feat: add google vertex support

anthropic/anthropic.go

@@ -14,7 +14,9 @@ import (
 	"github.com/anthropics/anthropic-sdk-go"
 	"github.com/anthropics/anthropic-sdk-go/option"
 	"github.com/anthropics/anthropic-sdk-go/packages/param"
+	"github.com/anthropics/anthropic-sdk-go/vertex"
 	"github.com/charmbracelet/fantasy/ai"
+	"golang.org/x/oauth2/google"
 )
 
 const (
@@ -28,6 +30,10 @@ type options struct {
 	name    string
 	headers map[string]string
 	client  option.HTTPClient
+
+	vertexProject  string
+	vertexLocation string
+	skipGoogleAuth bool
 }
 
 type provider struct {
@@ -61,6 +67,19 @@ func WithAPIKey(apiKey string) Option {
 	}
 }
 
+func WithVertex(project, location string) Option {
+	return func(o *options) {
+		o.vertexProject = project
+		o.vertexLocation = location
+	}
+}
+
+func WithSkipGoogleAuth(skip bool) Option {
+	return func(o *options) {
+		o.skipGoogleAuth = skip
+	}
+}
+
 func WithName(name string) Option {
 	return func(o *options) {
 		o.name = name
@@ -80,26 +99,46 @@ func WithHTTPClient(client option.HTTPClient) Option {
 }
 
 func (a *provider) LanguageModel(modelID string) (ai.LanguageModel, error) {
-	anthropicClientOptions := []option.RequestOption{}
+	clientOptions := make([]option.RequestOption, 0, 5+len(a.options.headers))
 	if a.options.apiKey != "" {
-		anthropicClientOptions = append(anthropicClientOptions, option.WithAPIKey(a.options.apiKey))
+		clientOptions = append(clientOptions, option.WithAPIKey(a.options.apiKey))
 	}
 	if a.options.baseURL != "" {
-		anthropicClientOptions = append(anthropicClientOptions, option.WithBaseURL(a.options.baseURL))
+		clientOptions = append(clientOptions, option.WithBaseURL(a.options.baseURL))
 	}
-
 	for key, value := range a.options.headers {
-		anthropicClientOptions = append(anthropicClientOptions, option.WithHeader(key, value))
+		clientOptions = append(clientOptions, option.WithHeader(key, value))
 	}
-
 	if a.options.client != nil {
-		anthropicClientOptions = append(anthropicClientOptions, option.WithHTTPClient(a.options.client))
+		clientOptions = append(clientOptions, option.WithHTTPClient(a.options.client))
+	}
+	if a.options.vertexProject != "" && a.options.vertexLocation != "" {
+		var credentials *google.Credentials
+		if a.options.skipGoogleAuth {
+			credentials = &google.Credentials{TokenSource: &googleDummyTokenSource{}}
+		} else {
+			var err error
+			credentials, err = google.FindDefaultCredentials(context.Background())
+			if err != nil {
+				return nil, err
+			}
+		}
+
+		clientOptions = append(
+			clientOptions,
+			vertex.WithCredentials(
+				context.Background(),
+				a.options.vertexLocation,
+				a.options.vertexProject,
+				credentials,
+			),
+		)
 	}
 	return languageModel{
 		modelID:  modelID,
 		provider: a.options.name,
 		options:  a.options,
-		client:   anthropic.NewClient(anthropicClientOptions...),
+		client:   anthropic.NewClient(clientOptions...),
 	}, nil
 }
 

anthropic/google.go

@@ -0,0 +1,11 @@
+package anthropic
+
+import (
+	"golang.org/x/oauth2"
+)
+
+type googleDummyTokenSource struct{}
+
+func (googleDummyTokenSource) Token() (*oauth2.Token, error) {
+	return &oauth2.Token{AccessToken: "dummy-token"}, nil
+}

go.mod

@@ -3,6 +3,7 @@ module github.com/charmbracelet/fantasy
 go 1.24.5
 
 require (
+	cloud.google.com/go/auth v0.9.3
 	github.com/anthropics/anthropic-sdk-go v1.10.0
 	github.com/charmbracelet/x/exp/slice v0.0.0-20250904123553-b4e2667e5ad5
 	github.com/charmbracelet/x/json v0.2.0
@@ -12,17 +13,21 @@ require (
 	github.com/openai/openai-go/v2 v2.3.0
 	github.com/stretchr/testify v1.11.1
 	go.yaml.in/yaml/v4 v4.0.0-rc.2
+	golang.org/x/oauth2 v0.30.0
 	google.golang.org/genai v1.26.0
 	gopkg.in/dnaeon/go-vcr.v4 v4.0.6-0.20250923044825-7b4892dd3117
 )
 
