When each applies

Each companion format is a slice of a document, separated for a job the whole document is too heavy for.

In short: Companion formats show up in distinct workflows: snippets when someone reuses a piece of a layout, libraries when that reuse becomes a habit, story-only / InCopy files when writing and layout are separate jobs, and assignment files when that editorial split scales to a team. In every case the file is a slice of what a full document holds, with the design map — the thing that makes parts into a document — stripped away. This page explains when you actually meet each format, how it relates back to the package you can open, and, honestly, what it would take for Paged to read it.

The previous page said what each companion format is. This page says when you actually meet one, how it relates back to the package you can open, and — honestly — what it would take for Paged to read it.

Not yet parsedall four formats below

When a workflow reaches for each

Each format answers a different need that a whole-document export does not.

• Snippets appear when someone wants to reuse a piece of a layout: drag a group of page items out as a .idms file, then drop it into another document later. The snippet travels with the styles and colors its items need, so it can re-create their formatting wherever it lands.

• Libraries appear when that reuse becomes a habit: a designer keeps a collection of ready-made items — a masthead, a pull-quote treatment, a logo lockup — and pulls from it across many documents. Because each library item is itself a snippet, the library is really a curated shelf of fragments.

• Story-only / InCopy files appear in editorial workflows where writing and layout are separate jobs. The layout lives in the InDesign document; an .icml carries one story's text out to an editor and back, so copy can be edited without touching — or even opening — the page it belongs to.

• Assignment files appear when that editorial split scales to a team: an .icma groups stories into a unit of work and tracks who has which, so several editors can work in parallel against one layout without colliding.

How they relate to the full package

Read against the package, the pattern is consistent: each companion format is a slice of what a document holds, separated for a job the whole document is too heavy for.

A package's design map ties everything together — it names the parts and enumerates the document's stories through StoryList, and the items live on spreads with their text in stories. The companion formats each carve out one layer of that whole:

• a snippet is page items lifted off their spread, carrying just enough style context to stand up again elsewhere;
• a story-only file is one entry of StoryList on its own, text with the spread and design map stripped away;
• an assignment is a list about stories rather than the stories themselves.

In every case the design map — the thing that makes a collection of parts into a document — is exactly what is missing. That is the same gap described in the package anatomy: without a root manifest there is no document to assemble.

What supporting them would require

Paged opens a ZIP archive, confirms the IDML-package mimetype, and reads designmap.xml as the root. A standalone companion file clears none of those steps, so support is not a matter of adding a few element handlers — it would mean a second way in alongside the package reader.

What that second path would have to provide differs by format:

• For snippets and library items, a renderer needs the host context a snippet assumes: a document to place the fragment into, and the name-reconciliation rules that decide whether an incoming Color or style defers to one already present. Rendered alone, a fragment has no page to sit on and no authority for its unresolved names.

• For story-only / InCopy files, a renderer needs the frame and geometry the text was separated from. A story with no frame has no measure to flow into and no place on a page; supporting .icml means manufacturing or supplying that missing scaffolding.

• For assignment files, there is no rendering question at all — they are workflow metadata that reference stories rather than carrying renderable content. Reading one would serve tooling, not the renderer.

Until such a path exists, the status across this chapter stays the same, and it is recorded honestly on every page: not yet parsed. The single document remains Paged's unit of work — see the package anatomy for the format Paged does read end to end.

Frequently asked questions

When would I use an InDesign Snippet instead of a full IDML export? You reach for a snippet when you want to reuse a piece of a layout rather than a whole document — dragging a group of page items out as a .idms file and dropping it into another document later. The snippet travels with the styles and colors its items need, so it can re-create their formatting wherever it lands; a library is the same idea turned into a habit, a curated shelf of those fragments.

Why do editorial teams use .icml and .icma files? Story-only .icml files appear when writing and layout are separate jobs: the layout stays in the InDesign document while an .icml carries one story's text out to an editor and back, so copy can be edited without touching the page it belongs to. Assignment .icma files appear when that split scales to a team — they group stories into a unit of work and track who has which, so several editors can work in parallel against one layout without colliding.

What would it take for Paged to support these formats? Because Paged's only entry point opens a ZIP archive, confirms the IDML-package mimetype, and reads designmap.xml as the root, supporting a standalone companion file would mean a second way in alongside the package reader — not just a few extra element handlers. Snippets and library items would need a host document to be placed into and the name-reconciliation rules that go with it; .icml files would need the frame and geometry their text was separated from; and .icma files raise no rendering question at all, since they are workflow metadata that reference stories rather than carrying renderable content.