Pins across servers, both ways

An account elsewhere that pins or unpins one of its posts (Add or Remove on its `featured`) now shows those pins on its
profile here (`pinned=true`), in its order and its public posts only; a community's announce of a moderator's Add does
the same for the community. The `featured` collection itself is read with the account's counts, at most once a day, so
pins made before PrivaPub ever saw an account show too. Any other target (Smithereen's wall, a community's moderators)
is dropped. A persona's pin and unpin go to the post's audience as Add and Remove on /trophies, as Mastodon sends them.

Checked live against Mastodon (scenarios/pins.sh, 8 checks). The town's checker learnt three peer rules from the
village: Misskey and Sharkey keep a forwarded reply only with its author's LD signature (only Mastodon signs), they
count no renote by a bot, and Mastodon never sees a Lemmy vote on a post in a community. The village of 2026-10-05
checks clean, 2454 of 2454.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01LsXgEaXee4GCU1hwYgPJXw

CLAUDE.md

@@ -559,6 +559,8 @@ tools/pasture/run.sh down                                            # removes e
   `connection`) and its API is v3 (`/api/v3`, `sort=New`, `resolve_object` answering views). It takes private messages
   only as `ChatMessage`, which PrivaPub sends it, a first message too (invariant 17). `scenarios/lemmy19.sh`, 30
   checks.
+- **Pins (`scenarios/pins.sh`, needs mastodon):** a Mastodon account pins and unpins while alice follows it, alice pins
+  and unpins while it follows her, and a fresh account's earlier pin shows once PrivaPub resolves it. 8 checks.
 - **Smithereen (1.0.3):** its image on the shared MySQL (database `smithereen`, its schema from the image's commit),
   with imgproxy and a file server behind Caddy as `smithereen.test` (`/i` and `/s`), trusting the CA through a JDK
   store with it added (`JAVA_TOOL_OPTIONS`). MySQL takes its stored functions only with

FEDERATION.md

@@ -149,6 +149,7 @@ Received:
 | `Delete` | deletes the object, or the actor and its follows; a deleted object id is remembered for 90 days, so a late `Create` cannot bring it back |
 | `Flag` | becomes a report for this server's moderators |
 | `Move` | an account moving: believed as Mastodon believes it, when the account sends it about itself and the new account, read again from its server, names it in `alsoKnownAs`. The old account then shows where it went (`moved`), and, as Mastodon does it (owner decision 2026-10-05), the personas following it follow the new one instead (a Follow to its server, an Undo to the old), in the same lists; a mute or a block of the old account carries over |
+| `Add`/`Remove` on the actor's `featured` | the account pins or unpins one of its own posts (fetched from its server when not held); inside a community's announce, the community features a post made in it. Its profile shows them first (`pinned=true`). The collection itself is read with the account's counts, at most once a day. Any other target (Smithereen's wall, a community's moderators) is dropped |
 | `Block` of a persona | the follows between them end, the blocker's posts and notifications are hidden from the persona, nothing of the persona's is addressed to the blocker, and the relationship says `blocked_by`; `Undo{Block}` lifts it |
 
 Sent: `Follow`, `Undo{Follow}`, `Create{Note}`, `Create{Question}` and poll votes, `EmojiReact` and its `Undo`, `Update{Note}`, `Update{Person}`, `Delete{Tombstone}`, `Accept{Follow}`,
@@ -157,7 +158,8 @@ persona's posts passed on to its followers. A deleted post answers 410 with a `T
 
 - **Attachments** are `Document`s with `mediaType`, `name` (alt text), `blurhash`, `focalPoint`, `width` and `height`.
   Uploaded files have all metadata removed.
-- **Pinned posts** are the actor's `featured` collection (`/trophies`); `featuredTags` is `/tattoos`.
+- **Pinned posts** are the actor's `featured` collection (`/trophies`); `featuredTags` is `/tattoos`. A pin or an unpin
+  is told to the post's audience as `Add` or `Remove` on `featured`, as Mastodon tells it.
 - **Blocks are sent.** A blocked remote account receives `Block` from the blocking account (and `Reject{Follow}` if it
   followed); an unblock sends `Undo{Block}`.
 - **Reports** are sent as `Flag` by the instance actor, never by the reporting account.
@@ -169,8 +171,9 @@ persona's posts passed on to its followers. A deleted post answers 410 with a `T
   to a persona's public, unlisted or followers-only post goes on to the persona's followers as its author's server sent
   and signed it, the way Mastodon forwards it: to every follower's server but the replier's own. Its `Update` and
   `Delete` follow the same way. Nothing is passed on for a local-only post, a group's post or a reply that is not public
-  or unlisted. A server that receives it checks it as it checks any forwarded activity (Mastodon by the LD signature
-  or by reading the reply from its origin).
+  or unlisted. A server that receives it checks it as it checks any forwarded activity: Mastodon, Misskey and Sharkey
+  keep it only when its author LD-signed it (Mastodon does; Misskey 2026.10 and Akkoma do not), others read the reply
+  from its origin.
 - **Events** (owner decision 2026-10-05). A persona joins another server's event with a `Join` and leaves it with a
   `Leave`, both sent to the event's organiser only (`…/grunts/join-<id>`, `…/grunts/leave-<id>`). The organiser's
   server answers `Accept` (Mobilizon at once for an open event) or `Reject`, which the persona sees as

