> ## Documentation Index
> Fetch the complete documentation index at: https://opentrain.ai/docs/llms.txt
> Use this file to discover all available pages before exploring further.

# Preflight a Job Instruction Tree

> Validate and sign a complete desired page tree without changing live instructions.

Validates a complete desired root-and-subpage tree without writing. Requires
`instructions:write` and employer access.

Send the current `expectedTreeChecksum`, a stable `ref` for each desired page,
existing `pageId` and `expectedChecksum` values where applicable, each page's
`parentRef`, zero-based `position`, TipTap `content`,
`confirmTreeReplace: true`, and an `idempotencyKey`.

The response returns normalized pages, semantic findings, the exact archive
set, resulting tree checksum, plan digest, short-lived `preflightToken`, and
`atomicVisibility: true`. Review and preserve the returned archive set for
apply.