n8n_create_variable

Create environment variables for n8n workflows to store reusable values accessed via $vars.variableName syntax.

Instructions

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.

Input Schema

TableJSON Schema

Name	Required	Description	Default
`key`	Yes	Variable key (alphanumeric + underscore, must start with letter or underscore)
`value`	Yes	Variable value

Implementation Reference

src/tools/variables.ts:126-133 (handler)

The handler function that executes the n8n_create_variable tool, performing a POST request to create a variable.

async (params: z.infer<typeof CreateVariableSchema>) => {
  const variable = await post<N8nVariable>('/variables', params);
  
  return {
    content: [{ type: 'text', text: `✅ Variable created!\n\n${formatVariable(variable)}\n\nUse in workflows: \`$vars.${variable.key}\`` }],
    structuredContent: variable
  };
}

src/schemas/index.ts:222-227 (schema)

Zod schema defining the input parameters for the Create Variable tool.

export const CreateVariableSchema = z.object({
  key: z.string().min(1).max(50).regex(/^[a-zA-Z_][a-zA-Z0-9_]*$/)
    .describe('Variable key (alphanumeric + underscore, must start with letter or underscore)'),
  value: z.string()
    .describe('Variable value')
}).strict();

src/tools/variables.ts:104-125 (registration)

Registration of the n8n_create_variable tool with the MCP server.

  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
      }
    },

n8n MCP Server