PrivaPub.Tests/Federation/FeaturedTests.cs

@@ -0,0 +1,143 @@
+using MongoDB.Entities;
+
+using PrivaPub.Models.Post;
+using PrivaPub.Models.Social;
+using PrivaPub.Tests.Support;
+
+using System.Text.Json.Nodes;
+
+namespace PrivaPub.Tests.Federation
+{
+	// pins across servers: an account elsewhere features its own posts (Add and Remove on its `featured` collection, and
+	// the collection itself), a community features posts made in it, and a persona's pin is told to its followers
+	[Trait("Category", "Integration")]
+	public sealed class FeaturedTests : IAsyncLifetime
+	{
+		Harness _harness;
+
+		public async ValueTask InitializeAsync()
+		{
+			Assert.SkipUnless(MongoFixture.Enabled, MongoFixture.Skip);
+			_harness = await Harness.Start();
+		}
+
+		public async ValueTask DisposeAsync()
+		{
+			if (_harness != default)
+				await _harness.DisposeAsync();
+		}
+
+		static string Origin(RemoteActor actor) => new Uri(actor.Id).GetLeftPart(UriPartial.Authority);
+
+		// a public note of the actor's, served where its id points
+		string Note(RemoteActor author, string text, string audience = default)
+		{
+			var path = $"/notes/{Guid.NewGuid():N}";
+			var note = new JsonObject
+			{
+				["id"] = Origin(author) + path, ["type"] = "Note", ["attributedTo"] = author.Id, ["content"] = $"<p>{text}</p>",
+				["to"] = new JsonArray("https://www.w3.org/ns/activitystreams#Public"), ["published"] = DateTime.UtcNow.ToString("O")
+			};
+			if (audience != default)
+				note["audience"] = audience;
+			_harness.Peer.Serve(path, note.ToJsonString());
+			return Origin(author) + path;
+		}
+
+		JsonObject Featuring(RemoteActor actor, string type, string objectUri, string target = default) => new()
+		{
+			["id"] = $"{actor.Id}#{type}-{Guid.NewGuid():N}", ["type"] = type, ["actor"] = actor.Id, ["object"] = objectUri,
+			["target"] = target ?? actor.Id + "/featured"
+		};
+
+		Task<List<RemoteFeatured>> FeaturedBy(RemoteActor actor) =>
+			DB.Default.Find<RemoteFeatured>().Match(f => f.ActorURI == actor.Id).Sort(f => f.Position, Order.Ascending).ExecuteAsync(TestContext.Current.CancellationToken);
+
+		[Fact]
+		public async Task An_account_features_its_own_post_and_takes_it_back_but_nothing_else()
+		{
+			var bob = new RemoteActor(_harness.Peer, "bob");
+			var carol = new RemoteActor(_harness.Peer, "carol", _harness.Peer.B);
+			var mine = Note(bob, "pinned");
+			var theirs = Note(carol, "not bob's");
+			var older = Note(bob, "pinned before");
+
+			await _harness.Deliver(bob, "/human-centipede", Featuring(bob, "Add", older));
+			await _harness.Deliver(bob, "/human-centipede", Featuring(bob, "Add", mine));
+			await _harness.Deliver(bob, "/human-centipede", Featuring(bob, "Add", theirs));
+			// Smithereen's wall is a collection of the actor's too, but no pin
+			await _harness.Deliver(bob, "/human-centipede", Featuring(bob, "Add", Note(bob, "on the wall"), bob.Id + "/wall"));
+
+			Assert.Equal(new[] { mine, older }, (await FeaturedBy(bob)).Select(f => f.ObjectURI));
+			var post = await DB.Default.Find<Post>().Match(p => p.ObjectURI == mine).ExecuteSingleAsync(TestContext.Current.CancellationToken);
+			Assert.Equal(post.ID, (await FeaturedBy(bob))[0].PostId);
+
+			await _harness.Deliver(bob, "/human-centipede", Featuring(bob, "Remove", mine));
+
+			Assert.Equal(new[] { older }, (await FeaturedBy(bob)).Select(f => f.ObjectURI));
+		}
+
+		[Fact]
+		public async Task The_featured_collection_is_read_in_its_order_from_the_accounts_own_server()
+		{
+			var token = TestContext.Current.CancellationToken;
+			var bob = new RemoteActor(_harness.Peer, "bob");
+			var first = Note(bob, "first pin");
+			var second = Note(bob, "second pin");
+			_harness.Peer.Serve(new Uri(bob.Id).AbsolutePath + "/featured", new JsonObject
+			{
+				["id"] = bob.Id + "/featured", ["type"] = "OrderedCollection", ["totalItems"] = 2,
+				["orderedItems"] = new JsonArray(new JsonObject { ["id"] = first, ["type"] = "Note" }, second)
+			}.ToJsonString());
+			var account = await _harness.Remote.GetActor(bob.Id, refresh: false, token);
+
+			await _harness.Featured.Sync(account, token);
+
+			Assert.Equal(new[] { first, second }, (await FeaturedBy(bob)).Select(f => f.ObjectURI));
+		}
+
+		[Fact]
+		public async Task A_personas_pin_and_unpin_reach_its_followers_as_add_and_remove()
+		{
+			var token = TestContext.Current.CancellationToken;
+			var (root, alice) = await _harness.Persona("alice");
+			var follower = new RemoteActor(_harness.Peer, "fan");
+			await _harness.FollowedBy(alice, follower);
+			await _harness.Posts.InsertPost(root, new PrivaPub.ClientModels.Post.InsertPostForm { AvatarId = alice.Id, Text = "worth a pin" }, token);
+			var post = await DB.Default.Find<Post>().Match(p => p.GroupUserId == alice.Id).ExecuteFirstAsync(token);
+
+			await _harness.Outbox.PublishFeatured(alice.Id, post, featured: true, token);
+			await _harness.Outbox.PublishFeatured(alice.Id, post, featured: false, token);
+
+			var sent = (await _harness.Outgoing(follower.SharedInbox)).Concat(await _harness.Outgoing(follower.Id + "/inbox"))
+				.Where(a => a["type"]!.GetValue<string>() is "Add" or "Remove").ToList();
+			Assert.Equal(new[] { "Add", "Remove" }, sent.Select(a => a["type"]!.GetValue<string>()));
+			Assert.All(sent, a => Assert.Equal((alice.PostUri(post.ID), alice.Featured), (a["object"]!.GetValue<string>(), a["target"]!.GetValue<string>())));
+		}
+
+		[Fact]
+		public async Task A_community_features_a_post_made_in_it()
+		{
+			var token = TestContext.Current.CancellationToken;
+			var (_, alice) = await _harness.Persona("alice");
+			var community = new RemoteActor(_harness.Peer, "books", type: "Group");
+			var member = new RemoteActor(_harness.Peer, "reader", _harness.Peer.B);
+			var account = await _harness.Remote.GetActor(community.Id, refresh: false, token);
+			await DB.Default.SaveAsync(new Following { AvatarId = alice.Id, TargetActorURI = community.Id, TargetAccountId = account.ID, State = FollowState.Accepted }, token);
+			var post = Note(member, "a thread in the community", community.Id);
+
+			await _harness.Deliver(community, "/human-centipede", new JsonObject
+			{
+				["id"] = $"{community.Id}#announce-{Guid.NewGuid():N}", ["type"] = "Announce", ["actor"] = community.Id,
+				["to"] = new JsonArray("https://www.w3.org/ns/activitystreams#Public"),
+				["object"] = new JsonObject
+				{
+					["id"] = $"{Origin(member)}/activities/{Guid.NewGuid():N}", ["type"] = "Add", ["actor"] = member.Id, ["object"] = post,
+					["target"] = community.Id + "/featured"
+				}
+			});
+
+			Assert.Equal(new[] { post }, (await FeaturedBy(community)).Select(f => f.ObjectURI));
+		}
+	}
+}

