diff --git a/src/mako/api/lib/mbuild.mako b/src/mako/api/lib/mbuild.mako
index f48a775b801..71c14fb0a4d 100644
--- a/src/mako/api/lib/mbuild.mako
+++ b/src/mako/api/lib/mbuild.mako
@@ -11,7 +11,7 @@
                       DELEGATE_PROPERTY_NAME, struct_type_bounds_s, scope_url_to_variant,
                       re_find_replacements, ADD_PARAM_FN, ADD_PARAM_MEDIA_EXAMPLE, upload_action_fn, METHODS_RESOURCE,
                       method_name_to_variant, unique_type_name, size_to_bytes, method_default_scope,
-                      is_repeated_property)
+                      is_repeated_property, setter_fn_name)
 
     def get_parts(part_prop):
         if not part_prop:
@@ -27,12 +27,6 @@
         part_desc += ''.join('* *%s*\n' % part for part in parts)
         part_desc = part_desc[:-1]
         return part_desc
-
-    def setter_fn_name(p):
-        fn_name = p.name
-        if is_repeated_property(p):
-            fn_name = 'add_' + fn_name
-        return fn_name
 %>\
 <%namespace name="util" file="../../lib/util.mako"/>\
 <%namespace name="lib" file="lib.mako"/>\
diff --git a/src/mako/cli/lib/engine.mako b/src/mako/cli/lib/engine.mako
index e940ace6a19..6a6b7b05d9f 100644
--- a/src/mako/cli/lib/engine.mako
+++ b/src/mako/cli/lib/engine.mako
@@ -1,21 +1,28 @@
 <%namespace name="util" file="../../lib/util.mako"/>\
 <%!
-    from util import (hub_type, mangle_ident, indent_all_but_first_by, activity_rust_type)
+    from util import (hub_type, mangle_ident, indent_all_but_first_by, activity_rust_type, setter_fn_name)
     from cli import (mangle_subcommand, new_method_context, PARAM_FLAG, STRUCT_FLAG, UPLOAD_FLAG, OUTPUT_FLAG, VALUE_ARG,
                      CONFIG_DIR, SCOPE_FLAG, is_request_value_property, FIELD_SEP, docopt_mode, FILE_ARG, MIME_ARG, OUT_ARG, 
-                     cmd_ident, call_method_ident, arg_ident, POD_TYPES, flag_ident)
+                     cmd_ident, call_method_ident, arg_ident, POD_TYPES, flag_ident, ident)
 
     v_arg = '<%s>' % VALUE_ARG
     SOPT = 'self.opt.'
     def to_opt_arg_ident(p):
         return SOPT + arg_ident(p.name)
+
+    def borrow_prefix(p):
+        ptype = p.get('type', None)
+        borrow = ''
+        if ptype not in POD_TYPES or ptype in ('string', None):
+            borrow = '&'
+        return borrow
 %>\
 <%def name="new(c)">\
 <%
     hub_type_name = 'api::' + hub_type(c.schemas, util.canonical_name())
 %>\
 mod cmn;
-use cmn::{InvalidOptionsError, CLIError, JsonTokenStorage, arg_from_str, writer_from_opts};
+use cmn::{InvalidOptionsError, CLIError, JsonTokenStorage, arg_from_str, writer_from_opts, parse_kv_arg};
 use std::default::Default;
 use std::str::FromStr;
 
