Class PromptTemplate<RunInput, PartialVariableName>

Schema to represent a basic prompt for an LLM.

Example

import { PromptTemplate } from "langchain/prompts";

const prompt = new PromptTemplate({
  inputVariables: ["foo"],
  template: "Say {foo}",
});

Type Parameters

RunInput extends InputValues = any
PartialVariableName extends string = any

Hierarchy

BaseStringPromptTemplate<RunInput, PartialVariableName>
- PromptTemplate

Implements

PromptTemplateInput<RunInput, PartialVariableName>

Constructors

constructor

new PromptTemplate<RunInput, PartialVariableName>(input): PromptTemplate<RunInput, PartialVariableName>
Type Parameters
- RunInput extends InputValues = any
- PartialVariableName extends string = any
Parameters
- input: PromptTemplateInput<RunInput, PartialVariableName>
Returns PromptTemplate<RunInput, PartialVariableName>
Overrides BaseStringPromptTemplate.constructor
- Defined in langchain/src/prompts/prompt.ts:116

Properties

PromptValueReturnType

PromptValueReturnType: StringPromptValue

inputVariables

inputVariables: Extract<keyof RunInput, string>[]

A list of variable names the prompt template expects

lc_kwargs

lc_kwargs: SerializedFields

lc_namespace

lc_namespace: string[] = ...

A path to the module that contains the class, eg. ["langchain", "llms"] Usually should be the same as the entrypoint the class is exported from.

lc_serializable

lc_serializable: boolean = true

partialVariables

partialVariables: PartialValues<PartialVariableName>

Partial variables

template

template: string

The prompt template

templateFormat

templateFormat: "f-string" = "f-string"

The format of the prompt template. Options are 'f-string'

Default Value

'f-string'

validateTemplate

validateTemplate: boolean = true

Whether or not to try validating the template on initialization

Default Value

true

`Optional` outputParser

outputParser?: BaseOutputParser<unknown>

How to parse the output of calling an LLM on this formatted prompt

`Protected` lc_runnable

lc_runnable: boolean = true

Accessors

lc_aliases

get lc_aliases(): undefined | {
[key: string]: string;
}
A map of aliases for constructor args. Keys are the attribute names, e.g. "foo". Values are the alias that will replace the key in serialization. This is used to eg. make argument names match Python.

Returns undefined | {
[key: string]: string;
}
Inherited from BaseStringPromptTemplate.lc_aliases
- Defined in langchain/src/load/serializable.ts:132

lc_attributes

get lc_attributes(): undefined | SerializedFields
A map of additional attributes to merge with constructor args. Keys are the attribute names, e.g. "foo". Values are the attribute values, which will be serialized. These attributes need to be accepted by the constructor as arguments.

Returns undefined | SerializedFields
Inherited from BaseStringPromptTemplate.lc_attributes
- Defined in langchain/src/prompts/base.ts:89

lc_id

get lc_id(): string[]
The final serialized identifier for the module.

Returns string[]
Inherited from BaseStringPromptTemplate.lc_id
- Defined in langchain/src/load/serializable.ts:100

lc_secrets

get lc_secrets(): undefined | {
[key: string]: string;
}
A map of secrets, which will be omitted from serialization. Keys are paths to the secret in constructor args, e.g. "foo.bar.baz". Values are the secret ids, which will be used when deserializing.

Returns undefined | {
[key: string]: string;
}
Inherited from BaseStringPromptTemplate.lc_secrets
- Defined in langchain/src/load/serializable.ts:112

Methods

_batchWithConfig

_batchWithConfig<T>(func, inputs, options?, batchOptions?): Promise<(Error | StringPromptValue)[]>
Internal method that handles batching and configuration for a runnable It takes a function, input values, and optional configuration, and returns a promise that resolves to the output values.
Type Parameters
- T extends InputValues
Parameters
- func: ((inputs, options?, runManagers?, batchOptions?) => Promise<(Error | StringPromptValue)[]>)
  
  The function to be executed for each input value.
  - - (inputs, options?, runManagers?, batchOptions?): Promise<(Error | StringPromptValue)[]>
    - Parameters
      
      inputs: T[]
      
      Optional options: Partial<BaseCallbackConfig>[]
      
