diff --git a/cmd/upload/root.go b/cmd/upload/root.go
index b7ecba44..83494f32 100644
--- a/cmd/upload/root.go
+++ b/cmd/upload/root.go
@@ -107,6 +107,7 @@ var Cmd = &cobra.Command{
 			preparation.WithAssumeUnchangedSources(rootFlags.assumeUnchangedSources),
 			preparation.WithEventBus(eb),
 			preparation.WithReplicas(cfg.Upload.Replicas),
+			preparation.WithPutHTTPClient(cmdutil.TracedHTTPClient),
 		)
 		allUploads, err := api.FindOrCreateUploads(ctx, spaceDID)
 		if err != nil {
diff --git a/cmd/upload/source/add.go b/cmd/upload/source/add.go
index 34bdd1d9..315649d1 100644
--- a/cmd/upload/source/add.go
+++ b/cmd/upload/source/add.go
@@ -73,7 +73,7 @@ var AddCmd = &cobra.Command{
 			return err
 		}
 
-		api := preparation.NewAPI(repo, client)
+		api := preparation.NewAPI(repo, client, preparation.WithPutHTTPClient(cmdutil.TracedHTTPClient))
 
 		// Parse shard size if provided
 		var spaceOptions []model.SpaceOption
diff --git a/internal/cmdutil/cmdutil.go b/internal/cmdutil/cmdutil.go
index 38cd85d9..19ef354e 100644
--- a/internal/cmdutil/cmdutil.go
+++ b/internal/cmdutil/cmdutil.go
@@ -43,8 +43,10 @@ func envSigner() (principal.Signer, error) {
 	return signer.Parse(str)
 }
 
-var tracedHttpClient = &http.Client{
-	Transport: otelhttp.NewTransport(http.DefaultTransport),
+// TracedHTTPClient is an HTTP client with OpenTelemetry tracing and a guppy
+// User-Agent header on all outbound requests.
+var TracedHTTPClient = &http.Client{
+	Transport: newUserAgentTransport(otelhttp.NewTransport(http.DefaultTransport)),
 }
 
 // MustGetClient creates a new client suitable for the CLI, using stored data,
@@ -77,7 +79,7 @@ func MustGetClientForNetwork(storePath string, networkCfg config.NetworkConfig,
 
 	conn, err := uclient.NewConnection(
 		network.UploadID,
-		uhttp.NewChannel(&network.UploadURL, uhttp.WithClient(tracedHttpClient)),
+		uhttp.NewChannel(&network.UploadURL, uhttp.WithClient(TracedHTTPClient)),
 		uclient.WithOutboundCodec(car.NewOutboundCodec()),
 	)
 	if err != nil {
@@ -90,7 +92,7 @@ func MustGetClientForNetwork(storePath string, networkCfg config.NetworkConfig,
 			append(
 				options,
 				client.WithConnection(conn),
-				client.WithReceiptsClient(receiptclient.New(&network.ReceiptsURL, receiptclient.WithHTTPClient(tracedHttpClient))),
+				client.WithReceiptsClient(receiptclient.New(&network.ReceiptsURL, receiptclient.WithHTTPClient(TracedHTTPClient))),
 			)...,
 		)...,
 	)
@@ -132,7 +134,7 @@ func MustGetIndexClient(networkCfg config.NetworkConfig) (*indexclient.Client, u
 func MustGetIndexClientForNetwork(networkCfg config.NetworkConfig, flagName string) (*indexclient.Client, ucan.Principal) {
 	network := MustGetNetworkConfig(networkCfg, flagName)
 
