Don't just fmt.Println

cmd/root/api.go

@@ -11,6 +11,7 @@ import (
 	"github.com/spf13/cobra"
 
 	"github.com/docker/cagent/pkg/agentfile"
+	"github.com/docker/cagent/pkg/cli"
 	"github.com/docker/cagent/pkg/config"
 	"github.com/docker/cagent/pkg/remote"
 	"github.com/docker/cagent/pkg/server"
@@ -58,6 +59,7 @@ func (f *apiFlags) runAPICommand(cmd *cobra.Command, args []string) error {
 	telemetry.TrackCommand("api", args)
 
 	ctx := cmd.Context()
+	out := cli.NewPrinter(cmd.OutOrStdout())
 	agentsPath := args[0]
 
 	// Make sure no question is ever asked to the user in api mode.
@@ -67,7 +69,7 @@ func (f *apiFlags) runAPICommand(cmd *cobra.Command, args []string) error {
 		return fmt.Errorf("--pull-interval flag can only be used with OCI references, not local files")
 	}
 
-	resolvedPath, err := agentfile.Resolve(ctx, agentsPath)
+	resolvedPath, err := agentfile.Resolve(ctx, out, agentsPath)
 	if err != nil {
 		return err
 	}
@@ -139,7 +141,7 @@ func (f *apiFlags) runAPICommand(cmd *cobra.Command, args []string) error {
 					}
 
 					// Resolve the OCI reference to get the updated file path
-					newResolvedPath, err := agentfile.Resolve(ctx, agentsPath)
+					newResolvedPath, err := agentfile.Resolve(ctx, out, agentsPath)
 					if err != nil {
 						slog.Error("Failed to resolve OCI reference after pull", "reference", agentsPath, "error", err)
 						continue

cmd/root/build.go

@@ -3,6 +3,7 @@ package root
 import (
 	"github.com/spf13/cobra"
 
+	"github.com/docker/cagent/pkg/cli"
 	"github.com/docker/cagent/pkg/filesystem"
 	"github.com/docker/cagent/pkg/oci"
 	"github.com/docker/cagent/pkg/telemetry"
@@ -33,11 +34,14 @@ func newBuildCmd() *cobra.Command {
 func (f *buildFlags) runBuildCommand(cmd *cobra.Command, args []string) error {
 	telemetry.TrackCommand("build", args)
 
+	ctx := cmd.Context()
+	out := cli.NewPrinter(cmd.OutOrStdout())
+
 	agentFilePath := args[0]
 	dockerImageName := ""
 	if len(args) > 1 {
 		dockerImageName = args[1]
 	}
 
-	return oci.BuildDockerImage(cmd.Context(), agentFilePath, filesystem.AllowAll, dockerImageName, f.opts)
+	return oci.BuildDockerImage(ctx, out, agentFilePath, filesystem.AllowAll, dockerImageName, f.opts)
 }

cmd/root/eval.go

@@ -1,10 +1,9 @@
 package root
 
 import (
-	"fmt"
-
 	"github.com/spf13/cobra"
 
+	"github.com/docker/cagent/pkg/cli"
 	"github.com/docker/cagent/pkg/config"
 	"github.com/docker/cagent/pkg/evaluation"
 	"github.com/docker/cagent/pkg/teamloader"
@@ -33,6 +32,8 @@ func newEvalCmd() *cobra.Command {
 func (f *evalFlags) runEvalCommand(cmd *cobra.Command, args []string) error {
 	telemetry.TrackCommand("eval", args)
 
+	out := cli.NewPrinter(cmd.OutOrStdout())
+
 	agents, err := teamloader.Load(cmd.Context(), args[0], f.runConfig)
 	if err != nil {
 		return err
@@ -44,9 +45,9 @@ func (f *evalFlags) runEvalCommand(cmd *cobra.Command, args []string) error {
 	}
 
 	for _, evalResult := range evalResults {
-		fmt.Printf("Eval file: %s\n", evalResult.EvalFile)
-		fmt.Printf("Tool trajectory score: %f\n", evalResult.Score.ToolTrajectoryScore)
-		fmt.Printf("Rouge-1 score: %f\n", evalResult.Score.Rouge1Score)
+		out.Printf("Eval file: %s\n", evalResult.EvalFile)
+		out.Printf("Tool trajectory score: %f\n", evalResult.Score.ToolTrajectoryScore)
+		out.Printf("Rouge-1 score: %f\n", evalResult.Score.Rouge1Score)
 	}
 
 	return nil

cmd/root/mcp.go

@@ -3,6 +3,7 @@ package root
 import (
 	"github.com/spf13/cobra"
 