PrivaPub.Tests/Http/MastodonAccountsTests.cs

@@ -183,6 +183,33 @@ namespace PrivaPub.Tests.Http
 			Assert.Contains(alice.Id, (await alice.Client.Get($"/api/v1/accounts/search?q={alice.UserName}")).Ok().Ids);
 		}
 
+		// an account elsewhere: what it features, in its order, its public posts only
+		[Fact]
+		public async Task A_remote_accounts_pinned_statuses_are_what_it_features()
+		{
+			var alice = await _host.Mastodon("alice");
+			var (bob, bobId) = await Remote();
+			Post Held(string text, PostVisibility visibility) => new()
+			{
+				ObjectURI = $"{bob.Id}/statuses/{Guid.NewGuid():N}", ActorURI = bob.Id, AuthorAccountId = bobId, IsFederatedCopy = true,
+				Visibility = visibility, ContentHtml = $"<p>{text}</p>", CreationDate = DateTime.UtcNow, UpdateDate = DateTime.UtcNow
+			};
+			var first = Held("first pin", PostVisibility.Public);
+			var second = Held("second pin", PostVisibility.Unlisted);
+			var hidden = Held("for followers", PostVisibility.FollowersOnly);
+			await DB.Default.SaveAsync(new[] { first, second, hidden }, Token);
+			await DB.Default.SaveAsync(new[]
+			{
+				new RemoteFeatured { ActorURI = bob.Id, ObjectURI = second.ObjectURI, PostId = second.ID, Position = 1 },
+				new RemoteFeatured { ActorURI = bob.Id, ObjectURI = hidden.ObjectURI, PostId = hidden.ID, Position = 2 },
+				new RemoteFeatured { ActorURI = bob.Id, ObjectURI = first.ObjectURI, PostId = first.ID, Position = 0 }
+			}, Token);
+
+			var pinned = (await alice.Client.Get($"/api/v1/accounts/{bobId}/statuses?pinned=true")).Ok();
+
+			Assert.Equal(new[] { first.ID, second.ID }, pinned.Ids);
+		}
+
 		[Fact]
 		public async Task Account_statuses_filter_pins_replies_reblogs_media_and_tags_and_page_both_ways()
 		{

PrivaPub.Tests/Support/Harness.cs

@@ -56,6 +56,7 @@ namespace PrivaPub.Tests.Support
 			Receiver = new InboxReceiver(Local, Remote, Queue, new NoBlocks(), NullLogger<InboxReceiver>.Instance, Ledger);
 			Follows = new FollowService(Db, Local, Remote, Delivery, new KeyLocalizer<GenericRes>(), NullLogger<FollowService>.Instance);
 			Relationships = new RelationshipService(Db, Follows, Delivery);
+			Featured = new FeaturedPosts(Db, Remote, RemotePosts);
 			Handlers = new IActivityHandler[]
 			{
 				new FollowHandler(Db, Local, Remote, Delivery),
@@ -74,7 +75,9 @@ namespace PrivaPub.Tests.Support
 				new FlagHandler(Db, Local),
 				new BlockHandler(Db, Local),
 				new LockHandler(Db),
-				new MoveHandler(Remote, Db, Local, Follows, Relationships)
+				new MoveHandler(Remote, Db, Local, Follows, Relationships),
+				new FeaturedHandler(Featured, add: true),
+				new FeaturedHandler(Featured, add: false)
 			};
 			((AnnounceHandler)Handlers.First(h => h is AnnounceHandler)).Relays = Handlers;
 			Processor = new InboxProcessor(Remote, Handlers, NullLogger<InboxProcessor>.Instance, Ledger, Local);
@@ -114,6 +117,7 @@ namespace PrivaPub.Tests.Support
 		public Participations Participations { get; }
 		public TimelineService Timelines { get; }
 		public RelationshipService Relationships { get; }
+		public FeaturedPosts Featured { get; }
 		public ReportService Reports { get; }
 
 		public async Task FollowedBy(LocalActor local, RemoteActor follower) =>

PrivaPub.Tests/Support/RemoteActor.cs

@@ -36,6 +36,7 @@ namespace PrivaPub.Tests.Support
 			["preferredUsername"] = Name,
 			["inbox"] = Id + "/inbox",
 			["followers"] = Id + "/followers",
+			["featured"] = Id + "/featured",
 			["publicKey"] = new JsonObject
 			{
 				["id"] = KeyId,

PrivaPub/Api/Mastodon/Controllers/AccountsController.cs

@@ -154,7 +154,12 @@ namespace PrivaPub.Api.Mastodon.Controllers
 			if (Params.Bool("pinned") == true)
 			{
 				if (local == default)
-					return Json(Array.Empty<Status>());
+				{
+					var featured = (await DB.Default.Find<RemoteFeatured>().Match(f => f.ActorURI == remote.ActorURI).Sort(f => f.Position, Order.Ascending)
+						.Limit(Federation.Actors.FeaturedPosts.MaxFeatured).ExecuteAsync(token)).Select(f => f.PostId).ToList();
+					var featuredPosts = await _dbEntities.Posts.Match(p => featured.Contains(p.ID) && !p.DeletedAt.HasValue).Match(VisibilityPolicy.IsPublic).ExecuteAsync(token);
+					return Json(await _mapper.Statuses(featured.Select(id => featuredPosts.FirstOrDefault(p => p.ID == id)).Where(p => p != default).ToList(), MyId, token));
+				}
 				var pinIds = (await DB.Default.Find<Pin>().Match(p => p.AvatarId == local.Id).Sort(p => p.ID, Order.Descending).ExecuteAsync(token)).Select(p => p.PostId).ToList();
 				var pinnedPosts = await _dbEntities.Posts.Match(p => pinIds.Contains(p.ID)).Match(VisibilityPolicy.IsPublic).ExecuteAsync(token);
 				return Json(await _mapper.Statuses(pinIds.Select(id => pinnedPosts.FirstOrDefault(p => p.ID == id)).Where(p => p != default).ToList(), MyId, token));

