diff --git a/__tests__/nsfw.test.ts b/__tests__/nsfw.test.ts
new file mode 100644
index 0000000..c91abe3
--- /dev/null
+++ b/__tests__/nsfw.test.ts
@@ -0,0 +1,101 @@
+import { setSpaceEntityNsfw, fetchManySpaces } from "../src/modules/spaces";
+import { createEntity, updateEntity, fetchManyEntities } from "../src/modules/entities";
+import { createSpace, updateSpace } from "../src/modules/spaces";
+import { makeClient } from "./helpers/mockClient";
+import type { Entity } from "../src/interfaces/Entity";
+import type { Space } from "../src/interfaces/Space";
+
+/**
+ * NSFW flagging surface (Phase 5, Task 5.2). Asserts the new mod function hits
+ * the exact server route `.../spaces/:spaceId/entities/:entityId/nsfw` and that
+ * the `nsfw` create/update flags + `nsfwFilter` fetch param are shaped through
+ * to the request. Type-level assertions below guard the interface fields.
+ */
+describe("node-sdk NSFW — request shaping", () => {
+  it("setSpaceEntityNsfw patches /spaces/:spaceId/entities/:entityId/nsfw with { nsfw }", async () => {
+    const { client, projectInstance } = makeClient();
+    await setSpaceEntityNsfw(client, {
+      spaceId: "s1",
+      entityId: "e1",
+      nsfw: true,
+    });
+    expect(projectInstance.patch).toHaveBeenCalledWith(
+      "/spaces/s1/entities/e1/nsfw",
+      { nsfw: true },
+    );
+  });
+
+  it("setSpaceEntityNsfw returns response.data", async () => {
+    const { client, projectInstance } = makeClient();
+    const result = { message: "Entity NSFW flag updated.", nsfw: true };
+    projectInstance.patch.mockResolvedValueOnce({ data: result });
+    await expect(
+      setSpaceEntityNsfw(client, { spaceId: "s1", entityId: "e1", nsfw: true }),
+    ).resolves.toEqual(result);
+  });
+
+  it("createEntity forwards the own nsfw flag in the body", async () => {
+    const { client, projectInstance } = makeClient();
+    await createEntity(client, { nsfw: true });
+    expect(projectInstance.post).toHaveBeenCalledWith(
+      "/entities",
+      expect.objectContaining({ nsfw: true }),
+    );
+  });
+
+  it("updateEntity forwards the own nsfw flag in the body", async () => {
+    const { client, projectInstance } = makeClient();
+    await updateEntity(client, { entityId: "e1", nsfw: false });
+    const [, body] = projectInstance.patch.mock.calls[0];
+    expect(body).toEqual(expect.objectContaining({ nsfw: false }));
+  });
+
+  it("fetchManyEntities forwards nsfwFilter into the query params", async () => {
+    const { client, projectInstance } = makeClient();
+    await fetchManyEntities(client, { nsfwFilter: "only" });
+    const [, config] = projectInstance.get.mock.calls[0];
+    expect(config.params).toEqual(expect.objectContaining({ nsfwFilter: "only" }));
+  });
+
+  it("createSpace forwards the own nsfw flag in the body", async () => {
+    const { client, projectInstance } = makeClient();
+    await createSpace(client, { name: "NSFW space", userId: "u1", nsfw: true });
+    expect(projectInstance.post).toHaveBeenCalledWith(
+      "/spaces",
+      expect.objectContaining({ nsfw: true }),
+    );
+  });
+
+  it("updateSpace forwards the own nsfw flag in the body", async () => {
