draft: add invoke interface to postgres source

## Description

---
Update out stream in `stdio` transport protocol.


**Before:** When `stdio=true`, log levels will automatically get set to
WARN (even if user explicitly set it as DEBUG or INFO). This is because
the DEBUG and INFO logger send logs to outStream. In `stdio`, server
MUST NOT write anything to `stdout` that is not a valid MCP message.

MCP specifications mentioned that "The server MAY write UTF-8 strings to
its standard error (stderr) for logging purposes. Client MAY capture,
forward, or ignore this logging."

**After:** When `stdio=true`, logger's DEBUG and INFO logger send logs
to outStream. This will still respect the `log-levels` set by user
(default as INFO).

cmd/root.go

@@ -655,20 +655,6 @@ func watchChanges(ctx context.Context, watchDirs map[string]bool, watchedFiles m
 	}
 }
 
-// updateLogLevel checks if Toolbox have to update the existing log level set by users.
-// stdio doesn't support "debug" and "info" logs.
-func updateLogLevel(stdio bool, logLevel string) bool {
-	if stdio {
-		switch strings.ToUpper(logLevel) {
-		case log.Debug, log.Info:
-			return true
-		default:
-			return false
-		}
-	}
-	return false
-}
-
 func resolveWatcherInputs(toolsFile string, toolsFiles []string, toolsFolder string) (map[string]bool, map[string]bool) {
 	var relevantFiles []string
 
@@ -697,10 +683,6 @@ func resolveWatcherInputs(toolsFile string, toolsFiles []string, toolsFolder str
 }
 
 func run(cmd *Command) error {
-	if updateLogLevel(cmd.cfg.Stdio, cmd.cfg.LogLevel.String()) {
-		cmd.cfg.LogLevel = server.StringLevel(log.Warn)
-	}
-
 	ctx, cancel := context.WithCancel(cmd.Context())
 	defer cancel()
 
@@ -724,16 +706,22 @@ func run(cmd *Command) error {
 		cancel()
 	}(ctx)
 
+	// If stdio, set logger's out stream (usually DEBUG and INFO logs) to errStream
+	loggerOut := cmd.outStream
+	if cmd.cfg.Stdio {
+		loggerOut = cmd.errStream
+	}
+
 	// Handle logger separately from config
 	switch strings.ToLower(cmd.cfg.LoggingFormat.String()) {
 	case "json":
-		logger, err := log.NewStructuredLogger(cmd.outStream, cmd.errStream, cmd.cfg.LogLevel.String())
+		logger, err := log.NewStructuredLogger(loggerOut, cmd.errStream, cmd.cfg.LogLevel.String())
 		if err != nil {
 			return fmt.Errorf("unable to initialize logger: %w", err)
 		}
 		cmd.logger = logger
 	case "standard":
-		logger, err := log.NewStdLogger(cmd.outStream, cmd.errStream, cmd.cfg.LogLevel.String())
+		logger, err := log.NewStdLogger(loggerOut, cmd.errStream, cmd.cfg.LogLevel.String())
 		if err != nil {
 			return fmt.Errorf("unable to initialize logger: %w", err)
 		}

cmd/root_test.go

@@ -1597,51 +1597,3 @@ func TestPrebuiltTools(t *testing.T) {
 		})
 	}
 }
-
-func TestUpdateLogLevel(t *testing.T) {
-	tcs := []struct {
-		desc     string
-		stdio    bool
-		logLevel string
-		want     bool
-	}{
-		{
-			desc:     "no stdio",
-			stdio:    false,
-			logLevel: "info",
-			want:     false,
-		},
-		{
-			desc:     "stdio with info log",
-			stdio:    true,
-			logLevel: "info",
-			want:     true,
-		},
-		{
-			desc:     "stdio with debug log",
-			stdio:    true,
-			logLevel: "debug",
-			want:     true,
-		},
-		{
-			desc:     "stdio with warn log",
-			stdio:    true,
-			logLevel: "warn",
-			want:     false,
-		},
-		{
-			desc:     "stdio with error log",
-			stdio:    true,
-			logLevel: "error",
-			want:     false,
-		},
-	}
-	for _, tc := range tcs {
-		t.Run(tc.desc, func(t *testing.T) {
-			got := updateLogLevel(tc.stdio, tc.logLevel)
-			if got != tc.want {
-				t.Fatalf("incorrect indication to update log level: got %t, want %t", got, tc.want)
-			}
-		})
-	}
-}

