n8n MCP Server

Instructions

Implementation Reference

• src/tools/variables.ts:158-165 (handler)

  The tool handler function for 'n8n_update_variable' that processes input parameters and updates the variable using a PUT request.

  async (params: z.infer<typeof UpdateVariableSchema>) => {
    const { id, ...updateData } = params;
    const variable = await put<N8nVariable>(`/variables/${id}`, updateData);
    
    return {
      content: [{ type: 'text', text: `✅ Variable updated!\n\n${formatVariable(variable)}` }],
      structuredContent: variable
    };

• src/schemas/index.ts:229-235 (schema)

  Zod schema definition for input validation of 'n8n_update_variable'.

  export const UpdateVariableSchema = z.object({
    id: z.string().min(1)
      .describe('Variable ID to update'),
    key: z.string().min(1).max(50).regex(/^[a-zA-Z_][a-zA-Z0-9_]*$/).optional()
      .describe('New variable key'),
    value: z.string().optional()
      .describe('New variable value')

• src/tools/variables.ts:137-157 (registration)

  Registration of the 'n8n_update_variable' tool with the MCP server.

    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
        }
      },