TypeScript SDK - Braintrust

Installation

npm install braintrust

Functions

BaseExperiment

Use this to specify that the dataset should actually be the data from a previous (base) experiment. If you do not specify a name, Braintrust will automatically figure out the best base experiment to use based on your git history (or fall back to timestamps).

options

Object

BraintrustMiddleware

Creates a Braintrust middleware for AI SDK v2 that automatically traces generateText and streamText calls with comprehensive metadata and metrics.

config

MiddlewareConfig

Configuration options for the middleware

buildLocalSummary

buildLocalSummary function

evaluator

EvaluatorDef

results

EvalResult[]

createFinalValuePassThroughStream

Create a stream that passes through the final value of the stream. This is used to implement BraintrustStream.finalValue().

onFinal

Object

A function to call with the final value of the stream.

onError

Object

currentExperiment

Returns the currently-active experiment (set by init). Returns undefined if no current experiment has been set.

options

OptionalStateArg

currentLogger

Returns the currently-active logger (set by initLogger). Returns undefined if no current logger has been set.

options

unknown

currentSpan

Return the currently-active span for logging (set by one of the traced methods). If there is no active span, returns a no-op span object, which supports the same interface as spans but does no logging. See Span for full details.

options

OptionalStateArg

deepCopyEvent

Creates a deep copy of the given event. Replaces references to user objects with placeholder strings to ensure serializability, except for Attachment and ExternalAttachment objects, which are preserved and not deep-copied.

event

defaultErrorScoreHandler

defaultErrorScoreHandler function

args

Object

deserializePlainStringAsJSON

deserializePlainStringAsJSON function

string

devNullWritableStream

devNullWritableStream function

Eval

Eval function

name

string

evaluator

Evaluator

reporterOrOpts

string | ReporterDef | EvalOptions

flush

Flush any pending rows to the server.

options

OptionalStateArg

getContextManager

getContextManager function

getIdGenerator

Factory function that creates a new ID generator instance each time. This eliminates global state and makes tests parallelizable. Each caller gets their own generator instance.

getPromptVersions

Get the versions for a prompt.

projectId

string

The ID of the project to query

promptId

string

The ID of the prompt to get versions for

getSpanParentObject

Mainly for internal use. Return the parent object for starting a span in a global context. Applies precedence: current span > propagated parent string > experiment > logger.

options

unknown

init

options

Readonly

Options for configuring init().

initDataset

Create a new dataset in a specified project. If the project does not exist, it will be created.

options

Readonly

Options for configuring initDataset().

initExperiment

Alias for init(options).

options

Readonly

initFunction

Creates a function that can be used as a task or scorer in the Braintrust evaluation framework. The returned function wraps a Braintrust function and can be passed directly to Eval(). When used as a task:

const myFunction = initFunction({projectName: "myproject", slug: "myfunction"});
await Eval("test", {
  task: myFunction,
  data: testData,
  scores: [...]
});

When used as a scorer:

const myScorer = initFunction({projectName: "myproject", slug: "myscorer"});
await Eval("test", {
  task: someTask,
  data: testData,
  scores: [myScorer]
});

options

Object

Options for the function.

initLogger

Create a new logger in a specified project. If the project does not exist, it will be created.

options

Readonly

Additional options for configuring init().

invoke

Invoke a Braintrust function, returning a BraintrustStream or the value as a plain Javascript object.

args

unknown

The arguments for the function (see InvokeFunctionArgs for more details).

loadPrompt

Load a prompt from the specified project.

options

LoadPromptOptions

Options for configuring loadPrompt().

log

Log a single event to the current experiment. The event will be batched and uploaded behind the scenes.

event

ExperimentLogFullArgs

The event to log. See Experiment.log for full details.

logError

logError function

span

Span

error

unknown

Log into Braintrust. This will prompt you for your API token, which you can find at https://www.braintrust.dev/app/token. This method is called automatically by init().

options

unknown

Options for configuring login().

loginToState

loginToState function

options

LoginOptions

newId

newId function

parseCachedHeader

parseCachedHeader function

value

undefined | null | string

permalink

Format a permalink to the Braintrust application for viewing the span represented by the provided slug. Links can be generated at any time, but they will only become viewable after the span and its root have been flushed to the server and ingested. If you have a Span object, use Span.link instead.

