diff --git a/x-pack/elastic-agent/CHANGELOG.next.asciidoc b/x-pack/elastic-agent/CHANGELOG.next.asciidoc
index 38b0e57ef2b..7c1d714e7c4 100644
--- a/x-pack/elastic-agent/CHANGELOG.next.asciidoc
+++ b/x-pack/elastic-agent/CHANGELOG.next.asciidoc
@@ -38,6 +38,7 @@
 - Fix issue of missing log messages from filebeat monitor {pull}23514[23514]
 - Increase checkin grace period to 30 seconds {pull}23568[23568]
 - Fix libbeat from reporting back degraded on config update {pull}23537[23537]
+- Fix issues with dynamic inputs and conditions {pull}23886[23886]
 
 ==== New features
 
diff --git a/x-pack/elastic-agent/pkg/agent/application/application.go b/x-pack/elastic-agent/pkg/agent/application/application.go
index f87cad3a09c..af50477d5fd 100644
--- a/x-pack/elastic-agent/pkg/agent/application/application.go
+++ b/x-pack/elastic-agent/pkg/agent/application/application.go
@@ -35,7 +35,7 @@ func New(log *logger.Logger, pathConfigFile string, reexec reexecManager, uc upg
 	// Load configuration from disk to understand in which mode of operation
 	// we must start the elastic-agent, the mode of operation cannot be changed without restarting the
 	// elastic-agent.
-	rawConfig, err := LoadConfigFromFile(pathConfigFile)
+	rawConfig, err := config.LoadFile(pathConfigFile)
 	if err != nil {
 		return nil, err
 	}
diff --git a/x-pack/elastic-agent/pkg/agent/application/config.go b/x-pack/elastic-agent/pkg/agent/application/config.go
index e42f3dcab28..8dfd093e040 100644
--- a/x-pack/elastic-agent/pkg/agent/application/config.go
+++ b/x-pack/elastic-agent/pkg/agent/application/config.go
@@ -5,16 +5,8 @@
 package application
 
 import (
-	"io/ioutil"
-
-	"github.com/elastic/go-ucfg"
-
-	"gopkg.in/yaml.v2"
-
-	"github.com/elastic/beats/v7/libbeat/common"
 	"github.com/elastic/beats/v7/x-pack/elastic-agent/pkg/agent/configuration"
 	"github.com/elastic/beats/v7/x-pack/elastic-agent/pkg/agent/errors"
-	"github.com/elastic/beats/v7/x-pack/elastic-agent/pkg/config"
 	"github.com/elastic/beats/v7/x-pack/elastic-agent/pkg/kibana"
 )
 
@@ -34,53 +26,3 @@ func createFleetConfigFromEnroll(accessAPIKey string, kbn *kibana.Config) (*conf
 	}
 	return cfg, nil
 }
-
-// LoadConfigFromFile loads the Agent configuration from a file.
-//
-// This must be used to load the Agent configuration, so that variables defined in the inputs are not
-// parsed by go-ucfg. Variables from the inputs should be parsed by the transpiler.
-func LoadConfigFromFile(path string) (*config.Config, error) {
-	in, err := ioutil.ReadFile(path)
-	if err != nil {
-		return nil, err
-	}
-	var m map[string]interface{}
-	if err := yaml.Unmarshal(in, &m); err != nil {
-		return nil, err
-	}
-	return LoadConfig(m)
-}
-
-// LoadConfig loads the Agent configuration from a map.
-//
-// This must be used to load the Agent configuration, so that variables defined in the inputs are not
-// parsed by go-ucfg. Variables from the inputs should be parsed by the transpiler.
-func LoadConfig(in map[string]interface{}) (*config.Config, error) {
-	// make copy of a map so we dont affect a caller
-	m := common.MapStr(in).Clone()
-
-	inputs, ok := m["inputs"]
-	if ok {
-		// remove the inputs
-		delete(m, "inputs")
-	}
-	cfg, err := config.NewConfigFrom(m)
-	if err != nil {
-		return nil, err
-	}
-	if ok {
-		inputsOnly := map[string]interface{}{
-			"inputs": inputs,
-		}
-		// convert to config without variable substitution
-		inputsCfg, err := config.NewConfigFrom(inputsOnly, ucfg.PathSep("."), ucfg.ResolveNOOP)
-		if err != nil {
-			return nil, err
-		}
-		err = cfg.Merge(inputsCfg, ucfg.PathSep("."), ucfg.ResolveNOOP)
-		if err != nil {
-			return nil, err
-		}
-	}
-	return cfg, err
-}
diff --git a/x-pack/elastic-agent/pkg/agent/application/config_test.go b/x-pack/elastic-agent/pkg/agent/application/config_test.go
index 09acd68dd83..824691295fe 100644
--- a/x-pack/elastic-agent/pkg/agent/application/config_test.go
+++ b/x-pack/elastic-agent/pkg/agent/application/config_test.go
@@ -6,8 +6,6 @@ package application
 
