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Agents

LangStream Version: 0.5.0


Compute chat completions (ai-chat-completions)
Sends the messages to the AI Service to compute chat completions. The result is stored in the specified field.
Text
Description
Type
Required
Default Value
ai-service
In case of multiple AI services configured, specify the id of the AI service to use.
string
​
​
completion-field
Field to use to store the completion results in the output topic. Use "value" to write the result without a structured schema. Use "value.<field>" to write the result in a specific field.
string
​
​
composable
Whether this step can be composed with other steps.
boolean
​
true
frequency-penalty
Parameter for the completion request. The parameters are passed to the AI Service as is.
number
​
​
log-field
Field to use to store the log of the completion results in the output topic. Use "value" to write the result without a structured schema. Use "value.<field>" to write the result in a specific field.
The log contains useful information for debugging the completion prompts.
string
​
​
logit-bias
Parameter for the completion request. The parameters are passed to the AI Service as is.
object
​
​
max-tokens
Parameter for the completion request. The parameters are passed to the AI Service as is.
integer
​
​
messages
Messages to use for chat completions. You can use the Mustache syntax.
​array of object​
✓
​
min-chunks-per-message
Minimum number of chunks to send to the stream-to-topic topic. The chunks are sent as soon as they are available.
The chunks are sent in the order they are received from the AI Service.
To improve the TTFB (Time-To-First-Byte), the chunk size starts from 1 and doubles until it reaches the max-chunks-per-message value.
integer
​
20
model
The model to use for chat completions. The model must be available in the AI Service.
string
✓
​
options
Additional options for the model configuration. The structure depends on the model and AI provider.
object
​
​
presence-penalty
Parameter for the completion request. The parameters are passed to the AI Service as is.
number
​
​
stop
Parameter for the completion request. The parameters are passed to the AI Service as is.
array of string
​
​
stream
Enable streaming of the results. Use in conjunction with the stream-to-topic parameter.
boolean
​
true
stream-response-completion-field
Field to use to store the completion results in the stream-to-topic topic. Use "value" to write the result without a structured schema. Use "value.<field>" to write the result in a specific field.
string
​
​
stream-to-topic
Enable streaming of the results. If enabled, the results are streamed to the specified topic in small chunks. The entire messages will be sent to the output topic instead.
string
​
​
temperature
Parameter for the completion request. The parameters are passed to the AI Service as is.
number
​
​
top-p
Parameter for the completion request. The parameters are passed to the AI Service as is.
number
​
​
user
Parameter for the completion request. The parameters are passed to the AI Service as is.
string
​
​
when
Execute the step only when the condition is met.
You can use the expression language to reference the message.
Example: when: "value.first == 'f1' && value.last.toUpperCase() == 'L1'"
string
​
​


Compute chat completions (ai-chat-completions).messages
Text
Description
Type
Required
Default Value
role
Role of the message. The role is used to identify the speaker in the chat.
string
✓
​
content
Content of the message. You can use the Mustache syntax.
string
✓
​


Compute text completions (ai-text-completions)
Sends the text to the AI Service to compute text completions. The result is stored in the specified field.
Text
Description
Type
Required
Default Value
ai-service
In case of multiple AI services configured, specify the id of the AI service to use.
string
​
​
completion-field
Field to use to store the completion results in the output topic. Use "value" to write the result without a structured schema. Use "value.<field>" to write the result in a specific field.
string
​
​
composable
Whether this step can be composed with other steps.
boolean
​
true
frequency-penalty
Parameter for the completion request. The parameters are passed to the AI Service as is.
number
​
​
log-field
Field to use to store the log of the completion results in the output topic. Use "value" to write the result without a structured schema. Use "value.<field>" to write the result in a specific field.
The log contains useful information for debugging the completion prompts.
string
​
​
logit-bias
Parameter for the completion request. The parameters are passed to the AI Service as is.
object
​
​
logprobs
Logprobs parameter (only valid for OpenAI).
string
​
​
logprobs-field
Log probabilities to a field.
string
​
​
max-tokens
Parameter for the completion request. The parameters are passed to the AI Service as is.
integer
​
​
min-chunks-per-message
Minimum number of chunks to send to the stream-to-topic topic. The chunks are sent as soon as they are available.
The chunks are sent in the order they are received from the AI Service.
To improve the TTFB (Time-To-First-Byte), the chunk size starts from 1 and doubles until it reaches the max-chunks-per-message value.
integer
​
20
model
The model to use for text completions. The model must be available in the AI Service.
string
✓
​
options
Additional options for the model configuration. The structure depends on the model and AI provider.
object
​
​
presence-penalty
Parameter for the completion request. The parameters are passed to the AI Service as is.
number
​
​
prompt
Prompt to use for text completions. You can use the Mustache syntax.
array of string
✓
​
stop
Parameter for the completion request. The parameters are passed to the AI Service as is.
array of string
​
​
stream
Enable streaming of the results. Use in conjunction with the stream-to-topic parameter.
boolean
​
true
stream-response-completion-field
Field to use to store the completion results in the stream-to-topic topic. Use "value" to write the result without a structured schema. Use "value.<field>" to write the result in a specific field.
string
​
​
stream-to-topic
Enable streaming of the results. If enabled, the results are streamed to the specified topic in small chunks. The entire messages will be sent to the output topic instead.
string
​
​
temperature
Parameter for the completion request. The parameters are passed to the AI Service as is.
number
​
​
top-p
Parameter for the completion request. The parameters are passed to the AI Service as is.
number
​
​
user
Parameter for the completion request. The parameters are passed to the AI Service as is.
string
​
​
when
Execute the step only when the condition is met.
You can use the expression language to reference the message.
Example: when: "value.first == 'f1' && value.last.toUpperCase() == 'L1'"
string
​
​


