diff --git a/gqlgen/go.mod b/gqlgen/go.mod
index 1ad9e8b..dd44a3d 100644
--- a/gqlgen/go.mod
+++ b/gqlgen/go.mod
@@ -4,5 +4,7 @@ go 1.15
 
 require (
 	github.com/99designs/gqlgen v0.13.0
-	github.com/graphmetrics/graphmetrics-go v0.2.3
+	github.com/graphmetrics/graphmetrics-go v0.3.0
+	github.com/graphmetrics/logger-go v0.2.1
+	github.com/vektah/gqlparser/v2 v2.1.0
 )
diff --git a/gqlgen/go.sum b/gqlgen/go.sum
index 2190c63..57e77f6 100644
--- a/gqlgen/go.sum
+++ b/gqlgen/go.sum
@@ -2,14 +2,17 @@ github.com/99designs/gqlgen v0.13.0 h1:haLTcUp3Vwp80xMVEg5KRNwzfUrgFdRmtBY8fuB8s
 github.com/99designs/gqlgen v0.13.0/go.mod h1:NV130r6f4tpRWuAI+zsrSdooO/eWUv+Gyyoi3rEfXIk=
 github.com/BurntSushi/toml v0.3.1/go.mod h1:xHWCNGjB5oqiDr8zfno3MHue2Ht5sIBksp03qcyfWMU=
 github.com/agnivade/levenshtein v1.0.1/go.mod h1:CURSv5d9Uaml+FovSIICkLbAUZ9S4RqaHDIsdSBg7lM=
+github.com/agnivade/levenshtein v1.0.3 h1:M5ZnqLOoZR8ygVq0FfkXsNOKzMCk0xRiow0R5+5VkQ0=
 github.com/agnivade/levenshtein v1.0.3/go.mod h1:4SFRZbbXWLF4MU1T9Qg0pGgH3Pjs+t6ie5efyrwRJXs=
 github.com/andreyvit/diff v0.0.0-20170406064948-c7f18ee00883 h1:bvNMNQO63//z+xNgfBlViaCIJKLlCJ6/fmUseuG0wVQ=
 github.com/andreyvit/diff v0.0.0-20170406064948-c7f18ee00883/go.mod h1:rCTlJbsFo29Kk6CurOXKm700vrz8f0KW0JNfpkRJY/8=
+github.com/arbovm/levenshtein v0.0.0-20160628152529-48b4e1c0c4d0 h1:jfIu9sQUG6Ig+0+Ap1h4unLjW6YQJpKZVmUzxsD4E/Q=
 github.com/arbovm/levenshtein v0.0.0-20160628152529-48b4e1c0c4d0/go.mod h1:t2tdKJDJF9BV14lnkjHmOQgcvEKgtqs5a1N3LNdJhGE=
 github.com/cpuguy83/go-md2man/v2 v2.0.0-20190314233015-f79a8a8ca69d/go.mod h1:maD7wRr/U5Z6m/iR4s+kqSMx2CaBsrgA7czyZG/E6dU=
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/dgryski/trifles v0.0.0-20190318185328-a8d75aae118c h1:TUuUh0Xgj97tLMNtWtNvI9mIV6isjEb9lBMNv+77IGM=
 github.com/dgryski/trifles v0.0.0-20190318185328-a8d75aae118c/go.mod h1:if7Fbed8SFyPtHLHbg49SI7NAdJiC5WIA09pe59rfAA=
 github.com/go-chi/chi v3.3.2+incompatible/go.mod h1:eB3wogJHnLi3x/kFX2A+IbTBlXxmMeXJVKy9tTv1XzQ=
 github.com/gogo/protobuf v1.0.0/go.mod h1:r8qH/GZQm5c6nD/R0oafs1akxWv10x8SbQlK7atdtwQ=
@@ -18,10 +21,10 @@ github.com/google/gofuzz v1.2.0/go.mod h1:dBl0BpW6vV/+mYPU4Po3pmUjxk6FQPldtuIdl/
 github.com/gorilla/context v0.0.0-20160226214623-1ea25387ff6f/go.mod h1:kBGZzfjB9CEq2AlWe17Uuf7NDRt0dE0s8S51q0aT7Yg=
 github.com/gorilla/mux v1.6.1/go.mod h1:1lud6UwP+6orDFRuTfBEV8e9/aOM/c4fVVCaMa2zaAs=
 github.com/gorilla/websocket v1.4.2/go.mod h1:YR8l580nyteQvAITg2hZ9XVh4b55+EU/adAjf1fMHhE=
-github.com/graphmetrics/graphmetrics-go v0.2.3 h1:xQv1P2YMEausj52YpYNpXK7otoaH5ZauUYRs1HXnaNU=
-github.com/graphmetrics/graphmetrics-go v0.2.3/go.mod h1:1LcstWZiHfrlCL3Usquk9vdYw6Z0Lptrnydq2KXecRY=
-github.com/graphmetrics/logger-go v0.2.0 h1:vzxwoe3wtvXHqh7urQ4MYtrOjlwDGDxEOsmEy9NH+o8=
-github.com/graphmetrics/logger-go v0.2.0/go.mod h1:T98PXH1RF/nRghhhnKr8S7N96H5A7beuXXwzJaBl0dw=
+github.com/graphmetrics/graphmetrics-go v0.3.0 h1:MdzpN7VYkw3/frjjbJV5IguCUzc3WKiSa7j9RcVpTHE=
+github.com/graphmetrics/graphmetrics-go v0.3.0/go.mod h1:rG6Yyqfux5SbrZIHzyHLoFR+d3utjsSThxY/VwC+QtU=
+github.com/graphmetrics/logger-go v0.2.1 h1:7XBJKij+sY+b7ENi35xVk1UJzMGtj2wEoIeLAlo8cok=
+github.com/graphmetrics/logger-go v0.2.1/go.mod h1:T98PXH1RF/nRghhhnKr8S7N96H5A7beuXXwzJaBl0dw=
 github.com/graphmetrics/sketches-go v0.2.0 h1:VVh4GE3rXlmiTa0jJN/MJgn2AIl/qV7fbUge0h8X9as=
 github.com/graphmetrics/sketches-go v0.2.0/go.mod h1:dQhQn7YYW04ysDLao9hlgtZmrC5PRvbyxrGUg57+I3o=
 github.com/hashicorp/go-cleanhttp v0.5.1 h1:dH3aiDG9Jvb5r5+bYHsikaOUIpcM0xvgMXVoDkXMzJM=
diff --git a/gqlgen/handler.go b/gqlgen/handler.go
index c4cb3f5..3f512c9 100644
--- a/gqlgen/handler.go
+++ b/gqlgen/handler.go
@@ -5,8 +5,12 @@ import (
 	"time"
 