slug

string

The identifier generated from Span.export.

opts

Object

Optional arguments.

promptDefinitionToPromptData

promptDefinitionToPromptData function

promptDefinition

unknown

rawTools

Object[]

renderMessage

renderMessage function

render

Object

message

renderPromptParams

renderPromptParams function

params

args

Record

options

Object

Reporter

Reporter function

name

string

reporter

ReporterBody

reportFailures

reportFailures function

evaluator

EvaluatorDef

failingResults

EvalResult[]

__namedParameters

ReporterOpts

runEvaluator

runEvaluator function

experiment

null | Experiment

evaluator

EvaluatorDef

progressReporter

ProgressReporter

filters

Filter[]

stream

undefined | Object

parameters

InferParameters

setFetch

Set the fetch implementation to use for requests. You can specify it here, or when you call login.

fetch

Object

The fetch implementation to use.

setMaskingFunction

Set a global masking function that will be applied to all logged data before sending to Braintrust. The masking function will be applied after records are merged but before they are sent to the backend.

maskingFunction

null | Object

A function that takes a JSON-serializable object and returns a masked version. Set to null to disable masking.

spanComponentsToObjectId

spanComponentsToObjectId function

__namedParameters

Object

startSpan

Lower-level alternative to traced. This allows you to start a span yourself, and can be useful in situations where you cannot use callbacks. However, spans started with startSpan will not be marked as the “current span”, so currentSpan() and traced() will be no-ops. If you want to mark a span as current, use traced instead. See traced for full details.

args

unknown

summarize

Summarize the current experiment, including the scores (compared to the closest reference experiment) and metadata.

options

Object

Options for summarizing the experiment.

traceable

A synonym for wrapTraced. If you’re porting from systems that use traceable, you can use this to make your codebase more consistent.

args

unknown

traced

Toplevel function for starting a span. It checks the following (in precedence order):

Currently-active span
Currently-active experiment
Currently-active logger

and creates a span under the first one that is active. Alternatively, if parent is specified, it creates a span under the specified parent row. If none of these are active, it returns a no-op span object. See Span.traced for full details.

callback

Object

args

unknown

updateSpan

Update a span using the output of span.export(). It is important that you only resume updating to a span once the original span has been fully written and flushed, since otherwise updates to the span may conflict with the original span.

__namedParameters

unknown

withCurrent

Runs the provided callback with the span as the current span.

span

Span

callback

Object

state

undefined | BraintrustState

withDataset

withDataset function

project

string

callback

Object

options

Readonly

withExperiment

withExperiment function

project

string

callback

Object

options

Readonly

withLogger

withLogger function

callback

Object

options

Readonly

withParent

withParent function

parent

string

callback

Object

state

undefined | BraintrustState

wrapAISDK

Wraps Vercel AI SDK methods with Braintrust tracing. Returns wrapped versions of generateText, streamText, generateObject, and streamObject that automatically create spans and log inputs, outputs, and metrics.

The AI SDK namespace (e.g., import * as ai from “ai”)

wrapAISDKModel

Wrap an ai-sdk model (created with .chat(), .completion(), etc.) to add tracing. If Braintrust is not configured, this is a no-op

model

wrapAnthropic

Wrap an Anthropic object (created with new Anthropic(...)) to add tracing. If Braintrust is not configured, nothing will be traced. If this is not an Anthropic object, this function is a no-op. Currently, this only supports the v4 API.

anthropic

wrapClaudeAgentSDK

Wraps the Claude Agent SDK with Braintrust tracing. This returns wrapped versions of query and tool that automatically trace all agent interactions.

sdk

The Claude Agent SDK module

wrapMastraAgent

Wraps a Mastra agent with Braintrust tracing. This function wraps the agent’s underlying language model with BraintrustMiddleware and traces all agent method calls. Important: This wrapper only supports AI SDK v5 methods such as generate and stream.

agent

The Mastra agent to wrap

options

Object

Optional configuration for the wrapper

wrapOpenAI

Wrap an OpenAI object (created with new OpenAI(...)) to add tracing. If Braintrust is not configured, nothing will be traced. If this is not an OpenAI object, this function is a no-op. Currently, this supports both the v4 and v5 API.