go.mod

@@ -6,7 +6,7 @@ toolchain go1.25.1
 
 require (
 	cloud.google.com/go/alloydbconn v1.15.5
-	cloud.google.com/go/bigquery v1.70.0
+	cloud.google.com/go/bigquery v1.71.0
 	cloud.google.com/go/bigtable v1.40.0
 	cloud.google.com/go/cloudsqlconn v1.18.1
 	cloud.google.com/go/dataplex v1.27.1
@@ -51,7 +51,7 @@ require (
 	go.opentelemetry.io/otel/sdk/metric v1.37.0
 	go.opentelemetry.io/otel/trace v1.38.0
 	golang.org/x/oauth2 v0.31.0
-	google.golang.org/api v0.249.0
+	google.golang.org/api v0.250.0
 	google.golang.org/genproto v0.0.0-20250922171735-9219d122eba9
 	modernc.org/sqlite v1.39.0
 )
@@ -74,7 +74,7 @@ require (
 	cloud.google.com/go/alloydb v1.18.0 // indirect
 	cloud.google.com/go/auth v0.16.5 // indirect
 	cloud.google.com/go/auth/oauth2adapt v0.2.8 // indirect
-	cloud.google.com/go/compute/metadata v0.8.0 // indirect
+	cloud.google.com/go/compute/metadata v0.8.4 // indirect
 	cloud.google.com/go/iam v1.5.2 // indirect
 	cloud.google.com/go/longrunning v0.6.7 // indirect
 	cloud.google.com/go/monitoring v1.24.2 // indirect
@@ -171,12 +171,12 @@ require (
 	golang.org/x/sync v0.17.0 // indirect
 	golang.org/x/sys v0.36.0 // indirect
 	golang.org/x/text v0.29.0 // indirect
-	golang.org/x/time v0.12.0 // indirect
+	golang.org/x/time v0.13.0 // indirect
 	golang.org/x/tools v0.36.0 // indirect
 	golang.org/x/xerrors v0.0.0-20240903120638-7835f813f4da // indirect
 	google.golang.org/genproto/googleapis/api v0.0.0-20250908214217-97024824d090 // indirect
 	google.golang.org/genproto/googleapis/rpc v0.0.0-20250908214217-97024824d090 // indirect
-	google.golang.org/grpc v1.75.0 // indirect
+	google.golang.org/grpc v1.75.1 // indirect
 	google.golang.org/protobuf v1.36.9 // indirect
 	gopkg.in/inf.v0 v0.9.1 // indirect
 	gopkg.in/ini.v1 v1.67.0 // indirect