Azure Blob Storage Source (azure-blob-storage-source)
Reads data from Azure blobs. There are three supported ways to authenticate:
- SAS token
- Storage account name and key
- Storage account connection string
Text
Description
Type
Required
Default Value
container
The name of the Azure econtainer to read from.
string
​
langstream-azure-source
endpoint
Endpoint to connect to. Usually it's https://<storage-account>.blob.core.windows.net.
string
✓
​
file-extensions
Comma separated list of file extensions to filter by.
string
​
pdf,docx,html,htm,md,txt
idle-time
Time in seconds to sleep after polling for new files.
integer
​
5
sas-token
Azure SAS token. If not provided, storage account name and key must be provided.
string
​
​
storage-account-connection-string
Azure storage account connection string. If not provided, SAS token must be provided.
string
​
​
storage-account-key
Azure storage account key. If not provided, SAS token must be provided.
string
​
​
storage-account-name
Azure storage account name. If not provided, SAS token must be provided.
string
​
​


Apache Camel Source (camel-source)
Use Apache Camel components as Source
Text
Description
Type
Required
Default Value
component-options
Additional parmaters to pass to the Camel component in the query string format.
The values are automatically encoded
object
​
​
component-uri
The Camel URI of the component to use as Source.
string
✓
​
key-header
Header to use as key of the record
string
​
​
max-buffered-records
Maximum number of records to buffer
integer
​
100


Cast record to another schema (cast)
Transforms the data to a target compatible schema.
Some step operations like cast or compute involve conversions from a type to another. When this happens the rules are:
- timestamp, date and time related object conversions assume UTC time zone if it is not explicit.
- date and time related object conversions to/from STRING use the RFC3339 format.
- timestamp related object conversions to/from LONG and DOUBLE are done using the number of milliseconds since EPOCH (1970-01-01T00:00:00Z).
- date related object conversions to/from INTEGER, LONG, FLOAT and DOUBLE are done using the number of days since EPOCH (1970-01-01).
- time related object conversions to/from INTEGER, LONG and DOUBLE are done using the number of milliseconds since midnight (00:00:00).
Text
Description
Type
Required
Default Value
composable
Whether this step can be composed with other steps.
boolean
​
true
part
When used with KeyValue data, defines if the transformation is done on the key or on the value. If empty, the transformation applies to both the key and the value.
string
​
​
schema-type
The target schema type.
string
✓
​
when
Execute the step only when the condition is met.
You can use the expression language to reference the message.
Example: when: "value.first == 'f1' && value.last.toUpperCase() == 'L1'"
string
​
​


Compute values from the record (compute)
Computes new properties, values or field values based on an expression evaluated at runtime. If the field already exists, it will be overwritten.
Text
Description
Type
Required
Default Value
composable
Whether this step can be composed with other steps.
boolean
​
true
fields
An array of objects describing how to calculate the field values
​array of object​
✓
​
when
Execute the step only when the condition is met.
You can use the expression language to reference the message.
Example: when: "value.first == 'f1' && value.last.toUpperCase() == 'L1'"
string
​
​


