feat(tools/postgres-list-views): add new postgres-list-views tool (#1709)

## Description

Adds a read-only PostgreSQL custom list_views tool, that returns the
details of views present in database. Each row includes: schema_name,
view_name, owner_name
Test Output:

<img width="2433" height="1274" alt="Screenshot 2025-10-19 at 3 59
31 PM"
src="https://github.com/user-attachments/assets/76e1e994-390a-4239-aba7-0d02253bbcc4"
/>
<img width="2533" height="1017" alt="Screenshot 2025-10-19 at 4 07
25 PM"
src="https://github.com/user-attachments/assets/537fbddd-d862-4044-a09b-cb9f180c21fa"
/>

## 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
- [x] Ensure the tests and linter pass
- [x] Code coverage does not decrease (if any source code was changed)
- [x] Appropriate docs were updated (if necessary)
- [x] Make sure to add `!` if this involve a breaking change

🛠️ Fixes #1738

Co-authored-by: Averi Kitsch <akitsch@google.com>

cmd/root.go

@@ -153,6 +153,7 @@ import (
 	_ "github.com/googleapis/genai-toolbox/internal/tools/postgres/postgreslistavailableextensions"
 	_ "github.com/googleapis/genai-toolbox/internal/tools/postgres/postgreslistinstalledextensions"
 	_ "github.com/googleapis/genai-toolbox/internal/tools/postgres/postgreslisttables"
+	_ "github.com/googleapis/genai-toolbox/internal/tools/postgres/postgreslistviews"
 	_ "github.com/googleapis/genai-toolbox/internal/tools/postgres/postgressql"
 	_ "github.com/googleapis/genai-toolbox/internal/tools/redis"
 	_ "github.com/googleapis/genai-toolbox/internal/tools/serverlessspark/serverlesssparkgetbatch"

cmd/root_test.go

@@ -1397,7 +1397,7 @@ func TestPrebuiltTools(t *testing.T) {
 			wantToolset: server.ToolsetConfigs{
 				"alloydb_postgres_database_tools": tools.ToolsetConfig{
 					Name:      "alloydb_postgres_database_tools",
-					ToolNames: []string{"execute_sql", "list_tables", "list_active_queries", "list_available_extensions", "list_installed_extensions", "list_autovacuum_configurations", "list_memory_configurations", "list_top_bloated_tables", "list_replication_slots", "list_invalid_indexes", "get_query_plan"},
+					ToolNames: []string{"execute_sql", "list_tables", "list_active_queries", "list_available_extensions", "list_installed_extensions", "list_autovacuum_configurations", "list_memory_configurations", "list_top_bloated_tables", "list_replication_slots", "list_invalid_indexes", "get_query_plan", "list_views"},
 				},
 			},
 		},
@@ -1427,7 +1427,7 @@ func TestPrebuiltTools(t *testing.T) {
 			wantToolset: server.ToolsetConfigs{
 				"cloud_sql_postgres_database_tools": tools.ToolsetConfig{
 					Name:      "cloud_sql_postgres_database_tools",
-					ToolNames: []string{"execute_sql", "list_tables", "list_active_queries", "list_available_extensions", "list_installed_extensions", "list_autovacuum_configurations", "list_memory_configurations", "list_top_bloated_tables", "list_replication_slots", "list_invalid_indexes", "get_query_plan"},
+					ToolNames: []string{"execute_sql", "list_tables", "list_active_queries", "list_available_extensions", "list_installed_extensions", "list_autovacuum_configurations", "list_memory_configurations", "list_top_bloated_tables", "list_replication_slots", "list_invalid_indexes", "get_query_plan", "list_views"},
 				},
 			},
 		},
@@ -1527,7 +1527,7 @@ func TestPrebuiltTools(t *testing.T) {
 			wantToolset: server.ToolsetConfigs{
 				"postgres_database_tools": tools.ToolsetConfig{
 					Name:      "postgres_database_tools",
-					ToolNames: []string{"execute_sql", "list_tables", "list_active_queries", "list_available_extensions", "list_installed_extensions", "list_autovacuum_configurations", "list_memory_configurations", "list_top_bloated_tables", "list_replication_slots", "list_invalid_indexes", "get_query_plan"},
+					ToolNames: []string{"execute_sql", "list_tables", "list_active_queries", "list_available_extensions", "list_installed_extensions", "list_autovacuum_configurations", "list_memory_configurations", "list_top_bloated_tables", "list_replication_slots", "list_invalid_indexes", "get_query_plan", "list_views"},
 				},
 			},
 		},

