The bug: Line 2 of dsv4_fp4_b200_vllm.sh was changed from set -euo pipefail to set -eo pipefail, silently dropping the nounset (-u) flag. Every other script in benchmarks/single_node/agentic/ — including the near-identical dsv4_fp4_b300_vllm.sh, plus dsv4_fp4_mi355x_vllm.sh, dsv4_fp4_b200_sglang.sh, dsv4_fp8_h200.sh, and all the kimik2.5_*/qwen3.5_*/minimaxm3_* variants — still uses set -euo pipefail. This script is now the sole outlier in the directory.\n\nWhy it happened: The diff rewrote several previously-guarded optional-variable references into bare, unguarded forms: DCP_SIZE=${DCP_SIZE:-1} became an if [ -z "$DCP_SIZE" ]; then DCP_SIZE=1; fi block (which still reads the bare $DCP_SIZE first), ${SLURM_JOB_ID:-}/${SLURMD_NODENAME:-unknown} became bare $SLURM_JOB_ID/$SLURMD_NODENAME, ${MODEL_PATH:-} became bare $MODEL_PATH, and the new case "$KV_OFFLOAD_BACKEND" in "") branch reads $KV_OFFLOAD_BACKEND unguarded (note it isn't even part of check_env_vars, so it can legitimately be unset). None of these would survive set -u if the variable is genuinely unset, so -u had to be dropped to make the rewritten code work as written.\n\nWhy this is avoidable: The sibling dsv4_fp4_b300_vllm.sh proves -u and this exact optional-variable pattern coexist fine: it keeps set -euo pipefail while using DCP_SIZE="${DCP_SIZE:-1}", declare -p SLURM_JOB_ID >/dev/null 2>&1 && [ -n "$SLURM_JOB_ID" ], and similar guards for MODEL_PATH. The new case statement here could equally have matched on "${KV_OFFLOAD_BACKEND:-}" instead of the bare variable. So dropping -u wasn't required by the case-statement refactor — it was a side effect of un-guarding several other references at the same time.\n\nImpact: With -u disabled, a future typo in a variable name anywhere in this script (e.g. RESULT_DIR misspelled as RESUT_DIR) will silently expand to an empty string and continue executing rather than aborting immediately with an "unbound variable" error — exactly the failure mode -u exists to catch. As written today the script runs correctly (all currently-referenced optional vars are handled, and required vars are separately validated by check_env_vars), so there's no concrete runtime failure right now. This is a latent robustness/consistency regression rather than an active bug.\n\nProof by example: Suppose a future edit adds echo "Writing to $RESUT_DIR" (a typo of $RESULT_DIR) somewhere in this script. With set -eo pipefail (current state), $RESUT_DIR expands to "", the echo prints "Writing to ", and the script continues — the typo goes unnoticed until output is inspected downstream. With set -euo pipefail (every sibling script's setting), the same line would immediately abort with RESUT_DIR: unbound variable, catching the bug at the point of introduction. This is precisely why the convention exists across all 23 other scripts in the directory.\n\nFix: Restore set -euo pipefail on line 2 and guard the newly-unguarded references the same way dsv4_fp4_b300_vllm.sh does: DCP_SIZE="${DCP_SIZE:-1}"/PCP_SIZE="${PCP_SIZE:-1}", [[ -n "${SLURM_JOB_ID:-}" ]] / ${SLURMD_NODENAME:-unknown}, [[ -n "${MODEL_PATH:-}" ]], and case "${KV_OFFLOAD_BACKEND:-}" in.