Add attributionDomains to Actor vocabulary

.agents/skills/add-vocab/SKILL.md

@@ -125,6 +125,11 @@ Embedded context entries are YAML mappings where:
  -  String value `"prefix:term"` or `"https://..."` defines a simple term alias
  -  Object value with `"@id"` and optionally `"@type": "@id"` defines a term
     that should be treated as an IRI (linked resource)
+ -  Object value may also carry `"@container": "@set"` or
+    `"@container": "@list"` to match a vocabulary whose context defines a
+    container.  A context term's `@container` is separate from the
+    property-level `container: list` option, which controls how the compact
+    serializer writes list values.
 
 ### Ensuring complete compaction coverage
 

CHANGES.md

@@ -60,6 +60,13 @@ To be released.
     for maps that will be rejected.  Policy-rejected maps now appear in
     `onRequestFinished` verification reports with their policy failure and no
     signature checks.  [[#1177], [#1264]]
+ -  Changed compound proof verification to accept `"@container": "@set"` term
+    definitions in actor contexts when deciding whether embedded portable keys
+    are covered by the actor's proof.  A `@set` container only forces expanded
+    values into arrays, so it does not make key expansion ambiguous; `@list`
+    and other containers remain rejected.  This keeps portable actors that
+    publish container terms such as Mastodon's `attributionDomains`
+    verifiable.  [[#1234], [#1353]]
  -  Fixed log entries emitted during an individual outbound activity delivery
     or inbound activity processing carrying the enclosing HTTP request's or
     queue worker's `traceId`/`spanId` instead of the delivery or processing
@@ -75,12 +82,14 @@ To be released.
 [#1030]: https://github.com/fedify-dev/fedify/issues/1030
 [#1177]: https://github.com/fedify-dev/fedify/issues/1177
 [#1205]: https://github.com/fedify-dev/fedify/pull/1205
+[#1234]: https://github.com/fedify-dev/fedify/issues/1234
 [#1264]: https://github.com/fedify-dev/fedify/pull/1264
 [#1289]: https://github.com/fedify-dev/fedify/issues/1289
 [#1290]: https://github.com/fedify-dev/fedify/issues/1290
 [#1299]: https://github.com/fedify-dev/fedify/pull/1299
 [#1318]: https://github.com/fedify-dev/fedify/issues/1318
 [#1328]: https://github.com/fedify-dev/fedify/pull/1328
+[#1353]: https://github.com/fedify-dev/fedify/pull/1353
 
 ### @fedify/cli
 
@@ -287,6 +296,17 @@ To be released.
     entries may not be visited.  Accessor and serialization traversal costs are
     unchanged.  [[#1243], [#1337]]
 
+ -  Added the `attributionDomains` property to `Application`, `Group`,
+    `Organization`, `Person`, and `Service`, so applications can publish the
+    domains an actor claims for Mastodon's `fediverse:creator` link credits
+    without subclassing the actor types.  Each value is a bare host name
+    without a scheme, port, path, or leading `*.`; Fedify treats the values as
+    opaque strings and does not normalize them.  Actor serialization and
+    `Update` documents that embed an actor now compact the property as
+    `attributionDomains` instead of `toot:attributionDomains`, which is the key
+    Mastodon reads when it refreshes an account, and parsing accepts both
+    a single string value and an array of strings.  [[#1234], [#1353]]
+
  -  Added vocabulary support for the [FEP-6757] draft, which marks
     ActivityPub content with explicit copyright license URIs.
     [[#1212], [#1241]]
@@ -327,6 +347,11 @@ To be released.
 
 ### @fedify/vocab-tools
 
+ -  Added `@container` support to embedded `defaultContext` term definitions
+    in the vocabulary schema.  Terms such as Mastodon's `attributionDomains`
+    can now use `"@container": "@set"` or `"@container": "@list"` to match
+    their published JSON-LD contexts, while existing term definitions keep
+    validating as before.  [[#1234], [#1353]]
  -  Added non-functional `redundantProperties` support with ordered fallback
     to the first non-empty value set, preserving lists and graphs without
     merging synonyms.  Added `redundantPropertiesWrite: canonical` to write

changes.d/fedify/compound-proof-set-contexts.md

@@ -0,0 +1,12 @@
+---
+links:
+  '#1234': https://github.com/fedify-dev/fedify/issues/1234
+  '#1353': https://github.com/fedify-dev/fedify/pull/1353
+---
+ -  Changed compound proof verification to accept `"@container": "@set"` term
+    definitions in actor contexts when deciding whether embedded portable keys
+    are covered by the actor's proof.  A `@set` container only forces expanded
+    values into arrays, so it does not make key expansion ambiguous; `@list`
+    and other containers remain rejected.  This keeps portable actors that
+    publish container terms such as Mastodon's `attributionDomains`
+    verifiable.  [[#1234], [#1353]]

changes.d/vocab-tools/context-container-terms.md

@@ -0,0 +1,10 @@
+---
+links:
+  '#1234': https://github.com/fedify-dev/fedify/issues/1234
+  '#1353': https://github.com/fedify-dev/fedify/pull/1353
+---
+ -  Added `@container` support to embedded `defaultContext` term definitions
+    in the vocabulary schema.  Terms such as Mastodon's `attributionDomains`
+    can now use `"@container": "@set"` or `"@container": "@list"` to match
+    their published JSON-LD contexts, while existing term definitions keep
+    validating as before.  [[#1234], [#1353]]

