diff --git a/benchmarks/single_node/agentic/dsv41flash_fp4_b300_sglang_mtp.sh b/benchmarks/single_node/agentic/dsv41flash_fp4_b300_sglang_mtp.sh
new file mode 100644
index 0000000000..dfb7056385
--- /dev/null
+++ b/benchmarks/single_node/agentic/dsv41flash_fp4_b300_sglang_mtp.sh
@@ -0,0 +1,174 @@
+#!/usr/bin/env bash
+set -eo pipefail
+
+# DeepSeek-V4.1-Flash AgentX on B300 with SGLang, supporting STP and DSpark.
+# The KV cache is GPU-resident; caller SPEC_DECODING selects the serving mode.
+# https://lmsysorg.mintlify.app/cookbook/autoregressive/DeepSeek/DeepSeek-V4_1
+source "$(dirname "$0")/../../benchmark_lib.sh"
+check_env_vars MODEL TP EP_SIZE CONC KV_OFFLOADING TOTAL_CPU_DRAM_GB RESULT_DIR DURATION
+check_env_vars EVAL_ONLY SPEC_DECODING
+require_agentic_kv_offload_none
+export GPU_COUNT="$TP"
+
+if [[ -n "${SLURM_JOB_ID:-}" ]]; then
+    echo "JOB $SLURM_JOB_ID running on ${SLURMD_NODENAME:-unknown}"
+fi
+
+# Complete/resume partial downloads instead of trusting nonempty directories.
+if [[ -n "${MODEL_PATH:-}" && "$MODEL_PATH" != "$MODEL" ]]; then
+    hf download "$MODEL" --local-dir "$MODEL_PATH"
+else
+    hf download "$MODEL"
+    MODEL_PATH=$(python3 -c 'from huggingface_hub import snapshot_download; import sys; print(snapshot_download(repo_id=sys.argv[1], local_files_only=True))' "$MODEL")
+    export MODEL_PATH
+fi
+
+nvidia-smi
+resolve_trace_source
+install_agentic_deps
+mkdir -p "$RESULT_DIR"
+SERVER_LOG="$RESULT_DIR/server.log"
+export PYTHONNOUSERSITE=1
+export PYTHONUNBUFFERED=1
+
+# Use the default DSpark precision shipped by the pinned SGLang nightly.
+
+# Agentic warmup dispatches hundreds of large prompts at once and SGLang's
+# tokenizer can leave bytes unacknowledged past AIPerf's default 30 s
+# TCP_USER_TIMEOUT, so Linux aborts live localhost connections.
+export AIPERF_HTTP_TCP_USER_TIMEOUT=900000
+# Outlast AIPerf's pooled connections so an inter-turn idle gap cannot race
+# Uvicorn's five-second keep-alive closure.
+export SGLANG_TIMEOUT_KEEP_ALIVE=900
+
+# AgentX measures the thinking-on regime, which is also the committed golden-AL
+# curve. SGLang ships thinking off by default for this model.
+export SGLANG_DEFAULT_THINKING=1
+export SGLANG_DSV41_REASONING_EFFORT=high
+
+# Keep Engram tables in host RAM to make room for long-context AgentX KV.
+# Per-rank anonymous mappings can use THP without requiring shared-memory THP
+# or host sysctl changes. The table payload remains native FP8.
+export SGLANG_ENABLE_DSV41_ENGRAM_HOST_TABLE=1
+export SGLANG_DSV41_ENGRAM_HOST_TABLE_LAYOUT=per_rank
+
+# AgentX concurrency counts live session trees, not individual requests.
+# Allow subagent fan-out to exceed CONC without clipping request bursts, but
+# never let the pool exceed the decode graph batch: a DSpark verify step for a
+# batch above the captured 64 runs eagerly and allocates its attention
+# workspace on the fly, which OOMed the H200 eval at 128 running requests
+# (6.4 GiB allocation with 2 GiB free, run 35306704553). Batches within the
+# graph tier reuse the capture-time workspace instead.