openai

wrapOpenAIv4

wrapOpenAIv4 function

openai

wrapTraced

Wrap a function with traced, using the arguments as input and return value as output. Any functions wrapped this way will automatically be traced, similar to the @traced decorator in Python. If you want to correctly propagate the function’s name and define it in one go, then you can do so like this:

const myFunc = wrapTraced(async function myFunc(input) {
 const result = await client.chat.completions.create({
   model: "gpt-3.5-turbo",
   messages: [{ role: "user", content: input }],
 });
 return result.choices[0].message.content ?? "unknown";
},
// Optional: if you're using a framework like NextJS that minifies your code, specify the function name and it will be used for the span name
{ name: "myFunc" },
);

Now, any calls to myFunc will be traced, and the input and output will be logged automatically. If tracing is inactive, i.e. there is no active logger or experiment, it’s just a no-op.

The function to wrap.

args

unknown

Span-level arguments (e.g. a custom name or type) to pass to traced.

Classes

AISpanProcessor

A span processor that filters spans to only export filtered telemetry. Only filtered spans and root spans will be forwarded to the inner processor. This dramatically reduces telemetry volume while preserving important observability. Methods forceFlush(), onEnd(), onStart(), shutdown()

Attachment

Represents an attachment to be uploaded and the associated metadata. Attachment objects can be inserted anywhere in an event, allowing you to log arbitrary file data. The SDK will asynchronously upload the file to object storage and replace the Attachment object with an AttachmentReference. Properties

reference

Object

The object that replaces this Attachment at upload time.

Methods data(), debugInfo(), upload()

BaseAttachment

BaseAttachment class Properties

reference

Object | Object

Methods data(), debugInfo(), upload()

BraintrustExporter

A trace exporter that sends OpenTelemetry spans to Braintrust. This exporter wraps the standard OTLP trace exporter and can be used with any OpenTelemetry setup, including @vercel/otel’s registerOTel function, NodeSDK, or custom tracer providers. It can optionally filter spans to only send AI-related telemetry. Environment Variables:

BRAINTRUST_API_KEY: Your Braintrust API key
BRAINTRUST_PARENT: Parent identifier (e.g., “project_name:test”)
BRAINTRUST_API_URL: Base URL for Braintrust API (defaults to https://api.braintrust.dev)

Methods export(), forceFlush(), shutdown()

BraintrustSpanProcessor

A span processor that sends OpenTelemetry spans to Braintrust. This processor uses a BatchSpanProcessor and an OTLP exporter configured to send data to Braintrust’s telemetry endpoint. Span filtering is disabled by default but can be enabled with the filterAISpans option. Environment Variables:

BRAINTRUST_API_KEY: Your Braintrust API key
BRAINTRUST_PARENT: Parent identifier (e.g., “project_name:test”)
BRAINTRUST_API_URL: Base URL for Braintrust API (defaults to https://api.braintrust.dev)

Methods forceFlush(), onEnd(), onStart(), shutdown()

BraintrustState

BraintrustState class Properties

apiUrl

null | string

appPublicUrl

null | string

appUrl

null | string

currentExperiment

undefined | Experiment

currentLogger

undefined | Logger

currentParent

IsoAsyncLocalStorage

currentSpan

IsoAsyncLocalStorage

fetch

Object

gitMetadataSettings

Object

string

loggedIn

boolean

orgId

null | string

orgName

null | string

promptCache

PromptCache

proxyUrl

null | string

contextManager

unknown

idGenerator

unknown

Methods apiConn(), appConn(), bgLogger(), copyLoginInfo(), disable(), enforceQueueSizeLimit(), httpLogger(), login(), loginReplaceApiConn(), proxyConn(), resetIdGenState(), resetLoginInfo(), serialize(), setFetch(), setMaskingFunction(), setOverrideBgLogger(), toJSON(), toString(), deserialize()

BraintrustStream

A Braintrust stream. This is a wrapper around a ReadableStream of BraintrustStreamChunk, with some utility methods to make them easy to log and convert into various formats. Methods [asyncIterator](), copy(), finalValue(), toReadableStream(), parseRawEvent(), serializeRawEvent()

CodeFunction

CodeFunction class Properties

description

string

handler

ifExists

"replace" | "error" | "ignore"

name

string

parameters

ZodType

project

Project

returns

ZodType

slug

string

type

"tool" | "task" | "scorer" | "llm"

