session/reportStartupPhases

Experimental

Reports the client’s measured startup spans once per launch; the host appends the durable phases record as single writer (ADR 50064 pick-1 D1).

Parameters

Type: SessionReportStartupPhasesParams

session/reportStartupPhases params (ADR 50064 pick-1 D1): the served session, the client-minted launch nonce (one UUID per process launch, any textual UUID form), and the finished spans. No commandId: the nonce is the idempotency key and the call is best-effort. Experimental: the stable bundle strips this until the surface stabilizes (in-v1 row 348).

Field	Type	Stability	Presence	Description
launchNonce	string	Experimental	required	The launch nonce (any UUID: hyphenated any-case or 32-hex simple).
phases	SessionReportStartupPhaseSpan[]	Experimental	required	The finished startup spans.
sessionId	string	Experimental	required	The target session.

Source

schema/msp/experimental/msp.schema.json#/methods/session~2FreportStartupPhases

{
  "description": "Reports the client's measured startup spans once per launch; the host appends the durable phases record as single writer (ADR 50064 pick-1 D1).",
  "params": {
    "$ref": "#/$defs/SessionReportStartupPhasesParams"
  },
  "result": {
    "$ref": "#/$defs/SessionReportStartupPhasesResult"
  },
  "x-msp-descriptor": "session/reportStartupPhases",
  "x-msp-stability": "experimental"
}