feat(source/cloud-sql-admin): Add User agent and attach sqldmin in cloud-sql-admin source. (#1441)

## Description

---
1. This change introduces a userAgentRoundTripper that correctly
prepends our custom user agent to the existing User-Agent header
2. Moves sqladmin client to source.
3. Updated cloudsql tools for above support.
4. Add test cases to validate User agent.

## PR Checklist

---
> Thank you for opening a Pull Request! Before submitting your PR, there
are a
> few things you can do to make sure it goes smoothly:

- [x] Make sure you reviewed

[CONTRIBUTING.md](https://github.com/googleapis/genai-toolbox/blob/main/CONTRIBUTING.md)
- [x] Make sure to open an issue as a

[bug/issue](https://github.com/googleapis/genai-toolbox/issues/new/choose)
before writing your code! That way we can discuss the change, evaluate
  designs, and agree on the general idea
- [ ] Ensure the tests and linter pass
- [ ] Code coverage does not decrease (if any source code was changed)
- [x] Appropriate docs were updated (if necessary)
- [ ] Make sure to add `!` if this involve a breaking change

🛠️ Fixes #<issue_number_goes_here>

docs/en/resources/tools/cloudsql/cloudsqlgetinstances.md

@@ -9,7 +9,7 @@ description: >
 The `cloud-sql-get-instance` tool retrieves a Cloud SQL instance resource using the Cloud SQL Admin API.
 
 {{< notice info >}}
-This tool uses a `source` of kind `cloud-sql-admin`. The source automatically generates a bearer token on behalf of the user with the `https://www.googleapis.com/auth/sqlservice.admin` scope to authenticate requests.
+This tool uses a `source` of kind `cloud-sql-admin`.
 {{< /notice >}}
 