PrivaPub/Api/Mastodon/Controllers/StatusesController.cs

@@ -405,6 +405,7 @@ namespace PrivaPub.Api.Mastodon.Controllers
 			try
 			{
 				await DB.Default.SaveAsync(new Models.Social.Pin { AvatarId = MyId, PostId = post.ID }, token);
+				await _outbox.PublishFeatured(MyId, post, featured: true, token);
 			}
 			catch (MongoDB.Driver.MongoWriteException ex) when (ex.WriteError?.Category == MongoDB.Driver.ServerErrorCategory.DuplicateKey)
 			{
@@ -415,7 +416,9 @@ namespace PrivaPub.Api.Mastodon.Controllers
 		[HttpPost("/api/v1/statuses/{id}/unpin"), Scope("write:accounts")]
 		public async Task<IActionResult> Unpin(string id, CancellationToken token)
 		{
-			await DB.Default.DeleteAsync<Models.Social.Pin>(p => p.AvatarId == MyId && p.PostId == id);
+			var unpinned = await DB.Default.DeleteAsync<Models.Social.Pin>(p => p.AvatarId == MyId && p.PostId == id);
+			if (unpinned is { IsAcknowledged: true, DeletedCount: > 0 } && await _dbEntities.Posts.MatchID(id).ExecuteFirstAsync(token) is { } post)
+				await _outbox.PublishFeatured(MyId, post, featured: false, token);
 			return await Unchanged(id, token);
 		}
 

PrivaPub/Federation/Actors/AccountCountsJob.cs

@@ -10,17 +10,20 @@ using PrivaPub.StaticServices;
 namespace PrivaPub.Federation.Actors
 {
 	// A remote account's follower, following and post counts, as its own server publishes them (the totalItems of its
-	// followers, following and outbox collections). Read when the account is fetched, at most once a day, never when
-	// someone looks at it; a hidden or missing collection leaves its count unknown. Mastodon and GoToSocial do the same.
+	// followers, following and outbox collections), and the posts it features. Read when the account is fetched, at most
+	// once a day, never when someone looks at it; a hidden or missing collection leaves its count unknown. Mastodon and
+	// GoToSocial do the same.
 	public class AccountCountsJob : IJobHandler
 	{
 		readonly IRemoteActorService _remoteActors;
 		readonly DbEntities _dbEntities;
+		readonly IFeaturedPosts _featured;
 
-		public AccountCountsJob(IRemoteActorService remoteActors, DbEntities dbEntities)
+		public AccountCountsJob(IRemoteActorService remoteActors, DbEntities dbEntities, IFeaturedPosts featured = default)
 		{
 			_remoteActors = remoteActors;
 			_dbEntities = dbEntities;
+			_featured = featured;
 		}
 
 		public JobKind Kind => JobKind.CountAccount;
@@ -41,6 +44,8 @@ namespace PrivaPub.Federation.Actors
 				.Modify(a => a.StatusesCount, await Total(actor, actor.OutboxURL, token))
 				.Modify(a => a.CountedAt, DateTime.UtcNow)
 				.ExecuteAsync(token);
+			if (_featured != default)
+				await _featured.Sync(actor, token);
 			return JobOutcome.Done;
 		}
 

PrivaPub/Federation/Actors/ActorDocument.cs

@@ -23,6 +23,7 @@ namespace PrivaPub.Federation.Actors
 		public string Outbox { get; init; }
 		public string Followers { get; init; }
 		public string Following { get; init; }
+		public string Featured { get; init; }
 		public string SharedInbox { get; init; }
 		public string Icon { get; init; }
 		public bool Discoverable { get; init; } = true;
@@ -73,6 +74,7 @@ namespace PrivaPub.Federation.Actors
 				Outbox = RemoteActorService.Text(root, "outbox"),
 				Followers = RemoteActorService.Text(root, "followers"),
 				Following = RemoteActorService.Text(root, "following"),
+				Featured = RemoteActorService.Text(root, "featured"),
 				SharedInbox = root.TryGetProperty("endpoints", out var endpoints) ? RemoteActorService.Text(endpoints, "sharedInbox") : default,
 				Icon = root.TryGetProperty("icon", out var icon) ? RemoteActorService.Text(icon, "url") : default,
 				Discoverable = !root.TryGetProperty("discoverable", out var discoverable) || discoverable.ValueKind != JsonValueKind.False,

