docstrings prompts (#7844)

Added missed docstrings in `prompts`
@baskaryan

langchain/prompts/base.py

@@ -95,7 +95,10 @@ def check_valid_template(
 
 
 class StringPromptValue(PromptValue):
+    """String prompt value."""
+
     text: str
+    """Prompt text."""
 
     def to_string(self) -> str:
         """Return prompt as string."""

langchain/prompts/chat.py

@@ -25,27 +25,53 @@ from langchain.schema.messages import (
 
 
 class BaseMessagePromptTemplate(Serializable, ABC):
+    """Base class for message prompt templates."""
+
     @property
     def lc_serializable(self) -> bool:
+        """Whether this object should be serialized.
+
+        Returns:
+            Whether this object should be serialized.
+        """
         return True
 
     @abstractmethod
     def format_messages(self, **kwargs: Any) -> List[BaseMessage]:
-        """To messages."""
+        """Format messages from kwargs. Should return a list of BaseMessages.
+
+        Args:
+            **kwargs: Keyword arguments to use for formatting.
+
+        Returns:
+            List of BaseMessages.
+        """
 
     @property
     @abstractmethod
     def input_variables(self) -> List[str]:
-        """Input variables for this prompt template."""
+        """Input variables for this prompt template.
+
+        Returns:
+            List of input variables.
+        """
 
 
 class MessagesPlaceholder(BaseMessagePromptTemplate):
     """Prompt template that assumes variable is already list of messages."""
 
     variable_name: str
+    """Name of variable to use as messages."""
 
     def format_messages(self, **kwargs: Any) -> List[BaseMessage]:
-        """To a BaseMessage."""
+        """To a BaseMessage.
+
+        Args:
+            **kwargs: Keyword arguments to use for formatting.
+
+        Returns:
+            List of BaseMessage.
+        """
         value = kwargs[self.variable_name]
         if not isinstance(value, list):
             raise ValueError(
@@ -62,18 +88,27 @@ class MessagesPlaceholder(BaseMessagePromptTemplate):
 
     @property
     def input_variables(self) -> List[str]:
-        """Input variables for this prompt template."""
+        """Input variables for this prompt template.
+
+        Returns:
+            List of input variable names.
+        """
         return [self.variable_name]
 
 
 MessagePromptTemplateT = TypeVar(
     "MessagePromptTemplateT", bound="BaseStringMessagePromptTemplate"
 )
+"""Type variable for message prompt templates."""
 
 
 class BaseStringMessagePromptTemplate(BaseMessagePromptTemplate, ABC):
+    """Base class for message prompt templates that use a string prompt template."""
+
     prompt: StringPromptTemplate
+    """String prompt template."""
     additional_kwargs: dict = Field(default_factory=dict)
+    """Additional keyword arguments to pass to the prompt template."""
 
     @classmethod
     def from_template(
@@ -82,6 +117,16 @@ class BaseStringMessagePromptTemplate(BaseMessagePromptTemplate, ABC):
         template_format: str = "f-string",
         **kwargs: Any,
     ) -> MessagePromptTemplateT:
+        """Create a class from a string template.
+
+        Args:
+            template: a template.
+            template_format: format of the template.
+            **kwargs: keyword arguments to pass to the constructor.
+
+        Returns:
+            A new instance of this class.
+        """
         prompt = PromptTemplate.from_template(template, template_format=template_format)
         return cls(prompt=prompt, **kwargs)
 
@@ -92,6 +137,16 @@ class BaseStringMessagePromptTemplate(BaseMessagePromptTemplate, ABC):
         input_variables: List[str],
         **kwargs: Any,
     ) -> MessagePromptTemplateT:
+        """Create a class from a template file.
+
+        Args:
+            template_file: path to a template file. String or Path.
+            input_variables: list of input variables.
+            **kwargs: keyword arguments to pass to the constructor.
+
+        Returns:
+            A new instance of this class.
+        """
         prompt = PromptTemplate.from_file(template_file, input_variables)
         return cls(prompt=prompt, **kwargs)
 
@@ -100,15 +155,32 @@ class BaseStringMessagePromptTemplate(BaseMessagePromptTemplate, ABC):
         """To a BaseMessage."""
 
     def format_messages(self, **kwargs: Any) -> List[BaseMessage]:
+        """Format messages from kwargs. Should return a list of BaseMessages.
+
+        Args:
+            **kwargs: Keyword arguments to use for formatting.
+
+        Returns:
+            List of BaseMessages.
+        """
         return [self.format(**kwargs)]
 
     @property
     def input_variables(self) -> List[str]:
+        """
+        Input variables for this prompt template.
+
+        Returns:
+            List of input variable names.
+        """
         return self.prompt.input_variables
 
 
 class ChatMessagePromptTemplate(BaseStringMessagePromptTemplate):
+    """Chat message prompt template."""
+
     role: str
+    """Role of the message."""
 
