Divide a combined file, e.g. a scanned bundle of invoices or a merged PDF of statements, into typed segments with page ranges (split group), using a saved splitter or inline split classifications. Also the right FIRST step to locate one document or section inside a larger bundle — split, then parse/extract only the relevant segment instead of processing the whole file. Provide exactly one of splitter or config; inline config.splitClassifications needs a type: "other" entry. Each split includes startPage/endPage and, when Extend materializes child files, a fileId usable directly in other tools. Raw text input is not supported — splitting is page-based. Async: a status: "running" result with a runId is not an error — resume with get_split_run passing that runId, the same workspaceId and environment, and wait: true, repeating until the status is terminal; never re-submit the document. On UNAUTHORIZED or NOT_FOUND, re-call get_me for the granted targets. Output shape is documented at https://docs.extend.ai/splitting/response-format.md (get_documentation).