switch (att.type) {
case MessageAttachmentKind.Resource: {
// already a string). For file URIs we inline the
// absolute path as a `@<path>` mention so the codex
// prompt template can render / read it.
const uri = URI.parse(att.uri);
if (uri.scheme === 'file') {
textChunks.push(`@${uri.fsPath}`);
} else {
// Non-file URIs (vscode-userdata://, untitled://, …)
// are surfaced as a plain string so they still show