sgl-project/sglang · error · Exception

Error: --model-path is required. Please provide the path to

Error message

Error: --model-path is required. Please provide the path to the model.

What it means

Raised by get_model_path() when no --model-path can be found in the CLI arguments and no help flag is present — i.e. a plain missing-required-argument error. The serve command cannot proceed because server type (LLM vs diffusion) is determined from the model path.

Source

Thrown at python/sglang/cli/utils.py:128

            break

    return model_path


def get_model_path(extra_argv):
    # Find the model_path argument
    model_path = try_get_model_path(extra_argv)

    if model_path is None:
        # Fallback for --help or other cases where model-path is not provided
        if any(h in extra_argv for h in ["-h", "--help"]):
            raise Exception(
                "Usage: sglang serve --model-path <model-name-or-path> [additional-arguments]\n\n"
                "This command can launch either a standard language model server or a diffusion model server.\n"
                "The server type is determined by the --model-path.\n"
            )
        else:
            raise Exception(
                "Error: --model-path is required. "
                "Please provide the path to the model."
            )
    return model_path


@lru_cache(maxsize=1)
def get_git_commit_hash() -> str:
    try:
        commit_hash = os.environ.get("SGLANG_GIT_COMMIT")
        if not commit_hash:
            commit_hash = (
                subprocess.check_output(
                    ["git", "rev-parse", "HEAD"], stderr=subprocess.DEVNULL
                )
                .strip()
                .decode("utf-8")
            )

View on GitHub (pinned to 0132848349)

Solutions

1. Add --model-path /path/or/model-name to the command.
2. Check spelling of the flag: it must be exactly --model-path (or a recognized alias).

Example fix

# before
sglang serve --port 30000
# after
sglang serve --model-path meta-llama/Llama-3-8B-Instruct --port 30000

if not any(a == "--model-path" or a.startswith("--model-path=") for a in argv):
    raise SystemExit("Error: --model-path is required.")

try:
    model_path = get_model_path(extra_argv)
except Exception as e:
    if "--model-path is required" in str(e):
        print(usage); exit(2)

When it happens

Trigger: `sglang serve` with no --model-path; passing the model positionally or via an unsupported flag (e.g. --model) that try_get_model_path doesn't recognize.

Common situations: Users used to `sglang.launch_server --model-path` omitting it by mistake; scripts assuming a default model or an environment variable that the CLI does not read.

Understand the failure class

Background: "missing required argument" and "the following required arguments were not provided": what required-argument errors mean and how to fix them — this error's family across 20 libraries.

Related errors

• Usage: sglang serve --model-path <model-name-or-path> [addit
• No config file specified after --config flag!
• Unknown serve backend {name!r}. Available values: {available
• Multiple distributions register serve backend {name!r}: {pro
• Failed to load serve backend {name!r} from {self._entry_poin

AI-assisted analysis of sgl-project/sglang@0132848349 (2026-08-28). Data as JSON: /api/errors/5443bda0c60896af. Report an issue: GitHub.