Add versioned scripting host model and entity coverage

crates/ocs_plugin_api/src/entity_coverage.rs

@@ -0,0 +1,342 @@
+//! Host-owned coverage generated from the traced entity registry and an
+//! explicit policy. `unmapped` fields remain accessible through the typed
+//! `CadDocument` snapshot but are not promised by the Python document model.
+
+pub use crate::entity_coverage_types::*;
+
+pub const EMBEDDED_ENTITY_COVERAGE_JSON: &str =
+    include_str!(concat!(env!("OUT_DIR"), "/entity_coverage.json"));
+
+pub fn get_embedded_entity_coverage_json() -> &'static str {
+    EMBEDDED_ENTITY_COVERAGE_JSON
+}
+
+/// Read-only JSON serialization of one typed entity. The outer object
+/// has one key: the `EntityType` variant name used by the coverage catalog.
+/// JSON does not preserve non-finite floating-point values, so this is an
+/// inspection format and must remain separate from the typed entity write path.
+#[cfg(feature = "host")]
+pub fn entity_snapshot(entity: &crate::host::EntityType) -> Result<serde_json::Value, serde_json::Error> {
+    serde_json::to_value(entity)
+}
+
+#[cfg(feature = "host")]
+fn finite_vector(name: &str, value: &crate::host::acadrust::types::Vector3) -> Result<(), String> {
+    if value.x.is_finite() && value.y.is_finite() && value.z.is_finite() { Ok(()) }
+    else { Err(format!("{name} must contain finite coordinates")) }
+}
+
+#[cfg(feature = "host")]
+fn unit_direction(name: &str, value: &crate::host::acadrust::types::Vector3) -> Result<(), String> {
+    finite_vector(name, value)?;
+    let length = value.x.hypot(value.y).hypot(value.z);
+    if (length - 1.0).abs() <= 1e-6 { Ok(()) }
+    else { Err(format!("{name} must be a unit vector")) }
+}
+
+#[cfg(feature = "host")]
+fn solid_normal(name: &str, value: &crate::host::acadrust::types::Vector3) -> Result<(), String> {
+    finite_vector(name, value)?;
+    if value.x.hypot(value.y).hypot(value.z) > 0.0 { Ok(()) }
+    else { Err(format!("{name} must be nonzero")) }
+}
+
+/// Validate newly created geometry for the kinds whose mapped fields have
+/// host checks. Called by the Python add path before an entity enters the document.
+#[cfg(feature = "host")]
+pub fn validate_new_canvas_entity(entity: &crate::host::EntityType) -> Result<(), String> {
+    use crate::host::EntityType;
+    if entity.common().layer.trim().is_empty() { return Err("layer name is empty".into()); }
+    match entity {
+        EntityType::Ray(value) => {
+            finite_vector("Ray.base_point", &value.base_point)?;
+            unit_direction("Ray.direction", &value.direction)?;
+        }
+        EntityType::XLine(value) => {
+            finite_vector("XLine.base_point", &value.base_point)?;
+            unit_direction("XLine.direction", &value.direction)?;
+        }
+        EntityType::Solid(value) => {
+            for (name, corner) in [
+                ("first_corner", &value.first_corner), ("second_corner", &value.second_corner),
+                ("third_corner", &value.third_corner), ("fourth_corner", &value.fourth_corner),
+            ] { finite_vector(&format!("Solid.{name}"), corner)?; }
+            solid_normal("Solid.normal", &value.normal)?;
+            if !value.thickness.is_finite() { return Err("Solid.thickness must be finite".into()); }
+        }
+        EntityType::Face3D(value) => {
+            for (name, corner) in [
+                ("first_corner", &value.first_corner), ("second_corner", &value.second_corner),
+                ("third_corner", &value.third_corner), ("fourth_corner", &value.fourth_corner),
+            ] { finite_vector(&format!("Face3D.{name}"), corner)?; }
+            if value.invisible_edges.bits() & !0x0f != 0 {
+                return Err("Face3D.invisible_edges has unknown bits".into());
+            }
+        }
+        _ => {}
+    }
+    Ok(())
+}
+
+/// Validate geometry changed by a typed replacement before an undoable
+/// transaction commits. Legacy invalid values in untouched fields remain
+/// untouched, so editing a layer does not unexpectedly reject an old drawing.
+#[cfg(feature = "host")]
+pub fn validate_entity_mutation(
+    before: &crate::host::EntityType,
+    after: &crate::host::EntityType,
+) -> Result<(), String> {
+    use crate::host::EntityType;
+    if before.common().layer != after.common().layer {
+        if after.common().layer.trim().is_empty() { return Err("layer name is empty".into()); }
+        if matches!(after, EntityType::Block(_) | EntityType::BlockEnd(_) | EntityType::Seqend(_)