PrivaPub/Federation/Actors/FeaturedPosts.cs

@@ -0,0 +1,156 @@
+using MongoDB.Driver;
+using MongoDB.Entities;
+
+using PrivaPub.Federation.Inbox;
+using PrivaPub.Federation.Objects;
+using PrivaPub.Infrastructure.Http;
+using PrivaPub.Models.Social;
+using PrivaPub.Models.User;
+using PrivaPub.StaticServices;
+
+using System.Text.Json;
+using System.Text.Json.Nodes;
+
+using static PrivaPub.Federation.Objects.ActivityJson;
+
+using PostEntity = PrivaPub.Models.Post.Post;
+
+namespace PrivaPub.Federation.Actors
+{
+	public interface IFeaturedPosts
+	{
+		Task Receive(JsonNode activity, ForeignAvatar owner, bool add, CancellationToken token);
+		Task Sync(ForeignAvatar owner, CancellationToken token);
+	}
+
+	// What an account elsewhere features (pins): its `featured` collection, read with its counts at most once a day, and
+	// the Add and Remove it sends when it pins or unpins. An account features only its own posts; a community (Lemmy's,
+	// inside its announce) features posts made in it. Shown first on its profile here, as Mastodon shows them.
+	public class FeaturedPosts : IFeaturedPosts
+	{
+		public const int MaxFeatured = 20;
+
+		readonly DbEntities _dbEntities;
+		readonly IRemoteActorService _remoteActors;
+		readonly IRemotePosts _remotePosts;
+
+		public FeaturedPosts(DbEntities dbEntities, IRemoteActorService remoteActors, IRemotePosts remotePosts)
+		{
+			_dbEntities = dbEntities;
+			_remoteActors = remoteActors;
+			_remotePosts = remotePosts;
+		}
+
+		public async Task Receive(JsonNode activity, ForeignAvatar owner, bool add, CancellationToken token)
+		{
+			if (string.IsNullOrEmpty(owner.FeaturedURL) || Id(activity["target"]) != owner.FeaturedURL)
+			{
+				Arrival.Drop("unknown-target");
+				return;
+			}
+			var objectUri = Id(activity["object"]);
+			if (objectUri == default)
+			{
+				Arrival.Drop("unparseable");
+				return;
+			}
+			if (!add)
+			{
+				var removed = await DB.Default.DeleteAsync<RemoteFeatured>(f => f.ActorURI == owner.ActorURI && f.ObjectURI == objectUri);
+				if (removed is { IsAcknowledged: true, DeletedCount: > 0 })
+					Arrival.Accept("unfeatured");
+				else
+					Arrival.Drop("unknown-object");
+				return;
+			}
+			var post = await Featurable(owner, objectUri, token);
+			if (post == default)
+			{
+				Arrival.Drop("unknown-object");
+				return;
+			}
+			Arrival.About(post.ObjectType ?? "Note", post.Visibility, post.CreationDate);
+			var first = await DB.Default.Find<RemoteFeatured>().Match(f => f.ActorURI == owner.ActorURI).Sort(f => f.Position, Order.Ascending).ExecuteFirstAsync(token);
+			try
+			{
+				await DB.Default.SaveAsync(new RemoteFeatured
+				{
+					ActorURI = owner.ActorURI,
+					ObjectURI = objectUri,
+					PostId = post.ID,
+					Position = (first?.Position ?? 0) - 1
+				}, token);
+				Arrival.Accept("featured");
+			}
+			catch (MongoWriteException ex) when (ex.WriteError?.Category == ServerErrorCategory.DuplicateKey)
+			{
+				Arrival.Drop("duplicate");
+			}
+		}
+
+		public async Task Sync(ForeignAvatar owner, CancellationToken token)
+		{
+			if (string.IsNullOrEmpty(owner.FeaturedURL) || !Origin.Same(owner.FeaturedURL, owner.ActorURI))
+				return;
+			var uris = await Items(owner, token);
+			if (uris == default)
+				return;
+			var featured = new List<RemoteFeatured>();
+			foreach (var uri in uris.Distinct(StringComparer.Ordinal).Take(MaxFeatured))
+				if (await Featurable(owner, uri, token) is { } post)
+					featured.Add(new RemoteFeatured { ActorURI = owner.ActorURI, ObjectURI = uri, PostId = post.ID, Position = featured.Count });
+			await DB.Default.DeleteAsync<RemoteFeatured>(f => f.ActorURI == owner.ActorURI);
+			if (featured.Count > 0)
+				await DB.Default.SaveAsync(featured, token);
+		}
+
+		// the post, held or fetched from its own server, when the owner may feature it
+		async Task<PostEntity> Featurable(ForeignAvatar owner, string objectUri, CancellationToken token)
+		{
+			var isGroup = owner.AvatarType is AvatarType.Group;
+			if (!isGroup && !Origin.Same(objectUri, owner.ActorURI))
+				return default;
+			var post = await _dbEntities.Posts.Match(p => p.ObjectURI == objectUri && !p.DeletedAt.HasValue).ExecuteFirstAsync(token)
+				?? await _remotePosts.StoreContext(objectUri, 0, token);
+			return post switch
+			{
+				null => default,
+				{ ReblogOfPostId: not null } => default,
+				_ when isGroup => post.AudienceURI == owner.ActorURI ? post : default,
+				_ => post.ActorURI == owner.ActorURI ? post : default
+			};
+		}
+
+		// the collection's items, in its order, from its first page when it pages: links or embedded objects alike
+		async Task<List<string>> Items(ForeignAvatar owner, CancellationToken token)
+		{
+			using var scope = HttpScope.For("collection");
+			using var collection = await _remoteActors.FetchObject(owner.FeaturedURL, token);
+			if (collection == default || collection.Root.ValueKind != JsonValueKind.Object)
+				return default;
+			var items = ItemsOf(collection.Root);
+			if (items.Count > 0 || !collection.Root.TryGetProperty("first", out var first))
+				return items;
+			if (first.ValueKind == JsonValueKind.Object)
+				return ItemsOf(first);
+			var page = first.ValueKind == JsonValueKind.String ? first.GetString() : default;
+			if (page == default || !Origin.Same(page, owner.ActorURI))
+				return items;
+			using var fetched = await _remoteActors.FetchObject(page, token);
+			return fetched == default || fetched.Root.ValueKind != JsonValueKind.Object ? items : ItemsOf(fetched.Root);
+		}
+
+		static List<string> ItemsOf(JsonElement collection)
+		{
+			var items = new List<string>();
+			foreach (var name in new[] { "orderedItems", "items" })
+				if (collection.TryGetProperty(name, out var list) && list.ValueKind == JsonValueKind.Array)
+					foreach (var item in list.EnumerateArray())
+						if (item.ValueKind == JsonValueKind.String)
+							items.Add(item.GetString());
+						else if (item.ValueKind == JsonValueKind.Object && item.TryGetProperty("id", out var id) && id.ValueKind == JsonValueKind.String)
+							items.Add(id.GetString());
+			return items;
+		}
+	}
+}

PrivaPub/Federation/Actors/RemoteActorService.cs

@@ -204,6 +204,7 @@ namespace PrivaPub.Federation.Actors
 				.Modify(a => a.OutboxURL, actor.Outbox)
 				.Modify(a => a.FollowersURL, actor.Followers)
 				.Modify(a => a.FollowingURL, actor.Following)
+				.Modify(a => a.FeaturedURL, Origin.Same(actor.Featured, actor.Id) ? actor.Featured : default)
 				.Modify(a => a.SharedInboxURL, actor.SharedInbox)
 				.Modify(a => a.PictureURL, actor.Icon)
 				.Modify(a => a.ThumbnailURL, actor.Header)