go.sum

@@ -137,8 +137,8 @@ cloud.google.com/go/bigquery v1.47.0/go.mod h1:sA9XOgy0A8vQK9+MWhEQTY6Tix87M/Zur
 cloud.google.com/go/bigquery v1.48.0/go.mod h1:QAwSz+ipNgfL5jxiaK7weyOhzdoAy1zFm0Nf1fysJac=
 cloud.google.com/go/bigquery v1.49.0/go.mod h1:Sv8hMmTFFYBlt/ftw2uN6dFdQPzBlREY9yBh7Oy7/4Q=
 cloud.google.com/go/bigquery v1.50.0/go.mod h1:YrleYEh2pSEbgTBZYMJ5SuSr0ML3ypjRB1zgf7pvQLU=
-cloud.google.com/go/bigquery v1.70.0 h1:V1OIhhOSionCOXWMmypXOvZu/ogkzosa7s1ArWJO/Yg=
-cloud.google.com/go/bigquery v1.70.0/go.mod h1:6lEAkgTJN+H2JcaX1eKiuEHTKyqBaJq5U3SpLGbSvwI=
+cloud.google.com/go/bigquery v1.71.0 h1:NvSZvXU1Hyb+YiRVKQPuQXGeZaw/0NP6M/WOrBqSx3g=
+cloud.google.com/go/bigquery v1.71.0/go.mod h1:GUbRtmeCckOE85endLherHD9RsujY+gS7i++c1CqssQ=
 cloud.google.com/go/bigtable v1.40.0 h1:iNeqGqkJvFdjg07Ku3F7KKfq5QZvBySisYHVsLB1RwE=
 cloud.google.com/go/bigtable v1.40.0/go.mod h1:LtPzCcrAFaGRZ82Hs8xMueUeYW9Jw12AmNdUTMfDnh4=
 cloud.google.com/go/billing v1.4.0/go.mod h1:g9IdKBEFlItS8bTtlrZdVLWSSdSyFUZKXNS02zKMOZY=
@@ -194,8 +194,8 @@ cloud.google.com/go/compute/metadata v0.1.0/go.mod h1:Z1VN+bulIf6bt4P/C37K4DyZYZ
 cloud.google.com/go/compute/metadata v0.2.0/go.mod h1:zFmK7XCadkQkj6TtorcaGlCW1hT1fIilQDwofLpJ20k=
 cloud.google.com/go/compute/metadata v0.2.1/go.mod h1:jgHgmJd2RKBGzXqF5LR2EZMGxBkeanZ9wwa75XHJgOM=
 cloud.google.com/go/compute/metadata v0.2.3/go.mod h1:VAV5nSsACxMJvgaAuX6Pk2AawlZn8kiOGuCv6gTkwuA=
-cloud.google.com/go/compute/metadata v0.8.0 h1:HxMRIbao8w17ZX6wBnjhcDkW6lTFpgcaobyVfZWqRLA=
-cloud.google.com/go/compute/metadata v0.8.0/go.mod h1:sYOGTp851OV9bOFJ9CH7elVvyzopvWQFNNghtDQ/Biw=
+cloud.google.com/go/compute/metadata v0.8.4 h1:oXMa1VMQBVCyewMIOm3WQsnVd9FbKBtm8reqWRaXnHQ=
+cloud.google.com/go/compute/metadata v0.8.4/go.mod h1:E0bWwX5wTnLPedCKqk3pJmVgCBSM6qQI1yTBdEb3C10=
 cloud.google.com/go/contactcenterinsights v1.3.0/go.mod h1:Eu2oemoePuEFc/xKFPjbTuPSj0fYJcPls9TFlPNnHHY=
 cloud.google.com/go/contactcenterinsights v1.4.0/go.mod h1:L2YzkGbPsv+vMQMCADxJoT9YiTTnSEd6fEvCeHTYVck=
 cloud.google.com/go/contactcenterinsights v1.6.0/go.mod h1:IIDlT6CLcDoyv79kDv8iWxMSTZhLxSCofVV5W6YFM/w=
@@ -1687,8 +1687,8 @@ golang.org/x/time v0.0.0-20191024005414-555d28b269f0/go.mod h1:tRJNPiyCQ0inRvYxb
 golang.org/x/time v0.0.0-20220922220347-f3bd1da661af/go.mod h1:tRJNPiyCQ0inRvYxbN9jk5I+vvW/OXSQhTDSoE431IQ=
 golang.org/x/time v0.1.0/go.mod h1:tRJNPiyCQ0inRvYxbN9jk5I+vvW/OXSQhTDSoE431IQ=