Methods key()

CodePrompt

CodePrompt class Properties

description

string

functionType

"tool" | "task" | "scorer" | "llm"

string

ifExists

"replace" | "error" | "ignore"

name

string

project

Project

prompt

Object

slug

string

toolFunctions

Object | Object | GenericCodeFunction[]

Methods toFunctionDefinition()

ContextManager

ContextManager class Methods getCurrentSpan(), getParentSpanIds(), runInContext()

Dataset

A dataset is a collection of records, such as model inputs and expected outputs, which represent data you can use to evaluate and fine-tune models. You can log production data to datasets, curate them with interesting examples, edit/delete records, and run evaluations against them. You should not create Dataset objects directly. Instead, use the braintrust.initDataset() method. Properties

unknown

loggingState

unknown

name

unknown

project

unknown

Methods [asyncIterator](), clearCache(), close(), delete(), fetch(), fetchedData(), flush(), getState(), insert(), summarize(), update(), version(), isDataset()

EvalResultWithSummary

EvalResultWithSummary class Properties

results

EvalResult[]

summary

ExperimentSummary

Methods toJSON(), toString()

Experiment

An experiment is a collection of logged events, such as model inputs and outputs, which represent a snapshot of your application at a particular point in time. An experiment is meant to capture more than just the model you use, and includes the data you use to test, pre- and post- processing code, comparison metrics (scores), and any other metadata you want to include. Experiments are associated with a project, and two experiments are meant to be easily comparable via their inputs. You can change the attributes of the experiments in a project (e.g. scoring functions) over time, simply by changing what you log. You should not create Experiment objects directly. Instead, use the braintrust.init() method. Properties

dataset

AnyDataset

kind

"experiment"

unknown

loggingState

unknown

name

unknown

project

unknown

Methods [asyncIterator](), clearCache(), close(), export(), fetch(), fetchBaseExperiment(), fetchedData(), flush(), getState(), log(), logFeedback(), startSpan(), summarize(), traced(), updateSpan(), version()

ExternalAttachment

Represents an attachment that resides in an external object store and the associated metadata. ExternalAttachment objects can be inserted anywhere in an event, similar to Attachment objects, but they reference files that already exist in an external object store rather than requiring upload. The SDK will replace the ExternalAttachment object with an AttachmentReference during logging. Properties

reference

Object

The object that replaces this ExternalAttachment at upload time.

Methods data(), debugInfo(), upload()

FailedHTTPResponse

FailedHTTPResponse class Properties

data

string

status

number

text

string

IDGenerator

Abstract base class for ID generators Methods getSpanId(), getTraceId(), shareRootSpanId()

JSONAttachment

Represents a JSON object that should be stored as an attachment. JSONAttachment is a convenience function that creates an Attachment from JSON data. It’s particularly useful for large JSON objects that would otherwise bloat the trace size. The JSON data is automatically serialized and stored as an attachment with content type “application/json”. Properties

reference

Object

The object that replaces this Attachment at upload time.

Methods data(), debugInfo(), upload()

LazyValue

LazyValue class Properties

hasSucceeded

unknown

Methods get(), getSync()

Logger

Logger class Properties

kind

"logger"

asyncFlush

unknown

loggingState

unknown

org_id

unknown

project

unknown

Methods export(), flush(), log(), logFeedback(), startSpan(), traced(), updateSpan()

NoopSpan

A fake implementation of the Span API which does nothing. This can be used as the default span. Properties

string

Row ID of the span.

kind

"span"

rootSpanId

string

Root span ID of the span.

spanId

string

Span ID of the span.

spanParents

string[]

Parent span IDs of the span.

Methods close(), end(), export(), flush(), link(), log(), logFeedback(), permalink(), setAttributes(), startSpan(), startSpanWithParents(), state(), toString(), traced()

OTELIDGenerator

ID generator that generates OpenTelemetry-compatible IDs Uses hex strings for compatibility with OpenTelemetry systems Methods getSpanId(), getTraceId(), shareRootSpanId()

Project

Project class Properties

string

name

string

prompts

PromptBuilder

scorers

ScorerBuilder

tools

ToolBuilder

Methods addCodeFunction(), addPrompt(), publish()

ProjectNameIdMap

ProjectNameIdMap class Methods getId(), getName(), resolve()

Prompt

Prompt class Properties

unknown

name

unknown

options

unknown

projectId

unknown

prompt

unknown

promptData

unknown

slug

unknown

version

unknown

Methods build(), buildWithAttachments(), fromPromptData(), isPrompt(), renderPrompt()

PromptBuilder

PromptBuilder class Methods create()

ReadonlyAttachment

A readonly alternative to Attachment, which can be used for fetching already-uploaded Attachments. Properties

reference

Object | Object

Attachment metadata.