      Optional runManagers: (undefined | CallbackManagerForChainRun)[]
      
      Optional batchOptions: RunnableBatchOptions
      
      Returns Promise<(Error | StringPromptValue)[]>
- inputs: T[]
- Optional options: Partial<BaseCallbackConfig & {
  runType?: string;
  }> | Partial<BaseCallbackConfig & {
  runType?: string;
  }>[]
- Optional batchOptions: RunnableBatchOptions
Returns Promise<(Error | StringPromptValue)[]>
A promise that resolves to the output values.
Inherited from BaseStringPromptTemplate._batchWithConfig
- Defined in langchain/src/schema/runnable/base.ts:289

_getPromptType

_getPromptType(): "prompt"
Return the string type key uniquely identifying this class of prompt template.

Returns "prompt"
Overrides BaseStringPromptTemplate._getPromptType
- Defined in langchain/src/prompts/prompt.ts:135

_patchConfig

_patchConfig(config?, callbackManager?): Partial<BaseCallbackConfig>
Parameters
- config: Partial<BaseCallbackConfig> = {}
- callbackManager: undefined | CallbackManager = undefined
Returns Partial<BaseCallbackConfig>
Inherited from BaseStringPromptTemplate._patchConfig
- Defined in langchain/src/schema/runnable/base.ts:431

_streamIterator

_streamIterator(input, options?): AsyncGenerator<StringPromptValue, any, unknown>
Default streaming implementation. Subclasses should override this method if they support streaming output.
Parameters
- input: RunInput
- Optional options: Partial<BaseCallbackConfig>
Returns AsyncGenerator<StringPromptValue, any, unknown>
Inherited from BaseStringPromptTemplate._streamIterator
- Defined in langchain/src/schema/runnable/base.ts:209

batch

batch(inputs, options?, batchOptions?): Promise<StringPromptValue[]>
Default implementation of batch, which calls invoke N times. Subclasses should override this method if they can batch more efficiently.
Parameters
- inputs: RunInput[]
  
  Array of inputs to each batch call.
- Optional options: Partial<BaseCallbackConfig> | Partial<BaseCallbackConfig>[]
  
  Either a single call options object to apply to each batch call or an array for each call.
- Optional batchOptions: RunnableBatchOptions & {
  returnExceptions?: false;
  }
Returns Promise<StringPromptValue[]>
An array of RunOutputs, or mixed RunOutputs and errors if batchOptions.returnExceptions is set
Inherited from BaseStringPromptTemplate.batch
- Defined in langchain/src/schema/runnable/base.ts:157
batch(inputs, options?, batchOptions?): Promise<(Error | StringPromptValue)[]>
Parameters
- inputs: RunInput[]
- Optional options: Partial<BaseCallbackConfig> | Partial<BaseCallbackConfig>[]
- Optional batchOptions: RunnableBatchOptions & {
  returnExceptions: true;
  }
Returns Promise<(Error | StringPromptValue)[]>
Inherited from BaseStringPromptTemplate.batch
- Defined in langchain/src/schema/runnable/base.ts:163
batch(inputs, options?, batchOptions?): Promise<(Error | StringPromptValue)[]>
Parameters
- inputs: RunInput[]
- Optional options: Partial<BaseCallbackConfig> | Partial<BaseCallbackConfig>[]
- Optional batchOptions: RunnableBatchOptions
Returns Promise<(Error | StringPromptValue)[]>
Inherited from BaseStringPromptTemplate.batch
- Defined in langchain/src/schema/runnable/base.ts:169

bind

bind(kwargs): Runnable<RunInput, StringPromptValue, BaseCallbackConfig>
Bind arguments to a Runnable, returning a new Runnable.
Parameters
- kwargs: Partial<BaseCallbackConfig>
Returns Runnable<RunInput, StringPromptValue, BaseCallbackConfig>
A new RunnableBinding that, when invoked, will apply the bound args.
Inherited from BaseStringPromptTemplate.bind
- Defined in langchain/src/schema/runnable/base.ts:66

format

format(values): Promise<string>
Formats the prompt template with the provided values.
Parameters
- values: TypedPromptInputValues<RunInput>
  
