Stream B.1 — registry invariant:
- DriverTypeMetadata gains a required `DriverTier Tier` field. Every registered
driver type must declare its stability tier so the downstream MemoryTracking,
MemoryRecycle, and resilience-policy layers can resolve the right defaults.
Stamped-at-registration-time enforcement makes the "every driver type has a
non-null Tier" compliance check structurally impossible to fail.
- DriverTypeRegistry API unchanged; one new property on the record.
Stream B.2 — MemoryTracking (Core.Stability):
- Tier-agnostic tracker per decision #146: captures baseline as the median of
samples collected during a post-init warmup window (default 5 min), then
classifies each subsequent sample with the hybrid formula
`soft = max(multiplier × baseline, baseline + floor)`, `hard = 2 × soft`.
- Per-tier constants wired: Tier A mult=3 floor=50 MB, Tier B mult=3 floor=100 MB,
Tier C mult=2 floor=500 MB.
- Never kills. Hard-breach action returns HardBreach; the supervisor that acts
on that signal (MemoryRecycle) is Tier C only per decisions #74, #145 and
lands in the next B.3 commit on this branch.
- Two phases: WarmingUp (samples collected, Warming returned) and Steady
(baseline captured, soft/hard checks active). Transition is automatic when
the warmup window elapses.
Tests (15 new, all pass):
- Warming phase returns Warming until the window elapses.
- Window-elapsed captures median baseline + transitions to Steady.
- Per-tier constants match decision #146 table exactly.
- Soft threshold uses max() — small baseline → floor wins; large baseline →
multiplier wins.
- Hard = 2 × soft.
- Sample below soft = None; at soft = SoftBreach; at/above hard = HardBreach.
- DriverTypeRegistry: theory asserts Tier round-trips for A/B/C.
Full solution dotnet test: 963 passing (baseline 906, +57 net for Phase 6.1
Stream A + Stream B.1/B.2). Pre-existing Client.CLI Subscribe flake unchanged.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Joseph Doherty
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