What probably matters to youSection of the release
What
On Linux, MCP server processes and up to 256 of their discovered child processes can be attached to a dedicated mcp control group so their memory is accounted separately from Claude Code's. Off unless the tengu_mcp_memory_cgroup flag is on (its fallback is false); CLAUDE_CODE_MCP_MEMORY_CGROUP forces it on, and a falsy value or none disables it.
Details
Processes spawned before the flag resolves are parked and attached once it does.
Reports a tengu_mcp_cgroup event with status enabled or disabled, plus mcp_memory_cgroup failure reasons.
Evidence
tengu_mcp_memory_cgroup
Strings lifted out of the shipped bundle, so the claim above can be checked against them.
The flag server returned off for the account this site reads and for the anonymous baseline. A reading of off cannot rule out a rollout these two readings sit outside of.
This account: off · anonymous baseline: off · compiled default in v2.1.239: off
Flag reading movedThe flag server now returns off for tengu_mcp_memory_cgroup, read as this account.A reading is one sample. Claude Code evaluates its flags remotely, so no client sees the targeting rule behind a value and this says nothing about your account.
Flag reading movedThe flag server now returns nothing at all, having stopped carrying it for tengu_mcp_memory_cgroup, read as this account.A reading is one sample. Claude Code evaluates its flags remotely, so no client sees the targeting rule behind a value and this says nothing about your account.