PrivaPub/Federation/Inbox/Handlers/AnnounceHandler.cs

@@ -228,6 +228,15 @@ namespace PrivaPub.Federation.Inbox.Handlers
 				case "Like" or "Dislike" or "Undo":
 					await Relayed(inner, group, token);
 					break;
+				// a moderator features a post in the community, or no longer: the community's own pins
+				case "Add" or "Remove" when Id(inner["target"]) is { } target && target == group.FeaturedURL:
+					var featured = (Relays ?? _services?.GetService(typeof(IEnumerable<IActivityHandler>)) as IEnumerable<IActivityHandler>)
+						?.FirstOrDefault(h => h.Type == Value(inner, "type"));
+					if (featured == default)
+						Arrival.Drop("unsupported");
+					else
+						await featured.Handle(inner, group, token);
+					break;
 				default:
 					Arrival.Drop("unsupported");
 					break;

PrivaPub/Federation/Inbox/Handlers/FeaturedHandler.cs

@@ -0,0 +1,26 @@
+using PrivaPub.Federation.Actors;
+using PrivaPub.Models.User;
+
+using System.Text.Json.Nodes;
+
+namespace PrivaPub.Federation.Inbox.Handlers
+{
+	// An account pins one of its posts (Add to its `featured` collection) or unpins it (Remove), as Mastodon and Akkoma
+	// send it; inside a community's announce, the community features a post made in it. Any other target (Smithereen's
+	// wall, a community's moderators) is not ours to keep.
+	public class FeaturedHandler : IActivityHandler
+	{
+		readonly IFeaturedPosts _featured;
+		readonly bool _add;
+
+		public FeaturedHandler(IFeaturedPosts featured, bool add)
+		{
+			_featured = featured;
+			_add = add;
+		}
+
+		public string Type => _add ? "Add" : "Remove";
+
+		public Task Handle(JsonNode activity, ForeignAvatar actor, CancellationToken token) => _featured.Receive(activity, actor, _add, token);
+	}
+}

PrivaPub/Federation/Outbox/OutboxPublisher.cs

@@ -20,6 +20,7 @@ namespace PrivaPub.Federation.Outbox
 		Task Publish(LocalActor author, PostEntity post, JsonObject activity, CancellationToken token);
 		Task PublishUpdate(LocalActor author, PostEntity post, string reason, CancellationToken token);
 		Task PublishProfile(LocalActor actor, CancellationToken token);
+		Task PublishFeatured(string personaId, PostEntity post, bool featured, CancellationToken token);
 	}
 
 	public class OutboxPublisher : IOutboxPublisher
@@ -110,6 +111,26 @@ namespace PrivaPub.Federation.Outbox
 				await _delivery.Enqueue(author, inboxes, activity, token);
 		}
 
+		// a persona pins its post or unpins it: Add or Remove on its featured collection (/trophies, which serves the same
+		// pins), told to the post's audience as Mastodon tells it
+		public async Task PublishFeatured(string personaId, PostEntity post, bool featured, CancellationToken token)
+		{
+			var author = await _localActors.FindById(LocalActorKind.Person, personaId, token);
+			if (author is not { IsFederated: true } || post.IsLocalOnly)
+				return;
+			await Publish(author, post, new JsonObject
+			{
+				["@context"] = ActivityPubRenderer.Context(),
+				["id"] = author.ActivityUri($"{(featured ? "feature" : "unfeature")}-{post.ID}-{DateTime.UtcNow.Ticks}"),
+				["type"] = featured ? "Add" : "Remove",
+				["actor"] = author.Uri,
+				["object"] = author.PostUri(post.ID),
+				["target"] = author.Featured,
+				["to"] = new JsonArray(Objects.Addressing.Public),
+				["cc"] = new JsonArray(author.Followers)
+			}, token);
+		}
+
 		public async Task PublishUpdate(LocalActor author, PostEntity post, string reason, CancellationToken token)
 		{
 			var group = string.IsNullOrEmpty(post.GroupId) ? default : await _localActors.FindById(LocalActorKind.Group, post.GroupId, token);

PrivaPub/Infrastructure/Data/Indexes.cs

@@ -121,7 +121,8 @@ namespace PrivaPub.Infrastructure.Data
 				(() => DB.Default.Index<Mute>().Key(m => m.AvatarId, KeyType.Ascending).Key(m => m.TargetActorURI, KeyType.Ascending).Option(o => o.Unique = true).CreateAsync(token), "mute"),
 				(() => DB.Default.Index<AccountDomainBlock>().Key(b => b.AvatarId, KeyType.Ascending).Key(b => b.Domain, KeyType.Ascending).Option(o => o.Unique = true).CreateAsync(token), "domain block"),
 				(() => DB.Default.Index<Bookmark>().Key(b => b.AvatarId, KeyType.Ascending).Key(b => b.PostId, KeyType.Ascending).Option(o => o.Unique = true).CreateAsync(token), "bookmark"),
-				(() => DB.Default.Index<Pin>().Key(p => p.AvatarId, KeyType.Ascending).Key(p => p.PostId, KeyType.Ascending).Option(o => o.Unique = true).CreateAsync(token), "pin")
+				(() => DB.Default.Index<Pin>().Key(p => p.AvatarId, KeyType.Ascending).Key(p => p.PostId, KeyType.Ascending).Option(o => o.Unique = true).CreateAsync(token), "pin"),
+				(() => DB.Default.Index<RemoteFeatured>().Key(f => f.ActorURI, KeyType.Ascending).Key(f => f.ObjectURI, KeyType.Ascending).Option(o => o.Unique = true).CreateAsync(token), "remote-featured")
 			})
 				await pair.Item1();
 			await Plain<Block>(token, b => b.TargetActorURI);

PrivaPub/Middleware/SocialPubConfigurations.cs

@@ -94,6 +94,9 @@ namespace PrivaPub.Middleware
 				.AddSingleton<IActivityHandler, FlagHandler>()
 				.AddSingleton<IActivityHandler, BlockHandler>()
 				.AddSingleton<IActivityHandler, LockHandler>()
+				.AddSingleton<Federation.Actors.IFeaturedPosts, Federation.Actors.FeaturedPosts>()
+				.AddSingleton<IActivityHandler>(services => new FeaturedHandler(services.GetRequiredService<Federation.Actors.IFeaturedPosts>(), add: true))
+				.AddSingleton<IActivityHandler>(services => new FeaturedHandler(services.GetRequiredService<Federation.Actors.IFeaturedPosts>(), add: false))
 				.AddSingleton<IActivityHandler, MoveHandler>()
 				.AddSingleton<IActivityHandler, CreateHandler>()
 				.AddSingleton<IActivityHandler, DeleteHandler>()

