Merge pull request #462 from ggozad/fix/multi-modal-embedder-config

Decouple multimodal embedding from the provider name; add VoyageAI & Cohere multimodal embedders

CHANGELOG.md

@@ -4,6 +4,13 @@
 ### Added
 
 - `haiku-rag doctor` checks a database for consistency (orphaned chunks/items, chunk-less documents classified by content and embedder modality, dangling `doc_item_refs`, vector-dimension mismatch, unembedded chunks, missing picture data, settings/embedding drift, pending migrations, vector-index coverage, provider API keys) and probes configured provider endpoints (Ollama `/api/tags` with model presence, docling-serve `/health`, OpenAI-compatible/vLLM `/models`); exits 1 when any check fails.
+- `embeddings.model.multimodal` (bool, default false) gates image embedding; `supports_images` derives from it instead of the provider name.
+- VoyageAI multimodal embedder (`provider: voyageai`, `multimodal: true`, e.g. `voyage-multimodal-3`) embedding text and pictures into a shared vector space.
+- Cohere multimodal embedder (`provider: cohere`, `multimodal: true`, e.g. `embed-v4.0`) embedding text and pictures into a shared vector space.
+
+### Changed
+
+- `provider: vllm` is text-only unless `embeddings.model.multimodal: true` is set. Existing multimodal vLLM configs must add the flag; `multimodal` is not part of the stored embedding identity, so changing it raises no drift error — re-ingest or `rebuild` to add or drop picture chunks.
 
 ## [0.60.0] - 2026-06-22
 

README.md

@@ -10,14 +10,14 @@ Agentic RAG built on [LanceDB](https://lancedb.com/), [Pydantic AI](https://ai.p
 ## Features
 
 - **Hybrid search** — Vector + full-text with Reciprocal Rank Fusion
-- **Multimodal & cross-modal search** — Multimodal embedders (vLLM) put picture vectors in the same space as text; supports text-as-query → figure hits and image-as-query
+- **Multimodal & cross-modal search** — Multimodal embedders (vLLM, VoyageAI, Cohere) put picture vectors in the same space as text; supports text-as-query → figure hits and image-as-query
 - **Question answering** — RAG skill with citations (page numbers, section headings)
 - **Vision QA** — Vision-capable models receive figure bytes alongside chunk text
 - **Reranking** — MxBAI, Cohere, Zero Entropy, or vLLM
 - **Analysis skill** — Complex analytical tasks via sandboxed Python code execution (aggregation, computation, multi-document analysis)
 - **Conversational RAG** — Chat TUI and web application for multi-turn conversations with session memory
 - **Document structure** — Stores full [DoclingDocument](https://docling-project.github.io/docling/concepts/docling_document/), enabling structure-aware context expansion
-- **Multiple providers** — Embeddings: Ollama, OpenAI, VoyageAI, LM Studio, vLLM (multimodal). QA: any model supported by Pydantic AI
+- **Multiple providers** — Embeddings: Ollama, OpenAI, VoyageAI, Cohere, LM Studio, vLLM (multimodal via `multimodal: true` on vLLM/VoyageAI/Cohere). QA: any model supported by Pydantic AI
 - **Local-first** — Embedded LanceDB, no servers required. Also supports S3, GCS, Azure, and LanceDB Cloud
 - **CLI & Python API** — Full functionality from command line or code
 - **MCP server** — Expose as tools for AI assistants (Claude Desktop, etc.)

docs/configuration/processing.md

@@ -283,9 +283,11 @@ Three independent settings drive ingest, retrieval, and QA:
 | Setting | Question it answers | Values |
 |---|---|---|
 | `processing.pictures` | Generate and/or describe pictures at ingest? | `none` / `description` / `image` (default) |
-| `embeddings.model.provider` | Can the embedder index image content? | text-only (`ollama`, `openai`, `cohere`, `sentence-transformers`) vs `vllm` (multimodal) |
+| `embeddings.model.multimodal` | Can the embedder index image content? | `false` (default, text-only) / `true` (supported on `vllm`, `voyageai`, `cohere`) |
 | `qa.model.vision` | Can the QA model interpret images? | `false` (default) / `true` |
 
