The compat cells drove the CLI with a fresh HOME per invocation and the
pytest process's own working directory, and both reach the request body.
The system prompt names a memory directory built from
$CLAUDE_CONFIG_DIR/projects/<cwd slug>, so a per-invocation config
directory rewrote every body, and the CLI adds a git block for its
working directory, so inheriting the checkout rewrote every body once
per candidate. The device id churned for the same reason: the CLI mints
it once and persists it in .claude.json, which we threw away each call.
Nothing here was load-bearing. All three ride in metadata.user_id, whose
job is abuse detection, not quota, caching or continuity. So pin the
config directory and the working directory at fixed paths, seed the
device id, and pin the session id.
HOME stays fresh and empty per invocation, so the isolation is no weaker
than before, and the CLI's own state no longer outlives the pod either.
The working directory is deliberately not the checkout, so a
model-directed Read now sees an empty directory rather than the
repository.
A pinned session id needs --no-session-persistence beside it: the CLI
refuses a session id another live process holds, and the matrix runs its
cells across xdist workers. Without the flag, six of eight concurrent
invocations die on "Session ID is already in use".
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