-	client, err := indexclient.New(network.IndexerID, network.IndexerURL, indexclient.WithHTTPClient(tracedHttpClient))
+	client, err := indexclient.New(network.IndexerID, network.IndexerURL, indexclient.WithHTTPClient(TracedHTTPClient))
 	if err != nil {
 		log.Fatal(err)
 	}
diff --git a/internal/cmdutil/useragent.go b/internal/cmdutil/useragent.go
new file mode 100644
index 00000000..267d41cc
--- /dev/null
+++ b/internal/cmdutil/useragent.go
@@ -0,0 +1,26 @@
+package cmdutil
+
+import (
+	"fmt"
+	"net/http"
+
+	"github.com/storacha/guppy/pkg/build"
+)
+
+type userAgentTransport struct {
+	userAgent string
+	base      http.RoundTripper
+}
+
+func (t *userAgentTransport) RoundTrip(req *http.Request) (*http.Response, error) {
+	req = req.Clone(req.Context())
+	req.Header.Set("User-Agent", t.userAgent)
+	return t.base.RoundTrip(req)
+}
+
+func newUserAgentTransport(base http.RoundTripper) http.RoundTripper {
+	return &userAgentTransport{
+		userAgent: fmt.Sprintf("guppy/%s", build.Version),
+		base:      base,
+	}
+}
diff --git a/pkg/preparation/preparation.go b/pkg/preparation/preparation.go
index c3a93b74..3341e37c 100644
--- a/pkg/preparation/preparation.go
+++ b/pkg/preparation/preparation.go
@@ -5,6 +5,7 @@ import (
 	"errors"
 	"fmt"
 	"io/fs"
+	"net/http"
 	"os"
 	"path/filepath"
 
@@ -12,6 +13,7 @@ import (
 	"github.com/storacha/go-ucanto/did"
 
 	"github.com/storacha/guppy/pkg/bus"
+	clientpkg "github.com/storacha/guppy/pkg/client"
 	"github.com/storacha/guppy/pkg/preparation/blobs"
 	"github.com/storacha/guppy/pkg/preparation/dags"
 	"github.com/storacha/guppy/pkg/preparation/dags/nodereader"
@@ -61,6 +63,7 @@ type config struct {
 	assumeUnchangedSources bool
 	bus                    bus.Bus
 	replicas               uint
+	putHTTPClient          *http.Client
 }
 
 const (
@@ -156,6 +159,10 @@ func NewAPI(repo Repo, client StorachaClient, options ...Option) API {
 		ShardEncoder:     blobs.NewCAREncoder(),
 	}
 
+	var blobAddOptions []clientpkg.SpaceBlobAddOption
+	if cfg.putHTTPClient != nil {
+		blobAddOptions = append(blobAddOptions, clientpkg.WithPutClient(cfg.putHTTPClient))
+	}
 	storachaAPI := storacha.API{
 		Repo:                  repo,
 		Client:                client,
@@ -164,6 +171,7 @@ func NewAPI(repo Repo, client StorachaClient, options ...Option) API {
 		BlobUploadParallelism: cfg.blobUploadParallelism,
 		Bus:                   cfg.bus,
 		Replicas:              cfg.replicas,
+		BlobAddOptions:        blobAddOptions,
 	}
 
 	uploadsAPI = uploads.API{
@@ -247,6 +255,14 @@ func WithReplicas(replicas uint) Option {
 	}
 }
 
+// WithPutHTTPClient sets the HTTP client used for blob PUT uploads.
+func WithPutHTTPClient(c *http.Client) Option {
+	return func(cfg *config) error {
+		cfg.putHTTPClient = c
+		return nil
+	}
+}
+
 func (a API) FindOrCreateSpace(ctx context.Context, spaceDID did.DID, name string, options ...spacesmodel.SpaceOption) (*spacesmodel.Space, error) {
 	return a.Spaces.FindOrCreateSpace(ctx, spaceDID, name, options...)
 }
diff --git a/pkg/preparation/storacha/storacha.go b/pkg/preparation/storacha/storacha.go
index 3fedf426..b51806b1 100644
--- a/pkg/preparation/storacha/storacha.go
+++ b/pkg/preparation/storacha/storacha.go
@@ -65,6 +65,7 @@ type API struct {
 	BlobUploadParallelism int
 	Bus                   bus.Publisher
 	Replicas              uint
+	BlobAddOptions        []client.SpaceBlobAddOption
 }
 
 var _ uploads.AddShardsForUploadFunc = API{}.AddShardsForUpload
@@ -336,7 +337,7 @@ func (a API) spaceBlobAdd(ctx context.Context, content io.Reader, spaceDID did.D
 	ctx, span := tracer.Start(ctx, "space-blob-add")
 	defer span.End()
 
-	return a.Client.SpaceBlobAdd(ctx, content, spaceDID, opts...)
+	return a.Client.SpaceBlobAdd(ctx, content, spaceDID, append(a.BlobAddOptions, opts...)...)
 }
 
 func (a API) spaceBlobReplicate(ctx context.Context, blob model.Blob, spaceDID did.DID, locationCommitment delegation.Delegation) error {