** Owner for a new policy: the current user, or {@code null} when login is disabled. */
     public String ownerForNewPolicy() {
         return enforced() ? userService.getCurrentUsername() : null;
     }
 
-    /** All stored policies are visible to every user (org-wide). */
+    /** Team a new policy is stamped with — the creator's team. {@code null} when login disabled. */
+    public Long teamForNewPolicy() {
+        return enforced() ? policyManagementAuthority.currentUserTeamId() : null;
+    }
+
+    /** Whether the policy belongs to the current user's team (so they may view/run/edit it). */
+    public boolean canAccess(Policy policy) {
+        if (!enforced()) {
+            return true;
+        }
+        return Objects.equals(policy.teamId(), policyManagementAuthority.currentUserTeamId());
+    }
+
+    /** The subset of {@code policies} scoped to the current user's team. */
     public List<Policy> visible(List<Policy> policies) {
-        return policies;
+        if (!enforced()) {
+            return policies;
+        }
+        Long teamId = policyManagementAuthority.currentUserTeamId();
+        return policies.stream().filter(policy -> Objects.equals(policy.teamId(), teamId)).toList();
     }
 
     private boolean enforced() {

app/proprietary/src/main/java/stirling/software/proprietary/policy/config/PolicyManagementAuthority.java

@@ -0,0 +1,19 @@
+package stirling.software.proprietary.policy.config;
+
+/**
+ * The current user's policy authority, pluggable per deployment so the policy layer needn't know
+ * the team model. Resolves who may edit policies (SaaS: a team leader; self-hosted: a global admin)
+ * and which team scopes them.
+ */
+public interface PolicyManagementAuthority {
+
+    /** Whether the current user may create, edit, or delete policies. */
+    boolean canEditPolicies();
+
+    /**
+     * The team that scopes the current user's policies: a new policy is stamped with it, and it is
+     * the only team whose policies the user may see, run, or edit. {@code null} when unresolved (no
+     * authenticated user or no team).
+     */
+    Long currentUserTeamId();
+}

app/proprietary/src/main/java/stirling/software/proprietary/policy/controller/PolicyController.java

@@ -36,10 +36,10 @@ import lombok.extern.slf4j.Slf4j;
 
 import stirling.software.common.model.ApplicationProperties;
 import stirling.software.common.model.job.JobResponse;
-import stirling.software.common.service.UserServiceInterface;
 import stirling.software.common.util.TempFile;
 import stirling.software.common.util.TempFileManager;
 import stirling.software.proprietary.policy.config.PolicyAccessGuard;
+import stirling.software.proprietary.policy.config.PolicyManagementAuthority;
 import stirling.software.proprietary.policy.engine.PolicyRunHandle;
 import stirling.software.proprietary.policy.engine.PolicyRunRegistry;
 import stirling.software.proprietary.policy.engine.PolicyRunner;
@@ -72,7 +72,7 @@ public class PolicyController {
     private final PolicyStore policyStore;
     private final PolicyValidator policyValidator;
     private final PolicyAccessGuard policyAccessGuard;
-    private final UserServiceInterface userService;
+    private final PolicyManagementAuthority policyManagementAuthority;
     private final ApplicationProperties applicationProperties;
     private final TempFileManager tempFileManager;
 
@@ -165,23 +165,29 @@ public class PolicyController {
     }
 
     /**
-     * Assign the owner: create stamps the current user; update preserves the existing owner — so
-     * the client can neither forge ownership on create nor reassign it on update. Editing is gated
-     * to admins by {@link #requirePolicyEditingAllowed}; policies are org-wide, so there is no
-     * per-owner access check here.
+     * Assign owner and team server-side: create stamps the current user and their team; update
+     * keeps the existing owner and team after checking the policy belongs to the caller's team. The
+     * client can't forge ownership on create or reach across teams on update (cross-team reads as
+     * not-found).
      */
     private Policy resolveOwnership(Policy incoming) {
         String id = incoming.id();
         if (id != null && !id.isBlank()) {
             Policy existing = policyStore.get(id).orElse(null);
             if (existing != null) {
-                return withOwner(incoming, existing.owner());
+                if (!policyAccessGuard.canAccess(existing)) {
+                    throw new ResponseStatusException(HttpStatus.NOT_FOUND, "No policy: " + id);
+                }
+                return withOwnerAndTeam(incoming, existing.owner(), existing.teamId());
             }
         }
-        return withOwner(incoming, policyAccessGuard.ownerForNewPolicy());
+        return withOwnerAndTeam(
+                incoming,
+                policyAccessGuard.ownerForNewPolicy(),
+                policyAccessGuard.teamForNewPolicy());
     }
 