 require (
 	cloud.google.com/go v0.116.0 // indirect
-	cloud.google.com/go/auth v0.9.3 // indirect
+	cloud.google.com/go/auth/oauth2adapt v0.2.4 // indirect
 	cloud.google.com/go/compute/metadata v0.5.0 // indirect
 	github.com/Azure/azure-sdk-for-go/sdk/azcore v1.17.0 // indirect
 	github.com/Azure/azure-sdk-for-go/sdk/internal v1.10.0 // indirect
 	github.com/davecgh/go-spew v1.1.1 // indirect
+	github.com/felixge/httpsnoop v1.0.4 // indirect
+	github.com/go-logr/logr v1.4.2 // indirect
+	github.com/go-logr/stdr v1.2.2 // indirect
 	github.com/golang/groupcache v0.0.0-20210331224755-41bb18bfe9da // indirect
 	github.com/google/go-cmp v0.6.0 // indirect
 	github.com/google/s2a-go v0.1.8 // indirect
@@ -34,12 +39,28 @@ require (
 	github.com/tidwall/pretty v1.2.1 // indirect
 	github.com/tidwall/sjson v1.2.5 // indirect
 	go.opencensus.io v0.24.0 // indirect
+	go.opentelemetry.io/contrib/instrumentation/google.golang.org/grpc/otelgrpc v0.54.0 // indirect
+	go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp v0.54.0 // indirect
+	go.opentelemetry.io/otel v1.29.0 // indirect
+	go.opentelemetry.io/otel/metric v1.29.0 // indirect
+	go.opentelemetry.io/otel/trace v1.29.0 // indirect
 	golang.org/x/crypto v0.40.0 // indirect
 	golang.org/x/net v0.41.0 // indirect
+	golang.org/x/sync v0.16.0 // indirect
 	golang.org/x/sys v0.34.0 // indirect
 	golang.org/x/text v0.27.0 // indirect
+	golang.org/x/time v0.6.0 // indirect
+	google.golang.org/api v0.197.0 // indirect
 	google.golang.org/genproto/googleapis/rpc v0.0.0-20240903143218-8af14fe29dc1 // indirect
 	google.golang.org/grpc v1.66.2 // indirect
 	google.golang.org/protobuf v1.34.2 // indirect
 	gopkg.in/yaml.v3 v3.0.1 // indirect
 )
+
+// NOTE(@andreynering): Temporarily pinning @fantasy branch with fixes:
+// https://github.com/charmbracelet/anthropic-sdk-go/commits/fantasy/
+replace github.com/anthropics/anthropic-sdk-go => github.com/charmbracelet/anthropic-sdk-go v0.0.0-20251010172108-7b952cdeeb9d
+
+// NOTE(@andreynering): Temporarily pinning @fantasy branch with fixes:
+// https://github.com/charmbracelet/anthropic-sdk-go/commits/fantasy/
+replace google.golang.org/genai => github.com/charmbracelet/go-genai v0.0.0-20251009191514-c6fa9e37d847

