ocs_doc_api: Phase 3 attributes + nested block traversal

- SetAttribute op + GetAttributes/GetBlockEntities queries (append-only).
- backend set_attribute (add/update Insert attribute), attributes (tag,value pairs),
  block_entities (read-only traversal via BlockRecord.entity_handles -> id+kind+bounds).
- facade Entity::set_attribute/attributes, Document::block_entities.
- spec Insert methods; api_reference + binding_schema regenerated; mocks + baseline.
- Query enum: drop Copy (GetBlockEntities carries String).
- Test phase3_attributes_and_block_traversal -> 608 host lib + 3 consistency green.

crates/ocs_doc_api/src/backend.rs

@@ -66,6 +66,15 @@ pub trait DocApiBackend {
     /// A dimension's measured value (distance for linear/radius, degrees for angular).
     fn dimension_measurement(&self, id: ObjectId) -> ApiResult<f64>;
 
+    /// Set an attribute `value` for `tag` on an insert (adds if absent). Insert-only.
+    fn set_attribute(&mut self, id: ObjectId, tag: &str, value: &str) -> ApiResult<()>;
+
+    /// An insert's attributes as (tag, value) pairs. Insert-only.
+    fn attributes(&self, id: ObjectId) -> ApiResult<Vec<(String, String)>>;
+
+    /// The entities inside a block definition (read-only traversal), as views.
+    fn block_entities(&self, block_name: &str) -> ApiResult<Vec<EntityView>>;
+
     /// Can `id` be modified in place right now (exists, is the expected family,
     /// not on a locked layer)? Read-only pre-check used before mutations.
     /// Default: existence + not-locked (backends narrow the family check).

crates/ocs_doc_api/src/executor.rs

@@ -227,6 +227,16 @@ pub fn apply_op<B: DocApiBackend>(b: &mut B, op: Operation) -> ApiResult<Receipt
             b.finalize_op();
             OpOutcome::NewId(id)
         }
+        Operation::SetAttribute { id, tag, value } => {
+            b.can_modify(*id).map_err(|e| match e {
+                ApiError::UnknownId(_) => ApiError::validation(name, format!("unknown ObjectId {id:?}")),
+                other => other,
+            })?;
+            b.push_undo(name);
+            b.set_attribute(*id, tag, value)?;
+            b.finalize_op();
+            OpOutcome::Updated(*id)
+        }
     };
     Ok(Receipt {
         outcome: Some(outcome),
@@ -253,20 +263,22 @@ pub fn apply_queries<B: DocApiBackend>(b: &mut B, queries: Vec<Query>) -> ApiRes
     }
     let mut results = Vec::with_capacity(queries.len());
     for q in &queries {
-        let r = match *q {
-            Query::GetEntity { id } => QueryResult::Entity(b.get_entity(id)?),
-            Query::GetBounds { id } => QueryResult::Bounds(b.bounds(id)?),
-            Query::GetCentroid { id } => QueryResult::Centroid(b.centroid(id)?),
-            Query::GetVolume { id } => QueryResult::Volume(b.volume(id)?),
+        let r = match q {
+            Query::GetEntity { id } => QueryResult::Entity(b.get_entity(*id)?),
+            Query::GetBounds { id } => QueryResult::Bounds(b.bounds(*id)?),
+            Query::GetCentroid { id } => QueryResult::Centroid(b.centroid(*id)?),
+            Query::GetVolume { id } => QueryResult::Volume(b.volume(*id)?),
             Query::GetIntersects { a, b: bid } => {
-                let ba = b.bounds(a)?;
-                let bb = b.bounds(bid)?;
+                let ba = b.bounds(*a)?;
+                let bb = b.bounds(*bid)?;
                 QueryResult::Intersects(ba.overlaps(&bb))
             }
             Query::GetGeometryRevision => QueryResult::Revision(b.revision()),
-            Query::GetTextContent { id } => QueryResult::TextContent(b.text_content(id)?),
-            Query::GetHatchBoundary { id } => QueryResult::HatchBoundary(b.hatch_boundary(id)?),
-            Query::GetDimensionMeasurement { id } => QueryResult::DimensionMeasurement(b.dimension_measurement(id)?),
+            Query::GetTextContent { id } => QueryResult::TextContent(b.text_content(*id)?),
+            Query::GetHatchBoundary { id } => QueryResult::HatchBoundary(b.hatch_boundary(*id)?),
+            Query::GetDimensionMeasurement { id } => QueryResult::DimensionMeasurement(b.dimension_measurement(*id)?),
+            Query::GetAttributes { id } => QueryResult::Attributes(b.attributes(*id)?),
+            Query::GetBlockEntities { block_name } => QueryResult::BlockEntities(b.block_entities(block_name)?),
         };
         results.push(r);
     }

