fix: resolve double URL-encoding in datatable filter/sortBy query params (#652)

src/mcp/handlers-n8n-manager.ts

@@ -2861,11 +2861,10 @@ export async function handleGetRows(args: unknown, context?: InstanceContext): P
     const { tableId, filter, sortBy, ...params } = getRowsSchema.parse(args);
     const queryParams: Record<string, unknown> = { ...params };
     if (filter) {
-      const filterStr = typeof filter === 'string' ? filter : JSON.stringify(filter);
-      queryParams.filter = encodeURIComponent(filterStr);
+      queryParams.filter = typeof filter === 'string' ? filter : JSON.stringify(filter);
     }
     if (sortBy) {
-      queryParams.sortBy = encodeURIComponent(sortBy);
+      queryParams.sortBy = sortBy;
     }
     const result = await client.getDataTableRows(tableId, queryParams as any);
     return {
@@ -2931,7 +2930,7 @@ export async function handleDeleteRows(args: unknown, context?: InstanceContext)
     const client = ensureApiConfigured(context);
     const { tableId, filter, ...params } = deleteRowsSchema.parse(args);
     const queryParams = {
-      filter: encodeURIComponent(JSON.stringify(filter)),
+      filter: JSON.stringify(filter),
       ...params,
     };
     const result = await client.deleteDataTableRows(tableId, queryParams as any);

src/mcp/tool-docs/workflow_management/n8n-manage-datatable.ts

@@ -9,7 +9,7 @@ export const n8nManageDatatableDoc: ToolDocumentation = {
     example: 'n8n_manage_datatable({action: "createTable", name: "Contacts", columns: [{name: "email", type: "string"}]})',
     performance: 'Fast (100-500ms)',
     tips: [
-      'Table actions: createTable, listTables, getTable, updateTable, deleteTable',
+      'Table actions: createTable, listTables, getTable, updateTable (rename only), deleteTable',
       'Row actions: getRows, insertRows, updateRows, upsertRows, deleteRows',
       'Use dryRun: true to preview update/upsert/delete before applying',
       'Filter supports: eq, neq, like, ilike, gt, gte, lt, lte conditions',
@@ -22,7 +22,7 @@ export const n8nManageDatatableDoc: ToolDocumentation = {
 - **createTable**: Create a new data table with optional typed columns
 - **listTables**: List all data tables (paginated)
 - **getTable**: Get table details and column definitions by ID
-- **updateTable**: Rename an existing table
+- **updateTable**: Rename an existing table (name only — column modifications not supported via API)
 - **deleteTable**: Permanently delete a table and all its rows
 
 **Row Actions:**

src/services/n8n-api-client.ts

@@ -637,7 +637,10 @@ export class N8nApiClient {
 
   async getDataTableRows(id: string, params: DataTableRowListParams = {}): Promise<{ data: DataTableRow[]; nextCursor?: string | null }> {
     try {
-      const response = await this.client.get(`/data-tables/${id}/rows`, { params });
+      const response = await this.client.get(`/data-tables/${id}/rows`, {
+        params,
+        paramsSerializer: (p) => this.serializeDataTableParams(p),
+      });
       return this.validateListResponse<DataTableRow>(response.data, 'data-table-rows');
     } catch (error) {
       throw handleN8nApiError(error);
@@ -673,13 +676,29 @@ export class N8nApiClient {
 
   async deleteDataTableRows(id: string, params: DataTableDeleteRowsParams): Promise<any> {
     try {
-      const response = await this.client.delete(`/data-tables/${id}/rows/delete`, { params });
+      const response = await this.client.delete(`/data-tables/${id}/rows/delete`, {
+        params,
+        paramsSerializer: (p) => this.serializeDataTableParams(p),
+      });
       return response.data;
     } catch (error) {
       throw handleN8nApiError(error);
     }
   }
 
+  /**
+   * Serializes data table query params with explicit encodeURIComponent.
+   * Axios's default serializer doesn't encode some reserved chars that n8n rejects.
+   */
+  private serializeDataTableParams(params: Record<string, any>): string {
+    const parts: string[] = [];
+    for (const [key, value] of Object.entries(params)) {
+      if (value === undefined || value === null) continue;
+      parts.push(`${encodeURIComponent(key)}=${encodeURIComponent(String(value))}`);
+    }
+    return parts.join('&');
+  }
+
   /**
    * Validates and normalizes n8n API list responses.
    * Handles both modern format {data: [], nextCursor?: string} and legacy array format.