+The Embedder column below is driven by `embeddings.model.multimodal`, not the provider name — a vision-capable model under a text-only configuration still indexes no images, and an image-only document then produces zero chunks. See [Multimodal embedders](providers.md#multimodal-embedders).
+
 **What gets stored** by `pictures` × embedder:
 
 | `pictures` | Embedder | Text chunks | Synthetic picture chunks |

docs/configuration/providers.md

@@ -228,11 +228,15 @@ embeddings:
     base_url: http://localhost:1234/v1
 ```
 
-**Note:** The `base_url` must include the `/v1` path for OpenAI-compatible endpoints.
+**Note:** The `base_url` must include the `/v1` path for OpenAI-compatible endpoints. This path is text-only. For a vision-language model served by vLLM, use `provider: vllm` with `multimodal: true` (below), not `provider: openai`.
 
-### vLLM (multimodal)
+### Multimodal embedders
 
-For cross-modal retrieval (text and pictures share a single vector space), use the dedicated `vllm` provider against a vLLM server hosting a multimodal embedding model:
+For cross-modal retrieval (text and pictures share a single vector space), set `embeddings.model.multimodal: true`. Capability is decided by this flag, not the provider name: each provider passes images in its own wire format, so multimodal is supported only on `vllm`, `voyageai`, and `cohere`. Setting it on any other provider raises at startup.
+
+A model produces picture chunks at ingest only when its embedder is multimodal. Without the flag, an image-only document produces zero chunks and is not retrievable. Switching `multimodal` on or off does not change the stored embedding identity, so it raises no drift error; re-ingest or `rebuild` to add or drop picture chunks.
+
+**vLLM** — a vLLM server hosting a multimodal embedding model. Text inputs use the standard OpenAI `input` field; image inputs use vLLM's `messages`-with-`image_url` superset. Tested with `Qwen/Qwen3-VL-Embedding-8B` (4096-dim) and `jinaai/jina-embeddings-v4` (2048-dim). Run vLLM separately; haiku.rag adds no Python ML dependencies for this path.
 
 ```yaml
 embeddings:
@@ -241,11 +245,34 @@ embeddings:
     name: Qwen/Qwen3-VL-Embedding-8B
     vector_dim: 4096
     base_url: http://localhost:8000/v1
+    multimodal: true
 ```
 
-Tested with `Qwen/Qwen3-VL-Embedding-8B` (4096-dim) and `jinaai/jina-embeddings-v4` (2048-dim). Run vLLM separately. haiku.rag adds no Python ML dependencies for this path. Text inputs use the standard OpenAI `input` field. Image inputs use vLLM's `messages`-with-`image_url` superset, transparently to the caller.
+**VoyageAI** — `voyage-multimodal-3` (1024-dim) via the `voyageai` extra. Reads `VOYAGE_API_KEY` from the environment.
 
-Picture chunks for retrieval are emitted at ingest under any embedder reporting `supports_images=True`. See [Picture Handling](processing.md#picture-handling).
+```yaml
+embeddings:
+  model:
+    provider: voyageai
+    name: voyage-multimodal-3
+    vector_dim: 1024
+    multimodal: true
+```
+
+**Cohere** — `embed-v4.0` (configurable `vector_dim`, e.g. 1536) via the `cohere` extra. Reads `CO_API_KEY` from the environment.
+
+```yaml
+embeddings:
+  model:
+    provider: cohere
+    name: embed-v4.0
+    vector_dim: 1536
+    multimodal: true
+```
+
+A text-only model served by vLLM uses `provider: vllm` without the flag (or `provider: openai` with a `base_url`).
+
+Picture chunks for retrieval are emitted at ingest under any multimodal embedder. See [Picture Handling](processing.md#picture-handling).
 
 ## Question Answering Providers
 

docs/python.md

@@ -260,7 +260,7 @@ results = await client.search(
 
 ### Image queries
 
-`client.search()` accepts an image instead of a text query when the configured embedder is multimodal (e.g. `provider: vllm` against a vision-language embedding model). The image is embedded once and the chunks table is searched vector-only. Full-text search and reranking don't apply without a text query.
+`client.search()` accepts an image instead of a text query when the configured embedder is multimodal (`embeddings.model.multimodal: true` on a vLLM, VoyageAI, or Cohere model). The image is embedded once and the chunks table is searched vector-only. Full-text search and reranking don't apply without a text query.
 
 ```python
 from PIL import Image

haiku_rag_slim/haiku/rag/client/search.py

@@ -58,8 +58,9 @@ async def search(
         embedder = client.embedder
         if not embedder.supports_images:
             raise ValueError(
-                "Image queries require a multimodal embedder. Configure "
-                "provider='vllm' (or another image-capable provider)."
+                "Image queries require a multimodal embedder. Set "
+                "embeddings.model.multimodal: true on a vllm, voyageai, or cohere "
+                "model."
             )
         query_vector = await embedder.embed_image(query)
         chunk_results = await client.chunk_repository.search(

haiku_rag_slim/haiku/rag/config/models.py

@@ -39,16 +39,20 @@ class EmbeddingModelConfig(BaseModel):
     """Configuration for an embedding model.
 
