Add SentenceTransformer embedder for Graphiti — self-hosted, no OpenAI dependency

scripts/st_embedder.py

@@ -0,0 +1,29 @@
+"""
+Custom SentenceTransformer embedder for Graphiti.
+Implements EmbedderClient interface using local all-MiniLM-L6-v2.
+No API cost, no external dependency, consistent with existing ingest pipeline.
+"""
+from collections.abc import Iterable
+from graphiti_core.embedder.client import EmbedderClient, EmbedderConfig
+
+class SentenceTransformerEmbedderConfig(EmbedderConfig):
+    model_name: str = "all-MiniLM-L6-v2"
+    embedding_dim: int = 384
+
+class SentenceTransformerEmbedder(EmbedderClient):
+    def __init__(self, config: SentenceTransformerEmbedderConfig | None = None):
+        self.config = config or SentenceTransformerEmbedderConfig()
+        from sentence_transformers import SentenceTransformer
+        self._model = SentenceTransformer(self.config.model_name)
+
+    async def create(
+        self, input_data: str | list[str] | Iterable[int] | Iterable[Iterable[int]]
+    ) -> list[float]:
+        if isinstance(input_data, str):
+            input_data = [input_data]
+        embeddings = self._model.encode(list(input_data))
+        return embeddings[0].tolist()
+
+    async def create_batch(self, input_data_list: list[str]) -> list[list[float]]:
+        embeddings = self._model.encode(input_data_list)
+        return [e.tolist() for e in embeddings]