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The following commit(s) were added to refs/heads/main by this push:
     new e4b8b14221 [#13840] docs: Add Semantic Model user documentation 
(#13842)
e4b8b14221 is described below

commit e4b8b14221e96a689c44cb981ab509473f9a1f44
Author: mchades <[email protected]>
AuthorDate: Fri Oct 16 17:07:39 2026 +0800

    [#13840] docs: Add Semantic Model user documentation (#13842)
    
    ### What changes were proposed in this pull request?
    
    Add Semantic Model concepts and operation guides with REST, Java, and
    Python examples, Ossie import/export, source requirements, and
    governance. Add documentation entry points, consolidate the Python
    example, and correct stale OpenAPI validation descriptions.
    
    ### Why are the changes needed?
    
    Provide a complete user guide for Semantic Model management.
    
    Fix: #13840
    
    ### Does this PR introduce _any_ user-facing change?
    
    Yes. Documentation only.
    
    ### How was this patch tested?
    
    - `./gradlew :docs:spotlessApply :docs:build` and `git diff --check`.
    - Compiled all six Markdown pages as MDX and checked 127 relative links.
    - Compiled the combined Java snippets and checked Python imports, method
    signatures, and definition construction.
    - Verified matching REST, Java, Python, and Ossie definitions, plus
    Ossie YAML/JSON round trips.
---
 .../service/SemanticModelMetaService.java          |   4 +-
 docs/gravitino-mcp-server.md                       |   2 +
 docs/how-to-use-python-client.md                   |  36 +-
 docs/index.md                                      |   3 +
 ...nage-semantic-model-metadata-using-gravitino.md | 596 +++++++++++++++++++++
 docs/manage-tags-in-gravitino.md                   |   2 +-
 docs/open-api/semantic-models.yaml                 |  15 +-
 docs/semantic-models.md                            | 102 ++++
 8 files changed, 724 insertions(+), 36 deletions(-)

diff --git 
a/core/src/main/java/org/apache/gravitino/storage/relational/service/SemanticModelMetaService.java
 
b/core/src/main/java/org/apache/gravitino/storage/relational/service/SemanticModelMetaService.java
index 624d038866..244f8b91d2 100644
--- 
a/core/src/main/java/org/apache/gravitino/storage/relational/service/SemanticModelMetaService.java
+++ 
b/core/src/main/java/org/apache/gravitino/storage/relational/service/SemanticModelMetaService.java
@@ -369,8 +369,8 @@ public class SemanticModelMetaService {
             identifier.namespace().level(1),
             identifier.namespace().level(2),
             observedSemanticModelPO.getSemanticModelName());
-    // TODO: Soft-delete Semantic Model owner, tag, and securable-object 
relations in this
-    // transaction and in the metalake/catalog/schema cascade delete paths.
+    // Orphaned owner, tag, and securable-object relations are cleaned up by
+    // OrphanedMetadataObjectRelationService during garbage collection.
     SessionUtils.doMultipleWithCommit(
         () ->
             OccWriteSupport.deleteWithVersion(
diff --git a/docs/gravitino-mcp-server.md b/docs/gravitino-mcp-server.md
index 71410670d8..086e744a6a 100644
--- a/docs/gravitino-mcp-server.md
+++ b/docs/gravitino-mcp-server.md
@@ -147,6 +147,8 @@ Gravitino MCP server supports the following tools, and you 
could export tool by
 ### Semantic Models
 
 Semantic Model tools manage schema-scoped semantic metadata through the 
Gravitino REST API.
+For concepts and source requirements, see [Semantic 
Models](./semantic-models.md). For governance
+and Ossie import/export, see [Manage Semantic Model 
Metadata](./manage-semantic-model-metadata-using-gravitino.md).
 Use the `semantic_model` tag with `--include-tool-tags` to expose these five 
tools.
 They use the same per-call `metalake` selection and authentication as other 
tools;
 Gravitino filters listings and enforces authorization, including access to 
referenced source tables.
diff --git a/docs/how-to-use-python-client.md b/docs/how-to-use-python-client.md
index 4dd9b1691d..ef84c623c8 100644
--- a/docs/how-to-use-python-client.md
+++ b/docs/how-to-use-python-client.md
@@ -31,39 +31,17 @@ pip install apache-gravitino
 
 1. [Manage metalake using Gravitino Python 
API](./manage-metalake-using-gravitino.md?language=python)
 2. [Manage fileset metadata using Gravitino Python 
API](./manage-fileset-metadata-using-gravitino.md?language=python)
+3. [Manage Semantic Model metadata using Gravitino Python 
API](./manage-semantic-model-metadata-using-gravitino.md?language=python)
 
