Environment variables

The WeHarness SDKs

Both SDKs read the same variables. A value passed to init() wins over the variable.

Variable	What it is	Default
WEHARNESS_INGEST_KEY	The ingest key (whk_…). Required unless you pass key.	—
OTEL_SERVICE_NAME	The service name, when service is not passed	unknown_service
WEHARNESS_OTLP_ENDPOINT	Where spans are sent	https://api.weharness.io/otlp/v1/traces
WEHARNESS_REVISION	The commit your application runs	See below

The code version

When revision is not passed, the SDKs take the first of these that is set:

1. WEHARNESS_REVISION
2. GITHUB_SHA (GitHub Actions)
3. CI_COMMIT_SHA (GitLab CI)
4. VERCEL_GIT_COMMIT_SHA (Vercel)
5. RENDER_GIT_COMMIT (Render)
6. SOURCE_VERSION (Heroku and others)
7. GIT_COMMIT (Jenkins and others)

It becomes the resource attribute vcs.ref.head.revision. Without any of them, the code version is unknown.

Plain OpenTelemetry

Variable	Value
OTEL_EXPORTER_OTLP_TRACES_ENDPOINT	https://api.weharness.io/otlp/v1/traces
OTEL_EXPORTER_OTLP_TRACES_HEADERS	Authorization=Bearer%20whk_… (the space is written %20)
OTEL_SERVICE_NAME	Your service’s name
OTEL_RESOURCE_ATTRIBUTES	Optional, for example vcs.ref.head.revision=<commit sha>,service.version=1.4.0

Inside a WeHarness sandbox

When WeHarness runs your code in a session’s sandbox, an evaluation run or a preview, it sets variables for it:

Variable	Set for	What it is
WEHARNESS_EVAL_INPUT	Evaluation runs	The path of the file holding the case’s input. See Evaluations.
The OTLP endpoint and a key	Evaluation runs	Your agent’s traces from the case go to a key that exists only for the run, so tool and error checks can read them
Model provider variables	Every sandbox	The variables the providers’ official SDKs read, pointing at models.weharness.io with a token that works only for that sandbox. See Cloud work.

The sandbox never receives a WeHarness key or your own model key.