// Variable Tools for n8n MCP Server
import type { McpServer } from '@modelcontextprotocol/sdk/server/mcp.js';
import { z } from 'zod';
import { get, post, put, del } from '../services/api-client.js';
import {
CreateVariableSchema,
UpdateVariableSchema,
ListVariablesSchema,
IdParamSchema
} from '../schemas/index.js';
import type { N8nVariable, N8nPaginatedResponse } from '../types.js';
// Format variable for display
const formatVariable = (variable: N8nVariable): string => {
// Mask potentially sensitive values
const displayValue = variable.value.length > 50
? variable.value.substring(0, 47) + '...'
: variable.value;
return `š **${variable.key}** = "${displayValue}" (ID: ${variable.id})`;
};
export const registerVariableTools = (server: McpServer): void => {
// ============ List Variables ============
server.registerTool(
'n8n_list_variables',
{
title: 'List n8n Variables',
description: `List all environment variables.
Variables are accessible in workflows using $vars.variableName syntax.
Args:
- limit (number): Maximum results (default: 100)
- cursor (string, optional): Pagination cursor
Returns:
List of variables with id, key, and value.`,
inputSchema: ListVariablesSchema,
annotations: {
readOnlyHint: true,
destructiveHint: false,
idempotentHint: true,
openWorldHint: false
}
},
async (params: z.infer<typeof ListVariablesSchema>) => {
const queryParams: Record<string, unknown> = { limit: params.limit };
if (params.cursor) queryParams.cursor = params.cursor;
const response = await get<N8nPaginatedResponse<N8nVariable>>('/variables', queryParams);
const formatted = response.data.map(formatVariable).join('\n');
const output = {
count: response.data.length,
variables: response.data,
nextCursor: response.nextCursor
};
let text = `Found ${response.data.length} variable(s):\n\n${formatted}`;
if (response.nextCursor) {
text += `\n\n_More results available. Use cursor: ${response.nextCursor}_`;
}
return {
content: [{ type: 'text', text }],
structuredContent: output
};
}
);
// ============ Get Variable ============
server.registerTool(
'n8n_get_variable',
{
title: 'Get n8n Variable',
description: `Get a specific variable by ID.
Args:
- id (string): Variable ID
Returns:
Variable details with id, key, and value.`,
inputSchema: IdParamSchema,
annotations: {
readOnlyHint: true,
destructiveHint: false,
idempotentHint: true,
openWorldHint: false
}
},
async (params: z.infer<typeof IdParamSchema>) => {
const variable = await get<N8nVariable>(`/variables/${params.id}`);
return {
content: [{ type: 'text', text: formatVariable(variable) }],
structuredContent: variable
};
}
);
// ============ Create Variable ============
server.registerTool(
'n8n_create_variable',
{
title: 'Create n8n Variable',
description: `Create a new environment variable.
Variables can be used in workflows with $vars.variableName syntax.
Args:
- key (string): Variable key (alphanumeric + underscore, must start with letter or underscore)
- value (string): Variable value
Returns:
The created variable.`,
inputSchema: CreateVariableSchema,
annotations: {
readOnlyHint: false,
destructiveHint: false,
idempotentHint: false,
openWorldHint: false
}
},
async (params: z.infer<typeof CreateVariableSchema>) => {
const variable = await post<N8nVariable>('/variables', params);
return {
content: [{ type: 'text', text: `ā
Variable created!\n\n${formatVariable(variable)}\n\nUse in workflows: \`$vars.${variable.key}\`` }],
structuredContent: variable
};
}
);
// ============ Update Variable ============
server.registerTool(
'n8n_update_variable',
{
title: 'Update n8n Variable',
description: `Update an existing variable.
Args:
- id (string): Variable ID to update
- key (string, optional): New variable key
- value (string, optional): New variable value
Returns:
The updated variable.`,
inputSchema: UpdateVariableSchema,
annotations: {
readOnlyHint: false,
destructiveHint: false,
idempotentHint: true,
openWorldHint: false
}
},
async (params: z.infer<typeof UpdateVariableSchema>) => {
const { id, ...updateData } = params;
const variable = await put<N8nVariable>(`/variables/${id}`, updateData);
return {
content: [{ type: 'text', text: `ā
Variable updated!\n\n${formatVariable(variable)}` }],
structuredContent: variable
};
}
);
// ============ Delete Variable ============
server.registerTool(
'n8n_delete_variable',
{
title: 'Delete n8n Variable',
description: `Delete a variable.
ā ļø WARNING: Workflows using this variable will break!
Args:
- id (string): Variable ID to delete
Returns:
Confirmation of deletion.`,
inputSchema: IdParamSchema,
annotations: {
readOnlyHint: false,
destructiveHint: true,
idempotentHint: true,
openWorldHint: false
}
},
async (params: z.infer<typeof IdParamSchema>) => {
await del(`/variables/${params.id}`);
return {
content: [{ type: 'text', text: `ā
Variable ${params.id} deleted successfully.` }],
structuredContent: { deleted: true, id: params.id }
};
}
);
};