docs/en/reference/prebuilt-tools.md

@@ -43,6 +43,8 @@ details on how to connect your AI tools (IDEs) to databases via Toolbox and MCP.
     *   `list_replication_slots`: Lists replication slots in the database.
     *   `list_invalid_indexes`: Lists invalid indexes in the database.
     *   `get_query_plan`: Generate the execution plan of a statement.
+    *   `list_views`: Lists views in the database from pg_views with a default
+        limit of 50 rows. Returns schemaname, viewname and the ownername.
 
 ## AlloyDB Postgres Admin
 
@@ -210,6 +212,8 @@ details on how to connect your AI tools (IDEs) to databases via Toolbox and MCP.
     *   `list_replication_slots`: Lists replication slots in the database.
     *   `list_invalid_indexes`: Lists invalid indexes in the database.
     *   `get_query_plan`: Generate the execution plan of a statement.
+    *   `list_views`: Lists views in the database from pg_views with a default
+        limit of 50 rows. Returns schemaname, viewname and the ownername.
 
 ## Cloud SQL for PostgreSQL Observability
 
@@ -492,6 +496,8 @@ details on how to connect your AI tools (IDEs) to databases via Toolbox and MCP.
     *   `list_replication_slots`: Lists replication slots in the database.
     *   `list_invalid_indexes`: Lists invalid indexes in the database.
     *   `get_query_plan`: Generate the execution plan of a statement.
+    *   `list_views`: Lists views in the database from pg_views with a default
+        limit of 50 rows. Returns schemaname, viewname and the ownername.
 
 ## Google Cloud Serverless for Apache Spark
 

docs/en/resources/sources/alloydb-pg.md

@@ -45,6 +45,9 @@ cluster][alloydb-free-trial].
 - [`postgres-list-installed-extensions`](../tools/postgres/postgres-list-installed-extensions.md)
   List installed extensions in a PostgreSQL database.
 
+- [`postgres-list-views`](../tools/postgres/postgres-list-views.md)
+  List views in an AlloyDB for PostgreSQL database.
+
 ### Pre-built Configurations
 
 - [AlloyDB using MCP](https://googleapis.github.io/genai-toolbox/how-to/connect-ide/alloydb_pg_mcp/)

docs/en/resources/sources/cloud-sql-pg.md

@@ -41,6 +41,9 @@ to a database by following these instructions][csql-pg-quickstart].
 - [`postgres-list-installed-extensions`](../tools/postgres/postgres-list-installed-extensions.md)
   List installed extensions in a PostgreSQL database.
 
+- [`postgres-list-views`](../tools/postgres/postgres-list-views.md)
+  List views in a PostgreSQL database.
+
 ### Pre-built Configurations
 
 - [Cloud SQL for Postgres using

docs/en/resources/sources/postgres.md

@@ -35,6 +35,9 @@ reputation for reliability, feature robustness, and performance.
 - [`postgres-list-installed-extensions`](../tools/postgres/postgres-list-installed-extensions.md)
   List installed extensions in a PostgreSQL database.
 
+- [`postgres-list-views`](../tools/postgres/postgres-list-views.md)
+  List views in a PostgreSQL database.
+
 ### Pre-built Configurations
 
 - [PostgreSQL using MCP](https://googleapis.github.io/genai-toolbox/how-to/connect-ide/postgres_mcp/)