go.sum

@@ -3,6 +3,8 @@ cloud.google.com/go v0.116.0 h1:B3fRrSDkLRt5qSHWe40ERJvhvnQwdZiHu0bJOpldweE=
 cloud.google.com/go v0.116.0/go.mod h1:cEPSRWPzZEswwdr9BxE6ChEn01dWlTaF05LiC2Xs70U=
 cloud.google.com/go/auth v0.9.3 h1:VOEUIAADkkLtyfr3BLa3R8Ed/j6w1jTBmARx+wb5w5U=
 cloud.google.com/go/auth v0.9.3/go.mod h1:7z6VY+7h3KUdRov5F1i8NDP5ZzWKYmEPO842BgCsmTk=
+cloud.google.com/go/auth/oauth2adapt v0.2.4 h1:0GWE/FUsXhf6C+jAkWgYm7X9tK8cuEIfy19DBn6B6bY=
+cloud.google.com/go/auth/oauth2adapt v0.2.4/go.mod h1:jC/jOpwFP6JBxhB3P5Rr0a9HLMC/Pe3eaL4NmdvqPtc=
 cloud.google.com/go/compute/metadata v0.5.0 h1:Zr0eK8JbFv6+Wi4ilXAR8FJ3wyNdpxHKJNPos6LTZOY=
 cloud.google.com/go/compute/metadata v0.5.0/go.mod h1:aHnloV2TPI38yx4s9+wAZhHykWvVCfu7hQbF+9CWoiY=
 github.com/Azure/azure-sdk-for-go/sdk/azcore v1.17.0 h1:g0EZJwz7xkXQiZAI5xi9f3WWFYBlX1CPTrR+NDToRkQ=
@@ -14,9 +16,11 @@ github.com/Azure/azure-sdk-for-go/sdk/internal v1.10.0/go.mod h1:iZDifYGJTIgIIkY
 github.com/AzureAD/microsoft-authentication-library-for-go v1.2.2 h1:XHOnouVk1mxXfQidrMEnLlPk9UMeRtyBTnEFtxkV0kU=
 github.com/AzureAD/microsoft-authentication-library-for-go v1.2.2/go.mod h1:wP83P5OoQ5p6ip3ScPr0BAq0BvuPAvacpEuSzyouqAI=
 github.com/BurntSushi/toml v0.3.1/go.mod h1:xHWCNGjB5oqiDr8zfno3MHue2Ht5sIBksp03qcyfWMU=
-github.com/anthropics/anthropic-sdk-go v1.10.0 h1:jDKQTfC0miIEj21eMmPrNSLKTNdNa3nHZOhd4wZz1cI=
-github.com/anthropics/anthropic-sdk-go v1.10.0/go.mod h1:WTz31rIUHUHqai2UslPpw5CwXrQP3geYBioRV4WOLvE=
 github.com/census-instrumentation/opencensus-proto v0.2.1/go.mod h1:f6KPmirojxKA12rnyqOA5BBL4O983OfeGPqjHWSTneU=
+github.com/charmbracelet/anthropic-sdk-go v0.0.0-20251010172108-7b952cdeeb9d h1:qP7F7r7aVY7AReYHHgkQ79weuUEZK7zXtDtSEydYb0w=
+github.com/charmbracelet/anthropic-sdk-go v0.0.0-20251010172108-7b952cdeeb9d/go.mod h1:WTz31rIUHUHqai2UslPpw5CwXrQP3geYBioRV4WOLvE=
+github.com/charmbracelet/go-genai v0.0.0-20251009191514-c6fa9e37d847 h1:Oyo6YZ59iygXWNUlRozIOFHO4WUG9cNFhiUYCTq4AnU=
+github.com/charmbracelet/go-genai v0.0.0-20251009191514-c6fa9e37d847/go.mod h1:7pAilaICJlQBonjKKJNhftDFv3SREhZcTe9F6nRcjbg=
 github.com/charmbracelet/x/exp/slice v0.0.0-20250904123553-b4e2667e5ad5 h1:DTSZxdV9qQagD4iGcAt9RgaRBZtJl01bfKgdLzUzUPI=
 github.com/charmbracelet/x/exp/slice v0.0.0-20250904123553-b4e2667e5ad5/go.mod h1:vI5nDVMWi6veaYH+0Fmvpbe/+cv/iJfMntdh+N0+Tms=
 github.com/charmbracelet/x/json v0.2.0 h1:DqB+ZGx2h+Z+1s98HOuOyli+i97wsFQIxP2ZQANTPrQ=
@@ -30,6 +34,13 @@ github.com/envoyproxy/go-control-plane v0.9.0/go.mod h1:YTl/9mNaCwkRvm6d1a2C3ymF
 github.com/envoyproxy/go-control-plane v0.9.1-0.20191026205805-5f8ba28d4473/go.mod h1:YTl/9mNaCwkRvm6d1a2C3ymFceY/DCBVvsKhRF0iEA4=
 github.com/envoyproxy/go-control-plane v0.9.4/go.mod h1:6rpuAdCZL397s3pYoYcLgu1mIlRU8Am5FuJP05cCM98=
 github.com/envoyproxy/protoc-gen-validate v0.1.0/go.mod h1:iSmxcyjqTsJpI2R4NaDN7+kN2VEUnK/pcBlmesArF7c=
+github.com/felixge/httpsnoop v1.0.4 h1:NFTV2Zj1bL4mc9sqWACXbQFVBBg2W3GPvqp8/ESS2Wg=
