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JavaScriptlangchainbrowserFakeToolCallingModel
Class●Since v1.2

FakeToolCallingModel

Fake chat model for testing tool calling functionality

Copy
class FakeToolCallingModel

Bases

BaseChatModel

Constructors

Properties

Methods

Inherited fromBaseChatModel(langchain_core)

Attributes

Arate_limiterAdisable_streamingAoutput_versionAmodel_config
View source on GitHub
A
OutputType

Methods

MainvokeMastreamMstream_eventsMastream_eventsMagenerateMgenerate_promptMagenerate_promptMdictMasdictMbindMbind_toolsMwith_structured_output

Inherited fromBaseLanguageModel(langchain_core)

Attributes

Acustom_get_token_idsAmodel_configAInputType

Methods

Mmodel_post_initMset_verboseMgenerate_promptMagenerate_promptMwith_structured_outputMget_token_idsMget_num_tokensMget_num_tokens_from_messages

Inherited fromRunnableSerializable(langchain_core)

Attributes

Amodel_config

Methods

Mto_jsonMconfigurable_fieldsMconfigurable_alternatives

Inherited fromSerializable

Properties

Plc_kwargs: SerializedFieldsPlc_namespace: string[]
—

A path to the module that contains the class, eg. ["langchain", "llms"]

Plc_serializable: booleanPlc_aliases: __type | undefinedPlc_attributes: SerializedFields | undefinedPlc_id: string[]Plc_secrets: __type | undefinedPlc_serializable_keys: string[] | undefined

Methods

MtoJSON→ SerializedMtoJSONNotImplemented→ SerializedNotImplementedMlc_name→ string
—

The name of the serializable. Override to provide an alias or

Inherited fromRunnable(langchain_core)

Attributes

AInputTypeAOutputTypeAinput_schemaAoutput_schemaAconfig_specs

Methods

Mget_nameMget_input_schemaMget_input_jsonschemaMget_output_schemaMget_output_jsonschemaMconfig_schema
constructor
constructor→ FakeToolCallingModel
property
cache: BaseCache<Generation[]>
property
callbacks: Callbacks
property
caller: AsyncCaller

The async caller should be used by subclasses to make any async calls, which will thus benefit from the concurrency and retry logic.

property
disableStreaming: boolean
property
lc_kwargs: SerializedFields
property
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.

property
lc_runnable: boolean
property
lc_serializable: boolean
property
metadata: Record<string, unknown>
property
name: string
property
outputVersion: MessageOutputVersion
property
ParsedCallOptions: Omit<CallOptions, Exclude<keyof RunnableConfig, "signal" | "timeout" | "maxConcurrency">>
property
structuredResponse: any
property
tags: string[]
property
toolCalls: ToolCall[][]
property
toolStyle: "openai" | "anthropic"
property
verbose: boolean

Whether to print out response text.

property
callKeys: string[]
property
index: number
property
lc_aliases: __type | undefined
property
lc_attributes: __type | undefined
property
lc_id: string[]
property
lc_secrets: __type | undefined
property
lc_serializable_keys: string[] | undefined
property
profile: ModelProfile
method
_addVersion
method
_batchWithConfig→ Promise<AIMessageChunk<MessageStructure<MessageToolSet>> | Error[]>

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.

method
_callWithConfig→ Promise<AIMessageChunk<MessageStructure<MessageToolSet>>>
method
_combineLLMOutput→ never[]
method
_filterInvocationParamsForTracing→ Record<string, any>

Filter out large/inappropriate fields from invocation params for tracing metadata. Removes fields like tools, functions, messages, response_format that can be large.

method
_generate→ Promise<ChatResult>
method
_generateCached→ Promise<LLMResult & __type>
method
_getCallOptionsForTracing→ Omit<BaseChatModelCallOptions, "configurable" | "recursionLimit" | "runName" | "tags" | "metadata" | "callbacks" | "runId">
method
_getInvocationParamsForTracing→ any
method
_getOptionsList→ Partial<O>[]
method
_getSerializedCacheKeyParametersForCall→ string

Create a unique cache key for a specific call to a specific language model.

method
_identifyingParams→ Record<string, any>

Get the identifying parameters of the LLM.

method
_llmType→ string
method
_modelType→ string
method
_separateRunnableConfigFromCallOptions→ [RunnableConfig<Record<string, any>>, Omit<Partial<BaseChatModelCallOptions>, keyof RunnableConfig<Record<string, any>>>]
method
_separateRunnableConfigFromCallOptionsCompat→ [RunnableConfig<Record<string, any>>, Omit<BaseChatModelCallOptions, "configurable" | "recursionLimit" | "runName" | "tags" | "metadata" | "callbacks" | "runId">]
method
_streamChatModelEvents→ AsyncGenerator<ChatModelStreamEvent>

Stream chat model events using the new content-block-centric protocol.