docs/en/resources/tools/postgres/postgres-list-views.md

@@ -0,0 +1,40 @@
+---
+title: "postgres-list-views"
+type: docs
+weight: 1
+description: >
+  The "postgres-list-views" tool lists views in a Postgres database, with a default limit of 50 rows.
+aliases:
+- /resources/tools/postgres-list-views
+---
+
+## About
+
+The `postgres-list-views` tool retrieves a list of top N (default 50) views from a Postgres database, excluding those in system schemas (`pg_catalog`, `information_schema`). It's compatible with any of the following sources:
+
+- [alloydb-postgres](../../sources/alloydb-pg.md)
+- [cloud-sql-postgres](../../sources/cloud-sql-pg.md)
+- [postgres](../../sources/postgres.md)
+
+`postgres-list-views` lists detailed view information (schemaname, viewname, ownername) as JSON for views in a database. The tool takes the following input parameters:
+
+- `viewname` (optional): A string pattern to filter view names. The search uses SQL 
+   LIKE operator to filter the views. Default: `""`
+- `limit` (optional): The maximum number of rows to return. Default: `50`.
+
+## Example
+
+```yaml
+tools:
+  list_views:
+    kind: postgres-list-views
+    source: cloudsql-pg-source
+```
+
+## Reference
+
+| **field**   | **type** | **required**  | **description**                                      |
+|-------------|:--------:|:-------------:|------------------------------------------------------|
+| kind        |  string  |     true      | Must be "postgres-list-views".                      |
+| source      |  string  |     true      | Name of the source the SQL should execute on.        |
+| description |  string  |     false     | Description of the tool that is passed to the agent. |

internal/prebuiltconfigs/tools/alloydb-postgres.yaml

@@ -156,6 +156,9 @@ tools:
               description: "The SQL statement for which you want to generate plan (omit the EXPLAIN keyword)."
               required: true
 
+    list_views:
+        kind: postgres-list-views
+        source: alloydb-pg-source
 toolsets:
     alloydb_postgres_database_tools:
         - execute_sql
@@ -169,3 +172,4 @@ toolsets:
         - list_replication_slots
         - list_invalid_indexes
         - get_query_plan
+        - list_views

internal/prebuiltconfigs/tools/cloud-sql-postgres.yaml

@@ -155,6 +155,10 @@ tools:
               description: "The SQL statement for which you want to generate plan (omit the EXPLAIN keyword)."
               required: true
 
+    list_views:
+        kind: postgres-list-views
+        source: cloudsql-pg-source
+
 toolsets:
     cloud_sql_postgres_database_tools:
         - execute_sql
@@ -168,3 +172,4 @@ toolsets:
         - list_replication_slots
         - list_invalid_indexes
         - get_query_plan
+        - list_views

internal/prebuiltconfigs/tools/postgres.yaml

@@ -154,6 +154,10 @@ tools:
               description: "The SQL statement for which you want to generate plan (omit the EXPLAIN keyword)."
               required: true
 
+    list_views:
+        kind: postgres-list-views
+        source: postgresql-source
+
 toolsets:
     postgres_database_tools:
         - execute_sql
@@ -167,3 +171,4 @@ toolsets:
         - list_replication_slots
         - list_invalid_indexes
         - get_query_plan
+        - list_views