+            | EntityType::Extended(_) | EntityType::Unknown(_)) {
+            return Err("entity kind does not support canvas layer edits".into());
+        }
+    }
+    let finite3 = |name: &str, x: f64, y: f64, z: f64| {
+        if x.is_finite() && y.is_finite() && z.is_finite() { Ok(()) }
+        else { Err(format!("{name} must contain finite coordinates")) }
+    };
+    let same3 = |a: &crate::host::acadrust::types::Vector3,
+                 b: &crate::host::acadrust::types::Vector3| {
+        a.x.to_bits() == b.x.to_bits() && a.y.to_bits() == b.y.to_bits() && a.z.to_bits() == b.z.to_bits()
+    };
+    let radius = |name: &str, value: f64| {
+        if value.is_finite() && value > 0.0 { Ok(()) }
+        else { Err(format!("{name} must be finite and greater than zero")) }
+    };
+    let changed3 = |name: &str, old: &crate::host::acadrust::types::Vector3,
+                    new: &crate::host::acadrust::types::Vector3| {
+        if !same3(old, new) { finite_vector(name, new) } else { Ok(()) }
+    };
+    match (before, after) {
+        (EntityType::Point(old), EntityType::Point(new)) => {
+            if !same3(&old.location, &new.location) {
+                finite3("Point.location", new.location.x, new.location.y, new.location.z)?;
+            }
+        }
+        (EntityType::Line(old), EntityType::Line(new)) => {
+            if !same3(&old.start, &new.start) {
+                finite3("Line.start", new.start.x, new.start.y, new.start.z)?;
+            }
+            if !same3(&old.end, &new.end) {
+                finite3("Line.end", new.end.x, new.end.y, new.end.z)?;
+            }
+        }
+        (EntityType::Circle(old), EntityType::Circle(new)) => {
+            if !same3(&old.center, &new.center) {
+                finite3("Circle.center", new.center.x, new.center.y, new.center.z)?;
+            }
+            if old.radius.to_bits() != new.radius.to_bits() { radius("Circle.radius", new.radius)?; }
+        }
+        (EntityType::Arc(old), EntityType::Arc(new)) => {
+            if !same3(&old.center, &new.center) {
+                finite3("Arc.center", new.center.x, new.center.y, new.center.z)?;
+            }
+            if old.radius.to_bits() != new.radius.to_bits() { radius("Arc.radius", new.radius)?; }
+        }
+        (EntityType::Ray(old), EntityType::Ray(new)) => {
+            changed3("Ray.base_point", &old.base_point, &new.base_point)?;
+            if !same3(&old.direction, &new.direction) { unit_direction("Ray.direction", &new.direction)?; }
+        }
+        (EntityType::XLine(old), EntityType::XLine(new)) => {
+            changed3("XLine.base_point", &old.base_point, &new.base_point)?;
+            if !same3(&old.direction, &new.direction) { unit_direction("XLine.direction", &new.direction)?; }
+        }
+        (EntityType::Solid(old), EntityType::Solid(new)) => {
+            for (name, old_corner, new_corner) in [
+                ("first_corner", &old.first_corner, &new.first_corner),
+                ("second_corner", &old.second_corner, &new.second_corner),
+                ("third_corner", &old.third_corner, &new.third_corner),
+                ("fourth_corner", &old.fourth_corner, &new.fourth_corner),
+            ] { changed3(&format!("Solid.{name}"), old_corner, new_corner)?; }
+            if !same3(&old.normal, &new.normal) { solid_normal("Solid.normal", &new.normal)?; }
+            if old.thickness.to_bits() != new.thickness.to_bits() && !new.thickness.is_finite() {
+                return Err("Solid.thickness must be finite".into());
+            }
+        }
+        (EntityType::Face3D(old), EntityType::Face3D(new)) => {
+            for (name, old_corner, new_corner) in [
+                ("first_corner", &old.first_corner, &new.first_corner),
+                ("second_corner", &old.second_corner, &new.second_corner),
+                ("third_corner", &old.third_corner, &new.third_corner),
+                ("fourth_corner", &old.fourth_corner, &new.fourth_corner),
+            ] { changed3(&format!("Face3D.{name}"), old_corner, new_corner)?; }
+            if old.invisible_edges != new.invisible_edges && new.invisible_edges.bits() & !0x0f != 0 {
+                return Err("Face3D.invisible_edges has unknown bits".into());
+            }
+        }
+        _ => {}
+    }
+    Ok(())
+}
+
+/// Clone a canvas entity with a new layer, preserving its other snapshot
+/// fields. Internal records and opaque fallbacks are excluded.
