diff --git a/tools/cli/go.mod b/tools/cli/go.mod
index 6ff94b0a2..099c2949c 100644
--- a/tools/cli/go.mod
+++ b/tools/cli/go.mod
@@ -3,12 +3,13 @@ module mongodb/openapi/tools/cli
 go 1.22.1
 
 require (
+	github.com/getkin/kin-openapi v0.120.0
 	github.com/spf13/cobra v1.8.0
 	github.com/tufin/oasdiff v1.9.5
 )
 
 require (
-	github.com/getkin/kin-openapi v0.120.0 // indirect
+	cloud.google.com/go v0.110.10 // indirect
 	github.com/go-openapi/jsonpointer v0.20.0 // indirect
 	github.com/go-openapi/swag v0.22.4 // indirect
 	github.com/inconshreveable/mousetrap v1.1.0 // indirect
diff --git a/tools/cli/go.sum b/tools/cli/go.sum
index d89a2c111..3fcc8a595 100644
--- a/tools/cli/go.sum
+++ b/tools/cli/go.sum
@@ -1,3 +1,7 @@
+cloud.google.com/go v0.110.10 h1:LXy9GEO+timppncPIAZoOj3l58LIU9k+kn48AN7IO3Y=
+cloud.google.com/go v0.110.10/go.mod h1:v1OoFqYxiBkUrruItNM3eT4lLByNjxmJSV/xDKJNnic=
+github.com/TwiN/go-color v1.4.1 h1:mqG0P/KBgHKVqmtL5ye7K0/Gr4l6hTksPgTgMk3mUzc=
+github.com/TwiN/go-color v1.4.1/go.mod h1:WcPf/jtiW95WBIsEeY1Lc/b8aaWoiqQpu5cf8WFxu+s=
 github.com/cpuguy83/go-md2man/v2 v2.0.3/go.mod h1:tgQtvFlXSQOSOSIRvRPT7W67SCa46tRHOmNcaadrF8o=
 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=
@@ -9,6 +13,8 @@ github.com/go-openapi/swag v0.22.4 h1:QLMzNJnMGPRNDCbySlcj1x01tzU8/9LTTL9hZZZogB
 github.com/go-openapi/swag v0.22.4/go.mod h1:UzaqsxGiab7freDnrUUra0MwWfN/q7tE4j+VcZ0yl14=
 github.com/go-test/deep v1.0.8 h1:TDsG77qcSprGbC6vTN8OuXp5g+J+b5Pcguhf7Zt61VM=
 github.com/go-test/deep v1.0.8/go.mod h1:5C2ZWiW0ErCdrYzpqxLbTX7MG14M9iiw8DgHncVwcsE=
+github.com/google/go-cmp v0.5.9 h1:O2Tfq5qg4qc4AmwVlvv0oLiVAGB7enBSJ2x2DqQFi38=
+github.com/google/go-cmp v0.5.9/go.mod h1:17dUlkBOakJ0+DkrSSNjCkIjxS6bF9zb3elmeNGIjoY=
 github.com/inconshreveable/mousetrap v1.1.0 h1:wN+x4NVGpMsO7ErUn/mUI3vEoE6Jt13X2s0bqwp9tc8=
 github.com/inconshreveable/mousetrap v1.1.0/go.mod h1:vpF70FUmC8bwa3OWnCshd2FqLfsEA9PFc4w1p2J65bw=
 github.com/invopop/yaml v0.2.0 h1:7zky/qH+O0DwAyoobXUqvVBwgBFRxKoQ/3FjcVpjTMY=
@@ -42,6 +48,8 @@ github.com/ugorji/go/codec v1.2.7 h1:YPXUKf7fYbp/y8xloBqZOw2qaVggbfwMlI8WM3wZUJ0
 github.com/ugorji/go/codec v1.2.7/go.mod h1:WGN1fab3R1fzQlVQTkfxVtIBhWDRqOviHU95kRgeqEY=
 github.com/yargevad/filepathx v1.0.0 h1:SYcT+N3tYGi+NvazubCNlvgIPbzAk7i7y2dwg3I5FYc=
 github.com/yargevad/filepathx v1.0.0/go.mod h1:BprfX/gpYNJHJfc35GjRRpVcwWXS89gGulUIU5tK3tA=
+golang.org/x/exp v0.0.0-20231108232855-2478ac86f678 h1:mchzmB1XO2pMaKFRqk/+MV3mgGG96aqaPXaMifQU47w=
+golang.org/x/exp v0.0.0-20231108232855-2478ac86f678/go.mod h1:zk2irFbV9DP96SEBUUAy67IdHUaZuSnrz1n472HUCLE=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/check.v1 v1.0.0-20201130134442-10cb98267c6c h1:Hei/4ADfdWqJk1ZMxUNpqntNwaWcugrBjAiHlqqRiVk=
 gopkg.in/check.v1 v1.0.0-20201130134442-10cb98267c6c/go.mod h1:JHkPIbrfpd72SG/EVd6muEfDQjcINNoR0C8j2r3qZ4Q=
diff --git a/tools/cli/internal/openapi/errors/pathConflictError.go b/tools/cli/internal/openapi/errors/pathConflictError.go
new file mode 100644
index 000000000..59fd5b8ae
--- /dev/null
+++ b/tools/cli/internal/openapi/errors/pathConflictError.go
@@ -0,0 +1,11 @@
+package errors
+
+import "fmt"
+
+type PathConflictError struct {