+CUDA_GRAPH_MAX_BS=64
+MAX_RUNNING_REQUESTS=$((2 * CONC))
+if (( MAX_RUNNING_REQUESTS > CUDA_GRAPH_MAX_BS )); then
+    MAX_RUNNING_REQUESTS=$CUDA_GRAPH_MAX_BS
+fi
+
+# AgentX reuses long prefixes across turns even at low session concurrency.
+# At memory fraction 0.70, TP4 has 110.55 GiB of KV budget but TP2 has only
+# 38.83 GiB. Give TP2's larger working sets more KV space before retaining
+# additional SWA tails; keep the conservative low-concurrency allocation.
+MEM_FRACTION_STATIC=0.70
+if (( TP == 2 && CONC >= 32 )); then
+    # At C64, 0.80 left 43.59 GiB after graphs but only 18.29M full tokens.
+    # Retain more long prefixes while leaving room for transient prefills.
+    MEM_FRACTION_STATIC=0.85
+elif (( TP == 2 && CONC >= 16 )); then
+    MEM_FRACTION_STATIC=0.80
+fi
+SWA_PREFIX_TAILS=$((64 * CONC))
+if (( SWA_PREFIX_TAILS > 4096 )); then
+    SWA_PREFIX_TAILS=4096
+fi
+if (( SWA_PREFIX_TAILS < 128 )); then
+    SWA_PREFIX_TAILS=128
+fi
+
+# Saturation arms carry a larger in-flight working set than the 30-minute
+# default warmup drain allows.
+if (( CONC >= 32 )); then
+    export AGENTIC_WARMUP_GRACE_PERIOD=3600
+fi
+
+# Pyxis shares the host network; port 8888 can already belong to a host service.
+select_available_server_port
+export AIPERF_SERVER_URL="http://localhost:${PORT}"
+export AIPERF_SERVER_METRICS_URLS="${AIPERF_SERVER_URL}/metrics"
+export AIPERF_REQUIRED_SERVER_METRIC_PREFIX="sglang:"
+echo "Using SGLang endpoint ${AIPERF_SERVER_URL}"
+
+# STP and accuracy evaluations must never inherit synthetic acceptance.
+unset SGLANG_SIMULATE_ACC_LEN SGLANG_SIMULATE_ACC_METHOD SGLANG_SIMULATE_ACC_TOKEN_MODE
+SPECULATIVE_ARGS=()
+case "$SPEC_DECODING" in
+    none)
+        echo "Non-speculative decoding; synthetic acceptance disabled"
+        ;;
+    mtp)
+        # Existing measured curve: dsv41flash_dspark.yaml, thinking_on, K5.
+        SPECULATIVE_ARGS=(--speculative-algorithm DSPARK --speculative-dspark-block-size 5)
+        if [[ "$EVAL_ONLY" != true ]]; then
+            export SGLANG_SIMULATE_ACC_LEN=3.51
+            export SGLANG_SIMULATE_ACC_METHOD=match-expected
+            export SGLANG_SIMULATE_ACC_TOKEN_MODE=real-draft-token
+        fi
+        ;;
+    *)
+        echo "Unsupported SPEC_DECODING: $SPEC_DECODING" >&2
+        exit 1
+        ;;
+esac
+
+# At high TP2 concurrency, test more prefill duty against the matched C64
+# baseline. Keep the latency-oriented cadence on low-C and TP4 points.
+PREFILL_DECODE_INTERVAL=16
+if (( TP == 2 && CONC >= 32 )); then
+    PREFILL_DECODE_INTERVAL=4
+fi
+
+SGLANG_CMD=(
+    python3 -m sglang.launch_server
+    --model-path "$MODEL_PATH" --served-model-name "$MODEL"
+    --host 0.0.0.0 --port "$PORT"
+    --trust-remote-code
+    # Feed mmap weight copies sequentially from shared Lustre storage.