 ### Semantic Model Ossie Import and Export
 
-Import a standalone Apache Ossie YAML or JSON document into an existing schema 
of a
-relational catalog. Its dataset sources must refer to existing tables or views 
in the
-same metalake. The document supplies the model name; importing an existing 
name raises
-`SemanticModelAlreadyExistsException` without replacing it.
-
-```python
-from pathlib import Path
-
-from gravitino import GravitinoClient, NameIdentifier
-from gravitino.namespace import Namespace
-
-client = GravitinoClient(uri="http://localhost:8090";, metalake_name="metalake")
-try:
-    models = client.load_catalog("catalog").as_semantic_model_catalog()
-    model = models.import_ossie_document(
-        Namespace.of("schema"), 
Path("sales.ossie.yaml").read_text(encoding="utf-8")
-    )
-    document = models.export_ossie_document(
-        NameIdentifier.of("schema", model.name()), document_format="json"
-    )
-    Path("sales.ossie.json").write_text(document, encoding="utf-8")
-finally:
-    client.close()
-```
+Use `as_semantic_model_catalog()` on a loaded relational catalog to manage 
Semantic Models.
+The [Semantic Model 
guide](./manage-semantic-model-metadata-using-gravitino.md?language=python)
+includes Python examples for native creation, list/load, alteration, deletion, 
and Apache Ossie
+YAML/JSON import and export, along with the source and permission requirements.
 
-Both methods default to `document_format="yaml"`; use `"json"` for JSON input 
or output.
-The SDK transfers document text directly and requires no YAML parser. Import 
returns a
-`SemanticModel` using the existing lossless JSON decoder, while export returns 
the server's
-text unchanged. Model properties are exchanged through the root 
`GRAVITINO_PROPERTIES`
-custom extension, and `ossie-version` supplies the document version.
+The SDK transfers Ossie document text directly and requires no YAML parser. 
Import and export
+default to `document_format="yaml"`; use `"json"` for JSON documents.
 