-    private static Policy withOwner(Policy policy, String owner) {
+    private static Policy withOwnerAndTeam(Policy policy, String owner, Long teamId) {
         return new Policy(
                 policy.id(),
                 policy.name(),
@@ -190,32 +196,32 @@ public class PolicyController {
                 policy.trigger(),
                 policy.sources(),
                 policy.steps(),
-                policy.output());
+                policy.output(),
+                teamId);
     }
 
     /**
-     * Creating, editing, pausing/resuming, and deleting policies is admin-only on multi-user
-     * deployments. Every mutation routes through {@link #savePolicy} (pause/resume re-save with a
-     * flipped {@code enabled} flag) or {@link #deletePolicy}, so gating those two covers them all;
-     * runs ({@code /run}) stay open. Single-user deployments (login disabled) have no admin
-     * concept, so they trust the local operator. The path allowlist for folder sources/outputs is
-     * enforced separately by {@link PolicyValidator} at validation time.
+     * Gate create/edit/delete to the policy-editor role ({@link PolicyManagementAuthority}; a team
+     * leader on SaaS). Pause/resume re-saves through {@link #savePolicy} and deletion through
+     * {@link #deletePolicy}, so gating those covers every mutation; runs stay open. Single-user
+     * deployments (login disabled) trust the local operator. Which team's policies a user may touch
+     * is scoped separately by {@link PolicyAccessGuard}.
      */
     private void requirePolicyEditingAllowed() {
         if (!applicationProperties.getSecurity().isEnableLogin()) {
             return;
         }
-        if (!userService.isCurrentUserAdmin()) {
+        if (!policyManagementAuthority.canEditPolicies()) {
             throw new ResponseStatusException(
                     HttpStatus.FORBIDDEN,
-                    "Policies may only be created or modified by an administrator");
+                    "Policies may only be created or modified by a team leader");
         }
     }
 
     @GetMapping
     @Operation(
             summary = "List policies",
-            description = "Lists all policies (org-wide; every user sees them all).")
+            description = "Lists the policies belonging to the caller's team.")
     public List<Policy> listPolicies() {
         return policyAccessGuard.visible(policyStore.all());
     }
@@ -225,6 +231,7 @@ public class PolicyController {
     public ResponseEntity<Policy> getPolicy(@PathVariable String policyId) {
         return policyStore
                 .get(policyId)
+                .filter(policyAccessGuard::canAccess)
                 .map(ResponseEntity::ok)
                 .orElseGet(() -> ResponseEntity.notFound().build());
     }
@@ -233,7 +240,10 @@ public class PolicyController {
     @Operation(summary = "Delete a policy by id")
     public ResponseEntity<Void> deletePolicy(@PathVariable String policyId) {
         requirePolicyEditingAllowed();
-        if (policyStore.get(policyId).isPresent() && policyStore.delete(policyId)) {
+        // Scope to the caller's team: a policy in another team reads as not-found.
+        boolean accessible =
+                policyStore.get(policyId).filter(policyAccessGuard::canAccess).isPresent();
+        if (accessible && policyStore.delete(policyId)) {
             return ResponseEntity.noContent().build();
         }
         return ResponseEntity.notFound().build();
@@ -253,6 +263,7 @@ public class PolicyController {
         Policy policy =
                 policyStore
                         .get(policyId)
+                        .filter(policyAccessGuard::canAccess)
                         .orElseThrow(
                                 () ->
                                         new ResponseStatusException(

app/proprietary/src/main/java/stirling/software/proprietary/policy/model/Policy.java