+    --weight-loader-prefetch-checkpoints
+    --tp "$TP" --ep-size "$EP_SIZE"
+    # Backends resolve automatically (dsv4 / flashinfer_mxfp4 / flashinfer_cutedsl
+    # on Blackwell); the cookbook warns that overriding them costs decode speed.
+    # Bound transient prefill allocations: the sparse-attention indexer and
+    # DSpark buffers scale with the chunk times the 1M context. Static KV
+    # memory is selected above from the measured TP2/TP4 weight footprints.
+    --mem-fraction-static "$MEM_FRACTION_STATIC"
+    --chunked-prefill-size 4096
+    # Long AgentX prefills otherwise starve ready decode requests.
+    --prefill-decode-interval "$PREFILL_DECODE_INTERVAL"
+    "${SPECULATIVE_ARGS[@]}"
+    --max-running-requests "$MAX_RUNNING_REQUESTS"
+    --swa-prefix-tails "$SWA_PREFIX_TAILS"
+    --cuda-graph-max-bs-decode "$CUDA_GRAPH_MAX_BS"
+    --reasoning-parser auto
+    --tool-call-parser auto
+    # Draft-token forward passes under long-context agentic load block the
+    # scheduler long enough to trip the 1800 s default watchdog mid-warmup.
+    --watchdog-timeout 3600
+    --enable-metrics
+)
+write_command "$RESULT_DIR/sglang_command.txt" "${SGLANG_CMD[@]}"
+{
+    echo "=== SGLANG_* env vars at launch ==="
+    env | grep -E '^SGLANG_' | sort
+    echo "==================================="
+} | tee "$SERVER_LOG"
+"${SGLANG_CMD[@]}" >> "$SERVER_LOG" 2>&1 &
+SERVER_PID=$!
+wait_for_server_ready --port "$PORT" --server-log "$SERVER_LOG" --server-pid "$SERVER_PID"
+
+if [[ "${EVAL_ONLY}" == true ]]; then
+    run_eval --port "$PORT"
+else
+    build_replay_cmd "$RESULT_DIR"
+    REPLAY_CMD+=" --server-metrics ${AIPERF_SERVER_METRICS_URLS}"
+    run_agentic_replay_and_write_outputs "$RESULT_DIR"
+fi
diff --git a/configs/nvidia-master.yaml b/configs/nvidia-master.yaml
index 97d4aa3934..9988ca1dc3 100644
--- a/configs/nvidia-master.yaml
+++ b/configs/nvidia-master.yaml
@@ -8701,3 +8701,21 @@ qwen3.5-fp8-b300-dynamo-sglang-agentic-disagg:
           tp: 2
           ep: 2
           dp-attn: false
+
+# Official 2026-09-21 CUDA 13 nightly, amd64 manifest pinned for B300.
+# Latest multiarch index: sha256:987c7e4bd26918647211a5dcad72a2bdf2a5f394ac1469eff730e7517fc139be.
+# Uses the cookbook's automatic backends and the existing B200 AgentX memory bounds.
+dsv41flash-fp4-b300-sglang-agentic-dspark:
+  image: lmsysorg/sglang:nightly-dev-cu13-20260922-582389ce@sha256:35ea4d321b0735051dcce2599fc495853ad1ef30f6a1908f0a75e74204362d14
+  model: deepseek-ai/DeepSeek-V4.1-Flash
+  model-prefix: dsv41flash
+  runner: cluster:b300-dsxe
+  precision: fp4
+  framework: sglang
+  multinode: false
+  scenarios:
+    agentic-coding:
+    - dram-utilization: 0.80
+      search-space:
+      - { tp: 4, ep: 4, kv-offloading: none, spec-decoding: mtp, conc-list: [1, 2, 4, 8, 16, 32, 64, 128] }
+      - { tp: 2, ep: 2, kv-offloading: none, spec-decoding: mtp, conc-list: [1, 2, 4, 8, 16, 32, 64, 128] }
diff --git a/docs/configuration-procedures.md b/docs/configuration-procedures.md
index f1e39af598..60fd748767 100644
--- a/docs/configuration-procedures.md
+++ b/docs/configuration-procedures.md
@@ -435,6 +435,8 @@ sweep remains required. Draft precision remains upstream default.