 ### Fileset Example
 
diff --git a/docs/index.md b/docs/index.md
index d8e5a6fcbd..3514a1e53b 100644
--- a/docs/index.md
+++ b/docs/index.md
@@ -62,6 +62,9 @@ Use either to manage metadata. See
   to learn how to manage relational metadata.
 * [Manage view metadata using 
Gravitino](./manage-view-metadata-using-gravitino.md)
   to learn how to manage view metadata.
+* [Manage Semantic Model metadata using 
Gravitino](./manage-semantic-model-metadata-using-gravitino.md)
+  to learn how to define, govern, and exchange semantic metadata. Start with
+  [Semantic Models](./semantic-models.md) for concepts and supported use cases.
 * [Manage fileset metadata using 
Gravitino](./manage-fileset-metadata-using-gravitino.md) to learn
   how to manage fileset metadata.
 * [Manage messaging metadata using 
Gravitino](./manage-messaging-metadata-using-gravitino.md) to learn how to 
manage
diff --git a/docs/manage-semantic-model-metadata-using-gravitino.md 
b/docs/manage-semantic-model-metadata-using-gravitino.md
new file mode 100644
index 0000000000..e1afece301
--- /dev/null
+++ b/docs/manage-semantic-model-metadata-using-gravitino.md
@@ -0,0 +1,596 @@
+---
+title: "Manage Semantic Model Metadata"
+slug: "/manage-semantic-model-metadata-using-gravitino"
+keyword: "semantic model management, semantic metadata, Ossie, Gravitino"
+license: "This software is licensed under the Apache License version 2."
+---
+
+import Tabs from '@theme/Tabs';
+import TabItem from '@theme/TabItem';
+
+## Introduction
+
+This page covers the Gravitino API for Semantic Models. For what a model 
contains, how its sources
+are validated, and how it relates to tables and views, see [Semantic 
Models](./semantic-models.md).
+For creating the catalog and schema a model lives in, see
+[Manage Catalogs and Schemas](./manage-catalogs-and-schemas.md).
+
+## Before You Start
+
+The examples use the `2.0.0` server and clients. They assume:
+
+* A server at `http://localhost:8090` and an existing metalake named `example`.
+* A relational catalog named `sales`, with a schema named `mart`.
+* An existing source table `sales.mart.orders` with `order_id`, `customer_id`, 
and `order_amount` columns.
+* An existing source table `sales.mart.customers` with `customer_id` and 
`customer_code` columns.
+
+See [Manage Relational 
Metadata](./manage-relational-metadata-using-gravitino.md) to create the
+source tables. Add the credentials required by your deployment as described in
+[Authentication](./security/how-to-authenticate.md). With authorization 
enabled, the caller also
+needs the [model and source privileges](#ownership-and-privileges).
+
+Choose one language tab and follow its examples. Each language manages the 
same model names, so
+running create or import again in another language reports that the model 
already exists.
+Run the [drop examples](#drop-a-semantic-model) when you have finished.
+
+Java and Python model identifiers are relative to the loaded catalog 
(`schema.model`). Dataset
+sources use `catalog.schema.object` within the same metalake. For SDK 
configuration, see
+[Client Setup](./how-to-use-gravitino-client.md) and [Python 
Client](./how-to-use-python-client.md).
+
+<details>
+<summary>Java and Python client setup and imports</summary>
+
+Place the operation snippets inside the client block below. The block closes 
the client when
+finished; Java file operations also require the calling method to handle or 
declare `IOException`.
+
+<Tabs groupId='language' queryString>
+<TabItem value="java" label="Java">
+
+```java
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.util.Map;
+import org.apache.gravitino.NameIdentifier;
+import org.apache.gravitino.Namespace;
+import org.apache.gravitino.client.GravitinoClient;
+import org.apache.gravitino.semantic.DataType;
+import org.apache.gravitino.semantic.Dataset;
+import org.apache.gravitino.semantic.DialectExpression;
+import org.apache.gravitino.semantic.Dialects;
+import org.apache.gravitino.semantic.Expression;
+import org.apache.gravitino.semantic.Field;
+import org.apache.gravitino.semantic.Metric;
+import org.apache.gravitino.semantic.OssieDocument;
+import org.apache.gravitino.semantic.OssieFormat;
+import org.apache.gravitino.semantic.Relationship;
+import org.apache.gravitino.semantic.SemanticModel;
+import org.apache.gravitino.semantic.SemanticModelCatalog;
+import org.apache.gravitino.semantic.SemanticModelChange;
+import org.apache.gravitino.semantic.SemanticModelDefinition;
+
+try (GravitinoClient client = GravitinoClient.builder("http://localhost:8090";)
+    .withMetalake("example").build()) {
+  SemanticModelCatalog models = 
client.loadCatalog("sales").asSemanticModelCatalog();
+  NameIdentifier ident = NameIdentifier.of("mart", "sales_model");
