diff --git a/directory/README.md b/directory/README.md
index 4858054..e5ea281 100644
--- a/directory/README.md
+++ b/directory/README.md
@@ -62,7 +62,9 @@ Mixed search requires the Directory's source-aware response format. A missing or
 is reported as a record issue; the client does not infer a document URL from the API origin.
 
 `Result.IndexedAt` reports Collection freshness; `Result.Service.IndexedAt` reports its parent's
-freshness. A Service may have `AvailableThrough` platform attribution. A Collection's attribution
+freshness. A Service may have `Publisher` attribution with `PublisherID`, `Name`, and `WebsiteURL`.
+The website is a display link, not a discovery or execution target. Additional response members
+are retained; publisher attribution may be absent or null. A Collection's attribution
 is its owning `Service`.
 
 Unknown types retain the wire type in `Type` and complete JSON in `Raw`; their `Service` and
diff --git a/directory/search.go b/directory/search.go
index 5a91932..b48959b 100644
--- a/directory/search.go
+++ b/directory/search.go
@@ -7,6 +7,7 @@ import (
 	"fmt"
 	"iter"
 	"net/http"
+	"net/url"
 	"strings"
 	"time"
 	"unicode/utf8"
@@ -122,13 +123,13 @@ func parseResult(data []byte) (Result, error) {
 	}
 	result := Result{Type: kind, Service: &service, IndexedAt: indexedAt}
 	if kind == "service" {
-		result.Additional = cloneAdditional(object, "type", "service", "indexed_at", "available_through")
-		if raw, present := object["available_through"]; present {
-			reference, err := parseServiceReference(raw)
+		result.Additional = cloneAdditional(object, "type", "service", "indexed_at", "publisher")
+		if raw, present := object["publisher"]; present && string(raw) != "null" {
+			reference, err := parsePublisher(raw)
 			if err != nil {
 				return Result{}, err
 			}
-			result.AvailableThrough = &reference
+			result.Publisher = &reference
 		}
 		return result, nil
 	}
@@ -155,29 +156,53 @@ func parseResult(data []byte) (Result, error) {
 	return result, nil
 }
 
-func parseServiceReference(data []byte) (ServiceReference, error) {
+func parsePublisher(data []byte) (Publisher, error) {
 	var object map[string]json.RawMessage
 	if err := json.Unmarshal(data, &object); err != nil {
-		return ServiceReference{}, err
+		return Publisher{}, err
+	}
+	id, err := requiredText(object["publisher_id"], "publisher_id", 1, 128)
+	if err != nil {
+		return Publisher{}, err
+	}
+	name, err := requiredText(object["name"], "name", 1, 128)
+	if err != nil {
+		return Publisher{}, err
+	}
+	website, err := requiredText(object["website_url"], "website_url", 1, 512)
+	if err != nil {
+		return Publisher{}, err
+	}
+	parsed, err := url.Parse(website)
+	if err != nil || parsed.Scheme != "https" || parsed.Hostname() == "" || parsed.User != nil {
+		return Publisher{}, errors.New("Publisher website must be an HTTPS URL without credentials")
+	}
+	return Publisher{PublisherID: id, Name: name, WebsiteURL: website, Additional: cloneAdditional(object, "publisher_id", "name", "website_url")}, nil
+}
+
+func parseServiceReference(data []byte) (serviceReference, error) {
+	var object map[string]json.RawMessage
+	if err := json.Unmarshal(data, &object); err != nil {
+		return serviceReference{}, err
 	}
 	id, err := requiredText(object["service_id"], "service_id", 1, 128)
 	if err != nil {
-		return ServiceReference{}, err
+		return serviceReference{}, err
 	}
 	origin, err := requiredText(object["service_origin"], "service_origin", 1, 2048)
 	if err != nil {
-		return ServiceReference{}, err
+		return serviceReference{}, err
 	}
 	canonical, err := odp.DeriveServiceOrigin(origin)
 	if err != nil || canonical != origin || !publicHTTPSOrigin(origin) {
-		return ServiceReference{}, errors.New("Attribution origin must be a canonical public HTTPS origin")
+		return serviceReference{}, errors.New("Service origin must be a canonical public HTTPS origin")
 	}
 	var name string
 	if raw, present := object["name"]; present {
 		name, err = requiredText(raw, "name", 1, 128)
 		if err != nil {
-			return ServiceReference{}, err
+			return serviceReference{}, err
 		}
 	}
-	return ServiceReference{ServiceID: id, ServiceOrigin: origin, Name: name, Additional: cloneAdditional(object, "service_id", "service_origin", "name")}, nil
+	return serviceReference{ServiceID: id, ServiceOrigin: origin, Name: name, Additional: cloneAdditional(object, "service_id", "service_origin", "name")}, nil
 }
diff --git a/directory/search_test.go b/directory/search_test.go
index 3b1d537..2b7adea 100644
--- a/directory/search_test.go
+++ b/directory/search_test.go
@@ -37,7 +37,7 @@ func mixedBody(t *testing.T, items ...any) string {
 