 ## Example
@@ -18,14 +18,14 @@ This tool uses a `source` of kind `cloud-sql-admin`. The source automatically ge
 tools:
   get-sql-instance:
     kind: cloud-sql-get-instance
-    description: "Get a Cloud SQL instance resource."
-    source: my-cloud-sql-source
+    source: my-cloud-sql-admin-source
+    description: "Gets a particular cloud sql instance."
 ```
 
 ## Reference
 
-| **field**   | **type** | **required** | **description**                                                                                                  |
-| ----------- | :------: | :----------: | ---------------------------------------------------------------------------------------------------------------- |
-| kind        |  string  |     true     | Must be "cloud-sql-get-instance".                                                                            |
-| description |  string  |     true     | A description of the tool.                                                                                       |
-| source      |  string  |     true     | The name of the `cloud-sql-admin` source to use.                                                                 |
+| **field**   | **type** | **required** | **description**                                  |
+| ----------- | :------: | :----------: | ------------------------------------------------ |
+| kind        |  string  |     true     | Must be "cloud-sql-get-instance".                |
+| source      |  string  |     true     | The name of the `cloud-sql-admin` source to use. |
+| description |  string  |     false    | A description of the tool.                       |

docs/en/resources/tools/cloudsql/cloudsqlwaitforoperation.md

@@ -32,8 +32,8 @@ tools:
 | ----------- | :------: | :----------: | ---------------------------------------------------------------------------------------------------------------- |
 | kind        |  string  |     true     | Must be "cloud-sql-wait-for-operation".                                                                          |
 | source      |  string  |     true     | The name of a `cloud-sql-admin` source to use for authentication.                                                |
-| description |  string  |    true      | A description of the tool.                                                                                       |
-| delay       | duration |    false     | The initial delay between polling requests (e.g., `3s`). Defaults to 3 seconds.                                  |
-| maxDelay    | duration |    false     | The maximum delay between polling requests (e.g., `4m`). Defaults to 4 minutes.                                  |
-| multiplier  |  float   |    false     | The multiplier for the polling delay. The delay is multiplied by this value after each request. Defaults to 2.0. |
-| maxRetries  |   int    |    false     | The maximum number of polling attempts before giving up. Defaults to 10.                                         |
+| description |  string  |     false    | A description of the tool.                                                                                       |
+| delay       | duration |     false    | The initial delay between polling requests (e.g., `3s`). Defaults to 3 seconds.                                  |
+| maxDelay    | duration |     false    | The maximum delay between polling requests (e.g., `4m`). Defaults to 4 minutes.                                  |
+| multiplier  |   float  |     false    | The multiplier for the polling delay. The delay is multiplied by this value after each request. Defaults to 2.0. |
+| maxRetries  |    int   |     false    | The maximum number of polling attempts before giving up. Defaults to 10.                                         |

internal/sources/cloudsqladmin/cloud_sql_admin.go

@@ -24,11 +24,32 @@ import (
 	"go.opentelemetry.io/otel/trace"
 	"golang.org/x/oauth2"
 	"golang.org/x/oauth2/google"
+	"google.golang.org/api/option"
 	sqladmin "google.golang.org/api/sqladmin/v1"
 )
 
 const SourceKind string = "cloud-sql-admin"
 
+type userAgentRoundTripper struct {
+	userAgent string
+	next      http.RoundTripper
+}
+
+func (rt *userAgentRoundTripper) RoundTrip(req *http.Request) (*http.Response, error) {
+	newReq := *req
+	newReq.Header = make(http.Header)
+	for k, v := range req.Header {
+		newReq.Header[k] = v
+	}
+	ua := newReq.Header.Get("User-Agent")
+	if ua == "" {
+		newReq.Header.Set("User-Agent", rt.userAgent)