Methods asBase64Url(), data(), metadata(), status()

ReadonlyExperiment

A read-only view of an experiment, initialized by passing open: true to init(). Properties

unknown

loggingState

unknown

name

unknown

Methods [asyncIterator](), asDataset(), clearCache(), fetch(), fetchedData(), getState(), version()

ScorerBuilder

ScorerBuilder class Methods create()

SpanImpl

Primary implementation of the Span interface. See Span for full details on each method. We suggest using one of the various traced methods, instead of creating Spans directly. See Span.startSpan for full details. Properties

kind

"span"

unknown

Row ID of the span.

rootSpanId

unknown

Root span ID of the span.

spanId

unknown

Span ID of the span.

spanParents

unknown

Parent span IDs of the span.

Methods close(), end(), export(), flush(), link(), log(), logFeedback(), permalink(), setAttributes(), setSpanParents(), startSpan(), startSpanWithParents(), state(), toString(), traced()

TestBackgroundLogger

TestBackgroundLogger class Methods drain(), flush(), log(), setMaskingFunction()

ToolBuilder

ToolBuilder class Methods create()

UUIDGenerator

ID generator that uses UUID4 for both span and trace IDs Methods getSpanId(), getTraceId(), shareRootSpanId()

Interfaces

AttachmentParams

AttachmentParams interface Properties

contentType

string

data

string | ArrayBuffer | Blob

filename

string

state

BraintrustState

BackgroundLoggerOpts

BackgroundLoggerOpts interface Properties

noExitFlush

boolean

onFlushError

Object

ContextParentSpanIds

ContextParentSpanIds interface Properties

rootSpanId

string

spanParents

string[]

DatasetSummary

Summary of a dataset’s scores and metadata. Properties

dataSummary

undefined | DataSummary

Summary of the dataset’s data.

datasetName

string

Name of the dataset.

datasetUrl

string

URL to the experiment’s page in the Braintrust app.

projectName

string

Name of the project that the dataset belongs to.

projectUrl

string

URL to the project’s page in the Braintrust app.

DataSummary

Summary of a dataset’s data. Properties

newRecords

number

New or updated records added in this session.

totalRecords

number

Total records in the dataset.

EvalHooks

EvalHooks interface Properties

expected

Expected

The expected output for the current evaluation.

Evaluator

Evaluator interface Properties

baseExperimentId

string

An optional experiment id to use as a base. If specified, the new experiment will be summarized and compared to this experiment. This takes precedence over baseExperimentName if specified.

baseExperimentName

string

An optional experiment name to use as a base. If specified, the new experiment will be summarized and compared to this experiment.

data

EvalData

A function that returns a list of inputs, expected outputs, and metadata.

description

string

An optional description for the experiment.

errorScoreHandler

ErrorScoreHandler

Optionally supply a custom function to specifically handle score values when tasks or scoring functions have errored. A default implementation is exported as defaultErrorScoreHandler which will log a 0 score to the root span for any scorer that was not run.

experimentName

string

An optional name for the experiment.

gitMetadataSettings

Object

Optional settings for collecting git metadata. By default, will collect all git metadata fields allowed in org-level settings.

isPublic

boolean

Whether the experiment should be public. Defaults to false.

maxConcurrency

number

The maximum number of tasks/scorers that will be run concurrently. Defaults to undefined, in which case there is no max concurrency.

metadata

Record

Optional additional metadata for the experiment.

parameters

Parameters

A set of parameters that will be passed to the evaluator. Can contain array values that will be converted to single values in the task.

projectId

string

If specified, uses the given project ID instead of the evaluator’s name to identify the project.

repoInfo

null | Object

Optionally explicitly specify the git metadata for this experiment. This takes precedence over gitMetadataSettings if specified.

scores

EvalScorer[]

