FD1 Client Protocol

tusp.entry Schema

A tusp.entry represents a debug "span" or collection of trace data for a single function call. For example a flow span might be created by the function "Email_PDF_Receipt" detailing the operation flow and issues encountered.

Date StartDate End
FieldDescription
fpInternal Flowpoint. Essentially a number indicating an exact point in code
thThread Id
seq
ds
de
lines[] Array of trace lines for this entry, in order from first to last. Lines are generally an object. Each line is free to use field names as suitable for its purpose. Common fields are below
lines[].funcSource code function name
lines[].lnSource code line number

Example

A span from a totally normal internal web page download.

{
    "fp": 2100260103,
    "th": 35548,
    "seq": 8,
    "ds": "2026-01-16 12:47.51",
    "lines": [
        {
            "func": "long __cdecl GeneralMaint::DownloadRandomURL(class ....,class GnapLibClient &,class ... *,long,long)",
            "ln": 8209
        },
        {
            "inurl": "https://..redacted..",
            "callerflags": 1,
            "httpresult": 200,
            "recvlen": 97,
            "recvheaders": [
                "HTTP/1.1 200 OK",
                "Date: Thu, 15 Jan 2026 23:47:51 GMT",
                "Content-Type: application/json",
                "Content-Length: 97",
                "Connection: keep-alive",
                "Accept-Ranges: bytes",
                "access-control-allow-credentials: true",
                "access-control-allow-headers: *",
                "access-control-allow-origin: *",
                "access-control-max-age: 36002",
                "Cache-Control: public, max-age=7600, no-transform",
                "expires: Fri, 16 Jan 2026 01:54:30 GMT",
                "x-frame-options: SAMEORIGIN",
                "cf-cache-status: MISS",
                "last-modified: Thu, 15 Jan 2026 23:47:51 GMT",
                "Nel: {\"report_to\":\"cf-nel\",\"success_fraction\":0.0,\"max_age\":604800}",
                "Vary: accept-encoding",
                "Report-To: {\"group\":\"cf-nel\",\"max_age\":604800,\"endpoints\":[{\"url\":\"https://...redacted...\"}]}",
                "Server: cloudflare",
                "CF-RAY: ...redacted..."
            ]
        }
    ],
    "de": "2026-01-16 12:47.51"
}