     def format(self, **kwargs: Any) -> BaseMessage:
         text = self.prompt.format(**kwargs)
@@ -118,40 +190,61 @@ class ChatMessagePromptTemplate(BaseStringMessagePromptTemplate):
 
 
 class HumanMessagePromptTemplate(BaseStringMessagePromptTemplate):
+    """Human message prompt template. This is a message that is sent to the user."""
+
     def format(self, **kwargs: Any) -> BaseMessage:
         text = self.prompt.format(**kwargs)
         return HumanMessage(content=text, additional_kwargs=self.additional_kwargs)
 
 
 class AIMessagePromptTemplate(BaseStringMessagePromptTemplate):
+    """AI message prompt template. This is a message that is not sent to the user."""
+
     def format(self, **kwargs: Any) -> BaseMessage:
         text = self.prompt.format(**kwargs)
         return AIMessage(content=text, additional_kwargs=self.additional_kwargs)
 
 
 class SystemMessagePromptTemplate(BaseStringMessagePromptTemplate):
+    """System message prompt template.
+    This is a message that is not sent to the user.
+    """
+
     def format(self, **kwargs: Any) -> BaseMessage:
         text = self.prompt.format(**kwargs)
         return SystemMessage(content=text, additional_kwargs=self.additional_kwargs)
 
 
 class ChatPromptValue(PromptValue):
+    """Chat prompt value."""
+
     messages: List[BaseMessage]
+    """List of messages."""
 
     def to_string(self) -> str:
         """Return prompt as string."""
         return get_buffer_string(self.messages)
 
     def to_messages(self) -> List[BaseMessage]:
-        """Return prompt as messages."""
+        """Return prompt as a list of messages."""
         return self.messages
 
 
 class BaseChatPromptTemplate(BasePromptTemplate, ABC):
+    """Base class for chat prompt templates."""
+
     def format(self, **kwargs: Any) -> str:
         return self.format_prompt(**kwargs).to_string()
 
     def format_prompt(self, **kwargs: Any) -> PromptValue:
+        """
+        Format prompt. Should return a PromptValue.
+        Args:
+            **kwargs: Keyword arguments to use for formatting.
+
+        Returns:
+            PromptValue.
+        """
         messages = self.format_messages(**kwargs)
         return ChatPromptValue(messages=messages)
 
@@ -161,11 +254,25 @@ class BaseChatPromptTemplate(BasePromptTemplate, ABC):
 
 
 class ChatPromptTemplate(BaseChatPromptTemplate, ABC):
+    """Chat prompt template. This is a prompt that is sent to the user."""
+
     input_variables: List[str]
+    """List of input variables."""
     messages: List[Union[BaseMessagePromptTemplate, BaseMessage]]
+    """List of messages."""
 
     @root_validator(pre=True)
     def validate_input_variables(cls, values: dict) -> dict:
+        """
+        Validate input variables. If input_variables is not set, it will be set to
+        the union of all input variables in the messages.
+
+        Args:
+            values: values to validate.
+
+        Returns:
+            Validated values.
+        """
         messages = values["messages"]
         input_vars = set()
         for message in messages:
@@ -186,6 +293,15 @@ class ChatPromptTemplate(BaseChatPromptTemplate, ABC):
 
     @classmethod
     def from_template(cls, template: str, **kwargs: Any) -> ChatPromptTemplate:
+        """Create a class from a template.
+
+        Args:
+            template: template string.
+            **kwargs: keyword arguments to pass to the constructor.
+
+        Returns:
+            A new instance of this class.
+        """
         prompt_template = PromptTemplate.from_template(template, **kwargs)
         message = HumanMessagePromptTemplate(prompt=prompt_template)
         return cls.from_messages([message])
@@ -194,6 +310,14 @@ class ChatPromptTemplate(BaseChatPromptTemplate, ABC):
     def from_role_strings(
         cls, string_messages: List[Tuple[str, str]]
     ) -> ChatPromptTemplate:
+        """Create a class from a list of (role, template) tuples.
+
+        Args:
+            string_messages: list of (role, template) tuples.
+
+        Returns:
+            A new instance of this class.
+        """
         messages = [
             ChatMessagePromptTemplate(
                 prompt=PromptTemplate.from_template(template), role=role
@@ -206,6 +330,14 @@ class ChatPromptTemplate(BaseChatPromptTemplate, ABC):
     def from_strings(
         cls, string_messages: List[Tuple[Type[BaseMessagePromptTemplate], str]]
     ) -> ChatPromptTemplate:
+        """Create a class from a list of (role, template) tuples.
+
+        Args:
+            string_messages: list of (role, template) tuples.
+
+        Returns:
+            A new instance of this class.
+        """
         messages = [
             role(prompt=PromptTemplate.from_template(template))
             for role, template in string_messages
@@ -216,6 +348,15 @@ class ChatPromptTemplate(BaseChatPromptTemplate, ABC):
     def from_messages(
         cls, messages: Sequence[Union[BaseMessagePromptTemplate, BaseMessage]]
     ) -> ChatPromptTemplate:
+        """
+        Create a class from a list of messages.
+
+        Args:
+            messages: list of messages.
+
+        Returns:
+            A new instance of this class.
+        """
         input_vars = set()
         for message in messages:
             if isinstance(message, BaseMessagePromptTemplate):
@@ -226,6 +367,15 @@ class ChatPromptTemplate(BaseChatPromptTemplate, ABC):
         return self.format_prompt(**kwargs).to_string()
 
