feat: add get_object tool for retrieving Cordra digital objects by ID with error handling

README.md

@@ -26,6 +26,8 @@ ensuring safe exploration without risk of data modification or corruption.
 
 ### Tools
 
+- `get_object` - Retrieve a digital object by its complete ID/handle.
+  - `object_id` - Complete object ID (e.g., "test/abc123")
 - `search_objects` - Search for digital objects using a query string with pagination support.
   - `query` - Lucene/Solr compatible search query
   - `type` - Optional filter by object type

src/cordra_mcp/server.py

@@ -134,6 +134,41 @@ async def count_objects(
         raise RuntimeError(f"Count failed: {e}") from e
 
 
+@mcp.tool(
+    name="get_object",
+    title="Get Cordra Object by ID",
+    description="""Retrieve a digital object by its complete ID/handle.
+
+Returns: Full object with metadata as JSON
+Example: get_object("test/abc123")""",
+)
+async def get_object(object_id: str) -> str:
+    """Retrieve a Cordra digital object by its complete ID.
+
+    Args:
+        object_id: The complete object ID/handle (e.g., "test/abc123" or "wildlive/7a4b7b65f8bb155ad36d")
+
+    Returns:
+        JSON string containing the complete digital object with all metadata
+
+    Raises:
+        RuntimeError: If the object is not found or there's an API error
+    """
+    try:
+        digital_object = await cordra_client.get_object(object_id)
+        object_dict = digital_object.model_dump()
+        return json.dumps(object_dict, indent=2)
+
+    except ValueError as e:
+        raise RuntimeError(f"Invalid object ID: {e}") from e
+    except CordraNotFoundError as e:
+        raise RuntimeError(f"Object not found: {object_id}") from e
+    except CordraAuthenticationError as e:
+        raise RuntimeError(f"Authentication failed: {e}") from e
+    except CordraClientError as e:
+        raise RuntimeError(f"Failed to retrieve object {object_id}: {e}") from e
+
+
 @mcp.resource(
     "cordra://objects/{prefix}/{suffix}",
     name="cordra-object",

tests/test_server.py

@@ -16,6 +16,7 @@ from cordra_mcp.server import (
     count_objects,
     get_cordra_design,
     get_cordra_object,
+    get_object,
     search_objects,
 )
 
@@ -162,6 +163,67 @@ class TestGetCordraObject:
         assert parsed_result["payloads"] is None
 
 
+class TestGetObject:
+    """Test the get_object tool."""
+
+    @patch("cordra_mcp.server.cordra_client")
+    async def test_get_object_success(
+        self, mock_client: Any, sample_digital_object: DigitalObject
+    ) -> None:
+        """Test successful object retrieval with complete ID."""
+        mock_client.get_object = AsyncMock(return_value=sample_digital_object)
+
+        result = await get_object("people/john-doe-123")
+
+        # Verify the result is valid JSON
+        parsed_result = json.loads(result)
+        assert parsed_result["id"] == "people/john-doe-123"
+        assert parsed_result["type"] == "Person"
+        assert parsed_result["content"]["name"] == "John Doe"
+
+        # Verify the client was called with the correct object ID
+        mock_client.get_object.assert_called_once_with("people/john-doe-123")
+
+    @patch("cordra_mcp.server.cordra_client")
+    async def test_get_object_not_found(self, mock_client: Any) -> None:
+        """Test object not found exception."""
+        mock_client.get_object = AsyncMock(
+            side_effect=CordraNotFoundError("Object not found: test/nonexistent")
+        )
+
+        with pytest.raises(RuntimeError) as exc_info:
+            await get_object("test/nonexistent")
+
+        assert "Object not found: test/nonexistent" in str(exc_info.value)
+        mock_client.get_object.assert_called_once_with("test/nonexistent")
+
+    @patch("cordra_mcp.server.cordra_client")
+    async def test_get_object_client_error(self, mock_client: Any) -> None:
+        """Test general client error handling."""
+        mock_client.get_object = AsyncMock(
+            side_effect=CordraClientError("Connection failed")
+        )
+
+        with pytest.raises(RuntimeError) as exc_info:
+            await get_object("test/obj123")
+
+        assert "Failed to retrieve object test/obj123" in str(exc_info.value)
+        mock_client.get_object.assert_called_once_with("test/obj123")
+
+    @patch("cordra_mcp.server.cordra_client")
+    async def test_get_object_authentication_error(self, mock_client: Any) -> None:
+        """Test authentication error handling."""
+        mock_client.get_object = AsyncMock(
+            side_effect=CordraAuthenticationError("Authentication failed")
+        )
+
+        with pytest.raises(RuntimeError) as exc_info:
+            await get_object("test/obj123")
+
+        assert "Authentication failed" in str(exc_info.value)
+        mock_client.get_object.assert_called_once_with("test/obj123")
+
+
 class TestSchemaResourceFunctions:
     """Test the schema resource functions."""