 The B200 launcher also converts pinned Docker digests to the installed Enroot
 manifest-reference syntax and stops immediately on import failure.
 
+DSpark uses the default precision shipped by the pinned official nightly, without custom draft quantization or precision patches. STP loads no draft; full accuracy and performance validation are still required.
+
 DSpark is the checkpoint's own bundled draft. SGLang exposes no EAGLE or MTP path and no
 `--speculative-num-steps` knob for it; the recipes pass `--speculative-algorithm DSPARK
 --speculative-dspark-block-size 5`. Throughput uses the same
diff --git a/docs/configuration-procedures_zh.md b/docs/configuration-procedures_zh.md
index 2f4ed95c9f..dc4b4cfcbb 100644
--- a/docs/configuration-procedures_zh.md
+++ b/docs/configuration-procedures_zh.md
@@ -378,6 +378,8 @@ TP2 每 GPU 加载约 147.76 GiB 的目标和草稿权重。配方校验固定
 B200 启动器还将固定 Docker digest
 转为已安装 Enroot 支持的 manifest 引用格式，并在导入失败时立即停止。
 
+DSpark 使用固定官方 nightly 默认提供的精度，不应用自定义草稿量化或精度补丁。STP 不加载草稿模型；完整准确率和性能验证仍然必需。
+
 DSpark 是检查点自带的草稿模型。SGLang 对它不提供 EAGLE 或 MTP 路径，也没有
 `--speculative-num-steps` 参数；配方传入 `--speculative-algorithm DSPARK
 --speculative-dspark-block-size 5`。吞吐测试通过 `SGLANG_SIMULATE_ACC_LEN`（`match-expected`、
diff --git a/perf-changelog.yaml b/perf-changelog.yaml
index 1941379e55..bf1d5652d0 100644
--- a/perf-changelog.yaml
+++ b/perf-changelog.yaml
@@ -8633,3 +8633,17 @@
     - "Test TP2 loading with the unmodified pinned stock loader and expandable CUDA allocator segments alone; preserve tensor payloads, layouts, and computation"
     - "Resolve local model snapshots, retain robust AgentX HTTP timeouts, and normalize digest-pinned images for the installed Enroot parser with immediate import failure handling"
   pr-link: https://github.com/SemiAnalysisAI/InferenceX/pull/3346
+
+- config-keys:
+  - dsv41flash-fp4-b300-sglang-agentic-dspark
+  scenario-type:
+  - agentic-coding
+  description:
+  - Add B300 SGLang DeepSeek-V4.1-Flash AgentX TP4/EP4 with the newest official CUDA 13 nightly (20260922-582389ce), pinned amd64 digest, native DSpark5, measured thinking-on AL 3.51 for throughput and real verification for evals.
+  - Keep automatic backends, host Engram tables, GPU-resident KV, bounded prefill and decode graphs; route the B300 SGLang runtime through /ix.
+  - Use per-rank anonymous host Engram tables to allow transparent huge pages without changing host settings; preserve native FP8 table payload and automatic backend selection.
+  - "Use the default MTP/DSpark precision shipped by the official nightly, without custom draft quantization or precision patches."
+  - "Add DSpark TP2/EP2 alongside TP4/EP4 to explore the vLLM parallelism frontier, keeping native host Engram tables and GPU KV; interleave 16 decode batches between prefill chunks to test long-context responsiveness."
+  - "Submit this SGLang AgentX lane through a Slurm batch allocation and launch its steps from the compute node, avoiding failed interactive allocation notifications on the runner login host while preserving GPU reservations and terminal-status checks."
