diff --git a/hive-matrix-mcp/src/bin/mcp.rs b/hive-matrix-mcp/src/bin/mcp.rs
index 778e5eec..8be34203 100644
--- a/hive-matrix-mcp/src/bin/mcp.rs
+++ b/hive-matrix-mcp/src/bin/mcp.rs
@@ -93,16 +93,10 @@ struct SendFileArgs {
 }
 
 #[derive(Debug, Deserialize, JsonSchema)]
-struct SendFileDmArgs {
-    /// Matrix user id of the recipient (`@user:server`). DM room is
+struct OpenDmArgs {
+    /// Matrix user id (`@user:server`) to open a DM with. The DM room is
     /// created if one doesn't already exist.
     user_id: String,
-    /// Absolute path to a local file readable by the agent. MIME type is
-    /// inferred from the extension. 50 MiB cap.
-    path: String,
-    /// Optional caption, sent as a follow-up text message in the DM.
-    #[serde(default)]
-    caption: Option<String>,
 }
 
 #[derive(Debug, Deserialize, JsonSchema)]
@@ -240,19 +234,14 @@ impl MatrixBridge {
         )
     }
 
-    #[tool(
-        description = "Open (or reuse) a DM with `user_id` (@user:server) and upload \
-            a local file as an attachment. `path` is an absolute local file path (MIME \
-            inferred, 50 MiB cap); optional `caption` is sent as a follow-up message. \
-            If the DM room already exists with unread messages, the send is rejected \
-            — read_room then mark_read first."
-    )]
-    async fn send_file_dm(&self, Parameters(args): Parameters<SendFileDmArgs>) -> String {
+    #[tool(description = "Resolve (find-or-create) the DM room with `user_id` \
+            (@user:server) and return its room id, without sending anything. Use the \
+            returned room id with the room-based tools (`send_file`, `send_message`, \
+            …) to deliver into the DM — there is no per-tool DM variant.")]
+    async fn open_dm(&self, Parameters(args): Parameters<OpenDmArgs>) -> String {
         render(
-            round_trip(DaemonRequest::SendFileDm {
+            round_trip(DaemonRequest::OpenDm {
                 user_id: args.user_id,
-                path: args.path,
-                caption: args.caption,
             })
             .await,
         )
diff --git a/hive-matrix-mcp/src/handlers.rs b/hive-matrix-mcp/src/handlers.rs
index 03d2b720..c07ba78f 100644
--- a/hive-matrix-mcp/src/handlers.rs
+++ b/hive-matrix-mcp/src/handlers.rs
@@ -185,7 +185,7 @@ pub async fn send_message(client: &Client, room_ref: &str, body: &str) -> Daemon
 }
 
 /// Find the existing DM room with `user_id` or create one. Shared by
-/// `send_dm` and `send_file_dm`. `direct_targets()` (cached state) is
+/// `send_dm` and `open_dm`. `direct_targets()` (cached state) is
 /// used rather than the async `is_direct()`.
 async fn resolve_or_create_dm(
     client: &Client,
@@ -304,20 +304,19 @@ pub async fn send_file(
     upload_attachment(&room, path, caption).await
 }
 
-pub async fn send_file_dm(
-    client: &Client,
-    user_id: &str,
-    path: &str,
-    caption: Option<&str>,
-) -> DaemonResponse {
+/// Resolve (find-or-create) the DM room with `user_id` and return its
+/// room id without sending anything. The caller then uses the room-based
+/// tools (`send_file`, `send_message`, …) against that id — so there is
+/// no per-tool `_dm` variant.
+pub async fn open_dm(client: &Client, user_id: &str) -> DaemonResponse {
     let room = match resolve_or_create_dm(client, user_id).await {
         Ok(r) => r,
         Err(e) => return e,
     };
-    if let Some(reject) = unread_guard(&room) {
-        return reject;
-    }
-    upload_attachment(&room, path, caption).await
+    DaemonResponse::ok(&serde_json::json!({
+        "room_id": room.room_id().to_string(),
+        "user_id": user_id,
+    }))
 }
 
 pub async fn send_reaction(
diff --git a/hive-matrix-mcp/src/protocol.rs b/hive-matrix-mcp/src/protocol.rs
index 64c4392e..58a3b231 100644
--- a/hive-matrix-mcp/src/protocol.rs
+++ b/hive-matrix-mcp/src/protocol.rs
@@ -37,15 +37,13 @@ pub enum DaemonRequest {
         caption: Option<String>,
     },
 
-    /// Open (or reuse) a DM with `user_id` and post a local file as an
-    /// attachment. `caption`, when set, is sent as a follow-up text
-    /// message in the DM.
-    #[serde(rename = "send_file_dm")]
-    SendFileDm {
-        user_id: String,
-        path: String,
-        caption: Option<String>,
-    },
+    /// Resolve (find-or-create) the DM room with `user_id` and return
+    /// its room id, without sending anything. Lets a caller obtain the
+    /// DM room id and then use the room-based tools (`send_file`,
+    /// `send_message`, …) against it — so there is no per-tool `_dm`
+    /// variant.
+    #[serde(rename = "open_dm")]
+    OpenDm { user_id: String },
 
     /// React to a specific event with an emoji `key`. Matrix-spec
     /// `m.reaction` annotation.
diff --git a/hive-matrix-mcp/src/socket.rs b/hive-matrix-mcp/src/socket.rs
index 8ba5a5e2..2a8a588f 100644
--- a/hive-matrix-mcp/src/socket.rs
+++ b/hive-matrix-mcp/src/socket.rs
@@ -70,11 +70,7 @@ async fn dispatch(req: DaemonRequest, client: &Client) -> DaemonResponse {
             path,
             caption,
         } => handlers::send_file(client, &room, &path, caption.as_deref()).await,
-        DaemonRequest::SendFileDm {
-            user_id,
-            path,
-            caption,
-        } => handlers::send_file_dm(client, &user_id, &path, caption.as_deref()).await,
+        DaemonRequest::OpenDm { user_id } => handlers::open_dm(client, &user_id).await,
         DaemonRequest::SendReaction {
             room,
             event_id,