Expose resource access explanation API

src/govoplan_access/backend/api/v1/admin_schemas.py

@@ -486,6 +486,15 @@ class AccessScopeExplanationItem(BaseModel):
     sources: list[AccessRoleSourceItem] = Field(default_factory=list)
 
 
+class AccessDecisionProvenanceItem(BaseModel):
+    kind: str
+    id: str | None = None
+    label: str | None = None
+    tenant_id: str | None = None
+    source: str | None = None
+    details: dict[str, object] = Field(default_factory=dict)
+
+
 class FunctionFactExplanationItem(BaseModel):
     source_module: str
     assignment_id: str
@@ -512,6 +521,14 @@ class UserAccessExplanationResponse(BaseModel):
     function_facts: list[FunctionFactExplanationItem] = Field(default_factory=list)
 
 
+class ResourceAccessExplanationResponse(BaseModel):
+    user: UserAdminItem
+    resource_type: str
+    resource_id: str
+    action: str
+    provenance: list[AccessDecisionProvenanceItem] = Field(default_factory=list)
+
+
 class UserListResponse(BaseModel):
     users: list[UserAdminItem]
 

src/govoplan_access/backend/api/v1/routes.py

@@ -110,6 +110,7 @@ from govoplan_access.backend.api.v1.admin_schemas import (
     RoleListResponse,
     RoleSummary,
     RoleUpdateRequest,
+    ResourceAccessExplanationResponse,
     SystemAccountCreateRequest,
     SystemAccountCreateResponse,
     SystemAccountItem,
@@ -154,6 +155,7 @@ from govoplan_core.core.configuration_control import (
     record_configuration_change_applied,
 )
 from govoplan_core.core.configuration_safety import configuration_safety_catalog, plan_configuration_change
+from govoplan_core.core.access import CAPABILITY_ACCESS_EXPLANATION, AccessExplanationService, AccessDecisionProvenance, PrincipalRef
 from govoplan_core.core.idm import CAPABILITY_IDM_DIRECTORY, IdmDirectory, OrganizationFunctionAssignmentRef
 from govoplan_core.core.organizations import CAPABILITY_ORGANIZATION_DIRECTORY, ORGANIZATIONS_MODULE_ID, OrganizationDirectory
 from govoplan_core.api.v1.schemas import DeltaDeletedItem
@@ -185,7 +187,8 @@ from govoplan_access.backend.db.models import (
     UserGroupMembership,
     UserRoleAssignment,
 )
-from govoplan_access.backend.semantic import identity_id_for_account
+from govoplan_access.backend.semantic import collect_external_function_roles, collect_function_assignment_ids, collect_function_delegation_ids, identity_id_for_account
+from govoplan_access.backend.security.sessions import collect_user_groups, collect_user_roles, collect_user_scopes
 from govoplan_core.db.session import get_session
 from govoplan_access.backend.permissions.catalog import (
     normalize_email,
@@ -514,6 +517,21 @@ def _optional_idm_directory() -> IdmDirectory | None:
     return capability
 
 
+def _access_explanation_service_or_error() -> AccessExplanationService:
+    registry = get_registry()
+    if registry is not None and registry.has_capability(CAPABILITY_ACCESS_EXPLANATION):
+        capability = registry.require_capability(CAPABILITY_ACCESS_EXPLANATION)
+        if not isinstance(capability, AccessExplanationService):
+            raise HTTPException(status_code=status.HTTP_500_INTERNAL_SERVER_ERROR, detail=f"Invalid capability: {CAPABILITY_ACCESS_EXPLANATION}")
+        return capability
+    from govoplan_access.backend.explanation import SqlAccessExplanationService
+
+    return SqlAccessExplanationService(
+        idm_directory=_optional_idm_directory(),
+        organization_directory=_optional_organization_directory(),
+    )
+
+
 def _idm_assignments_for_user(
     idm_directory: IdmDirectory | None,
     user: User,
@@ -523,6 +541,39 @@ def _idm_assignments_for_user(
     return tuple(idm_directory.organization_function_assignments_for_account(user.account_id, tenant_id=user.tenant_id))
 