@@ -17,7 +17,8 @@ public record Policy(
         TriggerConfig trigger,
         List<InputSpec> sources,
         List<PipelineStep> steps,
-        OutputSpec output) {
+        OutputSpec output,
+        Long teamId) {
 
     public Policy {
         sources = sources == null ? List.of() : List.copyOf(sources);
@@ -25,6 +26,19 @@ public record Policy(
         output = output == null ? OutputSpec.inline() : output;
     }
 
+    /** Without an owning team — for engine runs; stored policies are stamped with a team. */
+    public Policy(
+            String id,
+            String name,
+            String owner,
+            boolean enabled,
+            TriggerConfig trigger,
+            List<InputSpec> sources,
+            List<PipelineStep> steps,
+            OutputSpec output) {
+        this(id, name, owner, enabled, trigger, sources, steps, output, null);
+    }
+
     /** A policy with no configured sources (a generator, or files supplied directly to a run). */
     public Policy(
             String id,
@@ -34,7 +48,7 @@ public record Policy(
             TriggerConfig trigger,
             List<PipelineStep> steps,
             OutputSpec output) {
-        this(id, name, owner, enabled, trigger, List.of(), steps, output);
+        this(id, name, owner, enabled, trigger, List.of(), steps, output, null);
     }
 
     /** This policy's pipeline as the engine sees it. */

app/proprietary/src/main/java/stirling/software/proprietary/policy/store/InProcessPolicyStore.java

@@ -31,7 +31,8 @@ public class InProcessPolicyStore implements PolicyStore {
                         policy.trigger(),
                         policy.sources(),
                         policy.steps(),
-                        policy.output());
+                        policy.output(),
+                        policy.teamId());
         policies.put(id, stored);
         return stored;
     }

app/proprietary/src/main/java/stirling/software/proprietary/policy/store/JpaPolicyStore.java

@@ -38,7 +38,8 @@ public class JpaPolicyStore implements PolicyStore {
                         policy.trigger(),
                         policy.sources(),
                         policy.steps(),
-                        policy.output());
+                        policy.output(),
+                        policy.teamId());
 
         PolicyEntity entity = new PolicyEntity();
         entity.setId(id);

app/proprietary/src/test/java/stirling/software/proprietary/policy/config/AdminPolicyManagementAuthorityTest.java

@@ -0,0 +1,58 @@
+package stirling.software.proprietary.policy.config;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertNull;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+import static org.mockito.Mockito.when;
+
+import java.util.Optional;
+
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.ExtendWith;
+import org.mockito.Mock;
+import org.mockito.junit.jupiter.MockitoExtension;
+
+import stirling.software.proprietary.model.Team;
+import stirling.software.proprietary.security.model.User;
+import stirling.software.proprietary.security.service.UserService;
+
+/** Self-hosted policy context: a global admin may edit; scoping uses the current user's team. */
+@ExtendWith(MockitoExtension.class)
+class AdminPolicyManagementAuthorityTest {
+
+    @Mock private UserService userService;
+
+    private AdminPolicyManagementAuthority authority() {
+        return new AdminPolicyManagementAuthority(userService);
+    }
+
+    @Test
+    void adminMayEditPolicies() {
+        when(userService.isCurrentUserAdmin()).thenReturn(true);
+        assertTrue(authority().canEditPolicies());
+    }
+
+    @Test
+    void nonAdminMayNot() {
+        when(userService.isCurrentUserAdmin()).thenReturn(false);
+        assertFalse(authority().canEditPolicies());
+    }
+
+    @Test
+    void currentUserTeamIdResolvesFromTheCurrentUsersTeam() {
+        Team team = new Team();
+        team.setId(42L);
+        User user = new User();
+        user.setTeam(team);
+        when(userService.getCurrentUsername()).thenReturn("alice");
+        when(userService.findByUsername("alice")).thenReturn(Optional.of(user));
+        assertEquals(42L, authority().currentUserTeamId());
+    }
+
+    @Test
+    void currentUserTeamIdIsNullWhenNoCurrentUser() {
+        when(userService.getCurrentUsername()).thenReturn(null);
+        assertNull(authority().currentUserTeamId());
+    }
+}

app/proprietary/src/test/java/stirling/software/proprietary/policy/config/PolicyAccessGuardTest.java