+	} else {
+		newReq.Header.Set("User-Agent", rt.userAgent+" "+ua)
+	}
+	return rt.next.RoundTrip(&newReq)
+}
+
 // validate interface
 var _ sources.SourceConfig = Config{}
 
@@ -65,22 +86,36 @@ func (r Config) Initialize(ctx context.Context, tracer trace.Tracer) (sources.So
 
 	var client *http.Client
 	if r.UseClientOAuth {
-		client = nil
+		client = &http.Client{
+			Transport: &userAgentRoundTripper{
+				userAgent: ua,
+				next:      http.DefaultTransport,
+			},
+		}
 	} else {
 		// Use Application Default Credentials
 		creds, err := google.FindDefaultCredentials(ctx, sqladmin.SqlserviceAdminScope)
 		if err != nil {
 			return nil, fmt.Errorf("failed to find default credentials: %w", err)
 		}
-		client = oauth2.NewClient(ctx, creds.TokenSource)
+		baseClient := oauth2.NewClient(ctx, creds.TokenSource)
+		baseClient.Transport = &userAgentRoundTripper{
+			userAgent: ua,
+			next:      baseClient.Transport,
+		}
+		client = baseClient
+	}
+
+	service, err := sqladmin.NewService(ctx, option.WithHTTPClient(client))
+	if err != nil {
+		return nil, fmt.Errorf("error creating new sqladmin service: %w", err)
 	}
 
 	s := &Source{
 		Name:           r.Name,
 		Kind:           SourceKind,
 		BaseURL:        "https://sqladmin.googleapis.com",
-		Client:         client,
-		UserAgent:      ua,
+		Service:        service,
 		UseClientOAuth: r.UseClientOAuth,
 	}
 	return s, nil
@@ -92,8 +127,7 @@ type Source struct {
 	Name           string `yaml:"name"`
 	Kind           string `yaml:"kind"`
 	BaseURL        string
-	Client         *http.Client
-	UserAgent      string
+	Service        *sqladmin.Service
 	UseClientOAuth bool
 }
 
@@ -101,15 +135,17 @@ func (s *Source) SourceKind() string {
 	return SourceKind
 }
 
-func (s *Source) GetClient(ctx context.Context, accessToken string) (*http.Client, error) {
+func (s *Source) GetService(ctx context.Context, accessToken string) (*sqladmin.Service, error) {
 	if s.UseClientOAuth {
-		if accessToken == "" {
-			return nil, fmt.Errorf("client-side OAuth is enabled but no access token was provided")
-		}
 		token := &oauth2.Token{AccessToken: accessToken}
-		return oauth2.NewClient(ctx, oauth2.StaticTokenSource(token)), nil
+		client := oauth2.NewClient(ctx, oauth2.StaticTokenSource(token))
+		service, err := sqladmin.NewService(ctx, option.WithHTTPClient(client))
+		if err != nil {
+			return nil, fmt.Errorf("error creating new sqladmin service: %w", err)
+		}
+		return service, nil
 	}
-	return s.Client, nil
+	return s.Service, nil
 }
 
 func (s *Source) UseClientAuthorization() bool {

internal/tools/cloudsql/cloudsqlcreateusers/cloudsqlcreateusers.go

@@ -22,7 +22,6 @@ import (
 	"github.com/googleapis/genai-toolbox/internal/sources"
 	"github.com/googleapis/genai-toolbox/internal/sources/cloudsqladmin"
 	"github.com/googleapis/genai-toolbox/internal/tools"
-	"google.golang.org/api/option"
 	sqladmin "google.golang.org/api/sqladmin/v1"
 )
 
@@ -135,7 +134,7 @@ func (t Tool) Invoke(ctx context.Context, params tools.ParamValues, accessToken
 
 	iamUser, _ := paramsMap["iamUser"].(bool)
 
-	user := &sqladmin.User{
+	user := sqladmin.User{
 		Name: name,
 	}
 
@@ -150,19 +149,12 @@ func (t Tool) Invoke(ctx context.Context, params tools.ParamValues, accessToken
 		user.Password = password
 	}
 
-	client, err := t.Source.GetClient(ctx, string(accessToken))
+	service, err := t.Source.GetService(ctx, string(accessToken))
 	if err != nil {
 		return nil, err
 	}
 
-	service, err := sqladmin.NewService(ctx, option.WithHTTPClient(client))
-	if err != nil {
-		return nil, fmt.Errorf("error creating new sqladmin service: %w", err)
-	}
-
-	service.UserAgent = t.Source.UserAgent
-
-	resp, err := service.Users.Insert(project, instance, user).Do()
+	resp, err := service.Users.Insert(project, instance, &user).Do()
 	if err != nil {
 		return nil, fmt.Errorf("error creating user: %w", err)
 	}

internal/tools/cloudsql/cloudsqlgetinstances/cloudsqlgetinstances.go

@@ -22,8 +22,6 @@ import (
 	"github.com/googleapis/genai-toolbox/internal/sources"
 	"github.com/googleapis/genai-toolbox/internal/sources/cloudsqladmin"
 	"github.com/googleapis/genai-toolbox/internal/tools"
-	"google.golang.org/api/option"
-	sqladmin "google.golang.org/api/sqladmin/v1"
 )
 
 const kind string = "cloud-sql-get-instance"
@@ -46,7 +44,7 @@ func newConfig(ctx context.Context, name string, decoder *yaml.Decoder) (tools.T
 type Config struct {
 	Name         string   `yaml:"name" validate:"required"`
