The static projection

A static projection is what a capability prints where its escape sequence would not be understood. Every capability has one — fallback is required, and a capability without it is refused at registration — and emit returns it whenever support is absent or unknown.

Why unknown means noCopy Anchor Link

No terminal answers "do you do OSC 1337", and most OSC sequences cannot be asked about at all. A package that emits the bytes and hopes is what puts ]1337;File=inline=1;… across the screen of anyone who piped the output to a file, or into the transcript an agent reads back. So the safe default is the projection, and a capability says, as data, which terminals it believes understand it (Detecting support).

import { emit } from 'paratext';

const pipe = { env: {}, isTTY: { stdout: false } };

console.log(JSON.stringify(emit(pipe, 'link', { text: 'Docs', url: 'https://x.dev' })));
console.log(JSON.stringify(emit(pipe, 'link', { text: 'Docs' })));
console.log(JSON.stringify(emit(pipe, 'notify', { title: 'Done' })));
console.log(JSON.stringify(emit(pipe, 'notify', { title: 'Done', body: '3 files' })));
console.log(JSON.stringify(emit(pipe, 'image', { base64: 'iVBORw0KGgo=', caption: '[logo]' })));
console.log(JSON.stringify(emit(pipe, 'clipboard', { text: 'copied' })));
console.log(JSON.stringify(emit(pipe, 'not-registered', { text: 'plain text' })));

"Docs (https://x.dev)"
"Docs"
"Done"
"Done: 3 files"
"[logo]"
""
"plain text"

• A link keeps its address. text (url), not bare text: a link whose destination vanishes in a pipe has lost the half that mattered. With no URL it is just the text.
• Chrome projects to nothing. The window title, the clipboard, the working directory and the bell are about the terminal, not the content, so a log gets nothing rather than noise.
• A name nobody registered prints the caller's text rather than throwing.

TemplatesCopy Anchor Link

encode and fallback are strings, not functions, so a capability can travel as JSON. They are written in a three-rule language:

The third rule is what lets notify be {title}[: {body}] and print Done or Done: 3 files without a branch. An empty string counts as absent, because Done: with nothing after it is worse than Done. render(template, fields) and fieldsUsed(template) are exported for a caller writing its own.

Where the projection is not usedCopy Anchor Link

The CSI half of the ansi-escapes surface — cursor movement, erasing, scroll regions — does not degrade, because a cursor move silently dropped would corrupt the screen of a program that relied on it, and ansi-escapes' own does not degrade either. The two drop-ins that keep their incumbent's behaviour, paratext/terminal-link and paratext/term-img, project where their incumbents do (Links and images).