+#[cfg(feature = "host")]
+pub fn patch_canvas_layer(entity: &crate::host::EntityType, layer: &str) -> Result<crate::host::EntityType, String> {
+    use crate::host::EntityType;
+    if layer.trim().is_empty() { return Err("layer name is empty".into()); }
+    if matches!(entity, EntityType::Block(_) | EntityType::BlockEnd(_) | EntityType::Seqend(_)
+        | EntityType::Extended(_) | EntityType::Unknown(_)) {
+        return Err("entity kind does not support canvas layer edits".into());
+    }
+    let mut changed = entity.clone();
+    changed.common_mut().layer = layer.to_owned();
+    Ok(changed)
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::{get_embedded_type_registry_json, TypeId, TypeRegistry};
+
+    #[test]
+    fn every_entity_variant_has_exactly_one_classification() {
+        let catalog: EntityCoverageCatalog = serde_json::from_str(get_embedded_entity_coverage_json()).unwrap();
+        let registry: TypeRegistry = serde_json::from_str(get_embedded_type_registry_json()).unwrap();
+        let variants = &registry.types[&TypeId::new("EntityType")].variants;
+        assert_eq!(catalog.entity_kinds.len(), variants.len());
+        let mut names = std::collections::HashSet::new();
+        for entry in &catalog.entity_kinds {
+            assert!(names.insert(&entry.kind), "duplicate kind {}", entry.kind);
+            assert!(variants.iter().any(|v| v.name == entry.kind));
+            assert!(entry.properties.iter().any(|p| p.name == "handle" && p.model_access == ModelAccess::ReadOnly));
+            assert!(entry.properties.iter().any(|p| p.name == "kind" && p.model_access == ModelAccess::ReadOnly));
+            let mut source_paths = std::collections::HashSet::new();
+            for property in &entry.properties {
+                assert!(source_paths.insert(&property.source_path), "duplicate source path in {}: {}", entry.kind, property.source_path);
+                assert!(property.snapshot_readable, "unreadable traced property in {}: {}", entry.kind, property.name);
+                if property.model_access == ModelAccess::ReadWrite {
+                    assert!(matches!(property.validation.as_str(), "type_conversion_only" | "transaction_geometry" | "transaction_nonempty"));
+                }
+            }
+        }
+    }
+
+    #[test]
+    fn unsupported_kinds_have_no_editable_properties() {
+        let catalog: EntityCoverageCatalog = serde_json::from_str(get_embedded_entity_coverage_json()).unwrap();
+        for entry in &catalog.entity_kinds {
+            if entry.scope != EntityScope::Canvas || !matches!(entry.kind.as_str(),
+                "Point" | "Line" | "Circle" | "Arc" | "Ellipse" | "Polyline" |
+                "Polyline2D" | "Polyline3D" | "LwPolyline" | "Spline" | "Text" | "MText" |
+                "Ray" | "XLine" | "Solid" | "Face3D") {
+                assert!(entry.properties.iter().all(|p| p.model_access != ModelAccess::ReadWrite
+                    || (entry.scope == EntityScope::Canvas && p.name == "layer")), "{}", entry.kind);
+            }
+        }
+    }
+
+    #[test]
+    fn catalog_names_the_fields_with_transaction_geometry_checks() {
+        let catalog: EntityCoverageCatalog = serde_json::from_str(get_embedded_entity_coverage_json()).unwrap();
+        let checked: std::collections::HashSet<_> = catalog.entity_kinds.iter()
+            .flat_map(|entry| entry.properties.iter()
+                .filter(|property| property.validation == "transaction_geometry")
+                .map(|property| format!("{}.{}", entry.kind, property.name)))
+            .collect();
+        assert_eq!(checked, std::collections::HashSet::from([
+            "Point.location".to_owned(), "Line.start".to_owned(), "Line.end".to_owned(),
+            "Circle.center".to_owned(), "Circle.radius".to_owned(),
+            "Arc.center".to_owned(), "Arc.radius".to_owned(),
+            "Ray.base_point".to_owned(), "Ray.direction".to_owned(),
+            "XLine.base_point".to_owned(), "XLine.direction".to_owned(),
+            "Solid.first_corner".to_owned(), "Solid.second_corner".to_owned(),
+            "Solid.third_corner".to_owned(), "Solid.fourth_corner".to_owned(),
+            "Solid.normal".to_owned(), "Solid.thickness".to_owned(),
+            "Face3D.first_corner".to_owned(), "Face3D.second_corner".to_owned(),
+            "Face3D.third_corner".to_owned(), "Face3D.fourth_corner".to_owned(),
+            "Face3D.invisible_edges".to_owned(),