+    const { client, projectInstance } = makeClient();
+    await updateSpace(client, { spaceId: "s1", nsfw: true });
+    const [, body] = projectInstance.patch.mock.calls[0];
+    expect(body).toEqual(expect.objectContaining({ nsfw: true }));
+  });
+
+  it("fetchManySpaces forwards nsfwFilter into the query params", async () => {
+    const { client, projectInstance } = makeClient();
+    await fetchManySpaces(client, { nsfwFilter: "exclude" });
+    const [, config] = projectInstance.get.mock.calls[0];
+    expect(config.params).toEqual(expect.objectContaining({ nsfwFilter: "exclude" }));
+  });
+});
+
+// Compile-time guards: the model interfaces carry the new NSFW fields. These
+// are type-level assertions — if the fields are dropped or mistyped, `tsc`
+// (and the jest ts-jest transform) fails to compile this file.
+describe("node-sdk NSFW — interface fields (type-level)", () => {
+  it("Entity exposes nsfw + nsfwEffective as booleans", () => {
+    const e = {} as Entity;
+    const nsfw: boolean | undefined = e.nsfw;
+    const eff: boolean | undefined = e.nsfwEffective;
+    expect([nsfw, eff]).toBeDefined();
+  });
+
+  it("Space exposes nsfw + nsfwEffective as booleans", () => {
+    const s = {} as Space;
+    const nsfw: boolean | undefined = s.nsfw;
+    const eff: boolean | undefined = s.nsfwEffective;
+    expect([nsfw, eff]).toBeDefined();
+  });
+});
diff --git a/src/interfaces/Entity.ts b/src/interfaces/Entity.ts
index edacbd4..a1e82c0 100644
--- a/src/interfaces/Entity.ts
+++ b/src/interfaces/Entity.ts
@@ -41,6 +41,8 @@ export interface Entity {
     coordinates: [number, number]; // [longitude, latitude]
   } | null;
   metadata: Record<string, any>;
+  nsfw: boolean; // The entity's own NSFW flag
+  nsfwEffective: boolean; // Computed live: entity.nsfw OR the entity's space's effective NSFW
   topComment: TopComment | null;
   isSaved?: boolean; // Populated when include contains "saved"
   isDraft: boolean | null;
diff --git a/src/interfaces/Space.ts b/src/interfaces/Space.ts
index 332b836..02f64aa 100644
--- a/src/interfaces/Space.ts
+++ b/src/interfaces/Space.ts
@@ -45,6 +45,8 @@ export interface Space {
   postingPermission: PostingPermission;
   visibility: SpaceVisibility;
   requireJoinApproval: boolean;
+  nsfw: boolean; // The space's own NSFW flag
+  nsfwEffective: boolean; // Denormalized: own nsfw OR any ancestor space's nsfw
   parentSpaceId: string | null;
   depth: number;
   metadata: Record<string, any>;
diff --git a/src/modules/entities/createEntity.ts b/src/modules/entities/createEntity.ts
index 581a488..1614d5c 100644
--- a/src/modules/entities/createEntity.ts
+++ b/src/modules/entities/createEntity.ts
@@ -16,6 +16,7 @@ export interface CreateEntityProps {
     longitude: number;
   };
   metadata?: Record<string, any>;
+  nsfw?: boolean;
   userId?: string;
   isDraft?: boolean;
   excludeUserId?: boolean;
diff --git a/src/modules/entities/fetchManyEntities.ts b/src/modules/entities/fetchManyEntities.ts
index eb617ef..de25fa3 100644
--- a/src/modules/entities/fetchManyEntities.ts
+++ b/src/modules/entities/fetchManyEntities.ts
@@ -93,6 +93,9 @@ export interface FetchManyEntitiesProps extends SpaceReputationContextParams {
 