+github.com/felixge/httpsnoop v1.0.4/go.mod h1:m8KPJKqk1gH5J9DgRY2ASl2lWCfGKXixSwevea8zH2U=
+github.com/go-logr/logr v1.2.2/go.mod h1:jdQByPbusPIv2/zmleS9BjJVeZ6kBagPoEUsqbVz/1A=
+github.com/go-logr/logr v1.4.2 h1:6pFjapn8bFcIbiKo3XT4j/BhANplGihG6tvd+8rYgrY=
+github.com/go-logr/logr v1.4.2/go.mod h1:9T104GzyrTigFIr8wt5mBrctHMim0Nb2HLGrmQ40KvY=
+github.com/go-logr/stdr v1.2.2 h1:hSWxHoqTgW2S2qGc0LTAI563KZ5YKYRhT3MFKZMbjag=
+github.com/go-logr/stdr v1.2.2/go.mod h1:mMo/vtBO5dYbehREoey6XUKy/eSumjCCveDpRre4VKE=
 github.com/go-viper/mapstructure/v2 v2.4.0 h1:EBsztssimR/CONLSZZ04E8qAkxNYq4Qp9LvH92wZUgs=
 github.com/go-viper/mapstructure/v2 v2.4.0/go.mod h1:oJDH3BJKyqBA2TXFhDsKDGDTlndYOZ6rGS0BRZIxGhM=
 github.com/golang-jwt/jwt/v5 v5.2.1 h1:OuVbFODueb089Lh128TAcimifWaLhJwVflnrgM17wHk=
@@ -48,6 +59,8 @@ github.com/golang/protobuf v1.4.0-rc.4.0.20200313231945-b860323f09d0/go.mod h1:W
 github.com/golang/protobuf v1.4.0/go.mod h1:jodUvKwWbYaEsadDk5Fwe5c77LiNKVO9IDvqG2KuDX0=
 github.com/golang/protobuf v1.4.1/go.mod h1:U8fpvMrcmy5pZrNK1lt4xCsGvpyWQ/VVv6QDs8UjoX8=
 github.com/golang/protobuf v1.4.3/go.mod h1:oDoupMAO8OvCJWAcko0GGGIgR6R6ocIYbsSw735rRwI=
+github.com/golang/protobuf v1.5.4 h1:i7eJL8qZTpSEXOPTxNKhASYpMn+8e5Q6AdndVa1dWek=
+github.com/golang/protobuf v1.5.4/go.mod h1:lnTiLA8Wa4RWRcIUkrtSVa5nRhsEGBg48fD6rSs7xps=
 github.com/google/go-cmp v0.2.0/go.mod h1:oXzfMopK8JAjlY9xF4vHSVASa0yLyX7SntLO5aqRK0M=
 github.com/google/go-cmp v0.3.0/go.mod h1:8QqcDgzrUqlUb/G2PQTWiueGozuR1884gddMywk6iLU=
 github.com/google/go-cmp v0.3.1/go.mod h1:8QqcDgzrUqlUb/G2PQTWiueGozuR1884gddMywk6iLU=
@@ -102,6 +115,16 @@ github.com/tidwall/sjson v1.2.5 h1:kLy8mja+1c9jlljvWTlSazM7cKDRfJuR/bOJhcY5NcY=
 github.com/tidwall/sjson v1.2.5/go.mod h1:Fvgq9kS/6ociJEDnK0Fk1cpYF4FIW6ZF7LAe+6jwd28=
 go.opencensus.io v0.24.0 h1:y73uSU6J157QMP2kn2r30vwW1A2W2WFwSCGnAVxeaD0=
 go.opencensus.io v0.24.0/go.mod h1:vNK8G9p7aAivkbmorf4v+7Hgx+Zs0yY+0fOtgBfjQKo=
+go.opentelemetry.io/contrib/instrumentation/google.golang.org/grpc/otelgrpc v0.54.0 h1:r6I7RJCN86bpD/FQwedZ0vSixDpwuWREjW9oRMsmqDc=
+go.opentelemetry.io/contrib/instrumentation/google.golang.org/grpc/otelgrpc v0.54.0/go.mod h1:B9yO6b04uB80CzjedvewuqDhxJxi11s7/GtiGa8bAjI=
+go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp v0.54.0 h1:TT4fX+nBOA/+LUkobKGW1ydGcn+G3vRw9+g5HwCphpk=
+go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp v0.54.0/go.mod h1:L7UH0GbB0p47T4Rri3uHjbpCFYrVrwc1I25QhNPiGK8=
+go.opentelemetry.io/otel v1.29.0 h1:PdomN/Al4q/lN6iBJEN3AwPvUiHPMlt93c8bqTG5Llw=
+go.opentelemetry.io/otel v1.29.0/go.mod h1:N/WtXPs1CNCUEx+Agz5uouwCba+i+bJGFicT8SR4NP8=
+go.opentelemetry.io/otel/metric v1.29.0 h1:vPf/HFWTNkPu1aYeIsc98l4ktOQaL6LeSoeV2g+8YLc=
+go.opentelemetry.io/otel/metric v1.29.0/go.mod h1:auu/QWieFVWx+DmQOUMgj0F8LHWdgalxXqvp7BII/W8=
+go.opentelemetry.io/otel/trace v1.29.0 h1:J/8ZNK4XgR7a21DZUAsbF8pZ5Jcw1VhACmnYt39JTi4=
+go.opentelemetry.io/otel/trace v1.29.0/go.mod h1:eHl3w0sp3paPkYstJOmAimxhiFXPg+MMTlEh3nsQgWQ=
 go.yaml.in/yaml/v4 v4.0.0-rc.2 h1:/FrI8D64VSr4HtGIlUtlFMGsm7H7pWTbj6vOLVZcA6s=