+        ]));
+    }
+
+    #[test]
+    fn layer_write_coverage_matches_canvas_scope() {
+        let catalog: EntityCoverageCatalog = serde_json::from_str(get_embedded_entity_coverage_json()).unwrap();
+        assert_eq!(catalog.entity_kinds.iter().filter(|entry| entry.scope == EntityScope::Canvas).count(), 43);
+        for entry in &catalog.entity_kinds {
+            let layer = entry.properties.iter().find(|property| property.name == "layer").unwrap();
+            assert_eq!(layer.model_access == ModelAccess::ReadWrite, entry.scope == EntityScope::Canvas);
+            if entry.scope == EntityScope::Canvas {
+                assert_eq!(layer.validation, "transaction_nonempty");
+            }
+        }
+    }
+
+    #[cfg(feature = "host")]
+    #[test]
+    fn unsupported_canvas_kind_has_typed_snapshot_fields() {
+        use crate::host::acadrust;
+        let hatch = acadrust::EntityType::Hatch(acadrust::entities::Hatch::default());
+        let snapshot = entity_snapshot(&hatch).unwrap();
+        let fields = snapshot.get("Hatch").and_then(|value| value.as_object()).unwrap();
+        assert!(fields.contains_key("common"));
+        assert!(fields.len() > 1);
+    }
+
+    #[cfg(feature = "host")]
+    #[test]
+    fn changed_geometry_is_validated_without_rejecting_untouched_legacy_values() {
+        use crate::host::acadrust;
+        let mut before = acadrust::entities::Circle::default();
+        before.radius = f64::NAN;
+        let mut layer_only = before.clone();
+        layer_only.common.layer = "OTHER".into();
+        assert!(validate_entity_mutation(
+            &acadrust::EntityType::Circle(before.clone()),
+            &acadrust::EntityType::Circle(layer_only),
+        ).is_ok());
+        let mut bad_radius = before.clone();
+        bad_radius.radius = -1.0;
+        assert!(validate_entity_mutation(
+            &acadrust::EntityType::Circle(before),
+            &acadrust::EntityType::Circle(bad_radius),
+        ).unwrap_err().contains("Circle.radius"));
+    }
+
+    #[cfg(feature = "host")]
+    #[test]
+    fn new_phase_seven_shapes_reject_invalid_geometry_and_keep_legacy_fields() {
+        use crate::host::acadrust::{self, types::Vector3};
+        let mut ray = acadrust::entities::Ray::default();
+        ray.direction = Vector3::new(2.0, 0.0, 0.0);
+        assert!(validate_new_canvas_entity(&acadrust::EntityType::Ray(ray.clone())).unwrap_err().contains("Ray.direction"));
+        let before = acadrust::EntityType::Ray(ray.clone());
+        ray.common.layer = "CONSTRUCTION".into();
+        assert!(validate_entity_mutation(&before, &acadrust::EntityType::Ray(ray.clone())).is_ok());
+        ray.direction = Vector3::new(0.0, 1.0, 0.0);
+        assert!(validate_entity_mutation(&before, &acadrust::EntityType::Ray(ray)).is_ok());
+
+        let mut xline = acadrust::entities::XLine::default();
+        xline.base_point.x = f64::NAN;
+        assert!(validate_new_canvas_entity(&acadrust::EntityType::XLine(xline)).unwrap_err().contains("XLine.base_point"));
+
+        let solid = acadrust::entities::Solid::new(Vector3::ZERO, Vector3::UNIT_X, Vector3::UNIT_Y, Vector3::ZERO);
+        let mut changed = solid.clone();
+        changed.thickness = f64::INFINITY;
+        assert!(validate_entity_mutation(&acadrust::EntityType::Solid(solid), &acadrust::EntityType::Solid(changed))
+            .unwrap_err().contains("Solid.thickness"));
+
+        let face = acadrust::entities::Face3D::new(Vector3::ZERO, Vector3::UNIT_X, Vector3::UNIT_Y, Vector3::ZERO);
+        let mut changed = face.clone();
+        changed.invisible_edges = acadrust::entities::InvisibleEdgeFlags::from_bits(0x10);
+        assert!(validate_entity_mutation(&acadrust::EntityType::Face3D(face), &acadrust::EntityType::Face3D(changed))
+            .unwrap_err().contains("Face3D.invisible_edges"));
+    }
+
+    #[cfg(feature = "host")]
+    #[test]
+    fn canvas_layer_patch_preserves_unmapped_hatch_fields() {
+        use crate::host::acadrust;
+        let hatch = acadrust::EntityType::Hatch(acadrust::entities::Hatch::default());
+        let patched = patch_canvas_layer(&hatch, "HATCHES").unwrap();
+        assert_eq!(patched.common().layer, "HATCHES");
+        assert_eq!(hatch.common().layer, "0");
+        let mut expected = hatch.clone();
+        expected.common_mut().layer = "HATCHES".into();
+        assert_eq!(patched, expected);
+        assert!(patch_canvas_layer(&hatch, " ").is_err());
+    }
+}