changes.d/vocab/toot-attribution-domains.md

@@ -0,0 +1,15 @@
+---
+links:
+  '#1234': https://github.com/fedify-dev/fedify/issues/1234
+  '#1353': https://github.com/fedify-dev/fedify/pull/1353
+---
+ -  Added the `attributionDomains` property to `Application`, `Group`,
+    `Organization`, `Person`, and `Service`, so applications can publish the
+    domains an actor claims for Mastodon's `fediverse:creator` link credits
+    without subclassing the actor types.  Each value is a bare host name
+    without a scheme, port, path, or leading `*.`; Fedify treats the values as
+    opaque strings and does not normalize them.  Actor serialization and
+    `Update` documents that embed an actor now compact the property as
+    `attributionDomains` instead of `toot:attributionDomains`, which is the key
+    Mastodon reads when it refreshes an account, and parsing accepts both
+    a single string value and an array of strings.  [[#1234], [#1353]]

claude-plugin/skills/actor/SKILL.md

@@ -14,7 +14,9 @@ Walk through:
     object or `FederationBuilder`, including the `{identifier}` path
     parameter.
 2.  Returning a `Person`, `Service`, or other `Actor` vocabulary object
-    with the required fields (`id`, `inbox`, `publicKey`, etc.).
+    with the required fields (`id`, `inbox`, `publicKey`, etc.).  Set
+    `attributionDomains` to bare host names when the actor should be
+    credited on Mastodon link previews; Fedify does not normalize them.
 3.  Chaining `.setKeyPairsDispatcher()` to supply RSA and Ed25519 keys.
 4.  Optionally configuring `mapActorAlias()` for handle-based or
     fixed-path aliases.

packages/fedify/src/federation/handler.test.ts

@@ -217,6 +217,10 @@ test("handleActor()", async () => {
           "@type": "@id",
         },
         discoverable: "toot:discoverable",
+        attributionDomains: {
+          "@id": "toot:attributionDomains",
+          "@container": "@set",
+        },
         indexable: "toot:indexable",
         memorial: "toot:memorial",
         suspended: "toot:suspended",
@@ -326,6 +330,10 @@ test("handleActor()", async () => {
           "@type": "@id",
         },
         discoverable: "toot:discoverable",
+        attributionDomains: {
+          "@id": "toot:attributionDomains",
+          "@container": "@set",
+        },
         indexable: "toot:indexable",
         memorial: "toot:memorial",
         suspended: "toot:suspended",

packages/fedify/src/sig/compound-proof-verification.test.ts

@@ -795,6 +795,28 @@ test("verifyCompoundPortableObjectProofs() exempts keys embedded in portable act
   assert(result.status === "ok");
   assert(result.verified);
   assertEquals(result.portableObjects.map((o) => o.path), [""]);
+  // A parent context may carry a "@set" container term without making the
+  // keys ambiguous:
+  const actorWithSetTerm = await compatibleActor();
+  result = await verifyCompoundPortableObjectProofs(
+    await signCompatible({
+      ...actorWithSetTerm,
+      "@context": [
+        ...actorWithSetTerm["@context"] as unknown[],
+        {
+          tags: {
+            "@id": "https://example.com/tags",
+            "@container": "@set",
+          },
+        },
+      ],
+    }),
+    limits,
+    options,
+  );
+  assert(result.status === "ok");
+  assert(result.verified);
+  assertEquals(result.portableObjects.map((o) => o.path), [""]);
   // An ap: actor with gateway keys at compatible identifiers, as Fedify's
   // own portable actors have:
   result = await verifyCompoundPortableObjectProofs(
@@ -863,6 +885,18 @@ test("verifyCompoundPortableObjectProofs() exempts only keys of the parent itsel
         { kind: "@type" },
       ],
     },
+    "a parent context with a list container": {
+      ...actor,
+      "@context": [
+        ...actor["@context"] as unknown[],
+        {
+          tags: {
+            "@id": "https://example.com/tags",
+            "@container": "@list",
+          },
+        },
+      ],
+    },
     "a key with a scoped context": {
       ...actor,
       publicKey: {

packages/fedify/src/sig/compound-proof.ts

@@ -1319,6 +1319,8 @@ function isKeyIdOf(id: string, portableId: string): boolean {
  * Checks whether a `@context` value defines no keyword aliases and no scoped
  * contexts: only references to contexts and term definitions that map terms
  * to IRIs, optionally with an `@id` or `@vocab` type coercion or a datatype.
+ * A `@set` container is accepted because it only forces expanded values into
+ * arrays, which expansion does anyway; `@list` and other containers are not.
  */
 function isSimpleContext(context: CompoundProofJsonValue | undefined): boolean {
   if (typeof context === "string") return true;
@@ -1330,9 +1332,15 @@ function isSimpleContext(context: CompoundProofJsonValue | undefined): boolean {
     if (term.startsWith("@")) return false;
     if (typeof definition === "string") return !definition.startsWith("@");
     if (!isCompoundProofJsonObject(definition)) return false;
-    const { "@id": id, "@type": type, ...rest } = definition;
+    const {
+      "@id": id,
+      "@type": type,
+      "@container": container,
+      ...rest
+    } = definition;
     return Object.keys(rest).length < 1 &&
       typeof id === "string" && !id.startsWith("@") &&
+      (container === undefined || container === "@set") &&
       (type === undefined || type === "@id" || type === "@vocab" ||
         typeof type === "string" && !type.startsWith("@"));
   });