 func TestMixedSearchSequence(t *testing.T) {
 	service := mixedResult("service")
-	service["available_through"] = map[string]any{"service_id": "platform", "service_origin": "https://platform.example", "name": "Platform", "extra": true}
+	service["publisher"] = map[string]any{"publisher_id": "platform", "website_url": "https://platform.example/catalog", "name": "Platform", "extra": true}
 	service["extra"] = "retained"
 	collection := mixedResult("collection")
 	collection["collection"].(map[string]any)["extra"] = true
@@ -71,7 +71,7 @@ func TestMixedSearchSequence(t *testing.T) {
 		if err != nil || len(result.Items) != 3 || len(result.Issues) != 1 || result.Issues[0].Index != 3 || result.Issues[0].Scope != directory.IssueResult {
 			t.Fatalf("result = %#v, %v", result, err)
 		}
-		if result.Items[0].AvailableThrough.Name != "Platform" || string(result.Items[0].Additional["extra"]) != `"retained"` || string(result.Items[0].AvailableThrough.Additional["extra"]) != "true" {
+		if result.Items[0].Publisher.Name != "Platform" || string(result.Items[0].Additional["extra"]) != `"retained"` || string(result.Items[0].Publisher.Additional["extra"]) != "true" {
 			t.Fatalf("Service attribution or additional fields = %#v", result.Items[0])
 		}
 		if result.Items[1].Collection.ID != "Weather" || result.Items[1].Service.ServiceID == "" || result.Items[1].IndexedAt.Equal(result.Items[1].Service.IndexedAt) || string(result.Items[1].Collection.Additional["extra"]) != "true" {
@@ -121,9 +121,9 @@ func TestMixedSearchRejectsMalformedKnownEntries(t *testing.T) {
 			}
 		}
 	}
-	for _, reference := range []any{nil, false, map[string]any{}, map[string]any{"service_id": "x"}, map[string]any{"service_id": "x", "service_origin": "http://localhost"}, map[string]any{"service_id": "x", "service_origin": "https://platform.example", "name": nil}} {
+	for _, reference := range []any{false, map[string]any{}, map[string]any{"publisher_id": "x"}, map[string]any{"publisher_id": "x", "name": "Platform"}, map[string]any{"publisher_id": "x", "name": "Platform", "website_url": "http://localhost"}, map[string]any{"publisher_id": "x", "name": "Platform", "website_url": "https://user:secret@platform.example"}, map[string]any{"publisher_id": "x", "name": "Platform", "website_url": "://invalid"}} {
 		item := mixedResult("service")
-		item["available_through"] = reference
+		item["publisher"] = reference
 		value := client(t, func(*http.Request) (*http.Response, error) {
 			return response(200, mixedBody(t, item), nil), nil
 		}, directory.Production)
@@ -144,7 +144,9 @@ func TestMixedSearchOptionalFields(t *testing.T) {
 			item["collection"].(map[string]any)["description"] = description
 		}
 		service := mixedResult("service")
-		service["available_through"] = map[string]any{"service_id": "x", "service_origin": "https://platform.example"}
+		service["publisher"] = nil
+		service["available_through"] = map[string]any{"service_id": "legacy", "service_origin": "https://legacy.example"}
+		service["future_metadata"] = map[string]any{"arbitrary": true}
 		value := client(t, func(*http.Request) (*http.Response, error) {
 			return response(200, mixedBody(t, item, service), nil), nil
 		}, directory.Production)
diff --git a/directory/types.go b/directory/types.go
index 1049707..2b8d190 100644
--- a/directory/types.go
+++ b/directory/types.go
@@ -82,13 +82,20 @@ type Source struct {
 	X402Discovery bool
 }
 
-type ServiceReference struct {
+type serviceReference struct {
 	Additional    odp.AdditionalMembers
 	ServiceID     string
 	ServiceOrigin string
 	Name          string
 }
 
+type Publisher struct {
+	Additional  odp.AdditionalMembers
+	PublisherID string
+	Name        string
+	WebsiteURL  string
+}
+
 type CollectionSummary struct {
 	Additional  odp.AdditionalMembers
 	ID          string
@@ -98,13 +105,13 @@ type CollectionSummary struct {
 
 // Result retains unknown resource types in Raw without interpreting them as Services.
 type Result struct {
-	Additional       odp.AdditionalMembers
-	Type             string
-	Service          *IndexedService
-	Collection       *CollectionSummary
-	AvailableThrough *ServiceReference
-	IndexedAt        time.Time
-	Raw              json.RawMessage
+	Additional odp.AdditionalMembers
+	Type       string
+	Service    *IndexedService
+	Collection *CollectionSummary
+	Publisher  *Publisher
+	IndexedAt  time.Time
+	Raw        json.RawMessage
 }
 
 type IterationOptions struct {