 	Kind         string   `yaml:"kind" validate:"required"`
-	Description  string   `yaml:"description" validate:"required"`
+	Description  string   `yaml:"description"`
 	Source       string   `yaml:"source" validate:"required"`
 	AuthRequired []string `yaml:"authRequired"`
 }
@@ -80,9 +78,14 @@ func (cfg Config) Initialize(srcs map[string]sources.Source) (tools.Tool, error)
 	inputSchema := allParameters.McpManifest()
 	inputSchema.Required = []string{"projectId", "instanceId"}
 
+	description := cfg.Description
+	if description == "" {
+		description = "Gets a particular cloud sql instance."
+	}
+
 	mcpManifest := tools.McpManifest{
 		Name:        cfg.Name,
-		Description: cfg.Description,
+		Description: description,
 		InputSchema: inputSchema,
 	}
 
@@ -123,17 +126,11 @@ func (t Tool) Invoke(ctx context.Context, params tools.ParamValues, accessToken
 		return nil, fmt.Errorf("missing 'instanceId' parameter")
 	}
 
-	client, err := t.Source.GetClient(ctx, string(accessToken))
+	service, err := t.Source.GetService(ctx, string(accessToken))
 	if err != nil {
 		return nil, err
 	}
 
-	service, err := sqladmin.NewService(ctx, option.WithHTTPClient(client))
-	if err != nil {
-		return nil, fmt.Errorf("error creating new sqladmin service: %w", err)
-	}
-	service.UserAgent = t.Source.UserAgent
-
 	resp, err := service.Instances.Get(projectId, instanceId).Do()
 	if err != nil {
 		return nil, fmt.Errorf("error getting instance: %w", err)

internal/tools/cloudsql/cloudsqllistinstances/cloudsqllistinstances.go

@@ -16,10 +16,7 @@ package cloudsqllistinstances
 
 import (
 	"context"
-	"encoding/json"
 	"fmt"
-	"io"
-	"net/http"
 
 	"github.com/goccy/go-yaml"
 	"github.com/googleapis/genai-toolbox/internal/sources"
@@ -123,48 +120,34 @@ func (t Tool) Invoke(ctx context.Context, params tools.ParamValues, accessToken
 		return nil, fmt.Errorf("missing 'project' parameter")
 	}
 
-	client, err := t.source.GetClient(ctx, string(accessToken))
+	service, err := t.source.GetService(ctx, string(accessToken))
 	if err != nil {
 		return nil, err
 	}
 
-	urlString := fmt.Sprintf("%s/v1/projects/%s/instances", t.source.BaseURL, project)
-	req, err := http.NewRequestWithContext(ctx, http.MethodGet, urlString, nil)
+	resp, err := service.Instances.List(project).Do()
 	if err != nil {
-		return nil, fmt.Errorf("error creating request: %w", err)
+		return nil, fmt.Errorf("error listing instances: %w", err)
 	}
 
-	resp, err := client.Do(req)
-	if err != nil {
-		return nil, fmt.Errorf("error making HTTP request: %w", err)
-	}
-	defer resp.Body.Close()
-
-	body, err := io.ReadAll(resp.Body)
-	if err != nil {
-		return nil, fmt.Errorf("error reading response body: %w", err)
-	}
-
-	if resp.StatusCode != http.StatusOK {
-		return nil, fmt.Errorf("unexpected status code: %d, response body: %s", resp.StatusCode, string(body))
-	}
-
-	var v struct {
-		Items []struct {
-			Name         string `json:"name"`
-			InstanceType string `json:"instanceType"`
-		} `json:"items"`
-	}
-
-	if err := json.Unmarshal(body, &v); err != nil {
-		return nil, fmt.Errorf("error unmarshaling response body: %w", err)
-	}
-
-	if v.Items == nil {
+	if resp.Items == nil {
 		return []any{}, nil
 	}
 
-	return v.Items, nil
+	type instanceInfo struct {
+		Name         string `json:"name"`
+		InstanceType string `json:"instanceType"`
+	}
+
+	var instances []instanceInfo
+	for _, item := range resp.Items {
+		instances = append(instances, instanceInfo{
+			Name:         item.Name,
+			InstanceType: item.InstanceType,
+		})
+	}
+
+	return instances, nil
 }
 
 // ParseParams parses the parameters for the tool.

internal/tools/cloudsql/cloudsqlwaitforoperation/cloudsqlwaitforoperation.go

@@ -27,8 +27,6 @@ import (
 	"github.com/googleapis/genai-toolbox/internal/sources"
 	"github.com/googleapis/genai-toolbox/internal/sources/cloudsqladmin"
 	"github.com/googleapis/genai-toolbox/internal/tools"
-	"google.golang.org/api/option"
-	sqladmin "google.golang.org/api/sqladmin/v1"
 )
 
 const kind string = "cloud-sql-wait-for-operation"
@@ -93,7 +91,7 @@ type Config struct {
 	Name         string   `yaml:"name" validate:"required"`
 	Kind         string   `yaml:"kind" validate:"required"`
 	Source       string   `yaml:"source" validate:"required"`
-	Description  string   `yaml:"description" validate:"required"`
+	Description  string   `yaml:"description"`
 	AuthRequired []string `yaml:"authRequired"`
 	BaseURL      string   `yaml:"baseURL"`
 