  The values to be used to format the prompt template.
Returns Promise<string>
A promise that resolves to a string which is the formatted prompt.
Overrides BaseStringPromptTemplate.format
- Defined in langchain/src/prompts/prompt.ts:144

formatPromptValue

formatPromptValue(values): Promise<StringPromptValue>
Formats the prompt given the input values and returns a formatted prompt value.
Parameters
- values: TypedPromptInputValues<RunInput>
  
  The input values to format the prompt.
Returns Promise<StringPromptValue>
A Promise that resolves to a formatted prompt value.
Inherited from BaseStringPromptTemplate.formatPromptValue
- Defined in langchain/src/prompts/base.ts:248

invoke

invoke(input, options?): Promise<StringPromptValue>
Invokes the prompt template with the given input and options.
Parameters
- input: RunInput
  
  The input to invoke the prompt template with.
- Optional options: BaseCallbackConfig
  
  Optional configuration for the callback.
Returns Promise<StringPromptValue>
A Promise that resolves to the output of the prompt template.
Inherited from BaseStringPromptTemplate.invoke
- Defined in langchain/src/prompts/base.ts:150

map

map(): Runnable<RunInput[], StringPromptValue[], BaseCallbackConfig>
Return a new Runnable that maps a list of inputs to a list of outputs, by calling invoke() with each input.

Returns Runnable<RunInput[], StringPromptValue[], BaseCallbackConfig>
Inherited from BaseStringPromptTemplate.map
- Defined in langchain/src/schema/runnable/base.ts:77

mergePartialAndUserVariables

mergePartialAndUserVariables(userVariables): Promise<InputValues<PartialVariableName | Extract<keyof RunInput, string>>>
Merges partial variables and user variables.
Parameters
- userVariables: TypedPromptInputValues<RunInput>
  
  The user variables to merge with the partial variables.
Returns Promise<InputValues<PartialVariableName | Extract<keyof RunInput, string>>>
A Promise that resolves to an object containing the merged variables.
Inherited from BaseStringPromptTemplate.mergePartialAndUserVariables
- Defined in langchain/src/prompts/base.ts:121

partial

partial<NewPartialVariableName>(values): Promise<PromptTemplate<InputValues<Exclude<Extract<keyof RunInput, string>, NewPartialVariableName>>, any>>
Partially applies values to the prompt template.
Type Parameters
- NewPartialVariableName extends string
Parameters
- values: PartialValues<NewPartialVariableName>
  
  The values to be partially applied to the prompt template.
Returns Promise<PromptTemplate<InputValues<Exclude<Extract<keyof RunInput, string>, NewPartialVariableName>>, any>>
A new instance of PromptTemplate with the partially applied values.
Overrides BaseStringPromptTemplate.partial
- Defined in langchain/src/prompts/prompt.ts:217

pipe

pipe<NewRunOutput>(coerceable): RunnableSequence<RunInput, Exclude<NewRunOutput, Error>>
Create a new runnable sequence that runs each individual runnable in series, piping the output of one runnable into another runnable or runnable-like.
Type Parameters
- NewRunOutput
Parameters
- coerceable: RunnableLike<StringPromptValue, NewRunOutput>
  
  A runnable, function, or object whose values are functions or runnables.
Returns RunnableSequence<RunInput, Exclude<NewRunOutput, Error>>
A new runnable sequence.
Inherited from BaseStringPromptTemplate.pipe
- Defined in langchain/src/schema/runnable/base.ts:453

serialize

serialize(): SerializedPromptTemplate
Return a json-like object representing this prompt template.

Returns SerializedPromptTemplate

Deprecated
Overrides BaseStringPromptTemplate.serialize
- Defined in langchain/src/prompts/prompt.ts:239

stream

stream(input, options?): Promise<IterableReadableStream<StringPromptValue>>
Stream output in chunks.
Parameters
- input: RunInput
- Optional options: Partial<BaseCallbackConfig>
Returns Promise<IterableReadableStream<StringPromptValue>>
A readable stream that is also an iterable.
Inherited from BaseStringPromptTemplate.stream
- Defined in langchain/src/schema/runnable/base.ts:222