A set of functions that take an input, output, and expected value and return a score.

signal

AbortSignal

An abort signal that can be used to stop the evaluation.

state

BraintrustState

If specified, uses the logger state to initialize Braintrust objects. If unspecified, falls back to the global state (initialized using your API key).

summarizeScores

boolean

Whether to summarize the scores of the experiment after it has run. Defaults to true.

task

EvalTask

A function that takes an input and returns an output.

timeout

number

The duration, in milliseconds, after which to time out the evaluation. Defaults to undefined, in which case there is no timeout.

trialCount

number

The number of times to run the evaluator per input. This is useful for evaluating applications that have non-deterministic behavior and gives you both a stronger aggregate measure and a sense of the variance in the results.

update

boolean

Whether to update an existing experiment with experiment_name if one exists. Defaults to false.

ExperimentSummary

Summary of an experiment’s scores and metadata. Properties

comparisonExperimentName

string

The experiment scores are baselined against.

experimentId

string

ID of the experiment. May be undefined if the eval was run locally.

experimentName

string

Name of the experiment.

experimentUrl

string

URL to the experiment’s page in the Braintrust app.

metrics

Record

projectId

string

projectName

string

Name of the project that the experiment belongs to.

projectUrl

string

URL to the project’s page in the Braintrust app.

scores

Record

Summary of the experiment’s scores.

Exportable

Exportable interface

ExternalAttachmentParams

ExternalAttachmentParams interface Properties

contentType

string

filename

string

state

BraintrustState

url

string

FunctionEvent

FunctionEvent interface Properties

description

string

function_data

Object | Object | Object | Object | Object

function_type

"tool" | "task" | "scorer" | "llm"

if_exists

"replace" | "error" | "ignore"

name

string

project_id

string

prompt_data

Object

slug

string

InvokeFunctionArgs

Arguments for the invoke function. Properties

function_id

string

The ID of the function to invoke.

globalFunction

string

The name of the global function to invoke.

input

Input

The input to the function. This will be logged as the input field in the span.

messages

Additional OpenAI-style messages to add to the prompt (only works for llm functions).

metadata

Record

Additional metadata to add to the span. This will be logged as the metadata field in the span. It will also be available as the {{metadata}} field in the prompt and as the metadata argument to the function.

mode

null | "auto" | "parallel"

The mode of the function. If “auto”, will return a string if the function returns a string, and a JSON object otherwise. If “parallel”, will return an array of JSON objects with one object per tool call.

parent

string | Exportable

The parent of the function. This can be an existing span, logger, or experiment, or the output of .export() if you are distributed tracing. If unspecified, will use the same semantics as traced() to determine the parent and no-op if not in a tracing context.

projectName

string

The name of the project containing the function to invoke.

promptSessionFunctionId

string

The ID of the function in the prompt session to invoke.

promptSessionId

string

The ID of the prompt session to invoke the function from.

schema

unknown

A Zod schema to validate the output of the function and return a typed value. This is only used if stream is false.

slug

string

The slug of the function to invoke.

state

BraintrustState

(Advanced) This parameter allows you to pass in a custom login state. This is useful for multi-tenant environments where you are running functions from different Braintrust organizations.

stream

Stream

Whether to stream the function’s output. If true, the function will return a BraintrustStream, otherwise it will return the output of the function as a JSON object.

strict

boolean

Whether to use strict mode for the function. If true, the function will throw an error if the variable names in the prompt do not match the input keys.

LoginOptions

Options for logging in to Braintrust. Properties

apiKey

string

The API key to use. If the parameter is not specified, will try to use the BRAINTRUST_API_KEY environment variable.

appUrl

string

The URL of the Braintrust App. Defaults to https://www.braintrust.dev. You should not need to change this unless you are doing the “Full” deployment.

fetch

Object

A custom fetch implementation to use.

noExitFlush

boolean

By default, the SDK installs an event handler that flushes pending writes on the beforeExit event. If true, this event handler will not be installed.

onFlushError

Object

Calls this function if there’s an error in the background flusher.

orgName

string

The name of a specific organization to connect to. Since API keys are scoped to organizations, this parameter is usually unnecessary unless you are logging in with a JWT.