 import (
 	"io/ioutil"
-	"os"
-	"path/filepath"
 	"testing"
 	"time"
 
@@ -20,44 +18,6 @@ import (
 	"github.com/elastic/beats/v7/x-pack/elastic-agent/pkg/config"
 )
 
-func TestLoadConfig(t *testing.T) {
-	contents := map[string]interface{}{
-		"outputs": map[string]interface{}{
-			"default": map[string]interface{}{
-				"type":     "elasticsearch",
-				"hosts":    []interface{}{"127.0.0.1:9200"},
-				"username": "elastic",
-				"password": "changeme",
-			},
-		},
-		"inputs": []interface{}{
-			map[string]interface{}{
-				"type": "logfile",
-				"streams": []interface{}{
-					map[string]interface{}{
-						"paths": []interface{}{"/var/log/${host.name}"},
-					},
-				},
-			},
-		},
-	}
-
-	tmp, err := ioutil.TempDir("", "config")
-	require.NoError(t, err)
-	defer os.RemoveAll(tmp)
-
-	cfgPath := filepath.Join(tmp, "config.yml")
-	dumpToYAML(t, cfgPath, contents)
-
-	cfg, err := LoadConfigFromFile(cfgPath)
-	require.NoError(t, err)
-
-	cfgData, err := cfg.ToMapStr()
-	require.NoError(t, err)
-
-	assert.Equal(t, contents, cfgData)
-}
-
 func TestConfig(t *testing.T) {
 	testMgmtMode(t)
 	testLocalConfig(t)
diff --git a/x-pack/elastic-agent/pkg/agent/application/handler_action_policy_change.go b/x-pack/elastic-agent/pkg/agent/application/handler_action_policy_change.go
index 30a163a7b5e..b921569a19b 100644
--- a/x-pack/elastic-agent/pkg/agent/application/handler_action_policy_change.go
+++ b/x-pack/elastic-agent/pkg/agent/application/handler_action_policy_change.go
@@ -44,7 +44,7 @@ func (h *handlerPolicyChange) Handle(ctx context.Context, a action, acker fleetA
 		return fmt.Errorf("invalid type, expected ActionPolicyChange and received %T", a)
 	}
 
-	c, err := LoadConfig(action.Policy)
+	c, err := config.NewConfigFrom(action.Policy)
 	if err != nil {
 		return errors.New(err, "could not parse the configuration from the policy", errors.TypeConfig)
 	}
diff --git a/x-pack/elastic-agent/pkg/agent/application/inspect_config_cmd.go b/x-pack/elastic-agent/pkg/agent/application/inspect_config_cmd.go
index 4ea725898f2..15dccd83a88 100644
--- a/x-pack/elastic-agent/pkg/agent/application/inspect_config_cmd.go
+++ b/x-pack/elastic-agent/pkg/agent/application/inspect_config_cmd.go
@@ -61,7 +61,7 @@ func (c *InspectConfigCmd) inspectConfig() error {
 }
 
 func loadConfig(configPath string) (*config.Config, error) {
-	rawConfig, err := LoadConfigFromFile(configPath)
+	rawConfig, err := config.LoadFile(configPath)
 	if err != nil {
 		return nil, err
 	}
diff --git a/x-pack/elastic-agent/pkg/agent/cmd/enroll.go b/x-pack/elastic-agent/pkg/agent/cmd/enroll.go
index 2ae011db291..282ea2f4645 100644
--- a/x-pack/elastic-agent/pkg/agent/cmd/enroll.go
+++ b/x-pack/elastic-agent/pkg/agent/cmd/enroll.go
@@ -12,6 +12,7 @@ import (
 	"time"
 
 	"github.com/elastic/beats/v7/x-pack/elastic-agent/pkg/agent/control/client"
+	"github.com/elastic/beats/v7/x-pack/elastic-agent/pkg/config"
 
