T5Gemma 2 640-wide text encoder for vLLM
This checkpoint contains only the text encoder from google/t5gemma-2-270m-270m,
mapped without weight changes to the native Gemma3ForCausalLM layout used by
vLLM. Vision, decoder, and multimodal-only EOI embedding weights are omitted.
The configuration sets is_causal=false and
use_bidirectional_attention=true, causing vLLM's Gemma3 implementation to use
EncoderOnlyAttention. It has 18 layers, hidden size
640, and 4/1
attention/KV heads. Weights and activations are BF16.
vLLM
vllm serve <model-id-or-path> --runner generate --no-enable-prefix-caching --max-model-len 32768
--no-enable-prefix-caching is required on vLLM 0.24 because encoder-only
attention has no autoregressive KV cache.
Intended use
This is an infrastructure conversion for text encoding, retrieval, reranking, and experimentation. The tied LM head allows the vLLM generation runner to load the model, but this isolated encoder was not trained as a standalone causal language model.
The original Gemma terms apply. See the source model card.