A seed of -1 means random, as it does everywhere else

Omitting the seed was already random. Passing -1 was not: it went through the
uint64 wrap and arrived as 18446744073709551615, which is a perfectly valid
*fixed* seed -- so "give me something new" returned the identical picture every
time, silently, and the retry loop would have redrawn the same rejected image
until it ran out of attempts.

-1 is what ComfyUI's own interface uses for random, and A1111, and everything
else that has ever asked somebody for a seed. A model that has read any of them
will write it, so the one reading that had to work was the one that did not.

Any negative value, not only -1, because the sentinel is the *idea* rather than
the number and a model that writes -2 means the same thing. Zero stays a real
seed: it is the boundary this change could easily have swallowed, and it is one
somebody deliberately picks.

Confirmed against the real ComfyUI: -1 now sends a random uint64 that it accepts
and draws from.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

CLAUDE.md

@@ -1957,7 +1957,12 @@ what makes `"{{prompt}}, masterpiece"` work. Doing it textually would also mean
 a prompt containing a quotation mark produced a document that no longer parses,
 on the one input guaranteed to hold arbitrary text. `seed` has no fixed default
 — one would make every unspecified generation identical and make the retry loop
-redraw the same rejected picture four times.
+redraw the same rejected picture four times. **A negative seed means random**,
+because `-1` is what ComfyUI's own interface, A1111 and everything else that has
+ever asked for a seed use for it, so a model that has read any of them writes
+it: without that it went through the uint64 wrap and arrived as
+18446744073709551615, a perfectly valid *fixed* seed, so "give me something new"
+returned the same picture every time.
 
 **One call is one finished image, and the retrying is inside the tool.**
 Returning every attempt to the conversation would cost a round each, make the