Compute values from the record (compute).fields
Text
Description
Type
Required
Default Value
expression
It is evaluated at runtime and the result of the evaluation is assigned to the field.
Refer to the language expression documentation for more information on the expression syntax.
string
✓
​
name
The name of the field to be computed. Prefix with key. or value. to compute the fields in the key or value parts of the message.
In addition, you can compute values on the following message headers [destinationTopic, messageKey, properties.].
Please note that properties is a map of key/value pairs that are referenced by the dot notation, for example properties.key0.
string
✓
​
optional
If true, it marks the field as optional in the schema of the transformed message. This is useful when null is a possible value of the compute expression.
boolean
​
false
type
The type of the computed field. This
will translate to the schema type of the new field in the transformed message.
The following types are currently supported :STRING, INT8, INT16, INT32, INT64, FLOAT, DOUBLE, BOOLEAN, DATE, TIME, TIMESTAMP, LOCAL_DATE_TIME, LOCAL_TIME, LOCAL_DATE, INSTANT.
The type field is not required for the message headers [destinationTopic, messageKey, properties.] and STRING will be used.
For the value and key, if it is not provided, then the type will be inferred from the result of the expression evaluation.
string
✓
​


Compute embeddings of the record (compute-ai-embeddings)
Compute embeddings of the record. The embeddings are stored in the record under a specific field.
Text
Description
Type
Required
Default Value
ai-service
In case of multiple AI services configured, specify the id of the AI service to use.
string
​
​
arguments
Additional arguments to pass to the AI Service. (HuggingFace only)
object
​
​
batch-size
Batch size for submitting the embeddings requests.
integer
​
10
composable
Whether this step can be composed with other steps.
boolean
​
true
concurrency
Max number of concurrent requests to the AI Service.
integer
​
4
embeddings-field
Field where to store the embeddings.
string
✓
​
flush-interval
Flushing is disabled by default in order to avoid latency spikes.
You should enable this feature in the case of background processing.
integer
​
0
loop-over
Execute the agent over a list of documents
string
​
​
model
Model to use for the embeddings. The model must be available in the configured AI Service.
string
​
text-embedding-ada-002
model-url
URL of the model to use. (HuggingFace only). The default is computed from the model: "djl://ai.djl.huggingface.pytorch/{model}"
string
​
​
options
Additional options to pass to the AI Service. (HuggingFace only)
object
​
​
text
Text to create embeddings from. You can use Mustache syntax to compose multiple fields into a single text. Example:
text: "{{{ value.field1 }}} {{{ value.field2 }}}"
string
✓
​
when
Execute the step only when the condition is met.
You can use the expression language to reference the message.
Example: when: "value.first == 'f1' && value.last.toUpperCase() == 'L1'"
string
​
​


Dispatch agent (dispatch)
Dispatches messages to different destinations based on conditions.
Text
Description
Type
Required
Default Value
routes
Routes.
​array of object​
​
​


Dispatch agent (dispatch).routes
Text
Description
Type
Required
Default Value
destination
Destination of the message.
string
​
​
action
Action on the message. Possible values are "dispatch" or "drop".
string
​
dispatch
when
Condition to activate the route. This is a standard EL expression.
string
​
​


Document to JSON (document-to-json)
Convert raw text document to JSON. The result will be a JSON object with the text content in the specified field.
Text
Description
Type
Required
Default Value
copy-properties
Whether to copy the message properties/headers in the output message.
boolean
​
true
text-field
Field name to write the text content to.
string
​
text


Drop the record (drop)
Drops the record from further processing. Use in conjunction with when to selectively drop records.
Text
Description
Type
Required
Default Value
composable
Whether this step can be composed with other steps.
boolean
​
true
when
Execute the step only when the condition is met.
You can use the expression language to reference the message.
Example: when: "value.first == 'f1' && value.last.toUpperCase() == 'L1'"
string
​
​


Drop fields (drop-fields)
Drops the record fields.
Text
Description
Type
Required
Default Value
composable
Whether this step can be composed with other steps.
boolean
​
true
fields
Fields to drop from the input record.
array of string
✓
​
part
Part to drop. (value or key)
string
​
​
when
Execute the step only when the condition is met.
You can use the expression language to reference the message.
Example: when: "value.first == 'f1' && value.last.toUpperCase() == 'L1'"
string
​
​


Flare Controller (flare-controller)
Apply to the Flare pattern to enhance the quality of text completion results.
Text
Description
Type
Required
Default Value
logprobs-field
The field that contains the logprobs of tokens returned by the ai-text-completion agent.
string
✓
​
loop-topic
Name of the topic to forward the message in case of requesting more documents.
string
✓
​
retrieve-documents-field
Name of the field to set in order to request the retrival of more documents.
string
✓
​
tokens-field
The field that contains the list of tokens returned by the ai-text-completion agent.
string
✓
​


