Independent verification found the first cut had swapped one bug for a
worse one. The budgets were split by "did we send a request", so a 429
attempt counted as productive — but 429 is exempt from the retry budget,
so its time burned neither budget. Against a queueing gateway that holds
the request for the full timeout before answering 429, a call could hang
for 301 attempts / 25.2 hours, measured, versus 301 seconds before the
change.
The split is now by which budget the time consumes: time that burns
max_attempts is excluded from stall, time that does not (429 attempts
included) belongs to stall. Measured again: back to one attempt / 301s.
Only the chat loop needs this — embedding and ocr count 429 against
max_attempts unconditionally, so the gap never existed there. The stall
verdict moved into _stalled(), which both call sites had duplicated, to
keep __call__ under the complexity gate.
Six tasks: StallClock plus the chat loop, then embedding, ocr, the config
comments, the full-suite regression with doc sync, and independent
verification. Codex review raised four points, all confirmed and folded in:
a stale line reference in the fidelity section, explicit cancellation
acceptance for T2/T3 (the new attempting() wrapper now wraps their existing
cancel paths), a telemetry-boundary test pinning the design's claim that
telemetry jitter must not feed the stall verdict, and concrete test
construction for the embedding/ocr regressions.
Two internal-consistency fixes from the independent design review:
the 429 saturation argument wrongly claimed exponential backoff growth
(429 skips the retry budget, so max(fails, 1) pins the delay to the base
tier), and "productive" was defined as waiting on the response while the
StallClock actually wraps all of _attempt. The boundary is now stated as
_attempt itself, including per-attempt accounting and telemetry, with the
rationale that telemetry jitter must not participate in the stall verdict.
Issue #8: a single request that burns its full timeout_s also exhausts
stall_window_s, so the retry budget silently never applies. Root cause is
that both budgets charge the same wall-clock time. The design makes the two
budgets orthogonal — real attempts bill the retry budget, everything else
bills the stall budget — which drops the timeout_s / stall_window_s coupling
instead of guarding it with an assembly-time check.
iomgaa