crates/ocs_plugin_api/src/entity_coverage_types.rs

@@ -0,0 +1,52 @@
+/// Stable, language-neutral entity capability schema.
+
+use serde::{Deserialize, Serialize};
+
+#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
+#[serde(rename_all = "snake_case")]
+pub enum EntityScope {
+    Canvas,
+    Internal,
+    Opaque,
+}
+
+#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
+#[serde(rename_all = "snake_case")]
+pub enum ModelAccess {
+    ReadWrite,
+    ReadOnly,
+    Unmapped,
+}
+
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct PropertyCoverage {
+    /// Name shown in the document model, or source name when unmapped.
+    pub name: String,
+    /// Field in the acadrust snapshot; `kind` is synthesized from the variant.
+    pub source_path: String,
+    pub type_id: String,
+    pub optional: bool,
+    pub is_sequence: bool,
+    /// Whether the serialized host snapshot carries this property.
+    pub snapshot_readable: bool,
+    /// `unmapped` means no normalized Python property or setter; the raw
+    /// snapshot can still expose its serialized value.
+    pub model_access: ModelAccess,
+    /// Write validation applied by the v7 transaction path. Currently
+    /// `transaction_geometry` for selected primitive geometry, otherwise
+    /// `type_conversion_only` for writable properties or `none`.
+    pub validation: String,
+}
+
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct EntityKindCoverage {
+    pub kind: String,
+    pub scope: EntityScope,
+    pub properties: Vec<PropertyCoverage>,
+}
+
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct EntityCoverageCatalog {
+    pub schema_version: u32,
+    pub entity_kinds: Vec<EntityKindCoverage>,
+}

crates/ocs_plugin_api/src/host.rs

@@ -83,6 +83,10 @@ pub enum HostNotification {
     DocumentTabClosed { tab_id: u64 },
     /// V4 selection changed for a specific tab. Discriminant 7.
     SelectionChangedV4 { tab_id: u64, handles: Vec<Handle> },
+    /// V7 active interactive-command state for a tab. Discriminant 8.
+    CommandStateChanged { tab_id: u64, command: Option<String> },
+    /// V7 drawing epoch, broadcast even without an open shared view. Discriminant 9.
+    DrawingChanged { tab_id: u64, epoch: u64 },
     /// Fallback for notification variants added in future minor revisions.
     /// Carries the raw bincode payload so an older peer can ignore it without
     /// failing deserialization.
@@ -133,6 +137,20 @@ impl Serialize for HostNotification {
                 bincode::serialize_into(&mut bytes, handles)
                     .map_err(serde::ser::Error::custom)?;
             }
+            HostNotification::CommandStateChanged { tab_id, command } => {
+                bytes.push(8);
+                bincode::serialize_into(&mut bytes, tab_id)
+                    .map_err(serde::ser::Error::custom)?;
+                bincode::serialize_into(&mut bytes, command)
+                    .map_err(serde::ser::Error::custom)?;
+            }
+            HostNotification::DrawingChanged { tab_id, epoch } => {
+                bytes.push(9);
+                bincode::serialize_into(&mut bytes, tab_id)
+                    .map_err(serde::ser::Error::custom)?;
+                bincode::serialize_into(&mut bytes, epoch)
+                    .map_err(serde::ser::Error::custom)?;
+            }
             HostNotification::Unknown(raw) => bytes.extend_from_slice(raw),
         }
         bytes.serialize(serializer)
@@ -170,6 +188,12 @@ impl<'de> Deserialize<'de> for HostNotification {
             7 => bincode::deserialize(rest)
                 .map(|(tab_id, handles)| HostNotification::SelectionChangedV4 { tab_id, handles })
                 .map_err(serde::de::Error::custom),
+            8 => bincode::deserialize(rest)
+                .map(|(tab_id, command)| HostNotification::CommandStateChanged { tab_id, command })
+                .map_err(serde::de::Error::custom),
+            9 => bincode::deserialize(rest)
+                .map(|(tab_id, epoch)| HostNotification::DrawingChanged { tab_id, epoch })
+                .map_err(serde::de::Error::custom),
             _ => Ok(HostNotification::Unknown(bytes)),
         }
     }
@@ -575,6 +599,27 @@ pub trait HostApi {
     ) -> Result<HostSettingValue, String> {
         Err("system variable is not supported by this host".to_owned())
     }
+
+    /// Validate and replace existing entities as one undo step (API v7).
+    /// Callers clone entities from `document()`, change only supported fields,
+    /// and submit all replacements together. Identity and kind must be kept.
+    /// An error leaves the drawing and undo history unchanged.
+    fn update_entities_transaction(
+        &mut self,
+        _label: &str,
+        _entities: Vec<EntityType>,
+    ) -> Result<(), String> {
+        Err("entity transactions are not supported by this host".to_owned())
+    }
+
+    /// Current ordered selection in this session's tab (API v7).
+    fn selection(&self) -> Vec<Handle> { Vec::new() }
+
+    /// Replace this tab's selection with exactly these handles, in order.
+    /// Missing or duplicate handles reject the request (API v7).
+    fn set_selection(&mut self, _handles: &[Handle]) -> Result<(), String> {
+        Err("selection writes are not supported by this host".to_owned())
+    }
 }
 
