sgl-project/sglang · error · ValueError

Kimi-K3 image processor is missing deferred-preprocessing…

Error message

Kimi-K3 image processor is missing deferred-preprocessing config: {missing}

What it means

Raised by prepare_kimi_k3_encoder_inputs when the model's media processor config (media_proc_cfg) is missing one or more required deferred-preprocessing keys (e.g. patch_size, patch_limit_on_one_side, image_mean, image_std). The Kimi-K3 pipeline defers image preprocessing to the encoder side, so these fields must be present in the processor config for the run to proceed.

Solutions

1. Check the error's missing list and add each named key to the model's preprocessor_config.json / media_proc_cfg
2. Diff your processor config against the official Kimi-K3 repo config to restore any dropped fields
3. If building cfg programmatically, populate all required keys from the HF image processor config before calling prepare_kimi_k3_encoder_inputs

Example fix

// before
cfg = {"patch_size": 16}
prepare_kimi_k3_encoder_inputs(images, cfg, ...)
// after
cfg = {"patch_size": 16, "patch_limit_on_one_side": True, "image_mean": [0.5]*3, "image_std": [0.5]*3}
prepare_kimi_k3_encoder_inputs(images, cfg, ...)

REQUIRED = ("patch_size", "patch_limit_on_one_side", "image_mean", "image_std")
missing = [k for k in REQUIRED if k not in media_proc_cfg]
assert not missing, f"missing config keys: {missing}"

When it happens

Trigger: Calling prepare_kimi_k3_encoder_inputs (directly or via preprocess_mm_for_encoder / model_preprocessor) with a media_proc_cfg dict that lacks any of the required keys: patch_size, patch_limit_on_one_side, image_mean, image_std (and others in the required tuple).

Common situations: Using a custom or trimmed Kimi-K3 processor config JSON that omitted preprocessing fields; upgrading the model repo where config keys were renamed; constructing media_proc_cfg manually in tests or offline pipelines.

Related errors

• Attention backend ' ' is not supported by this attention…
• audio_cap must be non-negative, got
• capacity must be positive, got
• Expected image placeholder(s), found .
• Expected image placeholder token(s), found .

AI-assisted analysis of sgl-project/sglang@0132848349 (2026-08-28). Data as JSON: /api/errors/6d06bfc1af8b1514. Report an issue: GitHub.

Appendix: source

Thrown at python/sglang/srt/multimodal/kimi_k3_image_processing.py:72

            "image_processor.media_proc_cfg"
        ) from exc
    if not isinstance(media_proc_cfg, dict):
        raise ValueError(
            "Kimi-K3 EPD owner-side preprocessing requires "
            "image_processor.media_proc_cfg"
        )

    required = (
        "patch_size",
        "merge_kernel_size",
        "in_patch_limit",
        "patch_limit_on_one_side",
        "image_mean",
        "image_std",
    )
    missing = [name for name in required if name not in media_proc_cfg]
    if missing:
        raise ValueError(
            "Kimi-K3 image processor is missing deferred-preprocessing config: "
            + ", ".join(missing)
        )

    concrete_images = []
    content_digests = []
    for image in images:
        content_digest = None
        if isinstance(image, dict):
            if image.get("type") != "image" or "image" not in image:
                raise ValueError(f"Unsupported Kimi-K3 encoder media item: {image}")
            content_digest = image.get("content_hash")
            image = image["image"]
        concrete_images.append(image)
        content_digests.append(content_digest)

    patch_size = int(media_proc_cfg["patch_size"])
    merge_kernel_size = int(media_proc_cfg["merge_kernel_size"])

View on GitHub (pinned to 0132848349)