vm-global-get checked vm.globals before closure-env, while vm-global-set
wrote to closure-env first. This asymmetry meant set! mutations to mutable
closure variables (e.g. parser position counters) were invisible to sibling
closures reading via JIT — they saw stale snapshots in the globals table.
Reversed vm-global-get lookup order: closure env → globals → primitives,
matching vm-global-set. Also enabled JIT in the MCP harness (compiler.sx
loading, env_bind hook for live globals sync, jit_try_call hook) so
sx_harness_eval exercises the same code path as the server.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
giles
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