+	Entry string
+}
+
+func (e PathConflictError) Error() string {
+	return fmt.Sprintf("there was a conflict with the Path: %s", e.Entry)
+}
diff --git a/tools/cli/internal/openapi/oasdiff.go b/tools/cli/internal/openapi/oasdiff.go
new file mode 100644
index 000000000..b8ebf258a
--- /dev/null
+++ b/tools/cli/internal/openapi/oasdiff.go
@@ -0,0 +1,74 @@
+package openapi
+
+import (
+	"fmt"
+	"mongodb/openapi/tools/cli/internal/openapi/errors"
+	"os"
+
+	"github.com/tufin/oasdiff/diff"
+	"github.com/tufin/oasdiff/load"
+)
+
+type OasDiff struct {
+	base     *load.SpecInfo
+	external *load.SpecInfo
+	config   *diff.Config
+	specDiff *diff.Diff
+	parser   Parser
+}
+
+func (o *OasDiff) MergeOpenAPISpecs(paths []string) (*load.SpecInfo, error) {
+	for _, p := range paths {
+		spec, err := o.parser.CreateOpenAPISpecFromPath(p)
+		if err != nil {
+			return nil, err
+		}
+
+		o.config = &diff.Config{
+			IncludePathParams: true,
+		}
+
+		specDiff, err := diff.Get(o.config, o.base.Spec, spec.Spec)
+		if err != nil {
+			_, _ = fmt.Fprintf(os.Stderr, "error in calculating the diff of the specs: %s", err)
+			return nil, err
+		}
+
+		o.specDiff = specDiff
+		o.external = spec
+		err = o.mergeSpecIntoBase()
+		if err != nil {
+			return nil, err
+		}
+	}
+
+	return o.base, nil
+}
+
+func (o OasDiff) mergeSpecIntoBase() error {
+	return o.mergePaths()
+}
+
+func (o OasDiff) mergePaths() error {
+	pathsToMerge := o.external.Spec.Paths
+	basePaths := o.base.Spec.Paths
+	for k, v := range pathsToMerge {
+		if _, ok := basePaths[k]; !ok {
+			basePaths[k] = v
+		} else {
+			return errors.PathConflictError{
+				Entry: k,
+			}
+		}
+	}
+
+	o.base.Spec.Paths = basePaths
+	return nil
+}
+
+func NewOasDiff(base *load.SpecInfo) *OasDiff {
+	return &OasDiff{
+		base:   base,
+		parser: NewOpenAPI3(),
+	}
+}
diff --git a/tools/cli/internal/openapi/openapi.go b/tools/cli/internal/openapi/openapi.go
new file mode 100644
index 000000000..5bdb95939
--- /dev/null
+++ b/tools/cli/internal/openapi/openapi.go
@@ -0,0 +1,13 @@
+package openapi
+
+import (
+	"github.com/tufin/oasdiff/load"
+)
+
+type Merger interface {
+	MergeOpenAPISpecs([]string) (*load.SpecInfo, error)
+}
+
+type Parser interface {
+	CreateOpenAPISpecFromPath(string) (*load.SpecInfo, error)
+}
diff --git a/tools/cli/internal/openapi/openapi3.go b/tools/cli/internal/openapi/openapi3.go
new file mode 100644
index 000000000..3f5bef023
--- /dev/null
+++ b/tools/cli/internal/openapi/openapi3.go
@@ -0,0 +1,31 @@
+package openapi
+
+import (
+	"github.com/getkin/kin-openapi/openapi3"
+	"github.com/tufin/oasdiff/load"
+)
+
+type OpenAPI3 struct {
+	IsExternalRefsAllowed    bool
+	CircularReferenceCounter int
+}
+
+func (o *OpenAPI3) CreateOpenAPISpecFromPath(path string) (*load.SpecInfo, error) {
+	loader := openapi3.NewLoader()
+	loader.IsExternalRefsAllowed = true
+	openapi3.CircularReferenceCounter = 10
+
+	spec, err := load.LoadSpecInfo(loader, load.NewSource(path))
+	if err != nil {
+		return nil, err
+	}
+
+	return spec, nil
+}
+
+func NewOpenAPI3() *OpenAPI3 {
+	return &OpenAPI3{
+		IsExternalRefsAllowed:    true,
+		CircularReferenceCounter: 10,
+	}
+}