LogOptions

LogOptions interface Properties

asyncFlush

IsAsyncFlush

computeMetadataArgs

Record

MetricSummary

Summary of a metric’s performance. Properties

diff

number

Difference in metric between the current and reference experiment.

improvements

number

Number of improvements in the metric.

metric

number

Average metric across all examples.

name

string

Name of the metric.

regressions

number

Number of regressions in the metric.

unit

string

Unit label for the metric.

ObjectMetadata

ObjectMetadata interface Properties

fullInfo

Record

string

name

string

ParentExperimentIds

ParentExperimentIds interface Properties

experiment_id

string

ParentProjectLogIds

ParentProjectLogIds interface Properties

log_id

"g"

project_id

string

ReporterBody

ReporterBody interface

ScoreSummary

Summary of a score’s performance. Properties

diff

number

Difference in score between the current and reference experiment.

improvements

number

Number of improvements in the score.

name

string

Name of the score.

regressions

number

Number of regressions in the score.

score

number

Average score across all examples.

Span

A Span encapsulates logged data and metrics for a unit of work. This interface is shared by all span implementations. We suggest using one of the various traced methods, instead of creating Spans directly. See Span.traced for full details. Properties

string

Row ID of the span.

kind

"span"

rootSpanId

string

Root span ID of the span.

spanId

string

Span ID of the span.

spanParents

string[]

Parent span IDs of the span.

​Installation

​Functions

​BaseExperiment

​BraintrustMiddleware

​buildLocalSummary

​createFinalValuePassThroughStream

​currentExperiment

​currentLogger

​currentSpan

​deepCopyEvent

​defaultErrorScoreHandler

​deserializePlainStringAsJSON

​devNullWritableStream

​Eval

​flush

​getContextManager

​getIdGenerator

​getPromptVersions

​getSpanParentObject

​init

​initDataset

​initExperiment

​initFunction

​initLogger

​invoke

​loadPrompt

​log

​logError

​login

​loginToState

​newId

​parseCachedHeader

​permalink

​promptDefinitionToPromptData

​renderMessage

​renderPromptParams

​Reporter

​reportFailures

​runEvaluator

​setFetch

​setMaskingFunction

​spanComponentsToObjectId

​startSpan

​summarize

​traceable

​traced

​updateSpan

​withCurrent

​withDataset

​withExperiment

​withLogger

​withParent

​wrapAISDK

​wrapAISDKModel

​wrapAnthropic

​wrapClaudeAgentSDK

​wrapMastraAgent

​wrapOpenAI

​wrapOpenAIv4

​wrapTraced

​Classes

​AISpanProcessor

​Attachment

​BaseAttachment

​BraintrustExporter

​BraintrustSpanProcessor

​BraintrustState

​BraintrustStream

​CodeFunction

​CodePrompt

​ContextManager

​Dataset

​EvalResultWithSummary

​Experiment

​ExternalAttachment

​FailedHTTPResponse

​IDGenerator

​JSONAttachment

​LazyValue

​Logger

Installation

Functions

BaseExperiment

BraintrustMiddleware

buildLocalSummary

createFinalValuePassThroughStream

currentExperiment

currentLogger

currentSpan

deepCopyEvent

defaultErrorScoreHandler

deserializePlainStringAsJSON

devNullWritableStream

Eval

flush

getContextManager

getIdGenerator

getPromptVersions

getSpanParentObject

init

initDataset

initExperiment

initFunction

initLogger

invoke

loadPrompt

log

logError

login

loginToState

newId

parseCachedHeader

permalink

promptDefinitionToPromptData

renderMessage

renderPromptParams

Reporter

reportFailures

runEvaluator

setFetch

setMaskingFunction

spanComponentsToObjectId

startSpan

summarize

traceable

traced

updateSpan

withCurrent

withDataset

withExperiment

withLogger

withParent

wrapAISDK

wrapAISDKModel

wrapAnthropic

wrapClaudeAgentSDK

wrapMastraAgent

wrapOpenAI

wrapOpenAIv4

wrapTraced

Classes

AISpanProcessor

Attachment

BaseAttachment

BraintrustExporter

BraintrustSpanProcessor

BraintrustState

BraintrustStream

CodeFunction

CodePrompt

ContextManager

Dataset

EvalResultWithSummary

Experiment

ExternalAttachment

FailedHTTPResponse

IDGenerator

JSONAttachment

LazyValue

Logger