+	"github.com/docker/cagent/pkg/cli"
 	"github.com/docker/cagent/pkg/config"
 	"github.com/docker/cagent/pkg/mcp"
 	"github.com/docker/cagent/pkg/telemetry"
@@ -35,11 +36,13 @@ func newMCPCmd() *cobra.Command {
 
 func (f *mcpFlags) runMCPCommand(cmd *cobra.Command, args []string) error {
 	telemetry.TrackCommand("mcp", args)
+
 	ctx := cmd.Context()
+	out := cli.NewPrinter(cmd.OutOrStdout())
 
 	if err := setupWorkingDirectory(f.workingDir); err != nil {
 		return err
 	}
 
-	return mcp.StartMCPServer(ctx, args[0], f.runConfig)
+	return mcp.StartMCPServer(ctx, out, args[0], f.runConfig)
 }

cmd/root/run.go

@@ -94,7 +94,7 @@ func (f *runExecFlags) runOrExec(ctx context.Context, out *cli.Printer, args []s
 			return err
 		}
 	} else {
-		agentFileName, err = f.resolveAgentFile(ctx, args[0])
+		agentFileName, err = f.resolveAgentFile(ctx, out, args[0])
 		if err != nil {
 			return err
 		}
@@ -127,11 +127,11 @@ func (f *runExecFlags) setupWorkingDirectory() error {
 
 // resolveAgentFile is a wrapper method that calls the agentfile.Resolve function
 // after checking for remote address
-func (f *runExecFlags) resolveAgentFile(ctx context.Context, agentFilename string) (string, error) {
+func (f *runExecFlags) resolveAgentFile(ctx context.Context, out *cli.Printer, agentFilename string) (string, error) {
 	if f.remoteAddress != "" {
 		return agentFilename, nil
 	}
-	return agentfile.Resolve(ctx, agentFilename)
+	return agentfile.Resolve(ctx, out, agentFilename)
 }
 
 func (f *runExecFlags) loadAgents(ctx context.Context, agentFilename string) (*team.Team, error) {

cmd/root/run_test.go

@@ -78,7 +78,7 @@ agents:
 	defer cancel()
 
 	// Test resolving a local file
-	resolved, err := agentfile.Resolve(ctx, yamlFile)
+	resolved, err := agentfile.Resolve(ctx, nil, yamlFile)
 	require.NoError(t, err)
 
 	// Should return absolute path
@@ -115,7 +115,7 @@ agents:
 	defer cancel()
 
 	// First resolution
-	resolved1, err := agentfile.Resolve(ctx, ociRef)
+	resolved1, err := agentfile.Resolve(ctx, nil, ociRef)
 	require.NoError(t, err)
 	assert.NotEmpty(t, resolved1)
 
@@ -132,7 +132,7 @@ agents:
 	firstResolvedPath := resolved1
 
 	// Second resolution (simulating a reload)
-	resolved2, err := agentfile.Resolve(ctx, ociRef)
+	resolved2, err := agentfile.Resolve(ctx, nil, ociRef)
 	require.NoError(t, err)
 
 	// Should return the SAME filename
@@ -158,7 +158,7 @@ agents:
 	require.NoError(t, err)
 
 	// Third resolution (simulating reload after update)
-	resolved3, err := agentfile.Resolve(ctx, ociRef)
+	resolved3, err := agentfile.Resolve(ctx, nil, ociRef)
 	require.NoError(t, err)
 
 	// Should STILL use the same filename
@@ -211,10 +211,10 @@ agents:
 	defer cancel()
 