 go.yaml.in/yaml/v4 v4.0.0-rc.2/go.mod h1:aZqd9kCMsGL7AuUv/m/PvWLdg5sjJsZ4oHDEnfPPfY0=
 golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
@@ -121,6 +144,8 @@ golang.org/x/net v0.0.0-20201110031124-69a78807bb2b/go.mod h1:sp8m0HH+o8qH0wwXwY
 golang.org/x/net v0.41.0 h1:vBTly1HeNPEn3wtREYfy4GZ/NECgw2Cnl+nK6Nz3uvw=
 golang.org/x/net v0.41.0/go.mod h1:B/K4NNqkfmg07DQYrbwvSluqCJOOXwUjeb/5lOisjbA=
 golang.org/x/oauth2 v0.0.0-20180821212333-d2e6202438be/go.mod h1:N/0e6XlmueqKjAGxoOufVs8QHGRruUQn6yWY3a++T0U=
+golang.org/x/oauth2 v0.30.0 h1:dnDm7JmhM45NNpd8FDDeLhK6FwqbOf4MLCM9zb1BOHI=
+golang.org/x/oauth2 v0.30.0/go.mod h1:B++QgG3ZKulg6sRPGD/mqlHQs5rB3Ml9erfeDY7xKlU=
 golang.org/x/sync v0.0.0-20180314180146-1d60e4601c6f/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
 golang.org/x/sync v0.0.0-20181108010431-42b317875d0f/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
 golang.org/x/sync v0.0.0-20190423024810-112230192c58/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
@@ -136,16 +161,18 @@ golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
 golang.org/x/text v0.3.3/go.mod h1:5Zoc/QRtKVWzQhOtBMvqHzDpF6irO9z98xDceosuGiQ=
 golang.org/x/text v0.27.0 h1:4fGWRpyh641NLlecmyl4LOe6yDdfaYNrGb2zdfo4JV4=
 golang.org/x/text v0.27.0/go.mod h1:1D28KMCvyooCX9hBiosv5Tz/+YLxj0j7XhWjpSUF7CU=
+golang.org/x/time v0.6.0 h1:eTDhh4ZXt5Qf0augr54TN6suAUudPcawVZeIAPU7D4U=
+golang.org/x/time v0.6.0/go.mod h1:3BpzKBy/shNhVucY/MWOyx10tF3SFh9QdLuxbVysPQM=
 golang.org/x/tools v0.0.0-20180917221912-90fa682c2a6e/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=
 golang.org/x/tools v0.0.0-20190114222345-bf090417da8b/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=
 golang.org/x/tools v0.0.0-20190226205152-f727befe758c/go.mod h1:9Yl7xja0Znq3iFh3HoIrodX9oNMXvdceNzlUR8zjMvY=
 golang.org/x/tools v0.0.0-20190311212946-11955173bddd/go.mod h1:LCzVGOaR6xXOjkQ3onu1FJEFr0SW1gC7cKk1uF8kGRs=
 golang.org/x/tools v0.0.0-20190524140312-2c0ae7006135/go.mod h1:RgjU9mgBXZiqYHBnxXauZ1Gv1EHHAz9KjViQ78xBX0Q=
 golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
+google.golang.org/api v0.197.0 h1:x6CwqQLsFiA5JKAiGyGBjc2bNtHtLddhJCE2IKuhhcQ=
+google.golang.org/api v0.197.0/go.mod h1:AuOuo20GoQ331nq7DquGHlU6d+2wN2fZ8O0ta60nRNw=
 google.golang.org/appengine v1.1.0/go.mod h1:EbEs0AVv82hx2wNQdGPgUI5lhzA/G0D9YwlJXL52JkM=
 google.golang.org/appengine v1.4.0/go.mod h1:xpcJRLb0r/rnEns0DIKYYv+WjYCduHsrkT7/EB5XEv4=
-google.golang.org/genai v1.26.0 h1:r4HGL54kFv/WCRMTAbZg05Ct+vXfhAbTRlXhFyBkEQo=
-google.golang.org/genai v1.26.0/go.mod h1:OClfdf+r5aaD+sCd4aUSkPzJItmg2wD/WON9lQnRPaY=
 google.golang.org/genproto v0.0.0-20180817151627-c66870c02cf8/go.mod h1:JiN7NxoALGmiZfu7CAH4rXhgtRTLTxftemlI0sWmxmc=
 google.golang.org/genproto v0.0.0-20190819201941-24fa4b261c55/go.mod h1:DMBHOl98Agz4BDEuKkezgsaosCRResVns1a3J2ZsMNc=
 google.golang.org/genproto v0.0.0-20200526211855-cb27e3aa2013/go.mod h1:NbSheEEYHJ7i3ixzK3sjbqSGDJWnxyFXZblF3eUsNvo=