+
+  // Run the Java operation examples here.
+}
+```
+
+</TabItem>
+<TabItem value="python" label="Python">
+
+```python
+from pathlib import Path
+
+from gravitino import GravitinoClient, NameIdentifier
+from gravitino.api.semantic.data_type import DataType
+from gravitino.api.semantic.dataset import Dataset
+from gravitino.api.semantic.dialect_expression import DialectExpression
+from gravitino.api.semantic.dialects import Dialects
+from gravitino.api.semantic.expression import Expression
+from gravitino.api.semantic.field import Field
+from gravitino.api.semantic.metric import Metric
+from gravitino.api.semantic.relationship import Relationship
+from gravitino.api.semantic.semantic_model_change import SemanticModelChange
+from gravitino.api.semantic.semantic_model_definition import 
SemanticModelDefinition
+from gravitino.namespace import Namespace
+
+client = GravitinoClient(uri="http://localhost:8090";, metalake_name="example")
+try:
+    models = client.load_catalog("sales").as_semantic_model_catalog()
+    ident = NameIdentifier.of("mart", "sales_model")
+
+    # Run the Python operation examples here.
+finally:
+    client.close()
+```
+
+</TabItem>
+</Tabs>
+
+</details>
+
+## Semantic Model Operations
+
+### Create a Semantic Model
+
+A model needs a name and a definition with at least one dataset. This example 
defines a revenue
+metric over orders and links orders to customers by `customer_id`. The native 
REST API nests the
+definition under `definition`. Its field names include `primaryKey` and 
`datatype`.
+
+The relationship's `from` and `to` name datasets in the model. Its column 
lists and the datasets'
+keys use source table column names, even when those columns are not listed in 
`fields`. Each array
+inside `uniqueKeys` defines one unique key.
+
+<Tabs groupId='language' queryString>
+<TabItem value="shell" label="REST">
+
+```shell
+curl -X POST -H "Accept: application/vnd.gravitino.v1+json" \
+  -H "Content-Type: application/json" -d '{
+  "name": "sales_model",
+  "comment": "Governed sales definitions",
+  "properties": {"domain": "sales"},
+  "definition": {
+    "datasets": [
+      {
+        "name": "orders",
+        "source": {"namespace": ["sales", "mart"], "name": "orders"},
+        "primaryKey": ["order_id"],
+        "fields": [
+          {
+            "name": "order_amount",
+            "expression": {
+              "dialects": [{"dialect": "ANSI_SQL", "expression": 
"order_amount"}]
+            },
+            "datatype": "Decimal"
+          }
+        ]
+      },
+      {
+        "name": "customers",
+        "source": {"namespace": ["sales", "mart"], "name": "customers"},
+        "primaryKey": ["customer_id"],
+        "uniqueKeys": [["customer_code"]],
+        "fields": []
+      }
+    ],
+    "relationships": [
+      {
+        "name": "orders_to_customers",
+        "from": "orders",
+        "to": "customers",
+        "fromColumns": ["customer_id"],
+        "toColumns": ["customer_id"]
+      }
+    ],
+    "metrics": [
+      {
+        "name": "total_revenue",
+        "expression": {
+          "dialects": [{"dialect": "ANSI_SQL", "expression": 
"SUM(orders.order_amount)"}]
+        },
+        "datatype": "Decimal"
+      }
+    ]
+  }
+}' 
http://localhost:8090/api/metalakes/example/catalogs/sales/schemas/mart/semantic-models
+```
+
+</TabItem>
+<TabItem value="java" label="Java">
+
+```java
+Expression amountExpression = Expression.builder()
+    .withDialects(new DialectExpression[] {
+        DialectExpression.builder().withDialect(Dialects.ANSI_SQL)
+            .withExpression("order_amount").build()
+    }).build();
+Field amount = Field.builder().withName("order_amount")
+    .withExpression(amountExpression).withDatatype(DataType.DECIMAL).build();
+Dataset orders = Dataset.builder().withName("orders")
+    .withSource(NameIdentifier.of("sales", "mart", "orders"))
+    .withPrimaryKey(new String[] {"order_id"})
+    .withFields(new Field[] {amount}).build();
+Dataset customers = Dataset.builder().withName("customers")
+    .withSource(NameIdentifier.of("sales", "mart", "customers"))
+    .withPrimaryKey(new String[] {"customer_id"})
+    .withUniqueKeys(new String[][] {{"customer_code"}})
+    .withFields(new Field[0]).build();
+Relationship ordersToCustomers = 
Relationship.builder().withName("orders_to_customers")
+    .withFrom("orders").withTo("customers")
+    .withFromColumns(new String[] {"customer_id"})
+    .withToColumns(new String[] {"customer_id"}).build();
+
+Expression revenueExpression = Expression.builder()
+    .withDialects(new DialectExpression[] {
+        DialectExpression.builder().withDialect(Dialects.ANSI_SQL)
+            .withExpression("SUM(orders.order_amount)").build()