streamLog

streamLog(input, options?, streamOptions?): AsyncGenerator<RunLogPatch, any, unknown>
Stream all output from a runnable, as reported to the callback system. This includes all inner runs of LLMs, Retrievers, Tools, etc. Output is streamed as Log objects, which include a list of jsonpatch ops that describe how the state of the run has changed in each step, and the final state of the run. The jsonpatch ops can be applied in order to construct state.
Parameters
- input: RunInput
- Optional options: Partial<BaseCallbackConfig>
- Optional streamOptions: Omit<LogStreamCallbackHandlerInput, "autoClose">
Returns AsyncGenerator<RunLogPatch, any, unknown>
Inherited from BaseStringPromptTemplate.streamLog
- Defined in langchain/src/schema/runnable/base.ts:499

toJSON

toJSON(): Serialized
Returns Serialized
Inherited from BaseStringPromptTemplate.toJSON
- Defined in langchain/src/load/serializable.ts:140

toJSONNotImplemented

toJSONNotImplemented(): SerializedNotImplemented
Returns SerializedNotImplemented
Inherited from BaseStringPromptTemplate.toJSONNotImplemented
- Defined in langchain/src/load/serializable.ts:214

transform

transform(generator, options): AsyncGenerator<StringPromptValue, any, unknown>
Default implementation of transform, which buffers input and then calls stream. Subclasses should override this method if they can start producing output while input is still being generated.
Parameters
- generator: AsyncGenerator<RunInput, any, unknown>
- options: Partial<BaseCallbackConfig>
Returns AsyncGenerator<StringPromptValue, any, unknown>
Inherited from BaseStringPromptTemplate.transform
- Defined in langchain/src/schema/runnable/base.ts:470

withConfig

withConfig(config): RunnableBinding<RunInput, StringPromptValue, BaseCallbackConfig>
Bind config to a Runnable, returning a new Runnable.
Parameters
- config: BaseCallbackConfig
  
  New configuration parameters to attach to the new runnable.
Returns RunnableBinding<RunInput, StringPromptValue, BaseCallbackConfig>
A new RunnableBinding with a config matching what's passed.
Inherited from BaseStringPromptTemplate.withConfig
- Defined in langchain/src/schema/runnable/base.ts:106

withFallbacks

withFallbacks(fields): RunnableWithFallbacks<RunInput, StringPromptValue>
Create a new runnable from the current one that will try invoking other passed fallback runnables if the initial invocation fails.
Parameters
- fields: {
  fallbacks: Runnable<RunInput, StringPromptValue, BaseCallbackConfig>[];
  }
  - fallbacks: Runnable<RunInput, StringPromptValue, BaseCallbackConfig>[]
    
    Other runnables to call if the runnable errors.
Returns RunnableWithFallbacks<RunInput, StringPromptValue>
A new RunnableWithFallbacks.
Inherited from BaseStringPromptTemplate.withFallbacks
- Defined in langchain/src/schema/runnable/base.ts:123

withRetry

withRetry(fields?): RunnableRetry<RunInput, StringPromptValue, BaseCallbackConfig>
Add retry logic to an existing runnable.
Parameters
- Optional fields: {
  onFailedAttempt?: RunnableRetryFailedAttemptHandler;
  stopAfterAttempt?: number;
  }
  - Optional onFailedAttempt?: RunnableRetryFailedAttemptHandler
  - Optional stopAfterAttempt?: number
Returns RunnableRetry<RunInput, StringPromptValue, BaseCallbackConfig>
A new RunnableRetry that, when invoked, will retry according to the parameters.
Inherited from BaseStringPromptTemplate.withRetry
- Defined in langchain/src/schema/runnable/base.ts:87

`Static` deserialize

deserialize(data): Promise<PromptTemplate<any, any>>
Parameters
- data: SerializedPromptTemplate
Returns Promise<PromptTemplate<any, any>>

Deprecated
Load a prompt template from a json-like object describing it.

Remarks
Deserializing needs to be async because templates (e.g. FewShotPromptTemplate) can reference remote resources that we read asynchronously with a web request.
Overrides BaseStringPromptTemplate.deserialize
- Defined in langchain/src/prompts/prompt.ts:253

`Static` fromExamples

fromExamples(examples, suffix, inputVariables, exampleSeparator?, prefix?): PromptTemplate<any, any>
Take examples in list format with prefix and suffix to create a prompt.

