[leoafarias]

The two generator graph suites repeatedly enumerate and read every visible dependency asset. Cache immutable dependency bytes once per test isolate and copy them into a fresh reader/writer for each case. Fixtures, generated output, resolvers and tracking keep their existing per-build lifecycle. The snapshot retains about 60 MB per participating isolate and assumes package files stay unchanged during that isolate; fresh invocations reload them.

All 112 original graph cases, including 93 strict rejection cases, keep their fixtures and diagnostic/output assertions. Five added cases check byte parity, buffer/fixture/output/tracking isolation, concurrent readers and valid/missing-JSON-part ordering. Both generation phases and the real clean/rebuild/cycle/JSON/compilation/runtime/second-build contracts remain intact.

Validation:

• Independent full review of the exact final diff: no findings. Both graph files mechanically match base with only imports and six setup replacements.
• Both controlled graph orders pass 112 cases with zero skips: 290.229s → 238.186s (17.9%) and 281.994s → 220.038s (22.0%). SDK, dependency/config hashes, commands, case names and per-file orders match. The contaminated initial run is excluded. Added-test cost is separate; no whole-CI saving is claimed.
• Full local generator: all 399 tests pass. Strict workspace analysis, root/remaining Dart/example tests, Flutter adapter and both Chrome selections pass (Ack 161; JSON Schema builder 3), retaining five existing platform/live-service skips. All 11 local check selections completed; the aggregate exits 1 only for the unchanged-base formatting discrepancy below.
• Dependency-source/package-mapping refresh probes pass. Pinned CI formatting and five preflight jobs pass. Local Dart 3.13 formatting flags five byte-identical base files; none belongs to this patch.

Blocked: Minimum Dart SDK and main CI fail compiling json_serializable 6.14.1 with source_helper 1.4.0 (duplicate extensions/imports). A Dart 3.9 control reproduces this exact failure on original base sources: 648 files verified, both new cache files absent. Main CI's 12 failing real-build cases are unchanged; all 112 graph and five new cases pass there. Upstream's 6.15.1 ambiguity fix requires Dart 3.12. A separate compatibility correction is needed; no dependency/release change or gate bypass is included.

Base: 07df51338f8fcdf0c06c0c9d0e16e81ddf65f494. Head: c573ac4ebe77a3b9c7fee845b934d9f6f27f0b59. Exact commands, logs, review, measurements and risks are retained in rollout ack-results/RESULTS.md. The draft remains blocked until required gates pass.