@@ -133,9 +131,14 @@ func (cfg Config) Initialize(srcs map[string]sources.Source) (tools.Tool, error)
 	inputSchema := allParameters.McpManifest()
 	inputSchema.Required = []string{"project", "operation"}
 
+	description := cfg.Description
+	if description == "" {
+		description = "This will poll on operations API until the operation is done. For checking operation status we need projectId and operationId. Once instance is created give follow up steps on how to use the variables to bring data plane MCP server up in local and remote setup."
+	}
+
 	mcpManifest := tools.McpManifest{
 		Name:        cfg.Name,
-		Description: cfg.Description,
+		Description: description,
 		InputSchema: inputSchema,
 	}
 
@@ -219,16 +222,11 @@ func (t Tool) Invoke(ctx context.Context, params tools.ParamValues, accessToken
 		return nil, fmt.Errorf("missing 'operation' parameter")
 	}
 
-	client, err := t.Source.GetClient(ctx, string(accessToken))
+	service, err := t.Source.GetService(ctx, string(accessToken))
 	if err != nil {
 		return nil, err
 	}
 
-	service, err := sqladmin.NewService(ctx, option.WithHTTPClient(client))
-	if err != nil {
-		return nil, fmt.Errorf("error creating new sqladmin service: %w", err)
-	}
-
 	ctx, cancel := context.WithTimeout(ctx, 30*time.Minute)
 	defer cancel()
 
@@ -389,14 +387,10 @@ func (t Tool) generateCloudSQLConnectionMessage(opResponse map[string]any) (stri
 }
 
 func (t Tool) fetchInstanceData(ctx context.Context, project, instance string) (map[string]any, error) {
-	client, err := t.Source.GetClient(ctx, "")
+	service, err := t.Source.GetService(ctx, "")
 	if err != nil {
 		return nil, err
 	}
-	service, err := sqladmin.NewService(ctx, option.WithHTTPClient(client))
-	if err != nil {
-		return nil, fmt.Errorf("error creating new sqladmin service: %w", err)
-	}
 
 	resp, err := service.Instances.Get(project, instance).Do()
 	if err != nil {

tests/cloudsql/cloud_sql_create_users_test.go

@@ -62,6 +62,10 @@ type masterCreateUserHandler struct {
 }
 
 func (h *masterCreateUserHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+	if !strings.Contains(r.UserAgent(), "genai-toolbox/") {
+		h.t.Errorf("User-Agent header not found")
+	}
+
 	var body userCreateRequest
 	if err := json.NewDecoder(r.Body).Decode(&body); err != nil {
 		h.t.Fatalf("failed to decode request body: %v", err)

tests/cloudsql/cloud_sql_get_instances_test.go

@@ -59,12 +59,17 @@ type instance struct {
 type handler struct {
 	mu        sync.Mutex
 	instances map[string]*instance
+	t         *testing.T
 }
 
 func (h *handler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 	h.mu.Lock()
 	defer h.mu.Unlock()
 
+	if !strings.Contains(r.UserAgent(), "genai-toolbox/") {
+		h.t.Errorf("User-Agent header not found")
+	}
+
 	if !strings.HasPrefix(r.URL.Path, "/v1/projects/") {
 		http.Error(w, "unexpected path", http.StatusBadRequest)
 		return
@@ -92,6 +97,7 @@ func TestGetInstancesToolEndpoints(t *testing.T) {
 		instances: map[string]*instance{
 			"instance-1": {Name: "instance-1", Kind: "sql#instance"},
 		},
+		t: t,
 	}
 	server := httptest.NewServer(h)
 	defer server.Close()

tests/cloudsql/cloudsql_list_instances_test.go

@@ -49,6 +49,9 @@ func (t *transport) RoundTrip(req *http.Request) (*http.Response, error) {
 
 func TestListInstance(t *testing.T) {
 	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		if !strings.Contains(r.UserAgent(), "genai-toolbox/") {
+			t.Errorf("User-Agent header not found")
+		}
 		if r.URL.Path != "/v1/projects/test-project/instances" {
 			http.Error(w, fmt.Sprintf("unexpected path: got %q", r.URL.Path), http.StatusBadRequest)
 			return

tests/cloudsql/cloudsql_wait_for_operation_test.go

@@ -75,12 +75,17 @@ type cloudsqlHandler struct {
 	mu         sync.Mutex
 	operations map[string]*cloudsqlOperation
 	instances  map[string]*cloudsqlInstance
+	t          *testing.T
 }
 
 func (h *cloudsqlHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 	h.mu.Lock()
 	defer h.mu.Unlock()
 
+	if !strings.Contains(r.UserAgent(), "genai-toolbox/") {
+		h.t.Errorf("User-Agent header not found")
+	}
+
 	if match, _ := regexp.MatchString("/v1/projects/p1/operations/.*", r.URL.Path); match {
 		parts := regexp.MustCompile("/").Split(r.URL.Path, -1)
 		opName := parts[len(parts)-1]
@@ -139,6 +144,7 @@ func TestCloudSQLWaitToolEndpoints(t *testing.T) {
 		instances: map[string]*cloudsqlInstance{
 			"i1": {Region: "r1", DatabaseVersion: "POSTGRES_13"},
 		},
+		t: t,
 	}
 	server := httptest.NewServer(h)
 	defer server.Close()