Impact: image alt text is written by the poster and can contain line breaks. The .llm.md writes it unescaped into the Media References - Alt: row and into the bundle's  embed. A line break ends the embed, so Markdown viewers no longer render the image. A line in the alt text that starts with ## becomes a top-level section of the capsule, indistinguishable from SourceCapsule's own sections, for example a second ## Completeness.
A smaller defect in the same renderer: the quoted-post media list strips the trailing ] from bundle video lines and leaves [Video: ... source link preserved unclosed.
Where: sourcecapsule.user.js: llmMediaDescription (4656) passes alt text through markdownLineText (4302), which keeps \n despite its name. The Media References row comes from renderLlmMediaReference (4877). The quoted-post list (~4867) applies .replace(/^\[|\]$/g, ''), which strips only the closing bracket when the description starts with ![Poster of ...].
Evidence: Node repro with an image whose alt text contains a blank line followed by a ## heading line. The plain .llm.md gains two extra top-level sections, and the bundle embed spans seven lines. The bundle quoted-post list prints [Video: video-002 - full video not included in this bundle, poster frame media/video-002.poster.png, source link preserved with no closing bracket.
Environment: main 72777ef (v1.6.8). Engine loaded in Node through the module.exports guard. No browser.
Next action: collapse newlines to spaces for single-line Markdown contexts (alt text, link text, metadata rows) and escape [ and ] inside embed alt text. Strip the brackets only from the [Video: ...] tag itself, not from the joined description.
Impact: image alt text is written by the poster and can contain line breaks. The
.llm.mdwrites it unescaped into the Media References- Alt:row and into the bundle'sembed. A line break ends the embed, so Markdown viewers no longer render the image. A line in the alt text that starts with##becomes a top-level section of the capsule, indistinguishable from SourceCapsule's own sections, for example a second## Completeness.A smaller defect in the same renderer: the quoted-post media list strips the trailing
]from bundle video lines and leaves[Video: ... source link preservedunclosed.Where:
sourcecapsule.user.js:llmMediaDescription(4656) passes alt text throughmarkdownLineText(4302), which keeps\ndespite its name. The Media References row comes fromrenderLlmMediaReference(4877). The quoted-post list (~4867) applies.replace(/^\[|\]$/g, ''), which strips only the closing bracket when the description starts with![Poster of ...].Evidence: Node repro with an image whose alt text contains a blank line followed by a
##heading line. The plain.llm.mdgains two extra top-level sections, and the bundle embed spans seven lines. The bundle quoted-post list prints[Video: video-002 - full video not included in this bundle, poster frame media/video-002.poster.png, source link preservedwith no closing bracket.Environment: main 72777ef (v1.6.8). Engine loaded in Node through the
module.exportsguard. No browser.Next action: collapse newlines to spaces for single-line Markdown contexts (alt text, link text, metadata rows) and escape
[and]inside embed alt text. Strip the brackets only from the[Video: ...]tag itself, not from the joined description.