+    }).build();
+Metric revenue = Metric.builder().withName("total_revenue")
+    .withExpression(revenueExpression).withDatatype(DataType.DECIMAL).build();
+SemanticModelDefinition definition = SemanticModelDefinition.builder()
+    .withDatasets(new Dataset[] {orders, customers})
+    .withRelationships(new Relationship[] {ordersToCustomers})
+    .withMetrics(new Metric[] {revenue}).build();
+
+SemanticModel created = models.createSemanticModel(
+    ident, "Governed sales definitions", definition, Map.of("domain", 
"sales"));
+```
+
+</TabItem>
+<TabItem value="python" label="Python">
+
+```python
+amount = Field(
+    "order_amount",
+    Expression([DialectExpression(Dialects.ANSI_SQL, "order_amount")]),
+    datatype=DataType.DECIMAL)
+orders = Dataset(
+    "orders",
+    NameIdentifier.of("sales", "mart", "orders"),
+    primary_key=["order_id"],
+    fields=[amount])
+customers = Dataset(
+    "customers",
+    NameIdentifier.of("sales", "mart", "customers"),
+    primary_key=["customer_id"],
+    unique_keys=[["customer_code"]],
+    fields=[])
+orders_to_customers = Relationship(
+    "orders_to_customers",
+    from_dataset="orders",
+    to_dataset="customers",
+    from_columns=["customer_id"],
+    to_columns=["customer_id"])
+revenue = Metric(
+    "total_revenue",
+    Expression([DialectExpression(Dialects.ANSI_SQL, 
"SUM(orders.order_amount)")]),
+    datatype=DataType.DECIMAL)
+definition = SemanticModelDefinition(
+    datasets=[orders, customers],
+    relationships=[orders_to_customers],
+    metrics=[revenue])
+
+created = models.create_semantic_model(
+    ident, "Governed sales definitions", definition, {"domain": "sales"})
+```
+
+</TabItem>
+</Tabs>
+
+The REST response contains `code: 0` and a `semanticModel` object with `name`, 
`comment`,
+`properties`, `definition`, and `audit`. The SDKs return a `SemanticModel` 
directly. Creating a name
+that already exists reports a conflict without overwriting the model.
+
+### List Semantic Models
+
+Listing returns identifiers rather than complete definitions. With 
authorization enabled, it
+includes only models visible to the caller.
+
+<Tabs groupId='language' queryString>
+<TabItem value="shell" label="REST">
+
+```shell
+curl -X GET -H "Accept: application/vnd.gravitino.v1+json" \
+  
http://localhost:8090/api/metalakes/example/catalogs/sales/schemas/mart/semantic-models
+```
+
+</TabItem>
+<TabItem value="java" label="Java">
+
+```java
+NameIdentifier[] identifiers = models.listSemanticModels(Namespace.of("mart"));
+```
+
+</TabItem>
+<TabItem value="python" label="Python">
+
+```python
+identifiers = models.list_semantic_models(Namespace.of("mart"))
+```
+
+</TabItem>
+</Tabs>
+
+REST identifiers include the namespace `["example", "sales", "mart"]`. SDK 
identifiers are relative
+to the loaded catalog, such as `mart.sales_model`.
+
+### Load a Semantic Model
+
+Load returns the stored definition, properties, comment, and audit information.
+
+<Tabs groupId='language' queryString>
+<TabItem value="shell" label="REST">
+
+```shell
+curl -X GET -H "Accept: application/vnd.gravitino.v1+json" \
+  
http://localhost:8090/api/metalakes/example/catalogs/sales/schemas/mart/semantic-models/sales_model
+```
+
+</TabItem>
+<TabItem value="java" label="Java">
+
+```java
+SemanticModel loaded = models.loadSemanticModel(ident);
+```
+
+</TabItem>
+<TabItem value="python" label="Python">
+
+```python
+loaded = models.load_semantic_model(ident)
+```
+
+</TabItem>
+</Tabs>
+
+### Alter a Semantic Model
+
+Changes are applied in order in one request. If any change or the resulting 
model is invalid, none
+of the changes is persisted.
+
+| Change | REST update |
+|--------|-------------|
+| Rename within the schema | `{"@type":"rename","newName":"renamed_model"}` |
+| Update or clear the comment | 
`{"@type":"updateComment","newComment":"Reviewed sales definitions"}`; use 
`null` to clear it. |
+| Set a property | 
`{"@type":"setProperty","property":"domain","value":"finance"}` |
+| Remove a property | `{"@type":"removeProperty","property":"domain"}` |
+| Replace the definition | Set `@type` to `replaceDefinition` and supply the 
complete native definition in `definition`. |
+
+<Tabs groupId='language' queryString>
+<TabItem value="shell" label="REST">
+
+```shell
+curl -X PUT -H "Accept: application/vnd.gravitino.v1+json" \
+  -H "Content-Type: application/json" -d '{
+  "updates": [
+    {"@type": "updateComment", "newComment": "Reviewed sales definitions"},
+    {"@type": "setProperty", "property": "domain", "value": "finance"}
+  ]
+}' 
http://localhost:8090/api/metalakes/example/catalogs/sales/schemas/mart/semantic-models/sales_model
+```
+
+</TabItem>
+<TabItem value="java" label="Java">