 /// Simplified, read-only entity kind exposed by [`DocumentReader`].

crates/ocs_plugin_api/src/ipc/client.rs

@@ -444,6 +444,40 @@ impl HostApi for PluginHostApi {
             Err(error) => Err(error.to_string()),
         }
     }
+
+    fn update_entities_transaction(
+        &mut self,
+        label: &str,
+        entities: Vec<EntityType>,
+    ) -> Result<(), String> {
+        match self.client.request(PluginRequest::UpdateEntitiesTransaction {
+            label: label.to_owned(), entities,
+        }) {
+            Ok(PluginResponse::EntityTransactionResult(result)) => {
+                if result.is_ok() { self.document_cache = OnceCell::new(); }
+                result
+            }
+            Ok(PluginResponse::Error(error)) => Err(error),
+            Ok(other) => Err(format!("unexpected entity transaction response: {other:?}")),
+            Err(error) => Err(error.to_string()),
+        }
+    }
+
+    fn selection(&self) -> Vec<Handle> {
+        match self.client.request(PluginRequest::GetSelection) {
+            Ok(PluginResponse::Selection(handles)) => handles,
+            _ => Vec::new(),
+        }
+    }
+
+    fn set_selection(&mut self, handles: &[Handle]) -> Result<(), String> {
+        match self.client.request(PluginRequest::SetSelection { handles: handles.to_vec() }) {
+            Ok(PluginResponse::SelectionResult(result)) => result,
+            Ok(PluginResponse::Error(error)) => Err(error),
+            Ok(other) => Err(format!("unexpected selection response: {other:?}")),
+            Err(error) => Err(error.to_string()),
+        }
+    }
 }
 
 /// Sentinel reader used when the shared-memory view could not be initialized.

crates/ocs_plugin_api/src/ipc/protocol.rs

@@ -76,6 +76,8 @@ pub enum HostRequest {
         code: String,
         tab_index: usize,
     },
+    /// V7: release an interactive command after completion or cancellation.
+    DropInteractive { command_id: u64 },
 }
 
 /// Responses the plugin runner sends back for `HostRequest`.
@@ -142,6 +144,11 @@ pub enum PluginRequest {
     GetSystemVariable { name: String },
     /// Change a host-managed setting without nested command dispatch.
     SetSystemVariable { name: String, value: HostSettingValue },
+    /// V7: validate and replace existing entities in a single undo step.
+    UpdateEntitiesTransaction { label: String, entities: Vec<EntityType> },
+    /// V7: synchronous selection read/write for the dispatch tab.
+    GetSelection,
+    SetSelection { handles: Vec<Handle> },
 }
 