@@ -122,6 +129,7 @@ self.opt.${cmd_ident(method)} {
 <%
     mc = new_method_context(resource, method, c)
     handle_output = mc.response_schema or mc.m.get('supportsMediaDownload', False)
+    handle_props = mc.optional_props or parameters is not UNDEFINED
 %>\
     ## REQUIRED PARAMETERS
 % for p in mc.required_props:
@@ -141,17 +149,33 @@ let ${prop_name}: ${prop_type} = arg_from_str(&${opt_ident}, err, "<${mangle_sub
     for p in mc.required_props:
         borrow = ''
         # if type is not available, we know it's the request value, which should also be borrowed
-        ptype = p.get('type', None)
-        if ptype not in POD_TYPES or ptype in ('string', None):
-            borrow = '&'
+        borrow = borrow_prefix(p)
         arg_name = mangle_ident(p.name)
-        if ptype == 'string':
+        if p.get('type', '') == 'string':
             arg_name = to_opt_arg_ident(p)
         call_args.append(borrow + arg_name)
     # end for each required prop
 %>\
-let call = self.hub.${mangle_ident(resource)}().${mangle_ident(method)}(${', '.join(call_args)});
-## TODO: set parameters
+let mut call = self.hub.${mangle_ident(resource)}().${mangle_ident(method)}(${', '.join(call_args)});
+% if handle_props:
+<%
+    optional_props = [p for p in mc.optional_props if not p.get('skip_example', False)]
+%>\
+for parg in ${SOPT + arg_ident(VALUE_ARG)}.iter() {
+    let (key, value) = parse_kv_arg(&*parg, err, "default");
+    match key {
+% for p in optional_props:
+        "${ident(p.name)}" => call = call.${mangle_ident(setter_fn_name(p))}(\
+        % if p.type != 'string':
+arg_from_str(value, err, "${ident(p.name)}", "${p.type}")),
+        % else:
+value),
+        % endif # handle conversion
+% endfor # each property
+        _ => err.issues.push(CLIError::UnknownParameter(key.to_string())),
+    }
+}
+% endif # handle call parameters
 ## TODO: parse upload
 if dry_run {
     None
diff --git a/src/mako/lib/util.py b/src/mako/lib/util.py
index 9d0b9d4bb42..46c14531a99 100644
--- a/src/mako/lib/util.py
+++ b/src/mako/lib/util.py
@@ -551,6 +551,12 @@ def is_required_property(p):
 def is_repeated_property(p):
     return p.get('repeated', False)
 
+def setter_fn_name(p):
+    fn_name = p.name
+    if is_repeated_property(p):
+        fn_name = 'add_' + fn_name
+    return fn_name
+
 # method_params(...), request_value|None -> (required_properties, optional_properties, part_prop|None)
 def organize_params(params, request_value):
     part_prop = None
diff --git a/src/rust/cli/cmn.rs b/src/rust/cli/cmn.rs
index d319ad170a8..12b5eedcf21 100644
--- a/src/rust/cli/cmn.rs
+++ b/src/rust/cli/cmn.rs
@@ -12,6 +12,25 @@ use std::io::{Write, Read, stdout};
 
 use std::default::Default;
 
+pub fn parse_kv_arg<'a>(kv: &'a str, err: &mut InvalidOptionsError, default: &'static str)
+                                                                        -> (&'a str, &'a str) {
+    let mut add_err = || err.issues.push(CLIError::InvalidKeyValueSyntax(kv.to_string()));
+    match kv.rfind('=') {
+        None => {
+            add_err();
+            return (kv, default)
+        },
+        Some(pos) => {
+            let key = &kv[..pos];
+            if kv.len() <= pos + 1 {
+                add_err();
+                return (key, default)
+            }
+            (key, &kv[pos+1..])
+        }
+    }
+}
+
 // May panic if we can't open the file - this is anticipated, we can't currently communicate this 
 // kind of error: TODO: fix this architecture :)
 pub fn writer_from_opts(flag: bool, arg: &str) -> Box<Write> {
@@ -31,7 +50,7 @@ pub fn arg_from_str<T>(arg: &str, err: &mut InvalidOptionsError,
     match FromStr::from_str(arg) {
         Err(perr) => {
             err.issues.push(
-                CLIError::ParseError((arg_name, arg_type, format!("{}", perr)))
+                CLIError::ParseError((arg_name, arg_type, arg.to_string(), format!("{}", perr)))
             );
             Default::default()
         },
@@ -122,16 +141,23 @@ impl fmt::Display for ConfigurationError {
 #[derive(Debug)]
 pub enum CLIError {
     Configuration(ConfigurationError),
-    ParseError((&'static str, &'static str, String)),
+    ParseError((&'static str, &'static str, String, String)),
+    UnknownParameter(String),
+    InvalidKeyValueSyntax(String),
 }
 
 impl fmt::Display for CLIError {
     fn fmt(&self, f: &mut fmt::Formatter) -> Result<(), fmt::Error> {
         match *self {
             CLIError::Configuration(ref err) => writeln!(f, "Configuration -> {}", err),
-            CLIError::ParseError((arg_name, type_name, ref err_desc)) 
-                => writeln!(f, "Failed to parse argument {} as {} with error: {}",
-                            arg_name, type_name, err_desc),
+            CLIError::ParseError((arg_name, type_name, ref value, ref err_desc)) 
+                => writeln!(f, "Failed to parse argument '{}' with value '{}' as {} with error: {}",
+                            arg_name, value, type_name, err_desc),
+            CLIError::UnknownParameter(ref param_name) 
+                => writeln!(f, "Parameter '{}' is unknown.", param_name),
+            CLIError::InvalidKeyValueSyntax(ref kv)
+                => writeln!(f, "'{}' does not match <key>=<value>", kv),
+
         }
     }
 }