Intended to be used a a way to dynamically create a prompt from examples.
Parameters
- examples: string[]
  
  List of examples to use in the prompt.
- suffix: string
  
  String to go after the list of examples. Should generally set up the user's input.
- inputVariables: string[]
  
  A list of variable names the final prompt template will expect
- exampleSeparator: string = "\n\n"
  
  The separator to use in between examples
- prefix: string = ""
  
  String that should go before any examples. Generally includes examples.
Returns PromptTemplate<any, any>
The final prompt template generated.
- Defined in langchain/src/prompts/prompt.ts:162

`Static` fromTemplate

fromTemplate<RunInput, T>(template, __namedParameters?): PromptTemplate<RunInput extends Symbol
? ParamsFromFString<T>
: RunInput, any>
Load prompt template from a template f-string
Type Parameters
- RunInput extends InputValues = Symbol
- T extends string = string
Parameters
- template: T
- __namedParameters: Omit<PromptTemplateInput<RunInput, string>, "template" | "inputVariables"> = {}
Returns PromptTemplate<RunInput extends Symbol
? ParamsFromFString<T>
: RunInput, any>
- Defined in langchain/src/prompts/prompt.ts:179

`Static` isRunnable

isRunnable(thing): thing is Runnable<any, any, BaseCallbackConfig>
Parameters
- thing: any
Returns thing is Runnable<any, any, BaseCallbackConfig>
Inherited from BaseStringPromptTemplate.isRunnable
- Defined in langchain/src/schema/runnable/base.ts:549

`Static` lc_name

lc_name(): string
The name of the serializable. Override to provide an alias or to preserve the serialized module name in minified environments.

Implemented as a static method to support loading logic.

Returns string
Overrides BaseStringPromptTemplate.lc_name
- Defined in langchain/src/prompts/prompt.ts:106

`Protected` _callWithConfig

_callWithConfig<T>(func, input, options?): Promise<StringPromptValue>
Type Parameters
- T extends InputValues
Parameters
- func: ((input) => Promise<StringPromptValue>) | ((input, config?, runManager?) => Promise<StringPromptValue>)
- input: T
- Optional options: Partial<BaseCallbackConfig> & {
  runType?: string;
  }
Returns Promise<StringPromptValue>
Inherited from BaseStringPromptTemplate._callWithConfig
- Defined in langchain/src/schema/runnable/base.ts:248

`Protected` _getOptionsList

_getOptionsList(options, length?): Partial<BaseCallbackConfig & {
runType?: string;
}>[]
Parameters
- options: Partial<BaseCallbackConfig> | Partial<BaseCallbackConfig>[]
- length: number = 0
Returns Partial<BaseCallbackConfig & {
runType?: string;
}>[]
Inherited from BaseStringPromptTemplate._getOptionsList
- Defined in langchain/src/schema/runnable/base.ts:133

`Protected` _separateRunnableConfigFromCallOptions

_separateRunnableConfigFromCallOptions(options?): [BaseCallbackConfig, Omit<Partial<BaseCallbackConfig>, keyof BaseCallbackConfig>]
Parameters
- options: Partial<BaseCallbackConfig> = {}
Returns [BaseCallbackConfig, Omit<Partial<BaseCallbackConfig>, keyof BaseCallbackConfig>]
Inherited from BaseStringPromptTemplate._separateRunnableConfigFromCallOptions
- Defined in langchain/src/schema/runnable/base.ts:231

`Protected` _transformStreamWithConfig

_transformStreamWithConfig<I, O>(inputGenerator, transformer, options?): AsyncGenerator<O, any, unknown>
Helper method to transform an Iterator of Input values into an Iterator of Output values, with callbacks. Use this to implement stream() or transform() in Runnable subclasses.
Type Parameters
- I extends InputValues
- O extends StringPromptValue<O>
Parameters
- inputGenerator: AsyncGenerator<I, any, unknown>
- transformer: ((generator, runManager?, options?) => AsyncGenerator<O, any, unknown>)
  - - (generator, runManager?, options?): AsyncGenerator<O, any, unknown>
    - Parameters
      
      generator: AsyncGenerator<I, any, unknown>
      
      Optional runManager: CallbackManagerForChainRun
      
      Optional options: Partial<BaseCallbackConfig>
      
      Returns AsyncGenerator<O, any, unknown>
- Optional options: BaseCallbackConfig & {
  runType?: string;
  }
Returns AsyncGenerator<O, any, unknown>
Inherited from BaseStringPromptTemplate._transformStreamWithConfig
- Defined in langchain/src/schema/runnable/base.ts:341