internal/tools/postgres/postgreslistviews/postgreslistviews.go

@@ -0,0 +1,186 @@
+// Copyright 2025 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package postgreslistviews
+
+import (
+	"context"
+	"fmt"
+
+	yaml "github.com/goccy/go-yaml"
+	"github.com/googleapis/genai-toolbox/internal/sources"
+	"github.com/googleapis/genai-toolbox/internal/sources/alloydbpg"
+	"github.com/googleapis/genai-toolbox/internal/sources/cloudsqlpg"
+	"github.com/googleapis/genai-toolbox/internal/sources/postgres"
+	"github.com/googleapis/genai-toolbox/internal/tools"
+	"github.com/jackc/pgx/v5/pgxpool"
+)
+
+const kind string = "postgres-list-views"
+
+const listViewsStatement = `
+			SELECT schemaname, viewname, viewowner
+			FROM pg_views
+			WHERE
+				schemaname NOT IN ('pg_catalog', 'information_schema')
+				AND ($1::text IS NULL OR viewname LIKE '%' || $1::text || '%')
+			ORDER BY viewname
+			LIMIT COALESCE($2::int, 50);
+`
+
+func init() {
+	if !tools.Register(kind, newConfig) {
+		panic(fmt.Sprintf("tool kind %q already registered", kind))
+	}
+}
+
+func newConfig(ctx context.Context, name string, decoder *yaml.Decoder) (tools.ToolConfig, error) {
+	actual := Config{Name: name}
+	if err := decoder.DecodeContext(ctx, &actual); err != nil {
+		return nil, err
+	}
+	return actual, nil
+}
+
+type compatibleSource interface {
+	PostgresPool() *pgxpool.Pool
+}
+
+// validate compatible sources are still compatible
+var _ compatibleSource = &alloydbpg.Source{}
+var _ compatibleSource = &cloudsqlpg.Source{}
+var _ compatibleSource = &postgres.Source{}
+
+var compatibleSources = [...]string{alloydbpg.SourceKind, cloudsqlpg.SourceKind, postgres.SourceKind}
+
+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"`
+	AuthRequired []string `yaml:"authRequired"`
+}
+
+// validate interface
+var _ tools.ToolConfig = Config{}
+
+func (cfg Config) ToolConfigKind() string {
+	return kind
+}
+
+func (cfg Config) Initialize(srcs map[string]sources.Source) (tools.Tool, error) {
+	// verify source exists
+	rawS, ok := srcs[cfg.Source]
+	if !ok {
+		return nil, fmt.Errorf("no source named %q configured", cfg.Source)
+	}
+
+	// verify the source is compatible
+	s, ok := rawS.(compatibleSource)
+	if !ok {
+		return nil, fmt.Errorf("invalid source for %q tool: source kind must be one of %q", kind, compatibleSources)
+	}
+
+	allParameters := tools.Parameters{
+		tools.NewStringParameterWithDefault("viewname", "", "Optional: A specific view name to search for."),
+		tools.NewIntParameterWithDefault("limit", 50, "Optional: The maximum number of rows to return."),
+	}
+	paramManifest := allParameters.Manifest()
+	description := cfg.Description
+	if description == "" {
+		description = "Lists views in the database from pg_views with a default limit of 50 rows. Returns schemaname, viewname and the ownername."
+	}
+	mcpManifest := tools.GetMcpManifest(cfg.Name, description, cfg.AuthRequired, allParameters)
+
+	// finish tool setup
+	return Tool{
+		name:         cfg.Name,
+		kind:         kind,
+		authRequired: cfg.AuthRequired,
+		allParams:    allParameters,
+		pool:         s.PostgresPool(),
+		manifest: tools.Manifest{
+			Description:  cfg.Description,
+			Parameters:   paramManifest,
+			AuthRequired: cfg.AuthRequired,
+		},
+		mcpManifest: mcpManifest,
+	}, nil
+}
+
+// validate interface
+var _ tools.Tool = Tool{}
+
+type Tool struct {
+	name         string           `yaml:"name"`
+	kind         string           `yaml:"kind"`
+	authRequired []string         `yaml:"authRequired"`
+	allParams    tools.Parameters `yaml:"allParams"`
+	pool         *pgxpool.Pool
+	manifest     tools.Manifest
+	mcpManifest  tools.McpManifest
+}
+
+func (t Tool) Invoke(ctx context.Context, params tools.ParamValues, accessToken tools.AccessToken) (any, error) {
+	paramsMap := params.AsMap()
+
+	newParams, err := tools.GetParams(t.allParams, paramsMap)
+	if err != nil {
+		return nil, fmt.Errorf("unable to extract standard params %w", err)
+	}
+	sliceParams := newParams.AsSlice()
+
+	results, err := t.pool.Query(ctx, listViewsStatement, sliceParams...)
+	if err != nil {
+		return nil, fmt.Errorf("unable to execute query: %w", err)
+	}
+	defer results.Close()
+
+	fields := results.FieldDescriptions()
+	var out []map[string]any
+
+	for results.Next() {
+		values, err := results.Values()
+		if err != nil {
+			return nil, fmt.Errorf("unable to parse row: %w", err)
+		}
+		rowMap := make(map[string]any)
+		for i, field := range fields {
+			rowMap[string(field.Name)] = values[i]
+		}
+		out = append(out, rowMap)
+	}
+
+	return out, nil
+}
+
+func (t Tool) ParseParams(data map[string]any, claims map[string]map[string]any) (tools.ParamValues, error) {
+	return tools.ParseParams(t.allParams, data, claims)
+}
+
+func (t Tool) Manifest() tools.Manifest {
+	return t.manifest
+}
+
+func (t Tool) McpManifest() tools.McpManifest {
+	return t.mcpManifest
+}
+
+func (t Tool) Authorized(verifiedAuthServices []string) bool {
+	return tools.IsAuthorized(t.authRequired, verifiedAuthServices)
+}
+
+func (t Tool) RequiresClientAuthorization() bool {
+	return false
+}

