This is the blank agent chat, and it was not the transcript rewrite at all.
`hx-target` is inherited. The composer's form carries `hx-target="#thread"`
with `hx-swap="beforeend"`, which is what makes a sent message append a bubble.
The background-jobs chip I added last commit sits inside that form and declared
`hx-swap="outerHTML"` and nothing else -- which reads as "replace yourself" and
resolved, through the form, to "replace #thread with yourself". On load, and
then again every five seconds.
So an agent chat rendered its reply and then went blank, the reader's own prompt
along with it, because the entire transcript had been swapped out for a chip
that renders empty when no jobs are running. Only agent chats, because that is
the only place the chip exists. The server logged nothing, because nothing there
had gone wrong: every page render, every SSE frame and every stored row was
correct throughout, which is why four rounds of looking at the server found
nothing.
Both the chip and the element that loads it now carry `hx-target="this"`, and
`tests/test_chat.py` walks the composer's form and refuses anything that fetches
without saying where its answer goes. Checked against the bug before being kept.
Worth being precise about what made it invisible: the markup was correct. There
is nothing wrong with `hx-swap="outerHTML"` on an element with no target -- it
means "swap yourself" right up until an ancestor disagrees. It is the same
family as the trigger bound where the event does not go, and the same lesson:
assert the resolved property, not the attributes.
My earlier fix in ffe4966 was a real defect -- an sse-swap container must not
hold another -- but it was not this, and I should have said "best hypothesis"
rather than "found it" when I shipped it.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Jaroslav Beneš
51fa6be724