 	"github.com/spf13/cobra"
 
@@ -92,7 +93,7 @@ func enroll(streams *cli.IOStreams, cmd *cobra.Command, flags *globalFlags, args
 	}
 
 	pathConfigFile := flags.Config()
-	rawConfig, err := application.LoadConfigFromFile(pathConfigFile)
+	rawConfig, err := config.LoadFile(pathConfigFile)
 	if err != nil {
 		return errors.New(err,
 			fmt.Sprintf("could not read configuration file %s", pathConfigFile),
diff --git a/x-pack/elastic-agent/pkg/agent/cmd/run.go b/x-pack/elastic-agent/pkg/agent/cmd/run.go
index eb128585539..ecfac4ff740 100644
--- a/x-pack/elastic-agent/pkg/agent/cmd/run.go
+++ b/x-pack/elastic-agent/pkg/agent/cmd/run.go
@@ -79,7 +79,7 @@ func run(flags *globalFlags, streams *cli.IOStreams) error { // Windows: Mark se
 	service.HandleSignals(stopBeat, cancel)
 
 	pathConfigFile := flags.Config()
-	rawConfig, err := application.LoadConfigFromFile(pathConfigFile)
+	rawConfig, err := config.LoadFile(pathConfigFile)
 	if err != nil {
 		return errors.New(err,
 			fmt.Sprintf("could not read configuration file %s", pathConfigFile),
diff --git a/x-pack/elastic-agent/pkg/agent/cmd/watch.go b/x-pack/elastic-agent/pkg/agent/cmd/watch.go
index 01d73022f99..1124a950893 100644
--- a/x-pack/elastic-agent/pkg/agent/cmd/watch.go
+++ b/x-pack/elastic-agent/pkg/agent/cmd/watch.go
@@ -21,6 +21,7 @@ import (
 	"github.com/elastic/beats/v7/x-pack/elastic-agent/pkg/agent/configuration"
 	"github.com/elastic/beats/v7/x-pack/elastic-agent/pkg/agent/errors"
 	"github.com/elastic/beats/v7/x-pack/elastic-agent/pkg/cli"
+	"github.com/elastic/beats/v7/x-pack/elastic-agent/pkg/config"
 	"github.com/elastic/beats/v7/x-pack/elastic-agent/pkg/core/logger"
 	"github.com/elastic/beats/v7/x-pack/elastic-agent/pkg/release"
 )
@@ -182,7 +183,7 @@ func gracePeriod(marker *upgrade.UpdateMarker) (bool, time.Duration) {
 
 func configuredLogger(flags *globalFlags) (*logger.Logger, error) {
 	pathConfigFile := flags.Config()
-	rawConfig, err := application.LoadConfigFromFile(pathConfigFile)
+	rawConfig, err := config.LoadFile(pathConfigFile)
 	if err != nil {
 		return nil, errors.New(err,
 			fmt.Sprintf("could not read configuration file %s", pathConfigFile),
diff --git a/x-pack/elastic-agent/pkg/config/config.go b/x-pack/elastic-agent/pkg/config/config.go
index d2d366e526c..593631f0050 100644
--- a/x-pack/elastic-agent/pkg/config/config.go
+++ b/x-pack/elastic-agent/pkg/config/config.go
@@ -8,65 +8,116 @@ import (
 	"fmt"
 	"io"
 	"io/ioutil"
+	"os"
+
+	"gopkg.in/yaml.v2"
 
 	"github.com/elastic/go-ucfg"
 	"github.com/elastic/go-ucfg/cfgutil"
-	"github.com/elastic/go-ucfg/yaml"
 )
 
+// options hold the specified options
+type options struct {
+	skipKeys []string
+}
+
+// Option is an option type that modifies how loading configs work
+type Option func(*options)
+
+// VarSkipKeys prevents variable expansion for these keys.
+//
+// The provided keys only skip if the keys are top-level keys.
+func VarSkipKeys(keys ...string) Option {
+	return func(opts *options) {
+		opts.skipKeys = keys
+	}
+}
+
 // DefaultOptions defaults options used to read the configuration
-var DefaultOptions = []ucfg.Option{
+var DefaultOptions = []interface{}{
 	ucfg.PathSep("."),
 	ucfg.ResolveEnv,
 	ucfg.VarExp,
+	VarSkipKeys("inputs"),
 }
 