 golang.org/x/time v0.3.0/go.mod h1:tRJNPiyCQ0inRvYxbN9jk5I+vvW/OXSQhTDSoE431IQ=
-golang.org/x/time v0.12.0 h1:ScB/8o8olJvc+CQPWrK3fPZNfh7qgwCrY0zJmoEQLSE=
-golang.org/x/time v0.12.0/go.mod h1:CDIdPxbZBQxdj6cxyCIdrNogrJKMJ7pr37NYpMcMDSg=
+golang.org/x/time v0.13.0 h1:eUlYslOIt32DgYD6utsuUeHs4d7AsEYLuIAdg7FlYgI=
+golang.org/x/time v0.13.0/go.mod h1:eL/Oa2bBBK0TkX57Fyni+NgnyQQN4LitPmob2Hjnqw4=
 golang.org/x/tools v0.0.0-20180525024113-a5b4c53f6e8b/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=
 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=
@@ -1834,8 +1834,8 @@ google.golang.org/api v0.108.0/go.mod h1:2Ts0XTHNVWxypznxWOYUeI4g3WdP9Pk2Qk58+a/
 google.golang.org/api v0.110.0/go.mod h1:7FC4Vvx1Mooxh8C5HWjzZHcavuS2f6pmJpZx60ca7iI=
 google.golang.org/api v0.111.0/go.mod h1:qtFHvU9mhgTJegR31csQ+rwxyUTHOKFqCKWp1J0fdw0=
 google.golang.org/api v0.114.0/go.mod h1:ifYI2ZsFK6/uGddGfAD5BMxlnkBqCmqHSDUVi45N5Yg=
-google.golang.org/api v0.249.0 h1:0VrsWAKzIZi058aeq+I86uIXbNhm9GxSHpbmZ92a38w=
-google.golang.org/api v0.249.0/go.mod h1:dGk9qyI0UYPwO/cjt2q06LG/EhUpwZGdAbYF14wHHrQ=
+google.golang.org/api v0.250.0 h1:qvkwrf/raASj82UegU2RSDGWi/89WkLckn4LuO4lVXM=
+google.golang.org/api v0.250.0/go.mod h1:Y9Uup8bDLJJtMzJyQnu+rLRJLA0wn+wTtc6vTlOvfXo=
 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/appengine v1.5.0/go.mod h1:xpcJRLb0r/rnEns0DIKYYv+WjYCduHsrkT7/EB5XEv4=
@@ -2023,8 +2023,8 @@ google.golang.org/grpc v1.52.3/go.mod h1:pu6fVzoFb+NBYNAvQL08ic+lvB2IojljRYuun5v
 google.golang.org/grpc v1.53.0/go.mod h1:OnIrk0ipVdj4N5d9IUoFUx72/VlD7+jUsHwZgwSMQpw=
 google.golang.org/grpc v1.54.0/go.mod h1:PUSEXI6iWghWaB6lXM4knEgpJNu2qUcKfDtNci3EC2g=
 google.golang.org/grpc v1.56.3/go.mod h1:I9bI3vqKfayGqPUAwGdOSu7kt6oIJLixfffKrpXqQ9s=
-google.golang.org/grpc v1.75.0 h1:+TW+dqTd2Biwe6KKfhE5JpiYIBWq865PhKGSXiivqt4=
-google.golang.org/grpc v1.75.0/go.mod h1:JtPAzKiq4v1xcAB2hydNlWI2RnF85XXcV0mhKXr2ecQ=
+google.golang.org/grpc v1.75.1 h1:/ODCNEuf9VghjgO3rqLcfg8fiOP0nSluljWFlDxELLI=
+google.golang.org/grpc v1.75.1/go.mod h1:JtPAzKiq4v1xcAB2hydNlWI2RnF85XXcV0mhKXr2ecQ=
 google.golang.org/grpc/cmd/protoc-gen-go-grpc v1.1.0/go.mod h1:6Kw0yEErY5E/yWrBtf03jp27GLLJujG4z/JK95pnjjw=
 google.golang.org/protobuf v0.0.0-20200109180630-ec00e32a8dfd/go.mod h1:DFci5gLYBciE7Vtevhsrf46CRTquxDuWsQurQQe4oz8=
 google.golang.org/protobuf v0.0.0-20200221191635-4d8936d0db64/go.mod h1:kwYJMbMJ01Woi6D6+Kah6886xMZcty6N08ah7+eCXa0=