+
+```java
+SemanticModel altered = models.alterSemanticModel(
+    ident,
+    SemanticModelChange.updateComment("Reviewed sales definitions"),
+    SemanticModelChange.setProperty("domain", "finance"));
+```
+
+</TabItem>
+<TabItem value="python" label="Python">
+
+```python
+altered = models.alter_semantic_model(
+    ident,
+    SemanticModelChange.update_comment("Reviewed sales definitions"),
+    SemanticModelChange.set_property("domain", "finance"))
+```
+
+</TabItem>
+</Tabs>
+
+Definition replacement replaces all datasets, relationships, and metrics. 
Include everything you
+want to retain. In Java, use 
`SemanticModelChange.replaceDefinition(definition)`; in Python, use
+`SemanticModelChange.replace_definition(definition)`. Each replacement 
revalidates the complete
+definition and its source access. Comment and property changes do not 
revalidate sources.
+
+## Apache Ossie Import and Export
+
+An Ossie document uses snake_case names, string source identifiers, and 
root-level datasets,
+relationships, and metrics. See [Exchanging 
Definitions](./semantic-models.md#exchanging-definitions)
+for the mapping from the native REST format.
+
+### Import a Document
+
+Save the following as `sales.ossie.yaml`. It uses a different model name so it 
can be imported
+alongside the model created above:
+
+```yaml
+version: 0.2.0.dev0
+name: imported_sales_model
+description: Imported sales definitions
+datasets:
+  - name: orders
+    source: sales.mart.orders
+    primary_key: [order_id]
+    fields:
+      - name: order_amount
+        expression:
+          dialects:
+            - dialect: ANSI_SQL
+              expression: order_amount
+        datatype: Decimal
+  - name: customers
+    source: sales.mart.customers
+    primary_key: [customer_id]
+    unique_keys: [[customer_code]]
+    fields: []
+relationships:
+  - name: orders_to_customers
+    from: orders
+    to: customers
+    from_columns: [customer_id]
+    to_columns: [customer_id]
+metrics:
+  - name: total_revenue
+    expression:
+      dialects:
+        - dialect: ANSI_SQL
+          expression: SUM(orders.order_amount)
+    datatype: Decimal
+custom_extensions:
+  - vendor_name: GRAVITINO_PROPERTIES
+    data: '{"domain":"sales"}'
+```
+
+<Tabs groupId='language' queryString>
+<TabItem value="shell" label="REST">
+
+```shell
+curl -X POST -H "Accept: application/vnd.gravitino.v1+json" \
+  -H "Content-Type: application/yaml" --data-binary @sales.ossie.yaml \
+  
http://localhost:8090/api/metalakes/example/catalogs/sales/schemas/mart/semantic-models/ossie
+```
+
+</TabItem>
+<TabItem value="java" label="Java">
+
+```java
+SemanticModel importedModel = models.importOssieDocument(
+    Namespace.of("mart"), 
OssieDocument.yaml(Files.readString(Path.of("sales.ossie.yaml"))));
+```
+
+</TabItem>
+<TabItem value="python" label="Python">
+
+```python
+imported_model = models.import_ossie_document(
+    Namespace.of("mart"), Path("sales.ossie.yaml").read_text(encoding="utf-8"))
+```
+
+</TabItem>
+</Tabs>
+
+Import creates a new model using the name in the document and applies the same 
validation as
+native creation. An existing name reports a conflict. REST returns the native 
`semanticModel`
+response; the SDKs return a `SemanticModel`.
+
+Send the raw document text. For JSON, use `Content-Type: application/json` in 
REST,
+`OssieDocument.json(...)` in Java, or `document_format="json"` in Python. YAML 
requests use
+`application/yaml`; `application/x-yaml` and `text/yaml` are also accepted. An 
omitted content type
+defaults to YAML, while an unsupported content type returns `415`. Use an 
explicit content type
+with curl, since its data options otherwise send a form content type.
+
+### Export a Document
+
+Export the native model as an Ossie JSON document:
+
+<Tabs groupId='language' queryString>
+<TabItem value="shell" label="REST">
+
+```shell
+curl 
'http://localhost:8090/api/metalakes/example/catalogs/sales/schemas/mart/semantic-models/sales_model/ossie?format=json'
 \
+  -o exported-sales.ossie.json
+```
+
+</TabItem>
+<TabItem value="java" label="Java">
+
+```java
+OssieDocument exported = models.exportOssieDocument(ident, OssieFormat.JSON);
+Files.writeString(Path.of("exported-sales.ossie.json"), exported.content());
+```
+
+</TabItem>
+<TabItem value="python" label="Python">
+
+```python
+exported = models.export_ossie_document(ident, document_format="json")
+Path("exported-sales.ossie.json").write_text(exported, encoding="utf-8")
+```
+
+</TabItem>
+</Tabs>
+
+For YAML, use `format=yaml` in REST, `OssieFormat.YAML` in Java, or 
`document_format="yaml"` in
+Python. REST and Python default to YAML when the format is omitted. REST 
returns the document