PrivaPub/Models/Social/Relationships.cs

@@ -21,6 +21,17 @@ namespace PrivaPub.Models.Social
 		public DateTime CreatedAt { get; set; } = DateTime.UtcNow;
 	}
 
+	//a post an account elsewhere features (its `featured` collection, Add and Remove), shown first on its profile here;
+	//the lowest Position first
+	public class RemoteFeatured : Entity
+	{
+		public string ActorURI { get; set; }
+		public string ObjectURI { get; set; }
+		public string PostId { get; set; }
+		public int Position { get; set; }
+		public DateTime CreatedAt { get; set; } = DateTime.UtcNow;
+	}
+
 	public class Mute : Entity
 	{
 		public string AvatarId { get; set; }

PrivaPub/Models/User/Avatar.cs

@@ -75,6 +75,7 @@ namespace PrivaPub.Models.User
 		public string SharedInboxURL { get; set; }
 		public string InboxURL { get; set; }
 		public string OutboxURL { get; set; }
+		public string FeaturedURL { get; set; }//featured: the posts it pins
 		public string MovedToURL { get; set; }
 		public List<string> AlsoKnownAs { get; set; } = new();//alsoKnownAs: the accounts it says it also is
 		public string PictureURL { get; set; }//icon

docs/INTEROP.md

@@ -145,7 +145,7 @@ Priorities, used throughout:
 | Inbound `Move` with Mastodon's checks (`target` re-fetched, its `alsoKnownAs` lists the old account); move each persona's follow, lists, mutes and blocks (done 2026-10-05) | P1 | `Account.moved` |
 | Re-run WebFinger when `preferredUsername` changes; key accounts on the actor id | P2 | `Account.acct` |
 | Inbound `Block`: stop delivering, hide (**done** 2026-10-04) | P2 | `relationship.blocked_by` |
-| `Add`/`Remove` featured (pins, tags) | P2 | `GET /accounts/:id/statuses?pinned=true` |
+| `Add`/`Remove` featured (pins, tags): pins both ways and the collection read daily, done 2026-10-05; featured tags open | P2 | `GET /accounts/:id/statuses?pinned=true` |
 | Remote like and boost totals | P2 | counts |
 | Read the thread's `context` collection to complete a thread (**done** 2026-10-05, `FetchReplies`) | P2 | `/statuses/:id/context` |
 | Publish `context` and a paged `replies` | P2 | — |

docs/ROADMAP.md

@@ -664,7 +664,8 @@ it, raw where it doesn't.
   - inbound `Move` with Mastodon's checks: **done 2026-10-05** (the old account shows `moved`, the personas' follows,
     lists, mutes and blocks move to the new one, owner decision; checked live against GoToSocial);
   - re-run WebFinger on a rename;
-  - inbound `Block`, plus `Add`/`Remove` of pins;
+  - inbound `Block`; `Add`/`Remove` of pins: **done 2026-10-05** (both ways, a community's pins too, the `featured`
+    collection read with an account's counts; checked live against Mastodon);
   - FEP-8fcf followers sync;
   - `indexable`/`discoverable`/`searchableBy`;
   - edit history from `formerRepresentations`;

tools/pasture/scenarios/pins.sh

@@ -0,0 +1,54 @@
+# Pinned posts across servers (featured, FEP-e232's Add and Remove): a Mastodon account pins and unpins while alice
+# follows it; alice pins and unpins while it follows her; an account that pinned before PrivaPub ever saw it shows its
+# pins once resolved (its featured collection, read with its counts). Needs the mastodon peer.
+M=https://mastodon.test:6443
+mcurl() { curl -sk --resolve mastodon.test:6443:127.0.0.1 "$@"; }
+. "$here/peers/mastodon.sh"
+p_pinned() { curl -s -H "$PH" "$P/api/v1/accounts/$1/statuses?pinned=true" | j "print(' '.join(s['uri'] for s in d))"; }
+m_pinned() { mcurl -H "$MH" "$M/api/v1/accounts/$1/statuses?pinned=true" | j "print(' '.join(s['uri'] for s in d))"; }
+
+echo "pins"
+PT=$(privapub_token alice_pins)
+PH="Authorization: Bearer $PT"
+[ -n "$PT" ] && ok "PrivaPub token for alice_pins" || { ko "PrivaPub token for alice_pins"; return 1; }
+run=$(date +%s)
+mastodon_user pinner
+MT=$(mastodon_token pinner)
+MH="Authorization: Bearer $MT"
+[ -n "$MT" ] && ok "Mastodon token for pinner" || { ko "Mastodon token for pinner"; return 1; }
+
+echo "  following each other"
+pinner_on_p=$(curl -s -H "$PH" "$P/api/v2/search?q=pinner@mastodon.test&resolve=true&type=accounts" | j "print(d['accounts'][0]['id'])")
+curl -s -o /dev/null -X POST -H "$PH" "$P/api/v1/accounts/$pinner_on_p/follow"
+alice_on_m=$(mcurl -H "$MH" "$M/api/v2/search?q=@alice_pins@privapub.test&resolve=true&type=accounts" | j "print(d['accounts'][0]['id'])")
+mcurl -o /dev/null -X POST -H "$MH" "$M/api/v1/accounts/$alice_on_m/follow"
+until_true 45 '[ "$(curl -s -H "$PH" "$P/api/v1/accounts/relationships?id[]=$pinner_on_p" | j "print(d[0][\"following\"] and d[0][\"followed_by\"])")" = "True" ]' \
+	&& ok "alice and pinner follow each other" || ko "the follows between alice and pinner never took"
+
+echo "  pinner pins"
+m_post=$(mcurl -X POST -H "$MH" "$M/api/v1/statuses" -d "status=a Mastodon post worth pinning $run&visibility=public")
+m_post_id=$(echo "$m_post" | j "print(d['id'])"); m_post_uri=$(echo "$m_post" | j "print(d['uri'])")
+mcurl -o /dev/null -X POST -H "$MH" "$M/api/v1/statuses/$m_post_id/pin"
+until_true 45 '[ "$(p_pinned $pinner_on_p)" = "$m_post_uri" ]' && ok "pinner's pin shows on its profile here" || ko "pinner's pin never arrived ($(p_pinned $pinner_on_p))"
+mcurl -o /dev/null -X POST -H "$MH" "$M/api/v1/statuses/$m_post_id/unpin"
+until_true 45 '[ -z "$(p_pinned $pinner_on_p)" ]' && ok "and its unpin takes it off" || ko "pinner's unpin never arrived"
+
+echo "  alice pins"
+p_post=$(curl -s -X POST -H "$PH" "$P/api/v1/statuses" -d "status=a PrivaPub post worth pinning $run&visibility=public")
+p_post_id=$(echo "$p_post" | j "print(d['id'])"); p_post_uri=$(echo "$p_post" | j "print(d['uri'])")
+until_true 45 '[ "$(mcurl -H "$MH" "$M/api/v1/accounts/$alice_on_m/statuses?limit=5" | j "print(any(s[\"uri\"] == \"$p_post_uri\" for s in d))")" = "True" ]'
+curl -s -o /dev/null -X POST -H "$PH" "$P/api/v1/statuses/$p_post_id/pin"
+until_true 45 '[ "$(m_pinned $alice_on_m)" = "$p_post_uri" ]' && ok "alice's pin shows on her profile on Mastodon" || ko "alice's pin never reached Mastodon ($(m_pinned $alice_on_m))"
+curl -s -o /dev/null -X POST -H "$PH" "$P/api/v1/statuses/$p_post_id/unpin"
+until_true 45 '[ -z "$(m_pinned $alice_on_m)" ]' && ok "and her unpin takes it off" || ko "alice's unpin never reached Mastodon"
+
+echo "  pins made before"
+# a fresh account pins first; PrivaPub reads its featured collection when it first fetches it
+early="early$run"
+mastodon_user "$early"
+ET=$(mastodon_token "$early")
+e_post=$(mcurl -X POST -H "Authorization: Bearer $ET" "$M/api/v1/statuses" -d "status=pinned before anyone looked $run&visibility=public")
+mcurl -o /dev/null -X POST -H "Authorization: Bearer $ET" "$M/api/v1/statuses/$(echo "$e_post" | j "print(d['id'])")/pin"
+early_on_p=$(curl -s -H "$PH" "$P/api/v2/search?q=$early@mastodon.test&resolve=true&type=accounts" | j "print(d['accounts'][0]['id'])")
+until_true 45 '[ "$(p_pinned $early_on_p)" = "$(echo "$e_post" | j "print(d[\"uri\"])")" ]' \
+	&& ok "an account's earlier pin shows once it is resolved" || ko "the earlier pin never showed ($(p_pinned $early_on_p))"