internal/tools/postgres/postgreslistviews/postgreslistviews_test.go

@@ -0,0 +1,95 @@
+// Copyright 2025 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package postgreslistviews_test
+
+import (
+	"testing"
+
+	yaml "github.com/goccy/go-yaml"
+	"github.com/google/go-cmp/cmp"
+	"github.com/googleapis/genai-toolbox/internal/server"
+	"github.com/googleapis/genai-toolbox/internal/testutils"
+	"github.com/googleapis/genai-toolbox/internal/tools/postgres/postgreslistviews"
+)
+
+func TestParseFromYamlPostgresListViews(t *testing.T) {
+	ctx, err := testutils.ContextWithNewLogger()
+	if err != nil {
+		t.Fatalf("unexpected error: %s", err)
+	}
+	tcs := []struct {
+		desc string
+		in   string
+		want server.ToolConfigs
+	}{
+		{
+			desc: "basic example",
+			in: `
+			tools:
+				example_tool:
+					kind: postgres-list-views
+					source: my-postgres-instance
+					description: some description
+					authRequired:
+						- my-google-auth-service
+						- other-auth-service
+			`,
+			want: server.ToolConfigs{
+				"example_tool": postgreslistviews.Config{
+					Name:         "example_tool",
+					Kind:         "postgres-list-views",
+					Source:       "my-postgres-instance",
+					Description:  "some description",
+					AuthRequired: []string{"my-google-auth-service", "other-auth-service"},
+				},
+			},
+		},
+		{
+			desc: "basic example",
+			in: `
+			tools:
+				example_tool:
+					kind: postgres-list-views
+					source: my-postgres-instance
+					description: some description
+			`,
+			want: server.ToolConfigs{
+				"example_tool": postgreslistviews.Config{
+					Name:         "example_tool",
+					Kind:         "postgres-list-views",
+					Source:       "my-postgres-instance",
+					Description:  "some description",
+					AuthRequired: []string{},
+				},
+			},
+		},
+	}
+	for _, tc := range tcs {
+		t.Run(tc.desc, func(t *testing.T) {
+			got := struct {
+				Tools server.ToolConfigs `yaml:"tools"`
+			}{}
+			// Parse contents
+			err := yaml.UnmarshalContext(ctx, testutils.FormatYaml(tc.in), &got)
+			if err != nil {
+				t.Fatalf("unable to unmarshal: %s", err)
+			}
+			if diff := cmp.Diff(tc.want, got.Tools); diff != "" {
+				t.Fatalf("incorrect parse: diff %v", diff)
+			}
+		})
+	}
+
+}

tests/postgres/postgres_integration_test.go

@@ -45,6 +45,7 @@ var (
 	PostgresListActiveQueriesToolKind       = "postgres-list-active-queries"
 	PostgresListInstalledExtensionsToolKind = "postgres-list-installed-extensions"
 	PostgresListAvailableExtensionsToolKind = "postgres-list-available-extensions"
+	PostgresListViewsToolKind               = "postgres-list-views"
 	PostgresDatabase                        = os.Getenv("POSTGRES_DATABASE")
 	PostgresHost                            = os.Getenv("POSTGRES_HOST")
 	PostgresPort                            = os.Getenv("POSTGRES_PORT")
@@ -104,6 +105,11 @@ func addPrebuiltToolConfig(t *testing.T, config map[string]any) map[string]any {
 		"description": "Lists available extensions in the database.",
 	}
 
+	tools["list_views"] = map[string]any{
+		"kind":   PostgresListViewsToolKind,
+		"source": "my-instance",
+	}
+
 	config["tools"] = tools
 	return config
 }
@@ -189,6 +195,7 @@ func TestPostgres(t *testing.T) {
 