 // Config custom type over a ucfg.Config to add new methods on the object.
 type Config ucfg.Config
 
-// LoadYAML takes YAML configuration and return a concrete Config or any errors.
-func LoadYAML(path string, opts ...ucfg.Option) (*Config, error) {
-	if len(opts) == 0 {
-		opts = DefaultOptions
-	}
-	config, err := yaml.NewConfigWithFile(path, opts...)
-	if err != nil {
-		return nil, err
-	}
-	return newConfigFrom(config), nil
-}
-
 // New creates a new empty config.
 func New() *Config {
 	return newConfigFrom(ucfg.New())
 }
 
 // NewConfigFrom takes a interface and read the configuration like it was YAML.
-func NewConfigFrom(from interface{}, opts ...ucfg.Option) (*Config, error) {
+func NewConfigFrom(from interface{}, opts ...interface{}) (*Config, error) {
 	if len(opts) == 0 {
 		opts = DefaultOptions
 	}
-
-	if str, ok := from.(string); ok {
-		c, err := yaml.NewConfig([]byte(str), opts...)
-		return newConfigFrom(c), err
+	var ucfgOpts []ucfg.Option
+	var localOpts []Option
+	for _, o := range opts {
+		switch ot := o.(type) {
+		case ucfg.Option:
+			ucfgOpts = append(ucfgOpts, ot)
+		case Option:
+			localOpts = append(localOpts, ot)
+		default:
+			return nil, fmt.Errorf("unknown option type %T", o)
+		}
+	}
+	local := &options{}
+	for _, o := range localOpts {
+		o(local)
 	}
 
-	if in, ok := from.(io.Reader); ok {
+	var data map[string]interface{}
+	var err error
+	if bytes, ok := from.([]byte); ok {
+		err = yaml.Unmarshal(bytes, &data)
+		if err != nil {
+			return nil, err
+		}
+	} else if str, ok := from.(string); ok {
+		err = yaml.Unmarshal([]byte(str), &data)
+		if err != nil {
+			return nil, err
+		}
+	} else if in, ok := from.(io.Reader); ok {
 		if closer, ok := from.(io.Closer); ok {
 			defer closer.Close()
 		}
-
-		content, err := ioutil.ReadAll(in)
+		fData, err := ioutil.ReadAll(in)
+		if err != nil {
+			return nil, err
+		}
+		err = yaml.Unmarshal(fData, &data)
 		if err != nil {
 			return nil, err
 		}
-		c, err := yaml.NewConfig(content, opts...)
+	} else if contents, ok := from.(map[string]interface{}); ok {
+		data = contents
+	} else {
+		c, err := ucfg.NewFrom(from, ucfgOpts...)
 		return newConfigFrom(c), err
 	}
 
-	c, err := ucfg.NewFrom(from, opts...)
-	return newConfigFrom(c), err
+	skippedKeys := map[string]interface{}{}
+	for _, skip := range local.skipKeys {
+		val, ok := data[skip]
+		if ok {
+			skippedKeys[skip] = val
+			delete(data, skip)
+		}
+	}
+	cfg, err := ucfg.NewFrom(data, ucfgOpts...)
+	if err != nil {
+		return nil, err
+	}
+	if len(skippedKeys) > 0 {
+		err = cfg.Merge(skippedKeys, ucfg.ResolveNOOP)
+	}
+	return newConfigFrom(cfg), err
 }
 
 // MustNewConfigFrom try to create a configuration based on the type passed as arguments and panic
@@ -84,8 +135,12 @@ func newConfigFrom(in *ucfg.Config) *Config {
 }
 
 // Unpack unpacks a struct to Config.
-func (c *Config) Unpack(to interface{}) error {
-	return c.access().Unpack(to, DefaultOptions...)
+func (c *Config) Unpack(to interface{}, opts ...interface{}) error {
+	ucfgOpts, err := getUcfgOptions(opts...)
+	if err != nil {
+		return err
+	}
+	return c.access().Unpack(to, ucfgOpts...)
 }
 
 func (c *Config) access() *ucfg.Config {
@@ -93,11 +148,12 @@ func (c *Config) access() *ucfg.Config {
 }
 
