Round two of the from_env-only validation problem. Fifteen checks still lived
in the env parsing functions: six enum domains, the redis_url requirement for
redis-backed limiter/breaker/cache, cache namespace and TTL, telemetry path and
DSN, non-negative structured retries and non-blank scope. from_settings and
direct construction bypassed all of them.
The five asserts in client.py that claimed config had already validated
redis_url and the telemetry targets now hold on every path, so they revert to
what CLAUDE.md permits: internal invariant declarations that also narrow the
Optional for type checkers. Their comments now name the method that guarantees
them, since the previous wording is exactly what went stale.
Postgres DSNs built by hand now get the SQLAlchemy +driver suffix stripped the
way from_env has always stripped it, with a warning so the rewrite is not
silent. The env path strips earlier, so it stays quiet.
AIMD ceiling now respects per-source max_concurrency and the pacer is
assembled explicitly in the client; MIN_CALLS parses as strict int;
acceptance doc corrects source-5 attempt count to 549; design and
migration notes aligned with implemented 429/stall/suppression
semantics and AIMD constants documented.
Score is success-rate EWMA over (1 + inflight) with a 0.05 exploration
floor so quarantined sources can prove recovery; EWMA climb doubles as
slow-start. New optional OutcomeAwareSelector port feeds attempt
outcomes.
Classify empty completions as transient per human ruling (fixes flaky
real-gateway smoke and prevents caching empty responses), rename the
factory injection parameter gate to breaker per the frozen design,
rewrite the probe-entry cleanup without except BaseException, declare
python-dotenv explicitly, add a mid-backoff cancellation test, and
record all implementation errata in the design and architecture docs.
Includes config aggregation for multi-source env keys, from_env and
from_settings factories with explicit shared-backend injection,
gather_bounded, top-level exports, tightened import-linter layers with
the gate removed from the Makefile, and the finalized .env.example.