Add llm gateway wrapper function

README.md

@@ -170,6 +170,23 @@ client.write_to_dlo('output_DLO')
 > [!WARNING]
 > Currently we only support reading from DMOs and writing to DMOs or reading from DLOs and writing to DLOs, but they cannot mix.
 
+## LLM Capabilities
+
+* `llm_complete(prompt_col, model_id, max_tokens)` – Generate AI completions from a prompt column
+
+For example:
+```python
+from datacustomcode.ai import llm_complete
+from pyspark.sql.functions import concat_ws, lit, col
+
+# Generate summaries
+prompt = concat_ws(" ", 
+    lit("Summarize:"), 
+    col("Name__c"), 
+    col("Description__c")
+)
+df = df.withColumn("summary", llm_complete(prompt))
+```
 
 ## CLI
 

src/datacustomcode/__init__.py

@@ -13,6 +13,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+from datacustomcode.ai import llm_complete
 from datacustomcode.client import Client
 from datacustomcode.credentials import AuthType, Credentials
 from datacustomcode.io.reader.query_api import QueryAPIDataCloudReader
@@ -28,4 +29,5 @@
     "LocalProxyClientProvider",
     "PrintDataCloudWriter",
     "QueryAPIDataCloudReader",
+    "llm_complete",
 ]

src/datacustomcode/ai/__init__.py

@@ -0,0 +1,35 @@
+# Copyright (c) 2025, Salesforce, Inc.
+# SPDX-License-Identifier: Apache-2
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""LLM capabilities for Data Cloud Custom Code.
+
+This module provides LLM functions
+
+Available functions:
+    llm_complete: Generate completions from a prompt column
+
+Example:
+    from datacustomcode.ai import llm_complete
+    from pyspark.sql.functions import col
+
+    df = spark.read.table("Account_std__dll")
+    df = df.withColumn("summary", llm_complete("Name__c"))
+"""
+
+from datacustomcode.ai.llm import llm_complete
+
+__all__ = [
+    "llm_complete",
+]

src/datacustomcode/ai/llm.py

@@ -0,0 +1,83 @@
+# Copyright (c) 2025, Salesforce, Inc.
+# SPDX-License-Identifier: Apache-2
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""LLM completion functions for Data Cloud Custom Code.
+"""
+
+from typing import Union
+
+from pyspark.sql import Column
+from pyspark.sql.functions import call_function, lit
+
+# Default values for llm_complete function
+# TODO: Validate these defaults
+_DEFAULT_MODEL_ID = "sfdc_ai__DefaultGPT4Omni"
+_DEFAULT_MAX_TOKENS = 200
+_LLM_GATEWAY_UDF_NAME = "llm_gateway_generate"
+
+
+def llm_complete(
+    prompt_col: Union[Column, str],
+    *,
+    model_id: str = _DEFAULT_MODEL_ID,
+    max_tokens: int = _DEFAULT_MAX_TOKENS,
+) -> Column:
+    """Returns the AI-generated text response as a string column.
+
+    Args:
+        prompt_col: Column or column name containing the prompt text.
+            The prompt should be a string value (max 32KB recommended).
+            Use string functions like concat_ws(), format_string(), etc.
+            to construct complex prompts from multiple columns.
+        model_id: Defaults to "sfdc_ai__DefaultGPT4Omni".
+            Available models depend on your org's configuration.
+        max_tokens: Maximum tokens in the response. Defaults to 200.
+            Higher values allow longer responses but increase latency and cost.
+
+    Returns:
+        Column of StringType with AI-generated response.
+        Returns null if the input prompt is null.
+
+    Raises:
+        TypeError: If prompt_col is not a Column or string.
+        ValueError: If max_tokens is not positive.
+    """
+    # Input validation
+    if not isinstance(prompt_col, (Column, str)):
+        raise TypeError(
+            f"prompt_col must be a Column or str, got {type(prompt_col).__name__}"
+        )
+
+    if not isinstance(max_tokens, int) or max_tokens <= 0:
+        raise ValueError(f"max_tokens must be a positive integer, got {max_tokens}")
+
+    # Convert string column name to Column
+    if isinstance(prompt_col, str):
+        from pyspark.sql.functions import col
+
+        prompt_col = col(prompt_col)
+
+    from pyspark.sql.functions import named_struct
+
+    template = "{prompt}"
+    values_struct = named_struct(lit("prompt"), prompt_col)
+
+    return call_function(
+        _LLM_GATEWAY_UDF_NAME,
+        lit(template),
+        values_struct,
+        lit(model_id),
+        lit(max_tokens),
+    )

tests/ai/__init__.py

@@ -0,0 +1,14 @@
+# Copyright (c) 2025, Salesforce, Inc.
+# SPDX-License-Identifier: Apache-2
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.

tests/ai/test_llm.py

@@ -0,0 +1,51 @@
+# Copyright (c) 2025, Salesforce, Inc.
+# SPDX-License-Identifier: Apache-2
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""Tests for datacustomcode.ai.llm module."""
+
+import pytest
+
+from datacustomcode.ai import llm_complete
+
+
+class TestLlmComplete:
+    """Tests for llm_complete function."""
+
+    def test_invalid_prompt_col_type_int(self):
+        """Test that invalid prompt_col type raises TypeError."""
+        with pytest.raises(TypeError, match="prompt_col must be a Column or str"):
+            llm_complete(123)
+
+    def test_invalid_max_tokens_type_string(self):
+        """Test that string max_tokens raises ValueError."""
+        with pytest.raises(ValueError, match="max_tokens must be a positive integer"):
+            llm_complete("test_col", max_tokens="invalid")
+
+    def test_invalid_max_tokens_type_float(self):
+        """Test that float max_tokens raises ValueError."""
+        with pytest.raises(ValueError, match="max_tokens must be a positive integer"):
+            llm_complete("test_col", max_tokens=100.5)
+
+    def test_negative_max_tokens(self):
+        """Test that negative max_tokens raises ValueError."""
+        with pytest.raises(ValueError, match="max_tokens must be a positive integer"):
+            llm_complete("test_col", max_tokens=-1)
+
+    def test_zero_max_tokens(self):
+        """Test that zero max_tokens raises ValueError."""
+        with pytest.raises(ValueError, match="max_tokens must be a positive integer"):
+            llm_complete("test_col", max_tokens=0)
+
+