tools/pasture/town/check.py

@@ -37,10 +37,17 @@ NEEDS_PICTURE = {"pixelfed"}
 # others there (nobody relays a followers-only reply), nor anything under it
 THREAD_BOUND = {"friendica"}
 # Mastodon takes an activity another server passes on only with its author's LD signature (or a FEP-8b32 proof) and
-# drops it otherwise (ActivityPub::ProcessActivityService); of the platforms here only Mastodon and Misskey and its forks
-# sign their Creates that way, so another's reply PrivaPub passes on never lands there
-NEEDS_LD_SIGNATURE = {"mastodon"}
-LD_SIGNS = {"mastodon", "misskey", "sharkey"}
+# drops it otherwise (ActivityPub::ProcessActivityService); Misskey and Sharkey skip it the same way ("http-signature
+# verification failed and no LD-Signature"). Of the platforms here only Mastodon signs its Creates that way: Misskey
+# 2026.10's carry no signature (seen in the village of 2026-10-05), so another's reply PrivaPub passes on lands there
+# only when Mastodon wrote it
+NEEDS_LD_SIGNATURE = {"mastodon", "misskey", "sharkey"}
+LD_SIGNS = {"mastodon"}
+# Misskey and Sharkey count no renote by a bot (NoteCreateService: `!user.isBot` before incRenoteCount)
+BOT_RENOTES_UNCOUNTED = {"misskey", "sharkey"}
+# a Lemmy account's vote goes to the community alone, which announces it; Mastodon takes no Announce of a Like, so a
+# Lemmy vote on a Mastodon post in a community never counts there
+GROUP_VOTES_UNSEEN = {"mastodon"}
 
 
 class World:
@@ -256,6 +263,7 @@ class Sweep:
 	# -- counts on the object's own server, and PrivaPub's exact counts
 	def counts(self, stored):
 		likes, reacts, boosts, votes = defaultdict(int), defaultdict(lambda: defaultdict(int)), defaultdict(int), defaultdict(lambda: defaultdict(int))
+		bot_boosts = defaultdict(int)
 		for f in self.w.interactions:
 			ref = f["ref"]
 			if f["verb"] == "like":
@@ -269,6 +277,8 @@ class Sweep:
 					reacts[ref]["❤️" if f["emoji"] in HEARTS else f["emoji"]] += 1
 			elif f["verb"] == "boost":
 				boosts[ref] += 1
+				if self.w.planner.accounts[f["actor"]]["bot"]:
+					bot_boosts[ref] += 1
 			elif f["verb"] == "vote":
 				for c in f["choices"]:
 					votes[ref][c] += 1
@@ -293,12 +303,14 @@ class Sweep:
 					self.add(f"count.vote.{v}", "privapub", "privapub", row.votes == want, ref, want, row.votes)
 			elif origin != "lemmy":
 				# elsewhere: at least the plain likes that every platform sends as Like
-				plain = sum(1 for f in self.w.interactions if f["ref"] == ref and f["verb"] == "like")
+				plain = sum(1 for f in self.w.interactions if f["ref"] == ref and f["verb"] == "like"
+							and not (origin in GROUP_VOTES_UNSEEN and o.get("group") and self.w.platform(f["actor"]) == "lemmy"))
 				if plain:
 					total = (row.likes or 0)
 					self.add(f"count.like.{v}", "*", origin, total >= plain, ref, f">={plain}", total)
-				if boosts[ref]:
-					self.add(f"count.boost.{v}", "*", origin, (row.boosts or 0) >= boosts[ref], ref, f">={boosts[ref]}", row.boosts)
+				counted = boosts[ref] - (bot_boosts[ref] if origin in BOT_RENOTES_UNCOUNTED else 0)
+				if counted:
+					self.add(f"count.boost.{v}", "*", origin, (row.boosts or 0) >= counted, ref, f">={counted}", row.boosts)
 				if votes[ref]:
 					want = sum(votes[ref].values())
 					got = sum(row.votes or [])