 // Merge merges two configuration together.
-func (c *Config) Merge(from interface{}, opts ...ucfg.Option) error {
-	if len(opts) == 0 {
-		opts = DefaultOptions
+func (c *Config) Merge(from interface{}, opts ...interface{}) error {
+	ucfgOpts, err := getUcfgOptions(opts...)
+	if err != nil {
+		return err
 	}
-	return c.access().Merge(from, opts...)
+	return c.access().Merge(from, ucfgOpts...)
 }
 
 // ToMapStr takes the config and transform it into a map[string]interface{}
@@ -127,18 +183,16 @@ func (c *Config) Enabled() bool {
 
 // LoadFile take a path and load the file and return a new configuration.
 func LoadFile(path string) (*Config, error) {
-	c, err := yaml.NewConfigWithFile(path, DefaultOptions...)
+	fp, err := os.Open(path)
 	if err != nil {
 		return nil, err
 	}
-
-	cfg := newConfigFrom(c)
-	return cfg, err
+	return NewConfigFrom(fp)
 }
 
 // LoadFiles takes multiples files, load and merge all of them in a single one.
 func LoadFiles(paths ...string) (*Config, error) {
-	merger := cfgutil.NewCollector(nil, DefaultOptions...)
+	merger := cfgutil.NewCollector(nil)
 	for _, path := range paths {
 		cfg, err := LoadFile(path)
 		if err := merger.Add(cfg.access(), err); err != nil {
@@ -147,3 +201,22 @@ func LoadFiles(paths ...string) (*Config, error) {
 	}
 	return newConfigFrom(merger.Config()), nil
 }
+
+func getUcfgOptions(opts ...interface{}) ([]ucfg.Option, error) {
+	if len(opts) == 0 {
+		opts = DefaultOptions
+	}
+	var ucfgOpts []ucfg.Option
+	for _, o := range opts {
+		switch ot := o.(type) {
+		case ucfg.Option:
+			ucfgOpts = append(ucfgOpts, ot)
+		case Option:
+			// ignored during unpack
+			continue
+		default:
+			return nil, fmt.Errorf("unknown option type %T", o)
+		}
+	}
+	return ucfgOpts, nil
+}
diff --git a/x-pack/elastic-agent/pkg/config/config_test.go b/x-pack/elastic-agent/pkg/config/config_test.go
index f8b32e97d8e..105663dacce 100644
--- a/x-pack/elastic-agent/pkg/config/config_test.go
+++ b/x-pack/elastic-agent/pkg/config/config_test.go
@@ -21,6 +21,44 @@ func TestConfig(t *testing.T) {
 	testLoadFiles(t)
 }
 
+func TestInputsResolveNOOP(t *testing.T) {
+	contents := map[string]interface{}{
+		"outputs": map[string]interface{}{
+			"default": map[string]interface{}{
+				"type":     "elasticsearch",
+				"hosts":    []interface{}{"127.0.0.1:9200"},
+				"username": "elastic",
+				"password": "changeme",
+			},
+		},
+		"inputs": []interface{}{
+			map[string]interface{}{
+				"type": "logfile",
+				"streams": []interface{}{
+					map[string]interface{}{
+						"paths": []interface{}{"/var/log/${host.name}"},
+					},
+				},
+			},
+		},
+	}
+
+	tmp, err := ioutil.TempDir("", "config")
+	require.NoError(t, err)
+	defer os.RemoveAll(tmp)
+
+	cfgPath := filepath.Join(tmp, "config.yml")
+	dumpToYAML(t, cfgPath, contents)
+
+	cfg, err := LoadFile(cfgPath)
+	require.NoError(t, err)
+
+	cfgData, err := cfg.ToMapStr()
+	require.NoError(t, err)
+
+	assert.Equal(t, contents, cfgData)
+}
+
 func testToMapStr(t *testing.T) {
 	m := map[string]interface{}{
 		"hello": map[string]interface{}{
diff --git a/x-pack/elastic-agent/pkg/eql/eql_test.go b/x-pack/elastic-agent/pkg/eql/eql_test.go
index 5f67c516c81..c594a6c2a20 100644
--- a/x-pack/elastic-agent/pkg/eql/eql_test.go
+++ b/x-pack/elastic-agent/pkg/eql/eql_test.go
@@ -296,7 +296,7 @@ func TestEql(t *testing.T) {
 		{expression: "stringContains('hello world', 'rol')", result: false},
 		{expression: "stringContains('hello world', 'o w', 'too many')", err: true},
 		{expression: "stringContains(0, 'o w', 'too many')", err: true},
-		{expression: "stringContains('hello world', 0)", err: true},
+		{expression: "stringContains('hello world', 0)", result: false},
 