+text without the native response wrapper, and Python returns that text 
unchanged.
+
+The `ossie-version` model property supplies the document's `version`. Native 
creation records the
+server's default when the property is omitted; import records the document 
version. Other model
+properties are exchanged through the root `GRAVITINO_PROPERTIES` custom 
extension, whose `data`
+is a JSON object encoded as a string. Its values must be strings. Use 
`properties` when creating a
+model through the native API; the reserved extension is for Ossie exchange.
+
+## Ownership and Privileges
+
+When authorization is enabled, a model's creator becomes its owner. For 
callers using explicit
+privilege grants, access also requires `USE_CATALOG` and `USE_SCHEMA` on the 
parent objects:
+
+| Operation | Required model privilege or ownership |
+|-----------|---------------------------------------|
+| Create or import | `CREATE_SEMANTIC_MODEL` on the containing schema or an 
ancestor. |
+| Discover, load, or export | `USE_SEMANTIC_MODEL`, `MODIFY_SEMANTIC_MODEL`, 
or ownership. |
+| Alter or rename | `MODIFY_SEMANTIC_MODEL` or ownership. |
+| Drop | Ownership; `MODIFY_SEMANTIC_MODEL` alone is insufficient. |
+
+Parent owners can also operate on contained models under the
+[access-control rules](./security/access-control.md#required-privileges). A 
schema owner still
+needs access to the catalog. Create, import, and definition replacement 
additionally check the
+caller's access to every source table or view. Permission to load a Semantic 
Model does not itself
+grant permission to read its source data.
+
+Ownership and role grants use metadata object type `SEMANTIC_MODEL` and a name 
such as
+`sales.mart.sales_model` within the selected metalake. See
+[Ownership](./security/access-control.md#ownership) and the
+[access-control walkthrough](./security/access-control.md#walkthrough) to 
manage owners and roles.
+Setting a string property named `owner` does not transfer ownership.
+
+### Tags and Policies
+
+Create a tag in the metalake before attaching it to a Semantic Model. For an 
existing tag named
+`certified`, use the `semantic_model` object type in the REST path:
+
+```shell
+curl -X POST -H "Accept: application/vnd.gravitino.v1+json" \
+  -H "Content-Type: application/json" -d '{"tagsToAdd": ["certified"]}' \
+  
http://localhost:8090/api/metalakes/example/objects/semantic_model/sales.mart.sales_model/tags
+```
+
+Tag operations have their own authorization requirements. See
+[Manage Tags](./manage-tags-in-gravitino.md#object-operations) for creating, 
attaching, listing, and
+removing tags. Policies are selected through tags; see
+[Policy-to-Tag 
Associations](./manage-policies-in-gravitino.md#policy-to-tag-associations).
+
+## Drop a Semantic Model
+
+Drop the models after trying the examples. Dropping removes the semantic 
metadata and its
+governance associations without deleting source tables, views, or data.
+
+<Tabs groupId='language' queryString>
+<TabItem value="shell" label="REST">
+
+```shell
+curl -X DELETE -H "Accept: application/vnd.gravitino.v1+json" \
+  
http://localhost:8090/api/metalakes/example/catalogs/sales/schemas/mart/semantic-models/sales_model
+curl -X DELETE -H "Accept: application/vnd.gravitino.v1+json" \
+  
http://localhost:8090/api/metalakes/example/catalogs/sales/schemas/mart/semantic-models/imported_sales_model
+```
+
+</TabItem>
+<TabItem value="java" label="Java">
+
+```java
+boolean dropped = models.dropSemanticModel(ident);
+boolean importedDropped = models.dropSemanticModel(
+    NameIdentifier.of("mart", "imported_sales_model"));
+```
+
+</TabItem>
+<TabItem value="python" label="Python">
+
+```python
+dropped = models.drop_semantic_model(ident)
+imported_dropped = models.drop_semantic_model(
+    NameIdentifier.of("mart", "imported_sales_model"))
+```
+
+</TabItem>
+</Tabs>
+
+REST returns `{"code":0,"dropped":true}` when the model is dropped, while the 
SDKs return a boolean.
+An authorized request for an absent model returns `false` (`dropped: false` in 
REST).
+
+## Other Interfaces
+
+The [Gravitino MCP server](./gravitino-mcp-server.md#semantic-models) provides
+`list_of_semantic_models`, `load_semantic_model`, `create_semantic_model`, 
`alter_semantic_model`,
+and `drop_semantic_model`. Enable the `semantic_model` tool tag when filtering 
tools.
+Create and alter use the native REST definition format. Use REST or the SDKs 
for Ossie import and
+export. The current Web UI does not provide Semantic Model workflows.
diff --git a/docs/manage-tags-in-gravitino.md b/docs/manage-tags-in-gravitino.md
index 528c9dd18c..e99d8c5196 100644
--- a/docs/manage-tags-in-gravitino.md
+++ b/docs/manage-tags-in-gravitino.md
@@ -247,7 +247,7 @@ client.delete_tag("pii")
 