 /// Responses the host sends back for `PluginRequest`.
@@ -170,6 +177,9 @@ pub enum PluginResponse {
     DocumentPath(Option<std::ffi::OsString>),
     SystemVariable(Option<HostSettingValue>),
     SystemVariableResult(Result<HostSettingValue, String>),
+    EntityTransactionResult(Result<(), String>),
+    Selection(Vec<Handle>),
+    SelectionResult(Result<(), String>),
 }
 
 /// Messages sent from the host to the plugin runner.

crates/ocs_plugin_api/src/ipc/server.rs

@@ -83,5 +83,10 @@ pub fn handle_plugin_request(
         SetSystemVariable { name, value } => {
             PluginResponse::SystemVariableResult(host.set_system_variable(&name, value))
         }
+        UpdateEntitiesTransaction { label, entities } => PluginResponse::EntityTransactionResult(
+            host.update_entities_transaction(&label, entities),
+        ),
+        GetSelection => PluginResponse::Selection(host.selection()),
+        SetSelection { handles } => PluginResponse::SelectionResult(host.set_selection(&handles)),
     }
 }

crates/ocs_plugin_api/src/ipc/v4/client.rs

@@ -758,6 +758,40 @@ impl HostApi for V4PluginHostApi {
             Err(error) => Err(error.to_string()),
         }
     }
+
+    fn update_entities_transaction(
+        &mut self,
+        label: &str,
+        entities: Vec<EntityType>,
+    ) -> Result<(), String> {
+        match self.request(PluginRequest::UpdateEntitiesTransaction {
+            label: label.to_owned(), entities,
+        }) {
+            Ok(PluginResponse::EntityTransactionResult(result)) => {
+                if result.is_ok() { self.document_cache = OnceCell::new(); }
+                result
+            }
+            Ok(PluginResponse::Error(error)) => Err(error),
+            Ok(other) => Err(format!("unexpected entity transaction response: {other:?}")),
+            Err(error) => Err(error.to_string()),
+        }
+    }
+
+    fn selection(&self) -> Vec<Handle> {
+        match self.request(PluginRequest::GetSelection) {
+            Ok(PluginResponse::Selection(handles)) => handles,
+            _ => Vec::new(),
+        }
+    }
+
+    fn set_selection(&mut self, handles: &[Handle]) -> Result<(), String> {
+        match self.request(PluginRequest::SetSelection { handles: handles.to_vec() }) {
+            Ok(PluginResponse::SelectionResult(result)) => result,
+            Ok(PluginResponse::Error(error)) => Err(error),
+            Ok(other) => Err(format!("unexpected selection response: {other:?}")),
+            Err(error) => Err(error.to_string()),
+        }
+    }
 }
 
 #[cfg(test)]

crates/ocs_plugin_api/src/ipc/v4/protocol.rs

@@ -86,6 +86,37 @@ mod tests {
         }
     }
 
+    #[test]
+    fn command_state_notification_roundtrips() {
+        let notification = HostNotification::CommandStateChanged {
+            tab_id: 42,
+            command: Some("LINE".to_owned()),
+        };
+        let bytes = bincode::serialize(&notification).unwrap();
+        let decoded: HostNotification = bincode::deserialize(&bytes).unwrap();
+        assert_eq!(decoded, notification);
+        let stopped = HostNotification::CommandStateChanged { tab_id: 42, command: None };
+        let bytes = bincode::serialize(&stopped).unwrap();
+        let decoded: HostNotification = bincode::deserialize(&bytes).unwrap();
+        assert_eq!(decoded, stopped);
+        let changed = HostNotification::DrawingChanged { tab_id: 42, epoch: 7 };
+        let bytes = bincode::serialize(&changed).unwrap();
+        let decoded: HostNotification = bincode::deserialize(&bytes).unwrap();
+        assert_eq!(decoded, changed);
+    }
+
+    #[test]
+    fn selection_request_and_response_roundtrip() {
+        let request = PluginRequest::SetSelection { handles: vec![acadrust::Handle::new(9)] };
+        let bytes = bincode::serialize(&request).unwrap();
+        assert!(matches!(bincode::deserialize::<PluginRequest>(&bytes).unwrap(),
+            PluginRequest::SetSelection { handles } if handles == vec![acadrust::Handle::new(9)]));
+        let response = PluginResponse::Selection(vec![acadrust::Handle::new(9)]);
+        let bytes = bincode::serialize(&response).unwrap();
+        assert!(matches!(bincode::deserialize::<PluginResponse>(&bytes).unwrap(),
+            PluginResponse::Selection(handles) if handles == vec![acadrust::Handle::new(9)]));
+    }
+
     #[test]
     fn plugin_notification_roundtrip() {
         let frame = PluginToHostV4::Notification(NotificationEnvelope {

crates/ocs_plugin_api/src/lib.rs

@@ -36,6 +36,8 @@ pub mod manifest;
 pub mod ribbon;
 pub mod type_registry;
 pub mod type_registry_types;
+pub mod entity_coverage;
+pub mod entity_coverage_types;
 pub mod version_info;
 