Flatten record fields (flatten)
Converts structured nested data into a new single-hierarchy-level structured data. The names of the new fields are built by concatenating the intermediate level field names.
Text
Description
Type
Required
Default Value
composable
Whether this step can be composed with other steps.
boolean
​
true
delimiter
The delimiter to use when concatenating the field names.
string
​
_
part
When used with KeyValue data, defines if the transformation is done on the key or on the value. If empty, the transformation applies to both the key and the value.
string
​
​
when
Execute the step only when the condition is met.
You can use the expression language to reference the message.
Example: when: "value.first == 'f1' && value.last.toUpperCase() == 'L1'"
string
​
​


Http Request (http-request)
Agent for enriching data with an HTTP request.
Text
Description
Type
Required
Default Value
allow-redirects
Whether or not to follow redirects.
boolean
​
true
body
Body to send with the request. You can use the Mustache syntax to inject value from the context.
string
​
​
handle-cookies
Whether or not to handle cookies during the redirects.
boolean
​
true
headers
Headers to send with the request. You can use the Mustache syntax to inject value from the context.
object
​
​
method
Http method to use for the request.
string
​
GET
output-field
The field that will hold the results, it can be the same as "field" to override it.
string
✓
​
query-string
Query string to append to the url. You can use the Mustache syntax to inject value from the context.
Note that the values will be automatically escaped.
object
​
​
url
Url to send the request to. For adding query string parameters, use the `query-string` field.
string
✓
​


Identity function (identity)
Simple agent to move data from the input to the output. Could be used for testing or sample applications.


Invoke LangServe (langserve-invoke)
Agent for invoking LangServe based applications
Text
Description
Type
Required
Default Value
allow-redirects
Whet

Agents

Compute chat completions (`ai-chat-completions`)

Compute chat completions (`ai-chat-completions`).messages

Compute text completions (`ai-text-completions`)

Azure Blob Storage Source (`azure-blob-storage-source`)

Apache Camel Source (`camel-source`)

Cast record to another schema (`cast`)

Compute values from the record (`compute`)

Compute values from the record (`compute`).fields

Compute embeddings of the record (`compute-ai-embeddings`)

Dispatch agent (`dispatch`)

Dispatch agent (`dispatch`).routes

Document to JSON (`document-to-json`)

Drop the record (`drop`)

Drop fields (`drop-fields`)

Flare Controller (`flare-controller`)

Flatten record fields (`flatten`)

Http Request (`http-request`)

Identity function (`identity`)

Invoke LangServe (`langserve-invoke`)

Text	Description	Type	Required	Default Value
`ai-service`	In case of multiple AI services configured, specify the id of the AI service to use.	string
`completion-field`	Field to use to store the completion results in the output topic. Use "value" to write the result without a structured schema. Use "value.<field>" to write the result in a specific field.	string
`composable`	Whether this step can be composed with other steps.	boolean		true
`frequency-penalty`	Parameter for the completion request. The parameters are passed to the AI Service as is.	number
`log-field`	Field to use to store the log of the completion results in the output topic. Use "value" to write the result without a structured schema. Use "value.<field>" to write the result in a specific field. The log contains useful information for debugging the completion prompts.	string
`logit-bias`	Parameter for the completion request. The parameters are passed to the AI Service as is.	object
`max-tokens`	Parameter for the completion request. The parameters are passed to the AI Service as is.	integer
`messages`	Messages to use for chat completions. You can use the Mustache syntax.	array of object	✓
`min-chunks-per-message`	Minimum number of chunks to send to the stream-to-topic topic. The chunks are sent as soon as they are available. The chunks are sent in the order they are received from the AI Service. To improve the TTFB (Time-To-First-Byte), the chunk size starts from 1 and doubles until it reaches the max-chunks-per-message value.	integer		20
`model`	The model to use for chat completions. The model must be available in the AI Service.	string	✓
`options`	Additional options for the model configuration. The structure depends on the model and AI provider.	object
`presence-penalty`	Parameter for the completion request. The parameters are passed to the AI Service as is.	number
`stop`	Parameter for the completion request. The parameters are passed to the AI Service as is.	array of string
`stream`	Enable streaming of the results. Use in conjunction with the stream-to-topic parameter.	boolean		true
`stream-response-completion-field`	Field to use to store the completion results in the stream-to-topic topic. Use "value" to write the result without a structured schema. Use "value.<field>" to write the result in a specific field.	string
`stream-to-topic`	Enable streaming of the results. If enabled, the results are streamed to the specified topic in small chunks. The entire messages will be sent to the output topic instead.	string
`temperature`	Parameter for the completion request. The parameters are passed to the AI Service as is.	number
`top-p`	Parameter for the completion request. The parameters are passed to the AI Service as is.	number
`user`	Parameter for the completion request. The parameters are passed to the AI Service as is.	string
`when`	Execute the step only when the condition is met. You can use the expression language to reference the message. Example: when: "value.first == 'f1' && value.last.toUpperCase() == 'L1'"	string