Override this method to provide native event streaming from the provider SDK. The default implementation bridges from _streamResponseChunks by synthesizing lifecycle events from ChatGenerationChunk objects.

Event lifecycle

MessageStart
  -> ContentBlockStart(index, contentBlock)
    -> ContentBlockDelta(index, delta) ...
  -> ContentBlockFinish(index, contentBlock)
-> MessageFinish(reason, usage?)

Content blocks may interleave (e.g., parallel tool calls). The only invariant: a block's start precedes its deltas, and its deltas precede its finish.

method
_streamIterator→ AsyncGenerator<AIMessageChunk<MessageStructure<MessageToolSet>>>

Default streaming implementation. Subclasses should override this method if they support streaming output.

method
_streamLog→ AsyncGenerator<RunLogPatch>
method
_streamResponseChunks→ AsyncGenerator<ChatGenerationChunk>
method
_transformStreamWithConfig→ AsyncGenerator<O>

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.

method
assign→ Runnable

Assigns new fields to the dict output of this runnable. Returns a new runnable.

method
asTool→ RunnableToolLike<InteropZodType<T | ToolCall<string, Record<string, any>>>, AIMessageChunk<MessageStructure<MessageToolSet>>>

Convert a runnable to a tool. Return a new instance of RunnableToolLike which contains the runnable, name, description and schema.

method
batch→ Promise<AIMessageChunk<MessageStructure<MessageToolSet>>[]>

Default implementation of batch, which calls invoke N times. Subclasses should override this method if they can batch more efficiently.

method
bindTools→ FakeToolCallingModel | RunnableBinding<any, any, any>

Bind tool-like objects to this chat model.

method
generate→ Promise<LLMResult>

Generates chat based on the input messages.

method
generatePrompt→ Promise<LLMResult>

Generates a prompt based on the input prompt values.

method
getGraph→ Graph
method
getLsParams→ LangSmithParams
method
getLsParamsWithDefaults→ LangSmithParams

Wraps getLsParams() and always appends ls_integration. This ensures the integration tag is present even when partner packages fully override getLsParams().

method
getName→ string
method
getNumTokens→ Promise<number>

Get the number of tokens in the content.

method
invocationParams→ any

Get the parameters used to invoke the model

method
invoke→ Promise<AIMessageChunk<MessageStructure<MessageToolSet>>>

Invokes the chat model with a single input.

method
pick→ Runnable

Pick keys from the dict output of this runnable. Returns a new runnable.

method
pipe→ Runnable<BaseLanguageModelInput, 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.

method
stream→ Promise<IterableReadableStream<AIMessageChunk<MessageStructure<MessageToolSet>>>>

Stream output in chunks.

method
toJSON→ Serialized
method
toJSONNotImplemented→ SerializedNotImplemented
method
transform→ AsyncGenerator<AIMessageChunk<MessageStructure<MessageToolSet>>>

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.

method
withConfig→ Runnable<BaseLanguageModelInput, AIMessageChunk<MessageStructure<MessageToolSet>>, BaseChatModelCallOptions>

Bind config to a Runnable, returning a new Runnable.

method
withFallbacks→ RunnableWithFallbacks<BaseLanguageModelInput, AIMessageChunk<MessageStructure<MessageToolSet>>>

Create a new runnable from the current one that will try invoking other passed fallback runnables if the initial invocation fails.

method
withListeners→ Runnable<BaseLanguageModelInput, AIMessageChunk<MessageStructure<MessageToolSet>>, BaseChatModelCallOptions>

Bind lifecycle listeners to a Runnable, returning a new Runnable. The Run object contains information about the run, including its id, type, input, output, error, startTime, endTime, and any tags or metadata added to the run.

method
withRetry→ RunnableRetry<BaseLanguageModelInput, AIMessageChunk<MessageStructure<MessageToolSet>>, BaseChatModelCallOptions>

Add retry logic to an existing runnable.

method
withStructuredOutput→ RunnableLambda<unknown, any, RunnableConfig<Record<string, any>>>
method
_convertInputToPromptValue→ BasePromptValueInterface
method
isRunnable→ thing is Runnable<any, any, RunnableConfig<Record<string, any>>>
method
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.

deprecatedmethod
serialize→ SerializedLLM
deprecatedmethod
streamEvents→ IterableReadableStream<StreamEvent>
deprecatedmethod
streamLog→ AsyncGenerator<RunLogPatch>

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.

deprecatedmethod
streamV2→ ChatModelStream
deprecatedmethod
deserialize→ Promise<BaseLanguageModel<any, BaseLanguageModelCallOptions>>
Mget_config_jsonschema
Mget_graph
Mget_prompts
Mainvoke
Mbatch_as_completed
Mabatch
Mabatch_as_completed
Mastream
Mastream_log
Mastream_events
Mstream_events
Matransform
Mbind
Mwith_config
Mwith_listeners
Mwith_alisteners
Mwith_types
Mwith_retry
Mmap
Mwith_fallbacks
Mas_tool