1 files changed, 57 insertions, 0 deletions
diff --git a/src/protocol/endpoint.rs b/src/protocol/endpoint.rs
index a70ef568..640e594e 100644
--- a/src/protocol/endpoint.rs
+++ b/src/protocol/endpoint.rs
@@ -27,6 +27,8 @@ pub const PRESENTATION_EFFECTS_READY_KIND: &str = "endpoint.presentation.ready.v
 pub const HEALTH_CHECK_CAPABILITY: &str = "health_check";
 pub const HEALTH_PING_KIND: &str = "endpoint.health.ping.v1";
 pub const HEALTH_PONG_KIND: &str = "endpoint.health.pong.v1";
+pub const AGENT_VIEW_PROJECTION_CAPABILITY: &str = "agent_view_projection";
+pub const AGENT_VIEW_PROJECTION_KIND: &str = "endpoint.agent-view.v1";
 
 fn default_true() -> bool {
     true
@@ -60,6 +62,16 @@ pub struct EndpointHandshakeError {
     pub message: String,
 }
 
+/// Optional companion to a V1 snapshot. The view payload is intentionally opaque to this
+/// stable envelope so clients can ignore view language additions they do not understand.
+#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
+pub struct EndpointAgentViewProjection {
+    pub boot_id: String,
+    pub revision: u64,
+    #[serde(default)]
+    pub view: Option<serde_json::Value>,
+}
+
 #[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
 pub struct EndpointServerWelcome {
     pub generation: u32,
@@ -83,6 +95,22 @@ pub fn snapshot_message(snapshot: &ClientShellSnapshot) -> serde_json::Result<Se
     })
 }
 
+pub fn agent_view_projection_message(
+    boot_id: &str,
+    revision: u64,
+    view: Option<&crate::api::schema::AgentViewSetParams>,
+) -> serde_json::Result<ServerMessage> {
+    let projection = EndpointAgentViewProjection {
+        boot_id: boot_id.to_owned(),
+        revision,
+        view: view.map(serde_json::to_value).transpose()?,
+    };
+    Ok(ServerMessage::EndpointControl {
+        kind: AGENT_VIEW_PROJECTION_KIND.into(),
+        data: serde_json::to_string(&projection)?,
+    })
+}
+
 impl EndpointClientHello {
     pub fn supports_required_codecs(&self) -> bool {
         self.snapshot_codecs
@@ -114,6 +142,7 @@ impl EndpointServerWelcome {
                 SURFACE_INTEREST_CAPABILITY.into(),
                 PRESENTATION_EFFECTS_FENCE_CAPABILITY.into(),
                 HEALTH_CHECK_CAPABILITY.into(),
+                AGENT_VIEW_PROJECTION_CAPABILITY.into(),
             ],
             error: None,
         }
@@ -244,6 +273,33 @@ mod tests {
     }
 
     #[test]
+    fn agent_view_projection_is_an_optional_revision_bound_control() {
+        let view = crate::api::schema::AgentViewSetParams {
+            source: "example.views".into(),
+            label: Some("focus".into()),
+            filter: None,
+            sort: Vec::new(),
+        };
+        let ServerMessage::EndpointControl { kind, data } =
+            agent_view_projection_message("boot", 7, Some(&view)).unwrap()
+        else {
+            panic!("projection should use endpoint control");
+        };
+        assert_eq!(kind, AGENT_VIEW_PROJECTION_KIND);
+        let projection: EndpointAgentViewProjection = serde_json::from_str(&data).unwrap();
+        assert_eq!(projection.boot_id, "boot");
+        assert_eq!(projection.revision, 7);
+        assert_eq!(
+            projection
+                .view
+                .map(serde_json::from_value)
+                .transpose()
+                .unwrap(),
+            Some(view)
+        );
+    }
+
+    #[test]
     fn snapshot_json_tolerates_future_fields_and_command_actions() {
         let mut snapshot = match snapshot_message(&snapshot()).unwrap() {
             ServerMessage::EndpointControl { data, .. } => {
@@ -284,6 +340,7 @@ mod tests {
                 SURFACE_INTEREST_CAPABILITY.to_string(),
                 PRESENTATION_EFFECTS_FENCE_CAPABILITY.to_string(),
                 HEALTH_CHECK_CAPABILITY.to_string(),
+                AGENT_VIEW_PROJECTION_CAPABILITY.to_string(),
             ]
         );
     }