 	// Resolve both OCI refs
-	resolved1, err := agentfile.Resolve(ctx, ociRef1)
+	resolved1, err := agentfile.Resolve(ctx, nil, ociRef1)
 	require.NoError(t, err)
 
-	resolved2, err := agentfile.Resolve(ctx, ociRef2)
+	resolved2, err := agentfile.Resolve(ctx, nil, ociRef2)
 	require.NoError(t, err)
 
 	// Should have DIFFERENT filenames
@@ -262,7 +262,7 @@ agents:
 	ctx, cancel := context.WithCancel(t.Context())
 
 	// Resolve the OCI ref
-	resolved, err := agentfile.Resolve(ctx, ociRef)
+	resolved, err := agentfile.Resolve(ctx, nil, ociRef)
 	require.NoError(t, err)
 	assert.FileExists(t, resolved)
 

cmd/root/version.go

@@ -19,9 +19,10 @@ func newVersionCmd() *cobra.Command {
 	}
 }
 
-func runVersionCommand(_ *cobra.Command, args []string) {
+func runVersionCommand(cmd *cobra.Command, args []string) {
 	telemetry.TrackCommand("version", args)
 
-	fmt.Printf("cagent version %s\n", version.Version)
-	fmt.Printf("Commit: %s\n", version.Commit)
+	out := cmd.OutOrStdout()
+	fmt.Fprintf(out, "cagent version %s\n", version.Version)
+	fmt.Fprintf(out, "Commit: %s\n", version.Commit)
 }

pkg/agentfile/resolver.go

@@ -11,6 +11,7 @@ import (
 	"strings"
 
 	"github.com/docker/cagent/pkg/aliases"
+	"github.com/docker/cagent/pkg/cli"
 	"github.com/docker/cagent/pkg/content"
 	"github.com/docker/cagent/pkg/remote"
 )
@@ -55,7 +56,7 @@ func OciRefToFilename(ociRef string) string {
 }
 
 // Resolve resolves an agent file reference (local file or OCI image) to a local file path
-func Resolve(ctx context.Context, agentFilename string) (string, error) {
+func Resolve(ctx context.Context, out *cli.Printer, agentFilename string) (string, error) {
 	originalOCIRef := agentFilename // Store the original for OCI ref tracking
 
 	// Try to resolve as an alias first
@@ -83,7 +84,7 @@ func Resolve(ctx context.Context, agentFilename string) (string, error) {
 	// Treat as an OCI image reference. Try local store first, otherwise pull then load.
 	a, err := FromStore(agentFilename)
 	if err != nil {
-		fmt.Println("Pulling agent", agentFilename)
+		out.Println("Pulling agent", agentFilename)
 		if _, pullErr := remote.Pull(agentFilename); pullErr != nil {
 			return "", fmt.Errorf("failed to pull OCI image %s: %w", agentFilename, pullErr)
 		}

pkg/cli/runner.go

@@ -5,6 +5,7 @@ import (
 	"encoding/base64"
 	"fmt"
 	"io"
+	"log/slog"
 	"os"
 	"path/filepath"
 	"strings"
@@ -397,7 +398,7 @@ func createUserMessageWithAttachment(agentFilename, userContent, attachmentPath
 	// Convert file to data URL
 	dataURL, err := fileToDataURL(attachmentPath)
 	if err != nil {
-		fmt.Printf("Warning: Failed to attach file %s: %v\n", attachmentPath, err)
+		slog.Warn("Failed to attach file", "path", attachmentPath, "error", err)
 		return session.UserMessage(agentFilename, userContent)
 	}
 

pkg/creator/agent.go

@@ -5,6 +5,7 @@ import (
 	_ "embed"
 	"encoding/json"
 	"fmt"
+	"log/slog"
 	"os"
 	"path/filepath"
 	"strings"
@@ -91,7 +92,7 @@ func CreateAgent(ctx context.Context, baseDir, prompt string, runConfig config.R
 		return "", "", fmt.Errorf("failed to create LLM client: %w", err)
 	}
 
-	fmt.Println("Generating agent configuration....")
+	slog.Info("Generating agent configuration....")
 
