diff --git a/crates/adapters/postgres/src/activitypub.rs b/crates/adapters/postgres/src/activitypub.rs
index 44d7330..b51a184 100644
--- a/crates/adapters/postgres/src/activitypub.rs
+++ b/crates/adapters/postgres/src/activitypub.rs
@@ -10,7 +10,7 @@ use url::Url;
 use domain::{
     errors::DomainError,
     models::thought::{Thought, Visibility},
-    ports::{ActivityPubRepository, OutboxEntry},
+    ports::{ActivityPubRepository, ActorApUrls, OutboxEntry},
     value_objects::{Content, ThoughtId, UserId, Username},
 };
 
@@ -297,6 +297,34 @@ impl ActivityPubRepository for PgActivityPubRepository {
             .into_domain()?;
         Ok(n as u64)
     }
+
+    async fn get_thought_ap_id(
+        &self,
+        thought_id: &ThoughtId,
+    ) -> Result<Option<String>, DomainError> {
+        sqlx::query_scalar::<_, String>(
+            "SELECT ap_id FROM thoughts WHERE id = $1 AND ap_id IS NOT NULL",
+        )
+        .bind(thought_id.as_uuid())
+        .fetch_optional(&self.pool)
+        .await
+        .into_domain()
+    }
+
+    async fn get_actor_ap_urls(
+        &self,
+        user_id: &UserId,
+    ) -> Result<Option<ActorApUrls>, DomainError> {
+        sqlx::query_as::<_, (String, String)>(
+            "SELECT ap_id, inbox_url FROM users \
+             WHERE id = $1 AND ap_id IS NOT NULL AND inbox_url IS NOT NULL",
+        )
+        .bind(user_id.as_uuid())
+        .fetch_optional(&self.pool)
+        .await
+        .into_domain()
+        .map(|opt| opt.map(|(ap_id, inbox_url)| ActorApUrls { ap_id, inbox_url }))
+    }
 }
 
 #[cfg(test)]
diff --git a/crates/domain/src/ports.rs b/crates/domain/src/ports.rs
index 7063618..93147b7 100644
--- a/crates/domain/src/ports.rs
+++ b/crates/domain/src/ports.rs
@@ -331,6 +331,13 @@ pub trait SearchPort: Send + Sync {
     ) -> Result<Paginated<User>, DomainError>;
 }
 
+/// AP-protocol endpoints for a locally-stored user (local or interned remote).
+#[derive(Debug, Clone)]
+pub struct ActorApUrls {
+    pub ap_id: String,
+    pub inbox_url: String,
+}
+
 /// A local thought ready for AP serialization, with the author's username
 /// pre-joined so the handler can build AP URLs without a second query.
 #[derive(Debug, Clone)]
@@ -413,6 +420,18 @@ pub trait ActivityPubRepository: Send + Sync {
 
     /// Total locally-authored thought count for NodeInfo responses.
     async fn count_local_notes(&self) -> Result<u64, DomainError>;
+
+    /// Return the ActivityPub object URL for a thought, if one is stored.
+    /// Returns None for local thoughts (caller constructs URL from base_url + thought_id).
+    async fn get_thought_ap_id(
+        &self,
+        thought_id: &ThoughtId,
+    ) -> Result<Option<String>, DomainError>;
+
+    /// Return the AP actor URL and inbox URL for a user, if stored.
+    /// Returns None for users that have not been federated.
+    async fn get_actor_ap_urls(&self, user_id: &UserId)
+        -> Result<Option<ActorApUrls>, DomainError>;
 }
 
 #[async_trait]
diff --git a/crates/domain/src/testing.rs b/crates/domain/src/testing.rs
index 832624d..8fbce63 100644
--- a/crates/domain/src/testing.rs
+++ b/crates/domain/src/testing.rs
@@ -882,6 +882,18 @@ impl ActivityPubRepository for TestStore {
             .filter(|t| t.local)
             .count() as u64)
     }
+    async fn get_thought_ap_id(
+        &self,
+        _thought_id: &ThoughtId,
+    ) -> Result<Option<String>, DomainError> {
+        Ok(None)
+    }
+    async fn get_actor_ap_urls(
+        &self,
+        _user_id: &UserId,
+    ) -> Result<Option<ActorApUrls>, DomainError> {
+        Ok(None)
+    }
 }
 
 #[async_trait]