 	// Run specific Postgres tool tests
 	runPostgresListTablesTest(t, tableNameParam, tableNameAuth)
+	runPostgresListViewsTest(t, ctx, pool, tableNameParam)
 	runPostgresListActiveQueriesTest(t, ctx, pool)
 	runPostgresListAvailableExtensionsTest(t)
 	runPostgresListInstalledExtensionsTest(t)
@@ -525,6 +532,94 @@ func runPostgresListActiveQueriesTest(t *testing.T, ctx context.Context, pool *p
 	wg.Wait()
 }
 
+func setUpPostgresViews(t *testing.T, ctx context.Context, pool *pgxpool.Pool, viewName, tableName string) func() {
+	createView := fmt.Sprintf("CREATE VIEW %s AS SELECT name FROM %s", viewName, tableName)
+	_, err := pool.Exec(ctx, createView)
+	if err != nil {
+		t.Fatalf("failed to create view: %v", err)
+	}
+	return func() {
+		dropView := fmt.Sprintf("DROP VIEW %s", viewName)
+		_, err := pool.Exec(ctx, dropView)
+		if err != nil {
+			t.Fatalf("failed to drop view: %v", err)
+		}
+	}
+}
+
+func runPostgresListViewsTest(t *testing.T, ctx context.Context, pool *pgxpool.Pool, tableName string) {
+	viewName1 := "test_view_1" + strings.ReplaceAll(uuid.New().String(), "-", "")
+	dropViewfunc1 := setUpPostgresViews(t, ctx, pool, viewName1, tableName)
+	defer dropViewfunc1()
+
+	invokeTcs := []struct {
+		name           string
+		requestBody    io.Reader
+		wantStatusCode int
+		want           string
+	}{
+		{
+			name:           "invoke list_views with newly created view",
+			requestBody:    bytes.NewBuffer([]byte(fmt.Sprintf(`{"viewname": "%s"}`, viewName1))),
+			wantStatusCode: http.StatusOK,
+			want:           fmt.Sprintf(`[{"schemaname":"public","viewname":"%s","viewowner":"postgres"}]`, viewName1),
+		},
+		{
+			name:           "invoke list_views with non-existent_view",
+			requestBody:    bytes.NewBuffer([]byte(`{"viewname": "non_existent_view"}`)),
+			wantStatusCode: http.StatusOK,
+			want:           `null`,
+		},
+	}
+	for _, tc := range invokeTcs {
+		t.Run(tc.name, func(t *testing.T) {
+			const api = "http://127.0.0.1:5000/api/tool/list_views/invoke"
+			req, err := http.NewRequest(http.MethodPost, api, tc.requestBody)
+			if err != nil {
+				t.Fatalf("unable to create request: %v", err)
+			}
+			req.Header.Add("Content-type", "application/json")
+			resp, err := http.DefaultClient.Do(req)
+			if err != nil {
+				t.Fatalf("unable to send request: %v", err)
+			}
+			defer resp.Body.Close()
+
+			if resp.StatusCode != tc.wantStatusCode {
+				body, _ := io.ReadAll(resp.Body)
+				t.Fatalf("wrong status code: got %d, want %d, body: %s", resp.StatusCode, tc.wantStatusCode, string(body))
+			}
+			if tc.wantStatusCode != http.StatusOK {
+				return
+			}
+
+			var bodyWrapper struct {
+				Result json.RawMessage `json:"result"`
+			}
+			if err := json.NewDecoder(resp.Body).Decode(&bodyWrapper); err != nil {
+				t.Fatalf("error decoding response wrapper: %v", err)
+			}
+
+			var resultString string
+			if err := json.Unmarshal(bodyWrapper.Result, &resultString); err != nil {
+				resultString = string(bodyWrapper.Result)
+			}
+
+			var got, want any
+			if err := json.Unmarshal([]byte(resultString), &got); err != nil {
+				t.Fatalf("failed to unmarshal nested result string: %v", err)
+			}
+			if err := json.Unmarshal([]byte(tc.want), &want); err != nil {
+				t.Fatalf("failed to unmarshal want string: %v", err)
+			}
+
+			if diff := cmp.Diff(want, got); diff != "" {
+				t.Errorf("Unexpected result (-want +got):\n%s", diff)
+			}
+		})
+	}
+}
+
 func runPostgresListAvailableExtensionsTest(t *testing.T) {
 	invokeTcs := []struct {
 		name           string