Findings: live-API measurements across MiniMax M3/M2.7/M2.5, qwen and
deepseek, plus a survey of how nine unified gateways model per-model
parameter divergence. Key facts: reasoning_effort is MiniMax's real
switch, M2.x reasoning is mandatory and cannot be disabled, and the
relay's local token-count fallback silently drops reasoning_tokens.
Design: keep the parameter shape at provider level, push capability
down to model level, split "unknown" / "unsupported" / "no opinion"
into three distinct values, and fail at assembly time when a model
cannot honour enable_thinking=False.
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.
Records the human decision to test against the real gateway with real
data instead of building a mock gateway, six execution scenarios with
fault-source mixing, hard invariants scored from our own telemetry,
and the corpus inventory pulled from the lab server.
iomgaa