@@ -1,7 +1,9 @@
 package stirling.software.proprietary.policy.config;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
 import static org.junit.jupiter.api.Assertions.assertNull;
+import static org.junit.jupiter.api.Assertions.assertTrue;
 import static org.mockito.Mockito.when;
 
 import java.util.List;
@@ -17,47 +19,66 @@ import stirling.software.proprietary.policy.model.OutputSpec;
 import stirling.software.proprietary.policy.model.Policy;
 
 /**
- * Tests for {@link PolicyAccessGuard}. Policies are org-wide: every user sees them all (no
- * owner-based filtering). The owner is still assigned server-side — the current user when login is
- * enabled, {@code null} otherwise — purely for run/usage attribution.
+ * {@link PolicyAccessGuard}: policies are scoped to the caller's team. A user sees/accesses only
+ * their own team's policies (admins included — there is no cross-team escape). Login disabled
+ * (single-user) bypasses scoping.
  */
 @ExtendWith(MockitoExtension.class)
 class PolicyAccessGuardTest {
 
     @Mock private UserServiceInterface userService;
+    @Mock private PolicyManagementAuthority policyManagementAuthority;
 
     private PolicyAccessGuard guard(boolean loginEnabled) {
         ApplicationProperties properties = new ApplicationProperties();
         properties.getSecurity().setEnableLogin(loginEnabled);
-        return new PolicyAccessGuard(userService, properties);
+        return new PolicyAccessGuard(userService, properties, policyManagementAuthority);
     }
 
     @Test
-    void visibleReturnsEveryPolicyWhenLoginEnabled() {
-        // Org-wide: a non-admin sees every policy, not just the ones they own.
-        List<Policy> all = List.of(ownedBy("alice"), ownedBy("bob"), ownedBy("alice"));
-        assertEquals(all, guard(true).visible(all));
+    void visibleFiltersToTheCallersTeam() {
+        when(policyManagementAuthority.currentUserTeamId()).thenReturn(1L);
+        List<Policy> all = List.of(inTeam(1L), inTeam(2L), inTeam(1L), inTeam(null));
+        List<Policy> visible = guard(true).visible(all);
+        assertEquals(2, visible.size());
+        assertTrue(visible.stream().allMatch(p -> Long.valueOf(1L).equals(p.teamId())));
     }
 
     @Test
-    void visibleReturnsEveryPolicyWhenLoginDisabled() {
-        List<Policy> all = List.of(ownedBy("alice"), ownedBy("bob"));
+    void visibleReturnsEverythingWhenLoginDisabled() {
+        List<Policy> all = List.of(inTeam(1L), inTeam(2L));
         assertEquals(all, guard(false).visible(all));
     }
 
     @Test
-    void ownerForNewPolicyIsTheCurrentUserWhenLoginEnabled() {
-        when(userService.getCurrentUsername()).thenReturn("alice");
-        assertEquals("alice", guard(true).ownerForNewPolicy());
+    void canAccessOnlyOwnTeamsPolicy() {
+        when(policyManagementAuthority.currentUserTeamId()).thenReturn(1L);
+        assertTrue(guard(true).canAccess(inTeam(1L)));
+        assertFalse(guard(true).canAccess(inTeam(2L)));
+        assertFalse(guard(true).canAccess(inTeam(null)));
     }
 
     @Test
-    void ownerForNewPolicyIsNullWhenLoginDisabled() {
-        // Single-user deployment: no identity to attribute to.
-        assertNull(guard(false).ownerForNewPolicy());
+    void canAccessAnythingWhenLoginDisabled() {
+        assertTrue(guard(false).canAccess(inTeam(2L)));
     }
 
-    private static Policy ownedBy(String owner) {
-        return new Policy("p1", "p", owner, true, null, List.of(), List.of(), OutputSpec.inline());
+    @Test
+    void ownerAndTeamForNewPolicyComeFromTheCurrentUserWhenLoginEnabled() {
+        when(userService.getCurrentUsername()).thenReturn("alice");
+        when(policyManagementAuthority.currentUserTeamId()).thenReturn(7L);
+        assertEquals("alice", guard(true).ownerForNewPolicy());
+        assertEquals(7L, guard(true).teamForNewPolicy());
+    }
+
+    @Test
+    void ownerAndTeamForNewPolicyAreNullWhenLoginDisabled() {
+        assertNull(guard(false).ownerForNewPolicy());
+        assertNull(guard(false).teamForNewPolicy());
+    }
+
+    private static Policy inTeam(Long teamId) {
+        return new Policy(
+                "p1", "p", "owner", true, null, List.of(), List.of(), OutputSpec.inline(), teamId);
     }
 }

app/saas/src/main/java/stirling/software/saas/security/TeamLeaderPolicyManagementAuthority.java