 
+def _principal_ref_for_user(session: Session, user: User, *, idm_directory: IdmDirectory | None = None) -> PrincipalRef:
+    account = session.get(Account, user.account_id)
+    if account is None:
+        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="Account not found")
+    idm_assignments = _idm_assignments_for_user(idm_directory, user)
+    idm_roles = tuple(collect_external_function_roles(session, user, idm_assignments))
+    scopes = set(collect_user_scopes(session, user, include_system=True))
+    for role in idm_roles:
+        scopes.update(role.permissions or [])
+    role_ids = [role.id for role in collect_user_roles(session, user)]
+    role_ids.extend(role.id for role in idm_roles)
+    function_assignment_ids = list(collect_function_assignment_ids(session, user))
+    function_assignment_ids.extend(item.id for item in idm_assignments)
+    return PrincipalRef(
+        account_id=account.id,
+        membership_id=user.id,
+        tenant_id=user.tenant_id,
+        identity_id=identity_id_for_account(session, account.id),
+        scopes=frozenset(sorted(scopes)),
+        group_ids=frozenset(group.id for group in collect_user_groups(session, user)),
+        role_ids=frozenset(sorted(dict.fromkeys(role_ids))),
+        function_assignment_ids=frozenset(sorted(dict.fromkeys(function_assignment_ids))),
+        delegation_ids=frozenset(collect_function_delegation_ids(session, user)),
+        auth_method="session",
+        email=account.email,
+        display_name=account.display_name or user.display_name,
+    )
+
+
+def _provenance_payload(items: Iterable[AccessDecisionProvenance]) -> list[dict[str, object]]:
+    return [item.to_dict() for item in items]
+
+
 def _validate_external_function_source(*, tenant_id: str, source_module: str, function_id: str) -> None:
     if source_module != ORGANIZATIONS_MODULE_ID:
         raise HTTPException(
@@ -1988,6 +2039,37 @@ def get_user_access_explanation(
     )
 
 
+@router.get("/access/resource-explanation", response_model=ResourceAccessExplanationResponse)
+def get_resource_access_explanation(
+    user_id: str = Query(...),
+    resource_type: str = Query(..., min_length=1, max_length=100),
+    resource_id: str = Query(..., min_length=1, max_length=2048),
+    action: str = Query(..., min_length=1, max_length=255),
+    tenant_id: str | None = Query(default=None),
+    session: Session = Depends(get_session),
+    principal: ApiPrincipal = Depends(require_any_scope("admin:users:read", "admin:roles:read", "access:membership:read", "access:role:read")),
+):
+    tenant = _resolve_tenant(session, principal, tenant_id)
+    user = session.query(User).filter(User.id == user_id, User.tenant_id == tenant.id).one_or_none()
+    if user is None:
+        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="User not found")
+    idm_directory = _optional_idm_directory()
+    target_principal = _principal_ref_for_user(session, user, idm_directory=idm_directory)
+    provenance = _access_explanation_service_or_error().explain_resource_provenance(
+        target_principal,
+        resource_type=resource_type,
+        resource_id=resource_id,
+        action=action,
+    )
+    return ResourceAccessExplanationResponse(
+        user=_user_item_for_response(session, user, idm_directory=idm_directory),
+        resource_type=resource_type,
+        resource_id=resource_id,
+        action=action,
+        provenance=_provenance_payload(provenance),
+    )
+
+
 @router.post("/users", response_model=UserCreateResponse, status_code=status.HTTP_201_CREATED)
 def create_user(
     payload: UserCreateRequest,

src/govoplan_access/backend/explanation.py

@@ -26,7 +26,7 @@ from govoplan_access.backend.semantic import (
     active_function_delegations_for_account,
     identity_id_for_account,
 )
-from govoplan_core.core.access import AccessDecisionProvenance, AccessExplanationService, PrincipalRef
+from govoplan_core.core.access import AccessDecisionProvenance, AccessExplanationService, PrincipalRef, ResourceAccessExplanationProvider
 from govoplan_core.core.idm import IdmDirectory, OrganizationFunctionAssignmentRef
 from govoplan_core.core.organizations import OrganizationDirectory
 from govoplan_core.db.session import get_database
@@ -161,9 +161,11 @@ class SqlAccessExplanationService(AccessExplanationService):
         *,
         idm_directory: IdmDirectory | None = None,
         organization_directory: OrganizationDirectory | None = None,
+        resource_explanation_providers: Iterable[ResourceAccessExplanationProvider] = (),
     ) -> None:
         self._idm_directory = idm_directory
         self._organization_directory = organization_directory
+        self._resource_explanation_providers = tuple(resource_explanation_providers)
 
