# Check connectivity to an SVD endpoint

The Engine relays the check to the Video Intelligence Service, which owns the gRPC client: the channel is opened the way the analyzer would open it (plaintext, TLS or mutual TLS), then one detection call with an empty body tells whether a Synthetic Video Detector service answered and took the credentials. Unreachable and rejected are results, not errors; the response is a 200 either way. A 502 means the Video Intelligence Service itself did not answer.

Endpoint: POST /probes/svd-endpoint
Version: 2.0.0
Security: engineBasic

## Request fields (application/json):

  - `address` (string,null)
    gRPC host:port; absent or null uses the reference's effective address, and then its stored credentials unless explicit ones are given. When present, the reference's stored credentials are not used.

  - `tls` (object,null)
    Null auto-detects (TLS on port 443 or when material is set).

  - `tls.enabled` (boolean,null)
    Force TLS on or off; null auto-detects from the port and configured material.

  - `tls.ca_cert` (string,null)
    Path to the CA certificate on the VIS host, not the certificate itself (e.g. /certs/ca-cert.pem). Needed when the endpoint presents a private-CA certificate.

  - `tls.client_cert` (string,null)
    Path to the client certificate on the VIS host, for mutual TLS. Set it together with client_key; one without the other does not authenticate.

  - `tls.client_key` (string,null)
    Never echoed by a read. On a write: absent or null keeps the stored value, an empty string clears it.

  - `tls.client_key_secret` (string,null)
    Names a configured secret to use as the client key, resolved when the endpoint is used, so a rotation applies without a config write. Echoed by reads — a name is not a secret. Mutually exclusive with client_key in one write (400); setting either form clears the other stored one.

  - `api_key` (string,null)

  - `function_id` (string,null)

  - `stream_group_config` (string,null)
    A stored stream group config by name, whose effective SVD endpoint is the probe target: a synthetic config's endpoint.

  - `application` (string,null)

  - `stream` (string,null)

  - `stage` (string,null)
    A stage of the chain config stream_group_config names, by name: the probe targets that stage's stored address and credentials, each member it leaves blank inherited from the default config's synthetic baseline. Valid only for a chain config's synthetic stage; detector_type, when given, must match the stage's type. Anything else is a 422 whose detail starts with the offending field.

## Response 200 fields (application/json):

  - `reachable` (boolean, required)
    A gRPC server answered at the address over the chosen transport.

  - `accepted` (boolean, required)
    A Synthetic Video Detector service answered and took the credentials.

  - `code` (string,null)
    The gRPC status the probe call ended with; null when no channel came up.

  - `error` (string,null)
    Why the probe fell short; null when the endpoint accepted it.

## Response default fields (application/problem+json):

  - `type` (string)
    URI identifying the problem type.

  - `title` (string, required)
    Short, human-readable summary of the problem type.

  - `status` (integer, required)
    The HTTP status code, repeated from the response line.

  - `detail` (string)
    Human-readable explanation specific to this occurrence.

  - `instance` (string)
    URI identifying this specific occurrence of the problem.

  - `cause` (string)
    Why a VOD resume was refused, on a resume's 409 only: credentials_required — resume again with the detector and its credentials in the body; config_mismatch — the body asks for a configuration the job cannot take, so correct the request; config_drift — the source file or the config the job ran with has changed since, so the job cannot be resumed and must be submitted afresh.
    Enum: "credentials_required", "config_mismatch", "config_drift"