@@ -0,0 +1,27 @@
+package stirling.software.saas.security;
+
+import org.springframework.context.annotation.Profile;
+import org.springframework.stereotype.Component;
+
+import lombok.RequiredArgsConstructor;
+
+import stirling.software.proprietary.policy.config.PolicyManagementAuthority;
+
+/** SaaS policy authority: only a team leader may edit; scoping uses the current user's team. */
+@Component
+@Profile("saas")
+@RequiredArgsConstructor
+public class TeamLeaderPolicyManagementAuthority implements PolicyManagementAuthority {
+
+    private final TeamSecurityExpressions teamSecurity;
+
+    @Override
+    public boolean canEditPolicies() {
+        return teamSecurity.isCurrentUserTeamLeader();
+    }
+
+    @Override
+    public Long currentUserTeamId() {
+        return teamSecurity.currentUserTeamId();
+    }
+}

app/saas/src/main/java/stirling/software/saas/security/TeamSecurityExpressions.java

@@ -44,6 +44,27 @@ public class TeamSecurityExpressions {
                 .orElse(false);
     }
 
+    /** Whether the current authenticated user is a {@code LEADER} of their own team. */
+    public boolean isCurrentUserTeamLeader() {
+        User currentUser = getCurrentUser();
+        if (currentUser == null || currentUser.getTeam() == null) {
+            return false;
+        }
+        return membershipRepository
+                .findByTeamIdAndUserId(currentUser.getTeam().getId(), currentUser.getId())
+                .map(membership -> membership.getRole() == TeamRole.LEADER)
+                .orElse(false);
+    }
+
+    /** The current authenticated user's team id, or {@code null} if unauthenticated / teamless. */
+    public Long currentUserTeamId() {
+        User currentUser = getCurrentUser();
+        if (currentUser == null || currentUser.getTeam() == null) {
+            return null;
+        }
+        return currentUser.getTeam().getId();
+    }
+
     /** Whether the current authenticated user is any kind of member of the given team. */
     public boolean isTeamMember(Long teamId) {
         User currentUser = getCurrentUser();

app/saas/src/test/java/stirling/software/saas/security/TeamLeaderPolicyManagementAuthorityTest.java

@@ -0,0 +1,40 @@
+package stirling.software.saas.security;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+import static org.mockito.Mockito.when;
+
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.ExtendWith;
+import org.mockito.Mock;
+import org.mockito.junit.jupiter.MockitoExtension;
+
+/** SaaS policy context: team leader may edit; scoping uses the user's team. */
+@ExtendWith(MockitoExtension.class)
+class TeamLeaderPolicyManagementAuthorityTest {
+
+    @Mock private TeamSecurityExpressions teamSecurity;
+
+    private TeamLeaderPolicyManagementAuthority authority() {
+        return new TeamLeaderPolicyManagementAuthority(teamSecurity);
+    }
+
+    @Test
+    void teamLeaderMayEditPolicies() {
+        when(teamSecurity.isCurrentUserTeamLeader()).thenReturn(true);
+        assertTrue(authority().canEditPolicies());
+    }
+
+    @Test
+    void nonLeaderMayNot() {
+        when(teamSecurity.isCurrentUserTeamLeader()).thenReturn(false);
+        assertFalse(authority().canEditPolicies());
+    }
+
+    @Test
+    void currentUserTeamIdDelegatesToTeamSecurity() {
+        when(teamSecurity.currentUserTeamId()).thenReturn(9L);
+        assertEquals(9L, authority().currentUserTeamId());
+    }
+}

app/saas/src/test/java/stirling/software/saas/security/TeamSecurityExpressionsTest.java