 /// Runtime host surface — only built with the `host` feature (pulls `acadrust`).
@@ -73,6 +75,8 @@ pub use type_registry::{
     get_embedded_type_registry_json, EnumVariantInfo, FieldInfo, MethodInfo, ParameterInfo,
     TypeId, TypeInfo, TypeKind, TypeRegistry,
 };
+pub use entity_coverage::{get_embedded_entity_coverage_json, EntityCoverageCatalog,
+    EntityKindCoverage, EntityScope, ModelAccess, PropertyCoverage};
 pub use version_info::get_embedded_version_info_json;
 
 #[cfg(test)]

crates/ocs_plugin_api/src/manifest.rs

@@ -20,8 +20,9 @@
 /// a multiplexed socket while leaving the V2/V3 ABI and protocol untouched. v5
 /// adds the `BuiltinPlugin::on_load` lifecycle callback and
 /// `HostApi::document_path`. v6 appends generic host system-variable access
-/// (`HostApi::system_variable` / `set_system_variable`).
-pub const API_VERSION: u32 = 6;
+/// (`HostApi::system_variable` / `set_system_variable`). v7 appends atomic,
+/// undoable replacement of a set of existing entities.
+pub const API_VERSION: u32 = 7;
 
 /// Oldest plugin API major the current host still loads. This keeps previously
 /// compiled cdylibs usable as long as their vtable layout is a prefix of the

crates/ocs_plugin_api/src/process.rs

@@ -237,6 +237,7 @@ fn request_kind(req: &HostRequest) -> &'static str {
         HostRequest::GetPrompt { .. } => "GetPrompt",
         HostRequest::NeedsEntityPick { .. } => "NeedsEntityPick",
         HostRequest::ExecuteCode { .. } => "ExecuteCode",
+        HostRequest::DropInteractive { .. } => "DropInteractive",
         HostRequest::Shutdown => "Shutdown",
     }
 }
@@ -599,6 +600,15 @@ impl PluginProcess {
         }
     }
 
+    /// Release a completed or abandoned V4 interactive command in the runner.
+    pub fn drop_interactive(&self, command_id: u64) -> Result<(), PluginError> {
+        let Some(v4) = &self.v4 else { return Ok(()); };
+        match v4.call(&mut NullHost, HostRequest::DropInteractive { command_id }, &mut |_| {})? {
+            HostResponse::Bool(true) => Ok(()),
+            other => Err(PluginError::UnexpectedResponse(Box::new(other))),
+        }
+    }
+
     /// Ask the plugin process for the current prompt of an interactive command.
     pub fn get_prompt(&self, command_id: u64) -> Result<String, PluginError> {
         if let Some(v4) = &self.v4 {

crates/ocs_plugin_api/src/process/v4.rs

@@ -71,6 +71,7 @@ fn request_kind(req: &HostRequest) -> &'static str {
         HostRequest::GetPrompt { .. } => "GetPrompt",
         HostRequest::NeedsEntityPick { .. } => "NeedsEntityPick",
         HostRequest::ExecuteCode { .. } => "ExecuteCode",
+        HostRequest::DropInteractive { .. } => "DropInteractive",
         HostRequest::Shutdown => "Shutdown",
     }
 }

crates/ocs_plugin_api/src/runner.rs

@@ -191,6 +191,10 @@ fn handle_host_request(
                 Err(_) => HostResponse::Error("interactive command panicked".to_string()),
             }
         }
+        HostRequest::DropInteractive { command_id } => {
+            interactive.borrow_mut().remove(&command_id);
+            HostResponse::Bool(true)
+        }
         HostRequest::GetPrompt { command_id } => {
             let result = {
                 let registry = interactive.borrow();
@@ -290,6 +294,10 @@ fn handle_host_request_v4(
                 Err(_) => Some(HostResponse::Error("interactive command panicked".to_string())),
             }
         }
+        HostRequest::DropInteractive { command_id } => {
+            interactive.borrow_mut().remove(&command_id);
+            Some(HostResponse::Bool(true))
+        }
         HostRequest::GetPrompt { command_id } => {
             let result = {
                 let registry = interactive.borrow();