internal/sources/postgres/postgres.go

@@ -23,6 +23,7 @@ import (
 	"github.com/goccy/go-yaml"
 	"github.com/googleapis/genai-toolbox/internal/sources"
 	"github.com/googleapis/genai-toolbox/internal/util"
+	"github.com/googleapis/genai-toolbox/internal/tools"
 	"github.com/jackc/pgx/v5/pgxpool"
 	"go.opentelemetry.io/otel/trace"
 )
@@ -92,8 +93,29 @@ func (s *Source) SourceKind() string {
 	return SourceKind
 }
 
-func (s *Source) PostgresPool() *pgxpool.Pool {
-	return s.Pool
+func (s *Source) RunSQL(ctx context.Context, statement string, params any) (any, error) {
+	sliceParams := params.(tools.ParamValues).AsSlice()
+	results, err := s.Pool.Query(ctx, statement, sliceParams...)
+	if err != nil {
+		return nil, fmt.Errorf("unable to execute query: %w", err)
+	}
+
+	fields := results.FieldDescriptions()
+
+	var out []any
+	for results.Next() {
+		v, err := results.Values()
+		if err != nil {
+			return nil, fmt.Errorf("unable to parse row: %w", err)
+		}
+		vMap := make(map[string]any)
+		for i, f := range fields {
+			vMap[f.Name] = v[i]
+		}
+		out = append(out, vMap)
+	}
+
+	return out, nil
 }
 
 func initPostgresConnectionPool(ctx context.Context, tracer trace.Tracer, name, host, port, user, pass, dbname string, queryParams map[string]string) (*pgxpool.Pool, error) {

internal/tools/postgres/postgressql/postgressql.go

@@ -24,7 +24,6 @@ import (
 	"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-sql"
@@ -44,7 +43,7 @@ func newConfig(ctx context.Context, name string, decoder *yaml.Decoder) (tools.T
 }
 
 type compatibleSource interface {
-	PostgresPool() *pgxpool.Pool
+	RunSQL(ctx context.Context, statement string, params any) (any, error)
 }
 
 // validate compatible sources are still compatible
@@ -101,7 +100,7 @@ func (cfg Config) Initialize(srcs map[string]sources.Source) (tools.Tool, error)
 		AllParams:          allParameters,
 		Statement:          cfg.Statement,
 		AuthRequired:       cfg.AuthRequired,
-		Pool:               s.PostgresPool(),
+		source:             s,
 		manifest:           tools.Manifest{Description: cfg.Description, Parameters: paramManifest, AuthRequired: cfg.AuthRequired},
 		mcpManifest:        mcpManifest,
 	}
@@ -119,7 +118,7 @@ type Tool struct {
 	TemplateParameters tools.Parameters `yaml:"templateParameters"`
 	AllParams          tools.Parameters `yaml:"allParams"`
 
-	Pool        *pgxpool.Pool
+	source      compatibleSource
 	Statement   string
 	manifest    tools.Manifest
 	mcpManifest tools.McpManifest
@@ -136,28 +135,7 @@ func (t Tool) Invoke(ctx context.Context, params tools.ParamValues, accessToken
 	if err != nil {
 		return nil, fmt.Errorf("unable to extract standard params %w", err)
 	}
-	sliceParams := newParams.AsSlice()
-	results, err := t.Pool.Query(ctx, newStatement, sliceParams...)
-	if err != nil {
-		return nil, fmt.Errorf("unable to execute query: %w", err)
-	}
-
-	fields := results.FieldDescriptions()
-
-	var out []any
-	for results.Next() {
-		v, err := results.Values()
-		if err != nil {
-			return nil, fmt.Errorf("unable to parse row: %w", err)
-		}
-		vMap := make(map[string]any)
-		for i, f := range fields {
-			vMap[f.Name] = v[i]
-		}
-		out = append(out, vMap)
-	}
-
-	return out, nil
+	return t.source.RunSQL(ctx, newStatement, newParams)
 }
 
 func (t Tool) ParseParams(data map[string]any, claims map[string]map[string]any) (tools.ParamValues, error) {