 		// Bad expression and malformed expression
 		{expression: "length('hello')", err: true},
diff --git a/x-pack/elastic-agent/pkg/eql/methods_str.go b/x-pack/elastic-agent/pkg/eql/methods_str.go
index 781e193d924..b7c49a61036 100644
--- a/x-pack/elastic-agent/pkg/eql/methods_str.go
+++ b/x-pack/elastic-agent/pkg/eql/methods_str.go
@@ -25,12 +25,7 @@ func endsWith(args []interface{}) (interface{}, error) {
 	if len(args) != 2 {
 		return nil, fmt.Errorf("endsWith: accepts exactly 2 arguments; recieved %d", len(args))
 	}
-	input, iOk := args[0].(string)
-	suffix, sOk := args[1].(string)
-	if !iOk || !sOk {
-		return nil, fmt.Errorf("endsWith: accepts exactly 2 string arguments; recieved %T and %T", args[0], args[1])
-	}
-	return strings.HasSuffix(input, suffix), nil
+	return strings.HasSuffix(toString(args[0]), toString(args[1])), nil
 }
 
 // indexOf returns the starting index of substring
@@ -38,11 +33,8 @@ func indexOf(args []interface{}) (interface{}, error) {
 	if len(args) < 2 || len(args) > 3 {
 		return nil, fmt.Errorf("indexOf: accepts 2-3 arguments; recieved %d", len(args))
 	}
-	input, iOk := args[0].(string)
-	substring, sOk := args[1].(string)
-	if !iOk || !sOk {
-		return nil, fmt.Errorf("indexOf: argument 0 and 1 must be a string; recieved %T and %T", args[0], args[1])
-	}
+	input := toString(args[0])
+	substring := toString(args[1])
 	start := 0
 	if len(args) > 2 {
 		s, sOk := args[2].(int)
@@ -59,10 +51,7 @@ func match(args []interface{}) (interface{}, error) {
 	if len(args) < 2 {
 		return nil, fmt.Errorf("match: accepts minimum of 2 arguments; recieved %d", len(args))
 	}
-	input, iOk := args[0].(string)
-	if !iOk {
-		return nil, fmt.Errorf("match: argument 0 must be a string; recieved %T", args[0])
-	}
+	input := toString(args[0])
 	for i, reg := range args[1:] {
 		switch r := reg.(type) {
 		case string:
@@ -85,10 +74,7 @@ func number(args []interface{}) (interface{}, error) {
 	if len(args) < 1 || len(args) > 2 {
 		return nil, fmt.Errorf("number: accepts between 1-2 arguments; recieved %d", len(args))
 	}
-	input, iOk := args[0].(string)
-	if !iOk {
-		return nil, fmt.Errorf("number: argument 0 must be a string; recieved %T", args[0])
-	}
+	input := toString(args[0])
 	base := 10
 	if len(args) > 1 {
 		switch a := args[1].(type) {
@@ -113,12 +99,7 @@ func startsWith(args []interface{}) (interface{}, error) {
 	if len(args) != 2 {
 		return nil, fmt.Errorf("startsWith: accepts exactly 2 arguments; recieved %d", len(args))
 	}
-	input, iOk := args[0].(string)
-	prefix, pOk := args[1].(string)
-	if !iOk || !pOk {
-		return nil, fmt.Errorf("startsWith: accepts exactly 2 string arguments; recieved %T and %T", args[0], args[1])
-	}
-	return strings.HasPrefix(input, prefix), nil
+	return strings.HasPrefix(toString(args[0]), toString(args[1])), nil
 }
 
 // str converts the argument into a string
@@ -134,12 +115,7 @@ func stringContains(args []interface{}) (interface{}, error) {
 	if len(args) != 2 {
 		return nil, fmt.Errorf("stringContains: accepts exactly 2 arguments; recieved %d", len(args))
 	}
-	input, iOk := args[0].(string)
-	substr, sOk := args[1].(string)
-	if !iOk || !sOk {
-		return nil, fmt.Errorf("stringContains: accepts exactly 2 string arguments; recieved %T and %T", args[0], args[1])
-	}
-	return strings.Contains(input, substr), nil
+	return strings.Contains(toString(args[0]), toString(args[1])), nil
 }
 
 func toString(arg interface{}) string {