[AMD] [AgentX] Add MI355X Qwen3.5 FP4 SGLang MTP - #2562

build_replay_cmd in benchmark_lib.sh:1887-2053 constructs REPLAY_CMD as an $AIPERF_CLI profile --scenario inferencex-agentx-mvp ... invocation, targeting --endpoint /v1/chat/completions with --endpoint-type chat. Nowhere in this function (or anywhere in the aiperf profile argument set) is --use-chat-template handled — that flag is defined and consumed exclusively inside run_benchmark_serving (benchmark_lib.sh:520 for parsing, :636-638 for application), which drives utils/bench_serving/benchmark_serving.py for the fixed-seq-len scripts, not the agentic replay path.

In qwen3.5_fp4_mi355x_sglang_mtp.sh:176-179, the non-EVAL_ONLY branch calls build_replay_cmd "$RESULT_DIR" and then appends REPLAY_CMD+=" --use-chat-template" before calling run_agentic_replay_and_write_outputs "$RESULT_DIR". That function executes $REPLAY_CMD literally at benchmark_lib.sh:2112 ($REPLAY_CMD 2>&1 | tee "$result_dir/benchmark.log") and gates success on the exit code (replay_rc). Since aiperf profile has no such flag, it will reject the unrecognized CLI argument and exit non-zero, causing run_agentic_replay_and_write_outputs to treat the run as failed.

This is not a stylistic mismatch — it's a straightforward "passing an unsupported flag to a CLI tool" bug. The only reason it isn't obviously wrong from a shallow read is that --use-chat-template is a real, valid flag elsewhere in the same file, which makes it plausible at a glance that it belongs here too. But tracing which command REPLAY_CMD actually becomes shows it doesn't apply to this call site.

Corroborating evidence from the rest of the codebase: (1) the direct sibling B200 recipe qwen3.5_fp4_b200_sglang_mtp.sh appends --server-metrics after build_replay_cmd, never --use-chat-template; (2) no other agentic *_mtp.sh script (dsv4 variants, glm5.2, etc.) adds this flag to REPLAY_CMD; (3) kimik3_fp4_b300_vllm_mtp.sh:35-38 has an explicit comment stating exactly why agentic recipes must not add it: "AGENTS.md requires MTP scripts to pass --use-chat-template to run_benchmark_serving. Agentic recipes never call it -- the replay drives AIPerf against /v1/chat/completions, so prompts are already chat-formatted ... Nothing to add here."

Step-by-step proof of the failure: (1) Script reaches the else branch (EVAL_ONLY defaults to false, so this is the default/majority path — the sweep's agentic-coding scenario in configs/amd-master.yaml runs many conc-list throughput points, e.g. conc-list: [1, 4, 8, 12, 16, ...]). (2) build_replay_cmd "$RESULT_DIR" sets REPLAY_CMD="$AIPERF_CLI profile --scenario inferencex-agentx-mvp --url http://localhost:$PORT --endpoint /v1/chat/completions --endpoint-type chat ... --output-artifact-dir $RESULT_DIR/aiperf_artifacts ...". (3) Line 177 appends --use-chat-template to this string. (4) run_agentic_replay_and_write_outputs runs $REPLAY_CMD, i.e. invokes aiperf profile ... --use-chat-template. (5) aiperf's CLI parser (argparse or similar) has no such option registered for the profile subcommand and will error out ("unrecognized arguments: --use-chat-template") with a non-zero exit code. (6) replay_rc becomes non-zero, and the run is recorded as failed — for every throughput concurrency point across all four search-space rows in the new qwen3.5-fp4-mi355x-sglang-agentic-mtp config entry.

The fix is simply to delete line 177 (REPLAY_CMD+=" --use-chat-template"), leaving build_replay_cmd's output untouched, matching every other agentic *_mtp.sh script's pattern.