+  - "Test retained SWA tails at 64 times concurrency, bounded to 128–4096; use static memory 0.80 for TP2 C16 and 0.85 at C32 and above after measuring its smaller KV budget and 43.59 GiB of post-graph headroom at C64, otherwise retain 0.70. Prefetch checkpoints for shared Lustre loading. Test prefill/decode interval 4 at TP2 C32 and above against the interval-16 baseline; keep other points at 16."
+  pr-link: https://github.com/SemiAnalysisAI/InferenceX/pull/3342
diff --git a/runners/launch_b300-dsxe.sh b/runners/launch_b300-dsxe.sh
index 6d563ddf45..a9c21d65f9 100755
--- a/runners/launch_b300-dsxe.sh
+++ b/runners/launch_b300-dsxe.sh
@@ -13,6 +13,38 @@ source "$(dirname "${BASH_SOURCE[0]}")/slurm_utils.sh" || exit 1
 SLURM_PARTITION="batch_1"
 SLURM_ACCOUNT="benchmark"
 
+# This lane's interactive allocation notifications fail on login-02, while
+# batch submission and steps launched from the allocated node work. Keep the
+# workaround scoped to this recipe and use normal Slurm resource accounting.
+if [[ "$IS_MULTINODE" != true && "${MODEL_PREFIX:-}" == dsv41flash &&
+      "${FRAMEWORK:-}" == sglang && "${IS_AGENTIC:-}" == 1 &&
+      "${B300_AGENTX_BATCH:-}" != 1 ]]; then
+    check_env_vars GITHUB_WORKSPACE GPU_COUNT RUNNER_NAME
+    BATCH_SCRIPT=$(mktemp "${RUNNER_TEMP:-$GITHUB_WORKSPACE}/b300-agentx.XXXXXX.sh") || exit 1
+    BATCH_LOG="${BATCH_SCRIPT%.sh}.log"
+    {
+        printf '#!/usr/bin/env bash\nexport B300_AGENTX_BATCH=1\nexec bash '
+        printf '%q\n' "$GITHUB_WORKSPACE/runners/launch_b300-dsxe.sh"
+    } > "$BATCH_SCRIPT"
+    BATCH_ARGS=(--parsable --partition="$SLURM_PARTITION" --account="$SLURM_ACCOUNT"
+        --nodes=1 --ntasks=1 --gres="gpu:$GPU_COUNT" --exclusive --mem=0
+        --time="$SALLOC_TIME_LIMIT" --job-name="$RUNNER_NAME" --export=ALL
+        --chdir="$GITHUB_WORKSPACE" --output="$BATCH_LOG")
+    if [[ -n "${SALLOC_EXCLUDE:-}" ]]; then
+        BATCH_ARGS+=(--exclude="$SALLOC_EXCLUDE")
+    fi
+    JOB_ID=$(sbatch "${BATCH_ARGS[@]}" "$BATCH_SCRIPT") || { rm -f "$BATCH_SCRIPT"; exit 1; }
+    JOB_ID="${JOB_ID%%;*}"
+    [[ "$JOB_ID" =~ ^[0-9]+$ ]] || { echo 'ERROR: B300 batch allocation unavailable' >&2; rm -f "$BATCH_SCRIPT"; exit 1; }
+    trap 'rc=$?; scancel "$JOB_ID" 2>/dev/null || true; rm -f "$BATCH_SCRIPT"; exit "$rc"' EXIT
+    trap 'exit 130' INT
+    trap 'exit 143' TERM
+    echo "B300 AgentX batch job $JOB_ID; log: $BATCH_LOG"
+    stream_slurm_job_log "$JOB_ID" "$BATCH_LOG" || exit 1
+    verify_slurm_job_status "$JOB_ID"
+    exit $?