crates/ocs_doc_api/src/facade.rs

@@ -128,6 +128,14 @@ impl Document {
         }
     }
 
+    /// Read-only traversal of a block definition's entities (ids + kinds + bounds).
+    pub fn block_entities(&self, block_name: &str) -> ApiResult<Vec<EntityView>> {
+        match self.session.one_query(Query::GetBlockEntities { block_name: block_name.to_string() })? {
+            QueryResult::BlockEntities(v) => Ok(v),
+            _ => Err(ApiError::Transport("unexpected block-entities result".into())),
+        }
+    }
+
     /// Batch of read-only queries in ONE round-trip (safe: no mutation/undo).
     /// The closure records queries on a [`QueryBatch`]; the results are returned
     /// in the same order as a [`QueryResults`] view the caller destructures.
@@ -289,6 +297,18 @@ impl Entity {
             _ => Err(ApiError::Transport("unexpected entity result".into())),
         }
     }
+    /// This insert's attributes as (tag, value) pairs. Insert-only.
+    pub fn attributes(&self) -> ApiResult<Vec<(String, String)>> {
+        match self.session.one_query(Query::GetAttributes { id: self.id })? {
+            QueryResult::Attributes(v) => Ok(v),
+            _ => Err(ApiError::Transport("unexpected attributes result".into())),
+        }
+    }
+    /// Set an attribute `value` for `tag` on this insert (adds if absent). One undo step.
+    pub fn set_attribute(&self, tag: &str, value: &str) -> ApiResult<()> {
+        self.session.apply_op(Operation::SetAttribute { id: self.id, tag: tag.to_string(), value: value.to_string() })?;
+        Ok(())
+    }
     pub fn as_solid(&self) -> Option<Solid> {
         // Typed downcast is validated by the view's kind.
         matches!(self.view().ok()?.kind.as_str(), "Solid3D").then(|| Solid::new(self.session.clone(), self.id))

crates/ocs_doc_api/src/gen/api_reference.md

@@ -145,6 +145,11 @@ Block reference. Place an existing BlockRecord by name; transform moves its inse
 
 - **create_insert**(`block_name: &str, insert_point: [f64; 3], scale: f64, rotation: f64`) -> `Entity`
 
+### Methods
+
+- **attributes**(``) -> `Vec<(String, String)>` — query `GetAttributes`
+- **set_attribute**(`tag: &str, value: &str`) -> `()` — op `SetAttribute`
+
 ## `Entity` (acadrust `Viewport`, collection `entities`)
 
 Paper-space viewport: a width×height window at center looking at view_target with view_height zoom. bounds = center ± w/2,h/2; transform moves center.

crates/ocs_doc_api/src/gen/binding_schema.json

@@ -300,7 +300,39 @@
       "acadrust_variant": "Insert",
       "collection": "entities",
       "handle": "Entity",
-      "methods": [],
+      "methods": [
+        {
+          "args": [],
+          "bulk": false,
+          "fixed": null,
+          "kind": "query",
+          "name": "attributes",
+          "op": null,
+          "query": "GetAttributes",
+          "read_only": true,
+          "returns": "Vec<(String, String)>"
+        },
+        {
+          "args": [
+            {
+              "name": "tag",
+              "ty": "&str"
+            },
+            {
+              "name": "value",
+              "ty": "&str"
+            }
+          ],
+          "bulk": false,
+          "fixed": null,
+          "kind": "op",
+          "name": "set_attribute",
+          "op": "SetAttribute",
+          "query": null,
+          "read_only": false,
+          "returns": "()"
+        }
+      ],
       "name": "Insert"
     },
     {

crates/ocs_doc_api/src/gen/ops_gen.rs

@@ -40,4 +40,6 @@ pub enum Operation {
     CreateHatch(HatchSpec),
     // dimensions
     CreateDimensionLinear(DimensionSpec),
+    // attributes
+    SetAttribute { id: ObjectId, tag: String, value: String },
 }

crates/ocs_doc_api/src/gen/query_gen.rs

@@ -9,7 +9,8 @@ use crate::id::ObjectId;
 
 /// A typed read query (plan §5). Read-only: no mutation, no undo, no revision
 /// bump. Safe to batch (`EnvelopeBody::Queries`). Append new variants at the END only.
-#[derive(Debug, Clone, Copy, PartialEq, Serialize, Deserialize)]
+/// (Not `Copy`: some variants carry owned data like a block name.)
+#[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
 #[non_exhaustive]
 pub enum Query {
     GetEntity { id: ObjectId },
@@ -25,4 +26,8 @@ pub enum Query {
     GetHatchBoundary { id: ObjectId },
     /// The measured value of a Dimension (distance or angle).
     GetDimensionMeasurement { id: ObjectId },
+    /// An insert's attributes as (tag, value) pairs.
+    GetAttributes { id: ObjectId },
+    /// The entity ids + kinds inside a block definition (read-only traversal).
+    GetBlockEntities { block_name: String },
 }

crates/ocs_doc_api/src/ops.rs

@@ -169,6 +169,7 @@ impl crate::gen::Operation {
             SetTextContent { .. } => "SetTextContent",
             CreateHatch(_) => "CreateHatch",
             CreateDimensionLinear(_) => "CreateDimensionLinear",
+            SetAttribute { .. } => "SetAttribute",
         }
     }
 }

crates/ocs_doc_api/src/query.rs

@@ -49,6 +49,10 @@ pub enum QueryResult {
     HatchBoundary(Vec<Vec<[f64; 2]>>),
     /// A dimension's measured value (distance for linear/radius, degrees for angular).
     DimensionMeasurement(f64),
+    /// An insert's attributes as (tag, value) pairs.
+    Attributes(Vec<(String, String)>),
+    /// The entities inside a block definition (read-only traversal).
+    BlockEntities(Vec<EntityView>),
 }
 
 /// Convenience: the query name for diagnostics.
@@ -65,6 +69,8 @@ impl crate::gen::Query {
             GetTextContent { .. } => "GetTextContent",
             GetHatchBoundary { .. } => "GetHatchBoundary",
             GetDimensionMeasurement { .. } => "GetDimensionMeasurement",
+            GetAttributes { .. } => "GetAttributes",
+            GetBlockEntities { .. } => "GetBlockEntities",
         }
     }
 }