 	"github.com/99designs/gqlgen/graphql"
+	"github.com/graphmetrics/logger-go"
+	"github.com/vektah/gqlparser/v2/ast"
+
 	"github.com/graphmetrics/graphmetrics-go"
 	"github.com/graphmetrics/graphmetrics-go/client"
+	"github.com/graphmetrics/graphmetrics-go/signature"
 )
 
 type Extension interface {
@@ -18,54 +22,81 @@ type Extension interface {
 }
 
 func NewExtension(cfg *graphmetrics.Configuration) Extension {
-	clientExt := cfg.ClientExtractor
-	if clientExt == nil {
-		clientExt = func(context.Context) client.Details {
-			return client.Details{}
-		}
-	}
 	agg := graphmetrics.NewAggregator(cfg)
 	go agg.Start()
 	return &extensionImpl{
-		agg:       agg,
-		clientExt: clientExt,
+		aggregator:      agg,
+		clientExtractor: cfg.GetClientExtractor(),
+		logger:          cfg.GetLogger(),
 	}
 }
 
 type extensionImpl struct {
-	agg       *graphmetrics.Aggregator
-	clientExt client.Extractor
+	aggregator      *graphmetrics.Aggregator
+	clientExtractor client.Extractor
+	schema          *ast.Schema
+
+	logger logger.Logger
 }
 
 func (*extensionImpl) ExtensionName() string {
 	return "GraphMetricsExtension"
 }
 
-func (*extensionImpl) Validate(_ graphql.ExecutableSchema) error {
+func (e *extensionImpl) Validate(schema graphql.ExecutableSchema) error {
+	e.schema = schema.Schema()
 	return nil
 }
 
 func (e *extensionImpl) InterceptOperation(ctx context.Context, next graphql.OperationHandler) graphql.ResponseHandler {
-	// NOT IMPLEMENTED YET
-	return next(ctx)
+	operation := graphql.GetOperationContext(ctx)
+	caller := e.clientExtractor(ctx)
+	sign, err := signature.OperationSignature(e.schema, operation.RawQuery, operation.OperationName)
+	if err != nil {
+		e.logger.Error("unable to build operation signature", map[string]interface{}{
+			"err":       err,
+			"operation": operation.OperationName,
+		})
+	}
+	hash := signature.OperationHash(sign)
+
+	handler := next(ctx)
+	return func(ctx context.Context) *graphql.Response {
+		res := handler(ctx)
+		duration := time.Since(operation.Stats.OperationStart)
+		e.aggregator.PushOperation(&graphmetrics.OperationMessage{
+			Name:      operation.OperationName,
+			Type:      string(operation.Operation.Operation),
+			Hash:      hash,
+			Signature: sign,
+			HasErrors: len(res.Errors) > 0,
+			Duration:  duration,
+			Client:    caller,
+		})
+
+		return res
+	}
 }
 
 func (e *extensionImpl) InterceptField(ctx context.Context, next graphql.Resolver) (res interface{}, err error) {
-	field := graphql.GetFieldContext(ctx)
 	start := time.Now()
+
+	field := graphql.GetFieldContext(ctx)
+	caller := e.clientExtractor(ctx)
 	res, err = next(ctx)
 	duration := time.Since(start)
-	e.agg.PushField(&graphmetrics.FieldMessage{
+	e.aggregator.PushField(&graphmetrics.FieldMessage{
 		TypeName:   field.Object,
 		FieldName:  field.Field.Name,
 		ReturnType: field.Field.Definition.Type.String(),
 		Error:      err,
 		Duration:   duration,
-		Client:     e.clientExt(ctx),
+		Client:     caller,
 	})
+
 	return res, err
 }
 
 func (e *extensionImpl) Close() error {
-	return e.agg.Stop()
+	return e.aggregator.Stop()
 }