     def format_messages(self, **kwargs: Any) -> List[BaseMessage]:
+        """
+        Format kwargs into a list of messages.
+
+        Args:
+            **kwargs: keyword arguments to use for formatting.
+
+        Returns:
+            List of messages.
+        """
         kwargs = self._merge_partial_and_user_variables(**kwargs)
         result = []
         for message_template in self.messages:
@@ -251,4 +401,10 @@ class ChatPromptTemplate(BaseChatPromptTemplate, ABC):
         return "chat"
 
     def save(self, file_path: Union[Path, str]) -> None:
+        """
+        Save prompt to file.
+
+        Args:
+            file_path: path to file.
+        """
         raise NotImplementedError

langchain/prompts/few_shot.py

@@ -67,7 +67,7 @@ class FewShotPromptTemplate(StringPromptTemplate):
 
     @root_validator()
     def template_is_valid(cls, values: Dict) -> Dict:
-        """Check that prefix, suffix and input variables are consistent."""
+        """Check that prefix, suffix, and input variables are consistent."""
         if values["validate_template"]:
             check_valid_template(
                 values["prefix"] + values["suffix"],

langchain/prompts/few_shot_with_templates.py

@@ -59,7 +59,7 @@ class FewShotPromptWithTemplates(StringPromptTemplate):
 
     @root_validator()
     def template_is_valid(cls, values: Dict) -> Dict:
-        """Check that prefix, suffix and input variables are consistent."""
+        """Check that prefix, suffix, and input variables are consistent."""
         if values["validate_template"]:
             input_variables = values["input_variables"]
             expected_input_variables = set(values["suffix"].input_variables)

langchain/prompts/loading.py

@@ -1,4 +1,4 @@
-"""Load prompts from disk."""
+"""Load prompts."""
 import importlib
 import json
 import logging
@@ -31,7 +31,7 @@ def load_prompt_from_config(config: dict) -> BasePromptTemplate:
 
 
 def _load_template(var_name: str, config: dict) -> dict:
-    """Load template from disk if applicable."""
+    """Load template from the path if applicable."""
     # Check if template_path exists in config.
     if f"{var_name}_path" in config:
         # If it does, make sure template variable doesn't also exist.
@@ -88,7 +88,7 @@ def _load_output_parser(config: dict) -> dict:
 
 
 def _load_few_shot_prompt(config: dict) -> FewShotPromptTemplate:
-    """Load the few shot prompt from the config."""
+    """Load the "few shot" prompt from the config."""
     # Load the suffix and prefix templates.
     config = _load_template("suffix", config)
     config = _load_template("prefix", config)
@@ -128,7 +128,7 @@ def load_prompt(path: Union[str, Path]) -> BasePromptTemplate:
 
 def _load_prompt_from_file(file: Union[str, Path]) -> BasePromptTemplate:
     """Load prompt from file."""
-    # Convert file to Path object.
+    # Convert file to a Path object.
     if isinstance(file, str):
         file_path = Path(file)
     else:

langchain/prompts/pipeline.py

@@ -11,7 +11,7 @@ def _get_inputs(inputs: dict, input_variables: List[str]) -> dict:
 
 
 class PipelinePromptTemplate(BasePromptTemplate):
-    """A prompt template for composing multiple prompts together.
+    """A prompt template for composing multiple prompt templates together.
 
     This can be useful when you want to reuse parts of prompts.
     A PipelinePrompt consists of two main parts:
@@ -24,7 +24,9 @@ class PipelinePromptTemplate(BasePromptTemplate):
     """
 
     final_prompt: BasePromptTemplate
+    """The final prompt that is returned."""
     pipeline_prompts: List[Tuple[str, BasePromptTemplate]]
+    """A list of tuples, consisting of a string (`name`) and a Prompt Template."""
 
     @root_validator(pre=True)
     def get_input_variables(cls, values: Dict) -> Dict: