Streaming

An LLM emits a fence token by token, so every prefix of a fence is a real input the renderer will see.

While the message is still arriving, every block renders inert. A block that becomes clickable before its last option has streamed in is how someone answers a question they have not finished reading.

Hosts detect this however their pipeline allows — typically by checking whether the closing fence delimiter has arrived. parseAnvil(src, { partial: true }) marks the document so the renderer can show it as provisional.