 	fsToolset := fsToolset{inner: builtin.NewFilesystemTool([]string{baseDir})}
 	fileName := filepath.Base(fsToolset.path)
@@ -142,7 +143,7 @@ func Agent(ctx context.Context, baseDir string, runConfig config.RuntimeConfig,
 	if modelNameOverride != "" {
 		modelName = modelNameOverride
 	} else {
-		fmt.Printf("Using default model: %s\n", modelName)
+		slog.Info("Using default model: " + modelName)
 	}
 
 	// If not using a model gateway, avoid selecting a provider the user can't run

pkg/mcp/server.go

@@ -8,6 +8,7 @@ import (
 	"github.com/modelcontextprotocol/go-sdk/mcp"
 
 	"github.com/docker/cagent/pkg/agentfile"
+	"github.com/docker/cagent/pkg/cli"
 	"github.com/docker/cagent/pkg/config"
 	"github.com/docker/cagent/pkg/runtime"
 	"github.com/docker/cagent/pkg/session"
@@ -25,10 +26,10 @@ type ToolOutput struct {
 	Response string `json:"response" jsonschema:"the response from the agent"`
 }
 
-func StartMCPServer(ctx context.Context, agentFilename string, runConfig config.RuntimeConfig) error {
+func StartMCPServer(ctx context.Context, out *cli.Printer, agentFilename string, runConfig config.RuntimeConfig) error {
 	slog.Debug("Starting MCP server", "agent_ref", agentFilename)
 
-	agentFilename, err := agentfile.Resolve(ctx, agentFilename)
+	agentFilename, err := agentfile.Resolve(ctx, out, agentFilename)
 	if err != nil {
 		return err
 	}

pkg/modelsdev/store.go

@@ -5,6 +5,7 @@ import (
 	"encoding/json"
 	"fmt"
 	"io"
+	"log/slog"
 	"net/http"
 	"os"
 	"path/filepath"
@@ -91,7 +92,7 @@ func (s *Store) GetDatabase(ctx context.Context) (*Database, error) {
 	// Save to cache
 	if err := s.saveToCache(cacheFile, database); err != nil {
 		// Log the error but don't fail the request
-		fmt.Printf("Warning: failed to save to cache: %v\n", err)
+		slog.Warn("Warning: failed to save to cache", "error", err)
 	}
 
 	return database, nil

pkg/oci/build.go

@@ -4,7 +4,6 @@ import (
 	"bytes"
 	"context"
 	_ "embed"
-	"fmt"
 	"log/slog"
 	"os"
 	"os/exec"
@@ -14,6 +13,7 @@ import (
 
 	"github.com/goccy/go-yaml"
 
+	"github.com/docker/cagent/pkg/cli"
 	"github.com/docker/cagent/pkg/config"
 	"github.com/docker/cagent/pkg/filesystem"
 )
@@ -28,7 +28,7 @@ type Options struct {
 	Pull    bool
 }
 
-func BuildDockerImage(ctx context.Context, agentFilePath string, fs filesystem.FS, dockerImageName string, opts Options) error {
+func BuildDockerImage(ctx context.Context, out *cli.Printer, agentFilePath string, fs filesystem.FS, dockerImageName string, opts Options) error {
 	cfg, err := config.LoadConfig(agentFilePath, fs)
 	if err != nil {
 		return err
@@ -71,7 +71,7 @@ func BuildDockerImage(ctx context.Context, agentFilePath string, fs filesystem.F
 
 	dockerfile := dockerfileBuf.String()
 	if opts.DryRun {
-		fmt.Println(dockerfile)
+		out.Println(dockerfile)
 		return nil
 	}
 

pkg/remote/pull.go

@@ -30,7 +30,6 @@ func Pull(registryRef string, opts ...crane.Option) (string, error) {
 
 	if meta, metaErr := store.GetArtifactMetadata(localRef); metaErr == nil {
 		if meta.Digest == remoteDigest {
-			fmt.Printf("Artifact %s already exists in the store (digest %s). Using cache.\n", localRef, remoteDigest)
 			return meta.Digest, nil
 		}
 	}