diff --git a/hive-matrix-mcp/src/handlers.rs b/hive-matrix-mcp/src/handlers.rs
index 37277fa3..e1bb42d2 100644
--- a/hive-matrix-mcp/src/handlers.rs
+++ b/hive-matrix-mcp/src/handlers.rs
@@ -511,6 +511,19 @@ fn recipient_among(
         })
 }
 
+/// A bare agent name (`iris`, no `@` and no `:`) means that agent's account
+/// on the caller's own homeserver, `@iris:<own server>`; anything else is
+/// passed through for the normal user id parse. Lets a simple agent DM a peer
+/// by the name it knows it by.
+fn expand_user_id(own_server: Option<&str>, input: &str) -> String {
+    match own_server {
+        Some(server) if !input.is_empty() && !input.contains(['@', ':']) => {
+            format!("@{input}:{server}")
+        }
+        _ => input.to_owned(),
+    }
+}
+
 /// Find the existing DM room with `user_id` or create one, and say where the
 /// recipient stands in it. Shared by `send_dm` and `open_dm`.
 /// `direct_targets()` (cached state) is used rather than the async
@@ -523,6 +536,8 @@ async fn resolve_or_create_dm(
     client: &Client,
     user_id: &str,
 ) -> Result<(matrix_sdk::Room, Recipient), DaemonResponse> {
+    let own = client.user_id().map(|u| u.server_name().to_string());
+    let user_id = expand_user_id(own.as_deref(), user_id);
     let uid: OwnedUserId = user_id
         .parse()
         .map_err(|e| DaemonResponse::error(format!("invalid user_id {user_id}: {e}")))?;
@@ -568,6 +583,9 @@ fn recipient_fields(recipient: Recipient) -> serde_json::Value {
 }
 
 pub async fn send_dm(client: &Client, user_id: &str, body: &str) -> DaemonResponse {
+    let own = client.user_id().map(|u| u.server_name().to_string());
+    let user_id = expand_user_id(own.as_deref(), user_id);
+    let user_id = user_id.as_str();
     let (room, recipient) = match resolve_or_create_dm(client, user_id).await {
         Ok(r) => r,
         Err(e) => return e,
@@ -1321,9 +1339,9 @@ mod utd_body_tests {
 #[cfg(test)]
 mod unread_tests {
     use super::{
-        ParsedEvent, TimelineEvent, attachment_marker, collapse_edits, extract_body_sync,
-        extract_in_reply_to, is_intentional, media_parts, replacement_of, safe_file_name,
-        unread_verdict,
+        ParsedEvent, TimelineEvent, attachment_marker, collapse_edits, expand_user_id,
+        extract_body_sync, extract_in_reply_to, is_intentional, media_parts, replacement_of,
+        safe_file_name, unread_verdict,
     };
     use matrix_sdk::ruma::events::AnySyncTimelineEvent;
     use matrix_sdk::ruma::events::room::message::MessageType;
@@ -1368,6 +1386,18 @@ mod unread_tests {
             .map(|(id, sender, body)| (id.to_string(), sender.to_string(), body))
     }
 
+    #[test]
+    fn a_bare_agent_name_means_that_agent_on_the_own_homeserver() {
+        let own = Some("pr1ma.darkest.space");
+        assert_eq!(expand_user_id(own, "iris"), "@iris:pr1ma.darkest.space");
+        // Full ids and anything with a server part pass through untouched.
+        assert_eq!(expand_user_id(own, "@mara:matrix.org"), "@mara:matrix.org");
+        assert_eq!(expand_user_id(own, "iris:other.org"), "iris:other.org");
+        // No own server known, or nothing given: nothing to expand with.
+        assert_eq!(expand_user_id(None, "iris"), "iris");
+        assert_eq!(expand_user_id(own, ""), "");
+    }
+
     #[test]
     fn an_empty_room_is_caught_up() {
         assert_eq!(verdict(None, &[]), None);
diff --git a/hive-matrix-mcp/src/mcp.rs b/hive-matrix-mcp/src/mcp.rs
index ff5e0646..18c46f8c 100644
--- a/hive-matrix-mcp/src/mcp.rs
+++ b/hive-matrix-mcp/src/mcp.rs
@@ -280,7 +280,8 @@ impl MatrixMcp {
     }
 
     #[tool(description = "Open (or reuse) a direct message room with `user_id` \
-            (@user:server) and post `body` to it. If the DM room already exists \
+            (@user:server, or just an agent's name such as `iris` for that agent \
+            on this homeserver) and post `body` to it. If the DM room already exists \
             and has unread messages, the send is rejected with a hint — read_room \
             then mark_read the latest event first.")]
     async fn send_dm(&self, Parameters(args): Parameters<SendDmArgs>) -> String {