@@ -0,0 +1,116 @@
+package stirling.software.saas.security;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertNull;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+import static org.mockito.Mockito.lenient;
+import static org.mockito.Mockito.when;
+
+import java.util.List;
+import java.util.Optional;
+
+import org.junit.jupiter.api.AfterEach;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.ExtendWith;
+import org.mockito.Mock;
+import org.mockito.junit.jupiter.MockitoExtension;
+import org.springframework.security.authentication.UsernamePasswordAuthenticationToken;
+import org.springframework.security.core.context.SecurityContextHolder;
+
+import stirling.software.common.model.enumeration.TeamRole;
+import stirling.software.proprietary.model.Team;
+import stirling.software.proprietary.security.model.User;
+import stirling.software.proprietary.security.service.UserService;
+import stirling.software.saas.model.TeamMembership;
+import stirling.software.saas.repository.TeamMembershipRepository;
+
+/** {@link TeamSecurityExpressions}: current-user team leadership and team-id resolution. */
+@ExtendWith(MockitoExtension.class)
+class TeamSecurityExpressionsTest {
+
+    @Mock private TeamMembershipRepository membershipRepository;
+    @Mock private UserService userService;
+
+    private static final long TEAM_ID = 2L;
+    private static final long USER_ID = 1L;
+
+    private TeamSecurityExpressions expressions() {
+        return new TeamSecurityExpressions(membershipRepository, userService);
+    }
+
+    @AfterEach
+    void clearContext() {
+        SecurityContextHolder.clearContext();
+    }
+
+    private void authenticateAsUserWithTeam(boolean hasTeam) {
+        User user = new User();
+        user.setId(USER_ID);
+        if (hasTeam) {
+            Team team = new Team();
+            team.setId(TEAM_ID);
+            user.setTeam(team);
+        }
+        // API-key auth path: the principal is the User entity itself.
+        SecurityContextHolder.getContext()
+                .setAuthentication(new UsernamePasswordAuthenticationToken(user, null, List.of()));
+    }
+
+    private TeamMembership membershipWithRole(TeamRole role) {
+        TeamMembership membership = new TeamMembership();
+        membership.setRole(role);
+        return membership;
+    }
+
+    @Test
+    void leaderOfOwnTeamIsLeader() {
+        authenticateAsUserWithTeam(true);
+        when(membershipRepository.findByTeamIdAndUserId(TEAM_ID, USER_ID))
+                .thenReturn(Optional.of(membershipWithRole(TeamRole.LEADER)));
+        assertTrue(expressions().isCurrentUserTeamLeader());
+    }
+
+    @Test
+    void regularMemberIsNotLeader() {
+        authenticateAsUserWithTeam(true);
+        when(membershipRepository.findByTeamIdAndUserId(TEAM_ID, USER_ID))
+                .thenReturn(Optional.of(membershipWithRole(TeamRole.MEMBER)));
+        assertFalse(expressions().isCurrentUserTeamLeader());
+    }
+
+    @Test
+    void noMembershipIsNotLeader() {
+        authenticateAsUserWithTeam(true);
+        when(membershipRepository.findByTeamIdAndUserId(TEAM_ID, USER_ID))
+                .thenReturn(Optional.empty());
+        assertFalse(expressions().isCurrentUserTeamLeader());
+    }
+
+    @Test
+    void userWithoutTeamIsNotLeader() {
+        authenticateAsUserWithTeam(false);
+        assertFalse(expressions().isCurrentUserTeamLeader());
+    }
+
+    @Test
+    void currentUserTeamIdReturnsTheUsersTeam() {
+        authenticateAsUserWithTeam(true);
+        assertEquals(TEAM_ID, expressions().currentUserTeamId());
+    }
+
+    @Test
+    void currentUserTeamIdIsNullWithoutTeam() {
+        authenticateAsUserWithTeam(false);
+        assertNull(expressions().currentUserTeamId());
+    }
+
+    @Test
+    void unauthenticatedIsNotLeader() {
+        // No authentication set on the context.
+        lenient()
+                .when(membershipRepository.findByTeamIdAndUserId(TEAM_ID, USER_ID))
+                .thenReturn(Optional.of(membershipWithRole(TeamRole.LEADER)));
+        assertFalse(expressions().isCurrentUserTeamLeader());
+    }
+}