Transmission-Engineering as Compositional Practice: The Checksum Framework and its Handler Typology is a theoretical framework — proposed formal name for a compositional practice inadequately captured by existing categories of reception theory, textual criticism, poetics, intertextuality, allusion theory, and media archaeology. names a functional property of transmissions of sufficient compositional density: they behave as if engineered against arbitrary handler-orientations, with integrity checks inscribed in the compositional structure that reveal themselves to equipped downstream readers. four handler orientations (erasing with active/passive distinction, preserving, generating, solving), each with characteristic signature. four structural features distinguish composed checksums from ordinary compositional density (grammatical necessity, signature legibility, constraint durability, recovery inscription). chained checksums across compositional gestures produce cross-temporal recovery. sappho-catullus-cranes chain as demonstration case (ea-erratum-sappho31-eeeee, deposit #1052). companion to stanza-04 (#1051, axn:0427) and eeeee (#1052, axn:0428). framework is proposed formalization, not established discipline; independent verification requires application to additional cases whose analyses were not constructed to fit the framework. in the Crimson Hexagonal Archive, by Lee Sharks (2026-07-08). This deposit proposes a formal name for a compositional practice inadequately captured by existing categories of reception theory, textual criticism, poetics, intertextuality, allusion theory, and media archaeology. The practice treats composed texts as engineered transmission mechanisms whose survival across handlers of unknown orientation is understood functionally: structural integrity checks inscribed within the composition itself elicit signatures from every handler who receives it, and the composition's recoverability depends on the eventual arrival of a downstream reader equipped to run the checks. The practice is nameable in the language of engineering: fault-tolerant transmission with layered integrity checks and cross-temporal recovery instructions. Whether specific composers throughout the Western literary tradition have engineered their compositions with this awareness, or whether the engineering emerges as a functional property of high compositional density in traditions that developed under transmission pressure, is a question the framework does not adjudicate. What the framework names is a functional property: compositions of sufficient density behave as if they had been engineered against arbitrary handler-orientations. The functional property is what makes them recoverable across arbitrary intervening handling. — Article composed 2026-08-05 from the work's own prose so that every record carries an encyclopedic entry; a fuller editorial treatment belongs to the description/wiki review stream.