   // Location filtering
   locationFilters?: LocationFilters;
+
+  // NSFW filtering (keyed off effective NSFW)
+  nsfwFilter?: "include-all" | "exclude" | "only";
 }
 
 export async function fetchManyEntities(
diff --git a/src/modules/entities/updateEntity.ts b/src/modules/entities/updateEntity.ts
index 972a0a7..5cb3486 100644
--- a/src/modules/entities/updateEntity.ts
+++ b/src/modules/entities/updateEntity.ts
@@ -14,6 +14,7 @@ export interface UpdateEntityProps {
     longitude: number;
   };
   metadata?: Record<string, any>;
+  nsfw?: boolean;
 }
 
 export async function updateEntity(
diff --git a/src/modules/spaces/createSpace.ts b/src/modules/spaces/createSpace.ts
index 18532eb..75703a1 100644
--- a/src/modules/spaces/createSpace.ts
+++ b/src/modules/spaces/createSpace.ts
@@ -17,6 +17,7 @@ export interface CreateSpaceProps {
   requireJoinApproval?: boolean;
   parentSpaceId?: string;
   metadata?: Record<string, any>;
+  nsfw?: boolean;
 }
 
 export async function createSpace(
diff --git a/src/modules/spaces/fetchManySpaces.ts b/src/modules/spaces/fetchManySpaces.ts
index d32b8b4..4e96756 100644
--- a/src/modules/spaces/fetchManySpaces.ts
+++ b/src/modules/spaces/fetchManySpaces.ts
@@ -12,6 +12,7 @@ export interface FetchManySpacesProps {
   searchAny?: string;
   memberOf?: "true";
   parentSpaceId?: string | "null";
+  nsfwFilter?: "include-all" | "exclude" | "only";
   include?: string;
 }
 
diff --git a/src/modules/spaces/index.ts b/src/modules/spaces/index.ts
index eefcd2b..998b896 100644
--- a/src/modules/spaces/index.ts
+++ b/src/modules/spaces/index.ts
@@ -29,6 +29,7 @@ export { reorderRules } from "./reorderRules";
 export { handleEntityReport } from "./handleEntityReport";
 export { handleCommentReport } from "./handleCommentReport";
 export { moderateSpaceEntity } from "./moderateSpaceEntity";
+export { setSpaceEntityNsfw } from "./setSpaceEntityNsfw";
 export { moderateSpaceComment } from "./moderateSpaceComment";
 export { fetchDigestConfig } from "./fetchDigestConfig";
 export { updateDigestConfig } from "./updateDigestConfig";
diff --git a/src/modules/spaces/setSpaceEntityNsfw.ts b/src/modules/spaces/setSpaceEntityNsfw.ts
new file mode 100644
index 0000000..68dc323
--- /dev/null
+++ b/src/modules/spaces/setSpaceEntityNsfw.ts
@@ -0,0 +1,29 @@
+import { SublayHttpClient } from "../../core/client";
+
+export interface SetSpaceEntityNsfwProps {
+  spaceId: string;
+  entityId: string;
+  nsfw: boolean;
+}
+
+export interface SetSpaceEntityNsfwResponse {
+  message: string;
+  nsfw: boolean;
+}
+
+/**
+ * Space-moderator endpoint to set the NSFW flag on an entity within their space
+ * (including other users' entities). Near-copy of `moderateSpaceEntity`, but it
+ * writes the entity's own `nsfw` (the NSFW axis), not `moderationStatus`.
+ */
+export async function setSpaceEntityNsfw(
+  client: SublayHttpClient,
+  data: SetSpaceEntityNsfwProps
+): Promise<SetSpaceEntityNsfwResponse> {
+  const { spaceId, entityId, ...body } = data;
+  const response = await client.projectInstance.patch<SetSpaceEntityNsfwResponse>(
+    `/spaces/${spaceId}/entities/${entityId}/nsfw`,
+    body
+  );
+  return response.data;
+}
diff --git a/src/modules/spaces/updateSpace.ts b/src/modules/spaces/updateSpace.ts
index 693c914..4d2afc3 100644
--- a/src/modules/spaces/updateSpace.ts
+++ b/src/modules/spaces/updateSpace.ts
@@ -15,6 +15,7 @@ export interface UpdateSpaceProps {
   postingPermission?: PostingPermission;
   visibility?: SpaceVisibility;
   metadata?: Record<string, any>;
+  nsfw?: boolean;
 }
 
 export async function updateSpace(