+fi
+
 # enroot squash images. Must be on storage every compute node mounts and writable
 # by the runner user (/data/squash is root-owned, hence the per-user default).
 SQUASH_DIR="/data/home/sa-gha-runner/squash"
@@ -67,8 +99,13 @@ import_squash_image() {
         return 0
     fi
 
-    srun -N 1 -A "$SLURM_ACCOUNT" -p "$SLURM_PARTITION" \
-        --time="${ENROOT_IMPORT_TIME_LIMIT}" bash -c "
+    local import_launcher=(srun -N 1 -A "$SLURM_ACCOUNT" -p "$SLURM_PARTITION"
+        --time="${ENROOT_IMPORT_TIME_LIMIT}")
+    if [[ "${B300_AGENTX_BATCH:-}" == 1 ]]; then
+        # Already inside our exclusive compute-node allocation.
+        import_launcher=()
+    fi
+    "${import_launcher[@]}" bash -c "
         set -eo pipefail
         exec 9>\"$lock\"
         flock -w 3600 9
@@ -318,7 +355,7 @@ else
     fi
 
     # Keep all new AgentX runtime directories outside /workspace.
-    if [[ "$MODEL_PREFIX" == "dsv41flash" && "$FRAMEWORK" == "vllm" ]]; then
+    if [[ "$MODEL_PREFIX" == "dsv41flash" && ( "$FRAMEWORK" == "vllm" || "$FRAMEWORK" == "sglang" ) ]]; then
         CONTAINER_MOUNT_DIR=/ix
         export INFMAX_CONTAINER_WORKSPACE=/ix
         export RESULT_DIR=/ix/results
@@ -346,13 +383,17 @@ else
         SALLOC_ARGS+=(--exclude="$SALLOC_EXCLUDE")
     fi
     # Capture this allocation's ID; a runner name can also match an older job.
-    JOB_ID=$(
+    if [[ "${B300_AGENTX_BATCH:-}" == 1 ]]; then
+        JOB_ID="${SLURM_JOB_ID:?B300 batch execution requires a Slurm allocation}"
+    else
+        JOB_ID=$(
         set -o pipefail
         LC_ALL=C salloc "${SALLOC_ARGS[@]}" 2>&1 | tee /dev/stderr |
             sed -n 's/.*Granted job allocation \([0-9][0-9]*\)$/\1/p'
-    ) || exit 1
-    [[ "$JOB_ID" =~ ^[0-9]+$ ]] || { echo 'ERROR: B300 allocation unavailable' >&2; exit 1; }
-    trap 'rc=$?; scancel "$JOB_ID" 2>/dev/null || true; exit "$rc"' EXIT
+        ) || exit 1
+        [[ "$JOB_ID" =~ ^[0-9]+$ ]] || { echo 'ERROR: B300 allocation unavailable' >&2; exit 1; }
+        trap 'rc=$?; scancel "$JOB_ID" 2>/dev/null || true; exit "$rc"' EXIT
+    fi
     if [[ "$MODEL_MOUNT_DIR" == "$MODEL_ROOT" ]]; then
         # MODEL_ROOT is node-local: probe the allocated compute node, not the login host.
         srun --jobid="$JOB_ID" test -r "$MODEL_PATH/config.json" || {
@@ -377,8 +418,14 @@ else
     fi
     CONTAINER_MOUNTS_ARG=$(IFS=,; printf '%s' "${CONTAINER_MOUNTS[*]}")
 
+    B300_CONTAINER_MPI=none
+    if [[ "${B300_AGENTX_BATCH:-}" == 1 ]]; then
+        # The installed Enroot hook sees PMIx variables in batch jobs. Use the
+        # supported plugin so its required per-step mount directories exist.
+        B300_CONTAINER_MPI=pmix
+    fi
     srun --jobid="$JOB_ID" \
-        --mpi=none \
+        --mpi="$B300_CONTAINER_MPI" \
         --container-image="$SQUASH_FILE" \
         --container-mounts="$CONTAINER_MOUNTS_ARG" \
         --no-container-mount-home \