Class PromptTemplate<RunInput, PartialVariableName>

Example

Type Parameters

RunInput extends InputValues = any

PartialVariableName extends string = any

Hierarchy

Implements

Index

Constructors

Properties

Accessors

Methods

Constructors

constructor

Type Parameters

RunInput extends InputValues = any

PartialVariableName extends string = any

Parameters

input: PromptTemplateInput<RunInput, PartialVariableName>

Returns PromptTemplate<RunInput, PartialVariableName>

Properties

PromptValueReturnType

inputVariables

lc_kwargs

lc_namespace

lc_serializable

partialVariables

template

templateFormat

Default Value

validateTemplate

Default Value

Optional outputParser

Protected lc_runnable

Accessors

lc_aliases

Returns undefined | { [key: string]: string; }

lc_attributes

Returns undefined | SerializedFields

lc_id

Returns string[]

lc_secrets

Returns undefined | { [key: string]: string; }

Methods

_batchWithConfig

Type Parameters

T extends InputValues

Parameters

func: ((inputs, options?, runManagers?, batchOptions?) => Promise<(Error | StringPromptValue)[]>)

Parameters

inputs: T[]

Optional options: Partial<BaseCallbackConfig>[]

Optional runManagers: (undefined | CallbackManagerForChainRun)[]

Optional batchOptions: RunnableBatchOptions

Returns Promise<(Error | StringPromptValue)[]>

inputs: T[]

Optional options: Partial<BaseCallbackConfig & { runType?: string; }> | Partial<BaseCallbackConfig & { runType?: string; }>[]

Optional batchOptions: RunnableBatchOptions

Returns Promise<(Error | StringPromptValue)[]>

_getPromptType

Returns "prompt"

_patchConfig

Parameters

config: Partial<BaseCallbackConfig> = {}

callbackManager: undefined | CallbackManager = undefined

Returns Partial<BaseCallbackConfig>

_streamIterator

Parameters

input: RunInput

Optional options: Partial<BaseCallbackConfig>

Returns AsyncGenerator<StringPromptValue, any, unknown>

batch

Parameters

inputs: RunInput[]

Optional options: Partial<BaseCallbackConfig> | Partial<BaseCallbackConfig>[]

Optional batchOptions: RunnableBatchOptions & { returnExceptions?: false; }

Returns Promise<StringPromptValue[]>

Parameters

inputs: RunInput[]

Optional options: Partial<BaseCallbackConfig> | Partial<BaseCallbackConfig>[]

`Optional` outputParser

`Protected` lc_runnable

Returns undefined | {
[key: string]: string;
}

Returns undefined | {
[key: string]: string;
}

`Optional` options: Partial<BaseCallbackConfig>[]

`Optional` runManagers: (undefined | CallbackManagerForChainRun)[]

`Optional` batchOptions: RunnableBatchOptions

`Optional` options: Partial<BaseCallbackConfig & {
runType?: string;
}> | Partial<BaseCallbackConfig & {
runType?: string;
}>[]

`Optional` batchOptions: RunnableBatchOptions

`Optional` options: Partial<BaseCallbackConfig>

`Optional` options: Partial<BaseCallbackConfig> | Partial<BaseCallbackConfig>[]

`Optional` batchOptions: RunnableBatchOptions & {
returnExceptions?: false;
}

`Optional` options: Partial<BaseCallbackConfig> | Partial<BaseCallbackConfig>[]

`Optional` batchOptions: RunnableBatchOptions & {
returnExceptions: true;
}

`Optional` options: Partial<BaseCallbackConfig> | Partial<BaseCallbackConfig>[]

`Optional` batchOptions: RunnableBatchOptions

`Optional` options: BaseCallbackConfig

`Optional` options: Partial<BaseCallbackConfig>

`Optional` options: Partial<BaseCallbackConfig>

`Optional` streamOptions: Omit<LogStreamCallbackHandlerInput, "autoClose">