google/README.md

@@ -0,0 +1,63 @@
+# Google Provider
+
+This document describes how to get an API keys for Google Gemini and Vertex.
+
+## Gemini
+
+Simply navigate to [this page](https://aistudio.google.com/apikey) in the
+Google AI Studio and create a new API key.
+
+## Vertex
+
+### Install `gcloud`
+
+Install the `gcloud` command line tool. Install via Homebrew, Nix, or download
+it from [here](https://cloud.google.com/sdk/docs/install).
+
+```bash
+# Homebrew
+brew install --cask google-cloud-sdk
+
+# Nix
+nix-env -iA nixpkgs.google-cloud-sdk
+```
+
+### Authenticate
+
+Then authenticate with your Google account:
+
+```bash
+gcloud auth login
+```
+
+### Create And Setup Project
+
+Navigate here to create a new project if you haven't already:
+https://console.cloud.google.com/projectcreate
+
+Alternatively, you can create a new project via the command line:
+
+```bash
+gcloud projects create {YOUR_PROJECT_ID} --name="{YOUR_PROJECT_NAME}"
+```
+
+Set the project on your machine:
+
+```bash
+gcloud config set project {YOUR_PROJECT_ID}
+```
+
+Enable the Vertex AI API:
+
+```bash
+gcloud services enable aiplatform.googleapis.com
+```
+
+### Setup Env
+
+Finally, you need to run this command to ensure that libraries will be able to
+find your credentials.
+
+```bash
+gcloud auth application-default login
+```

google/auth.go

@@ -0,0 +1,13 @@
+package google
+
+import (
+	"context"
+
+	"cloud.google.com/go/auth"
+)
+
+type dummyTokenProvider struct{}
+
+func (dummyTokenProvider) Token(ctx context.Context) (*auth.Token, error) {
+	return &auth.Token{Value: "dummy-token"}, nil
+}