     def explain_scope_provenance(
         self,
@@ -189,8 +191,28 @@ class SqlAccessExplanationService(AccessExplanationService):
         resource_id: str,
         action: str,
     ) -> tuple[AccessDecisionProvenance, ...]:
-        del resource_type, resource_id
+        with get_database().session() as session:
-        return self.explain_scope_provenance(principal, action)
+            items = _scope_provenance(
+                session,
+                principal,
+                action,
+                idm_directory=self._idm_directory,
+                organization_directory=self._organization_directory,
+            )
+            for provider in self._resource_explanation_providers:
+                provider_items = tuple(
+                    provider.explain_resource_provenance(
+                        session,
+                        principal,
+                        resource_type=resource_type,
+                        resource_id=resource_id,
+                        action=action,
+                    )
+                )
+                if provider_items:
+                    items.extend(provider_items)
+                    break
+            return tuple(_dedupe_provenance(items))
 
 
 def build_user_access_explanation(

src/govoplan_access/backend/manifest.py

@@ -17,7 +17,10 @@ from govoplan_core.core.access import (
     CAPABILITY_AUTH_PERMISSION_EVALUATOR,
     CAPABILITY_AUTH_PRINCIPAL_RESOLVER,
     CAPABILITY_AUTH_TENANT_CONTEXT_SWITCHER,
+    ResourceAccessExplanationProvider,
 )
+from govoplan_core.core.campaigns import CAPABILITY_CAMPAIGNS_ACCESS
+from govoplan_core.core.files import CAPABILITY_FILES_ACCESS
 from govoplan_core.core.idm import CAPABILITY_IDM_DIRECTORY, IdmDirectory
 from govoplan_core.core.organizations import CAPABILITY_ORGANIZATION_DIRECTORY, OrganizationDirectory
 from govoplan_core.core.module_guards import persistent_table_uninstall_guard
@@ -507,12 +510,24 @@ def _optional_organization_directory(context: ModuleContext) -> OrganizationDire
     return capability
 
 
+def _resource_explanation_providers(context: ModuleContext) -> tuple[ResourceAccessExplanationProvider, ...]:
+    providers: list[ResourceAccessExplanationProvider] = []
+    for capability_name in (CAPABILITY_FILES_ACCESS, CAPABILITY_CAMPAIGNS_ACCESS):
+        if not context.registry.has_capability(capability_name):
+            continue
+        capability = context.registry.require_capability(capability_name)
+        if isinstance(capability, ResourceAccessExplanationProvider):
+            providers.append(capability)
+    return tuple(providers)
+
+
 def _access_explanation_service(context: ModuleContext) -> object:
     from govoplan_access.backend.explanation import SqlAccessExplanationService
 
     return SqlAccessExplanationService(
         idm_directory=_optional_idm_directory(context),
         organization_directory=_optional_organization_directory(context),
+        resource_explanation_providers=_resource_explanation_providers(context),
     )
 
 

webui/src/api/admin.ts

@@ -132,6 +132,15 @@ export type AccessScopeExplanationItem = {
   sources: AccessRoleSourceItem[];
 };
 
+export type AccessDecisionProvenanceItem = {
+  kind: string;
+  id?: string | null;
+  label?: string | null;
+  tenant_id?: string | null;
+  source?: string | null;
+  details: Record<string, unknown>;
+};
+
 export type FunctionFactExplanationItem = {
   source_module: string;
   assignment_id: string;
@@ -158,6 +167,14 @@ export type UserAccessExplanationResponse = {
   function_facts: FunctionFactExplanationItem[];
 };
 
+export type ResourceAccessExplanationResponse = {
+  user: UserAdminItem;
+  resource_type: string;
+  resource_id: string;
+  action: string;
+  provenance: AccessDecisionProvenanceItem[];
+};
+
 export type SystemAccountItem = {
   account_id: string;
   email: string;
@@ -463,6 +480,20 @@ export function fetchUserAccessExplanation(settings: ApiSettings, userId: string
   return apiFetch(settings, `/api/v1/admin/users/${userId}/access-explanation`);
 }
 
+export function fetchResourceAccessExplanation(
+  settings: ApiSettings,
+  options: { userId: string; resourceType: string; resourceId: string; action: string; tenantId?: string | null }
+): Promise<ResourceAccessExplanationResponse> {
+  const params = new URLSearchParams({
+    user_id: options.userId,
+    resource_type: options.resourceType,
+    resource_id: options.resourceId,
+    action: options.action
+  });
+  if (options.tenantId) params.set("tenant_id", options.tenantId);
+  return apiFetch(settings, `/api/v1/admin/access/resource-explanation?${params.toString()}`);
+}
+
 export async function fetchGroups(settings: ApiSettings): Promise<GroupSummary[]> {
   const response = await apiFetch<{ groups: GroupSummary[] }>(settings, "/api/v1/admin/groups");
   return response.groups;