Text	Description	Type	Required	Default Value
`role`	Role of the message. The role is used to identify the speaker in the chat.	string	✓
`content`	Content of the message. You can use the Mustache syntax.	string	✓

Text	Description	Type	Required	Default Value
`container`	The name of the Azure econtainer to read from.	string		langstream-azure-source
`endpoint`	Endpoint to connect to. Usually it's https://<storage-account>.blob.core.windows.net.	string	✓
`file-extensions`	Comma separated list of file extensions to filter by.	string		pdf,docx,html,htm,md,txt
`idle-time`	Time in seconds to sleep after polling for new files.	integer		5
`sas-token`	Azure SAS token. If not provided, storage account name and key must be provided.	string
`storage-account-connection-string`	Azure storage account connection string. If not provided, SAS token must be provided.	string
`storage-account-key`	Azure storage account key. If not provided, SAS token must be provided.	string
`storage-account-name`	Azure storage account name. If not provided, SAS token must be provided.	string

Text	Description	Type	Required	Default Value
`component-options`	Additional parmaters to pass to the Camel component in the query string format. The values are automatically encoded	object
`component-uri`	The Camel URI of the component to use as Source.	string	✓
`key-header`	Header to use as key of the record	string
`max-buffered-records`	Maximum number of records to buffer	integer		100

Text	Description	Type	Required	Default Value
`expression`	It is evaluated at runtime and the result of the evaluation is assigned to the field. Refer to the language expression documentation for more information on the expression syntax.	string	✓
`name`	The name of the field to be computed. Prefix with key. or value. to compute the fields in the key or value parts of the message. In addition, you can compute values on the following message headers [destinationTopic, messageKey, properties.]. Please note that properties is a map of key/value pairs that are referenced by the dot notation, for example properties.key0.	string	✓
`optional`	If true, it marks the field as optional in the schema of the transformed message. This is useful when null is a possible value of the compute expression.	boolean		false
`type`	The type of the computed field. This will translate to the schema type of the new field in the transformed message. The following types are currently supported :STRING, INT8, INT16, INT32, INT64, FLOAT, DOUBLE, BOOLEAN, DATE, TIME, TIMESTAMP, LOCAL_DATE_TIME, LOCAL_TIME, LOCAL_DATE, INSTANT. The type field is not required for the message headers [destinationTopic, messageKey, properties.] and STRING will be used. For the value and key, if it is not provided, then the type will be inferred from the result of the expression evaluation.	string	✓

Text	Description	Type	Default Value
`destination`	Destination of the message.	string
`action`	Action on the message. Possible values are "dispatch" or "drop".	string	dispatch
`when`	Condition to activate the route. This is a standard EL expression.	string

Text	Description	Type	Required	Default Value
`copy-properties`	Whether to copy the message properties/headers in the output message.	boolean		true
`text-field`	Field name to write the text content to.	string		text

Text	Description	Type	Required
`logprobs-field`	The field that contains the logprobs of tokens returned by the ai-text-completion agent.	string	✓
`loop-topic`	Name of the topic to forward the message in case of requesting more documents.	string	✓
`retrieve-documents-field`	Name of the field to set in order to request the retrival of more documents.	string	✓
`tokens-field`	The field that contains the list of tokens returned by the ai-text-completion agent.	string	✓

Text	Description	Type	Required	Default Value
`allow-redirects`	Whether or not to follow redirects.	boolean		true
`body`	Body to send with the request. You can use the Mustache syntax to inject value from the context.	string
`handle-cookies`	Whether or not to handle cookies during the redirects.	boolean		true
`headers`	Headers to send with the request. You can use the Mustache syntax to inject value from the context.	object
`method`	Http method to use for the request.	string		GET
`output-field`	The field that will hold the results, it can be the same as "field" to override it.	string	✓
`query-string`	Query string to append to the url. You can use the Mustache syntax to inject value from the context. Note that the values will be automatically escaped.	object
`url`	Url to send the request to. For adding query string parameters, use the `query-string` field.	string	✓