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Claude Code has a known memory leak where the mutableMessages array grows monotonically (~600+ MB/min). In a 4 GiB VM without swap, this exhausts guest RAM in ~60 seconds and the Linux OOM killer SIGKILLs the process — appearing as a mysterious sudden exit. Add NodeHeapPercent to the Agent domain type: when set, the sandbox computes NODE_OPTIONS=--max-old-space-size based on the effective VM memory. For claude-code this is 75%, giving a 3072 MiB heap cap in a 4 GiB VM that scales automatically if the user increases --memory. Also add DefaultEnv to Agent for static per-agent env vars, and NODE_OPTIONS to claude-code's EnvForward so users can override the default by exporting NODE_OPTIONS on the host. Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
JAORMX
approved these changes
Mar 17, 2026
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Add NodeHeapPercent to the Agent domain type: when set, the sandbox
computes NODE_OPTIONS=--max-old-space-size based on the effective VM
memory. For claude-code this is 75%, giving a 3072 MiB heap cap in a
4 GiB VM that scales automatically if the user increases --memory.
Also add DefaultEnv to Agent for static per-agent env vars, and
NODE_OPTIONS to claude-code's EnvForward so users can override the
default by exporting NODE_OPTIONS on the host.
Co-Authored-By: Claude Opus 4.6 (1M context) noreply@anthropic.com