 Both happen in one request, and either list can be omitted. The object type 
and full name go in the
 path, so the same call covers catalogs, schemas, tables, views, columns, 
filesets, topics, models,
-and functions.
+functions, and [Semantic 
Models](./manage-semantic-model-metadata-using-gravitino.md#tags-and-policies).
 
 <Tabs groupId='language' queryString>
 <TabItem value="shell" label="REST">
diff --git a/docs/open-api/semantic-models.yaml 
b/docs/open-api/semantic-models.yaml
index d81640988c..81b8eb0441 100644
--- a/docs/open-api/semantic-models.yaml
+++ b/docs/open-api/semantic-models.yaml
@@ -53,8 +53,9 @@ paths:
       summary: Create a Semantic Model
       description: >-
         Creates a schema-scoped Semantic Model in a relational catalog. The 
complete definition is
-        validated before the model is stored, including source identifier 
shape. Source existence,
-        source columns, and source authorization checks are not yet 
implemented.
+        validated before the model is stored, including source identifier 
shape, source existence,
+        and primary-key, unique-key, and relationship columns. When 
authorization is enabled,
+        source lookups also require the caller's permission to access the 
source metadata.
       operationId: createSemanticModel
       requestBody:
         required: true
@@ -95,6 +96,10 @@ paths:
       summary: Import an Apache Ossie Semantic Model
       description: >-
         Imports one standalone Apache Ossie document and creates the 
represented Semantic Model.
+        The imported definition is validated before the model is stored, 
including source identifier
+        shape, source existence, and primary-key, unique-key, and relationship 
columns. When
+        authorization is enabled, source lookups also require the caller's 
permission to access the
+        source metadata.
         The request body is the raw JSON or YAML document, not a JSON-encoded 
string. Content-Type
         selects the parser; when the header is absent, the body is parsed as 
YAML. Parsing does not
         fall back to another format.
@@ -182,8 +187,10 @@ paths:
       description: >-
         Applies the ordered updates atomically. The server validates and 
converts the complete
         update batch before dispatch; if any update or the resulting model is 
invalid, none of the
-        updates is applied. Only replaceDefinition revalidates the complete 
definition. Source
-        existence, source columns, and source authorization checks are not yet 
implemented.
+        updates is applied. Each replaceDefinition revalidates the complete 
definition, source
+        existence, and primary-key, unique-key, and relationship columns. When 
authorization is
+        enabled, source lookups also require the caller's permission to access 
the source metadata.
+        Metadata-only updates do not revalidate sources.
       operationId: alterSemanticModel
       requestBody:
         required: true
diff --git a/docs/semantic-models.md b/docs/semantic-models.md
new file mode 100644
index 0000000000..71e7d1bc2c
--- /dev/null
+++ b/docs/semantic-models.md
@@ -0,0 +1,102 @@
+---
+title: "Semantic Models"
+slug: "/semantic-models"
+keyword: "semantic model, semantic metadata, Ossie, metrics, Gravitino"
+license: "This software is licensed under the Apache License version 2."
+---
+
+## Introduction
+
+A Semantic Model describes the business meaning of data: the datasets to use, 
their fields and
+relationships, and the metrics calculated from them. A sales model, for 
example, can give
+analytical applications and AI tools a shared definition of revenue.
+
+Semantic Models live in schemas of relational catalogs. Gravitino stores their 
definitions and
+manages their lifecycle, ownership, privileges, and tags, even when the 
underlying catalog system
+has no semantic-model feature. They are separate from [SQL 
views](./tables-and-views.md) and the
+AI/ML artifacts managed by a [model catalog](./model-catalog.md).
+
+Gravitino manages the definitions. Query compilation, execution, 
materialization, and publishing
+engine-specific semantic objects are responsibilities of the applications that 
consume them.
+
+## Quick Start
+
+**1. Choose the source data.** Connect a relational catalog and identify the 
tables or logical views
+the model will describe. See [Catalogs and Schemas](./catalogs-and-schemas.md).
+
+**2. Create or import a model.** Define datasets and metrics through REST or a 
client SDK, or import
+an Apache Ossie YAML or JSON document. The source objects must already exist.
+
+**3. Govern and share the definition.** Assign access through roles, attach 
tags, and let consumers
+load the model or export it as an Ossie document. Permission to read a 
definition does not itself
+grant access to the source data.
+
+Worked examples are in [Manage Semantic Model 
Metadata](./manage-semantic-model-metadata-using-gravitino.md).
+
+## The Semantic Model
+
+A model has a name, an optional comment, string-valued Gravitino properties, a 
structured
+definition, and audit information. The definition uses these components:
+
+| Component | Purpose |
+|-----------|---------|
+| `datasets` | A required, non-empty list of named sources. Each dataset can 
define fields, a primary key, and unique keys. |
+| `fields` | Named expressions within a dataset, with optional data types, 
labels, descriptions, and dimension information. |
+| `relationships` | Links between datasets in the same model, using source 
column names in `fromColumns` and `toColumns`. |
+| `metrics` | Named expressions such as `SUM(orders.order_amount)`, with 
optional data types and descriptions. |
+| `aiContext` | Context for consumers, represented as text or a structured 
object. |
+| `customExtensions` | Vendor-specific information preserved with the 
definition. |
+
+Expressions contain one or more dialect-specific representations. The Java and 
Python SDKs provide
+`Dialects` constants for `ANSI_SQL`, `SNOWFLAKE`, `MDX`, `TABLEAU`, 
`DATABRICKS`, `MAQL`, and `BIGQUERY`.
+Other non-empty dialect identifiers are also accepted and preserved. Choose 
identifiers supported
+by the application consuming the model. Gravitino validates the definition's 
structure but does
+not parse or execute the expression text.
+
+### Sources and Validation
+
+Dataset sources use `catalog.schema.object` within the model's metalake. They 
may reference another
+catalog or schema in that metalake. Each source must resolve to an existing 
table or a logical view
+supported by its catalog. Cross-metalake references are not supported.
+
+The `from` and `to` endpoints of a relationship name datasets within the model.
+Primary-key, unique-key, and relationship columns refer to columns of the 
source table or view,
+rather than field aliases in the model. Gravitino checks that these columns 
exist; it does not
+check whether the data satisfies the declared keys or relationships.
+
+Creating, importing, or replacing a definition checks source existence and 
these columns, even
+when authorization is disabled. With authorization enabled, source lookups 
also require the
+caller's access to the source metadata.
+
+Loading or exporting a model, renaming it, and changing only its comment or 
properties do not
+revalidate source metadata. Review definitions when their source schemas 
change: a stored model
+can become stale after a source column is changed or removed.
+
+### Exchanging Definitions
+
+The native REST API and standalone Apache Ossie documents represent the same 
definition in
+different forms:
+
+| Aspect | Native REST API | Ossie document |
+|--------|-----------------|----------------|
+| Definition location | Nested under `definition` in the model object | 
Datasets, relationships, and metrics at the document root |
+| Field names | `primaryKey`, `uniqueKeys`, `fromColumns`, `toColumns`, 
`datatype` | `primary_key`, `unique_keys`, `from_columns`, `to_columns`, 
`datatype` |
+| Dataset source | `{"namespace":["sales","mart"],"name":"orders"}` | 
`sales.mart.orders` |
+| Model description | `comment` | `description` |
+| Gravitino properties | `properties` on the model | A root 
`GRAVITINO_PROPERTIES` custom extension |
+
+Use the Ossie export endpoint to produce a portable document. A native load 
response is not an
+Ossie import document. Import creates a new model and reports a conflict if 
its name already
+exists. See [Import and 
Export](./manage-semantic-model-metadata-using-gravitino.md#apache-ossie-import-and-export).
+
+## Governance and Interfaces
+
+The creator becomes the model's owner when authorization is enabled. Role 
grants control creation,
+discovery, and modification; deletion requires ownership. Tags classify models 
and select policies
+through policy-to-tag associations. See
+[Ownership and 
Privileges](./manage-semantic-model-metadata-using-gravitino.md#ownership-and-privileges)
+and [Tags and 
Policies](./manage-semantic-model-metadata-using-gravitino.md#tags-and-policies).
+
+Use REST, the Java or Python client, or the
+[MCP server](./gravitino-mcp-server.md#semantic-models) to manage Semantic 
Models. The current Web UI
+does not provide Semantic Model workflows.

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