fix(mcp): one namespace call where one is needed; upload prep falls back to the active space

listNamespaces fetches a single page instead of up to 20; set_active_tag checks access with namespaces.get (404 means no access) so namespaces past the first page work. prepare-file-upload resolves the namespace like every other tool, so an old cached widget that sends no namespace still uploads.

apps/mcp/src/server/client/index.ts

@@ -22,7 +22,6 @@ export const DEFAULT_NAMESPACE = "sm_project_default"
 const FETCH_TIMEOUT_MS = 30_000
 const MCP_SOURCE = "supermemory-mcp"
 const NAMESPACE_PAGE_LIMIT = 100
-const MAX_NAMESPACE_PAGES = 20
 // v4 defaults; v5 lowered the threshold to 0.3.
 const SEARCH_THRESHOLD = 0.6
 // Analytics matches on this text to tag quota errors, keep them in sync.
@@ -154,6 +153,18 @@ function extractApiErrorMessage(raw: unknown): string | undefined {
 	}
 }
 
+export interface NamespaceSettings {
+	namespace: string
+	supportingContext: string | null
+	createdAt: string
+	updatedAt: string
+}
+
+const isNotFound = (error: unknown): boolean => {
+	const e = error as { statusCode?: number; status?: number }
+	return e?.statusCode === 404 || e?.status === 404
+}
+
 export class SupermemoryClient {
 	private client: Supermemory
 	private namespace: string
@@ -273,30 +284,35 @@ export class SupermemoryClient {
 		}
 	}
 
-	async listNamespaces(): Promise<NamespaceInfo[]> {
+	// v5 get returns settings only (no counts); null means missing or no access
+	async getNamespace(namespace: string): Promise<NamespaceSettings | null> {
 		try {
-			const namespaces: NamespaceInfo[] = []
-			for (let page = 1; page <= MAX_NAMESPACE_PAGES; page++) {
-				const result = await this.client.namespaces.list({
-					page,
-					limit: NAMESPACE_PAGE_LIMIT,
-				})
-				for (const entry of result.namespaces) {
-					namespaces.push({
-						id: entry.id,
-						namespace: entry.namespace,
-						description: entry.description,
-						documentCount: entry.documentCount,
-						memoryCount: entry.memoryCount,
-						createdAt: entry.system.createdAt,
-						updatedAt: entry.system.updatedAt,
-					})
-				}
-				if (result.pagination.currentPage >= result.pagination.totalPages) {
-					break
-				}
+			const entry = await this.client.namespaces.get(namespace)
+			return {
+				namespace: entry.namespace,
+				supportingContext: entry.supportingContext,
+				createdAt: entry.system.createdAt,
+				updatedAt: entry.system.updatedAt,
 			}
-			return namespaces
+		} catch (error) {
+			if (isNotFound(error)) return null
+			this.handleError(error)
+		}
+	}
+
+	// One page is enough for pickers; single-namespace reads use getNamespace
+	async listNamespaces(limit = NAMESPACE_PAGE_LIMIT): Promise<NamespaceInfo[]> {
+		try {
+			const result = await this.client.namespaces.list({ page: 1, limit })
+			return result.namespaces.map((entry) => ({
+				id: entry.id,
+				namespace: entry.namespace,
+				description: entry.description,
+				documentCount: entry.documentCount,
+				memoryCount: entry.memoryCount,
+				createdAt: entry.system.createdAt,
+				updatedAt: entry.system.updatedAt,
+			}))
 		} catch (error) {
 			this.handleError(error)
 		}

apps/mcp/src/server/tools/compat.test.ts

@@ -26,6 +26,16 @@ function fakeDeps() {
 			status: "queued",
 			namespace: "legacy_ns",
 		}),
+		getNamespace: vi.fn().mockImplementation(async (ns: string) =>
+			ns === "legacy_ns"
+				? {
+						namespace: ns,
+						supportingContext: null,
+						createdAt: "2026-01-01",
+						updatedAt: "2026-01-02",
+					}
+				: null,
+		),
 		listNamespaces: vi.fn().mockResolvedValue([
 			{
 				id: "1",

apps/mcp/src/server/tools/prepare-file-upload.ts

@@ -21,9 +21,7 @@ export function register(deps: ToolDeps) {
 		},
 		async (args) => {
 			try {
-				const namespace = namespaceArg(args)
-				if (!namespace)
-					return deps.errorResult(new Error("namespace is required"))
+				const namespace = await deps.resolveNamespace(namespaceArg(args))
 				const preparation = await deps.createUploadSession(namespace)
 
 				return {

apps/mcp/src/server/tools/set-active-tag.ts

@@ -26,8 +26,7 @@ export function register(deps: ToolDeps) {
 				return deps.errorResult(new Error("namespace is required"))
 			try {
 				const viewId = args.viewId ?? crypto.randomUUID()
-				const namespaces = await deps.getClient().listNamespaces()
-				if (!namespaces.some((entry) => entry.namespace === namespace)) {
+				if (!(await deps.getClient().getNamespace(namespace))) {
 					return deps.errorResult(
 						new Error(`No access to namespace '${namespace}'.`),
 					)