     Attributes:
-        provider: Model provider (ollama, openai, voyageai, cohere, sentence-transformers)
+        provider: Model provider (ollama, openai, voyageai, cohere, sentence-transformers, vllm)
         name: Model name/identifier
         vector_dim: Vector dimensions produced by the model
         base_url: Optional base URL for OpenAI-compatible servers (vLLM, LM Studio, etc.)
+        multimodal: Whether the model embeds images into the same vector space as
+            text. Supported on the vllm, voyageai, and cohere providers; other
+            providers raise when this is set.
     """
 
     provider: str = "ollama"
     name: str = "qwen3-embedding:4b"
     vector_dim: int = 2560
     base_url: str | None = None
+    multimodal: bool = False
 
 
 class StorageConfig(BaseModel):

haiku_rag_slim/haiku/rag/doctor.py

@@ -209,7 +209,10 @@ def _classify_unchunked(
                     f"{len(picture_docs)} image-only document(s) have no chunks; "
                     "a text-only embedder cannot index images."
                 ),
-                remediation="Configure a multimodal embedder and rebuild to index images.",
+                remediation=(
+                    "Set embeddings.model.multimodal: true on a vllm, voyageai, or "
+                    "cohere model and rebuild to index images."
+                ),
                 details=_sample(sorted(picture_docs)),
             )
         )

haiku_rag_slim/haiku/rag/embeddings/__init__.py

@@ -1,3 +1,5 @@
+import base64
+import io
 from typing import TYPE_CHECKING, Any
 
 from pydantic_ai.embeddings import Embedder
@@ -10,6 +12,7 @@ from haiku.rag.config import AppConfig, Config
 if TYPE_CHECKING:
     from PIL import Image as PILImage
 
+    from haiku.rag.config.models import EmbeddingModelConfig
     from haiku.rag.store.models.chunk import Chunk
 
 
@@ -19,15 +22,23 @@ ImageInput = "bytes | PILImage.Image"
 class EmbedderWrapper:
     """Wrapper around pydantic-ai Embedder with explicit query/document methods.
 
-    Subclasses set ``supports_images = True`` and override the image methods
-    when the underlying model can encode pictures into the same vector space.
+    Subclasses that can encode pictures into the same vector space as text either
+    set the ``supports_images`` class attribute or pass ``supports_images=True``,
+    and override the image methods.
     """
 
     supports_images: bool = False
 
-    def __init__(self, embedder: Embedder | None, vector_dim: int):
+    def __init__(
+        self,
+        embedder: Embedder | None,
+        vector_dim: int,
+        supports_images: bool | None = None,
+    ):
         self._embedder = embedder
         self._vector_dim = vector_dim
+        if supports_images is not None:
+            self.supports_images = supports_images
 
     @property
     def vector_dim(self) -> int:
@@ -55,11 +66,28 @@ class EmbedderWrapper:
         ``messages`` superset. Callers loop when they need many.
         """
         raise NotImplementedError(
-            f"{type(self).__name__} does not support image embedding. "
-            "Configure a multimodal provider (e.g. provider='vllm')."
+            f"{type(self).__name__} does not support image embedding. Set "
+            "embeddings.model.multimodal: true on a vllm, voyageai, or cohere model."
         )
 
 
+def _to_data_uri(image: "bytes | PILImage.Image") -> str:
+    """Render an image as a ``data:image/png;base64,...`` URI."""
+    if isinstance(image, bytes):
+        return f"data:image/png;base64,{base64.b64encode(image).decode('ascii')}"
+
+    from PIL import Image as PILImageModule
+
+    if isinstance(image, PILImageModule.Image):
+        buf = io.BytesIO()
+        image.save(buf, format="PNG")
+        return (
+            f"data:image/png;base64,{base64.b64encode(buf.getvalue()).decode('ascii')}"
+        )
+
+    raise TypeError(f"Unsupported image type: {type(image)!r}")
+
+
 def contextualize(chunks: list["Chunk"]) -> list[str]:
     """Prepare chunk content for embedding/FTS by adding context.
 
@@ -117,8 +145,9 @@ async def embed_chunks(
     if picture_chunks:
         if not embedder.supports_images:
             raise ValueError(
-                "Picture chunks require a multimodal embedder. Configure "
-                "provider='vllm', or omit picture chunks."
+                "Picture chunks require a multimodal embedder. Set "
+                "embeddings.model.multimodal: true on a vllm, voyageai, or cohere "
+                "model, or omit picture chunks."
             )
         for chunk in picture_chunks:
             picture_embeddings.append(await embedder.embed_image(chunk._picture_data))
@@ -159,6 +188,9 @@ def get_embedder(config: AppConfig = Config) -> EmbedderWrapper:
     model_name = embedding_model.name
     vector_dim = embedding_model.vector_dim
 
+    if embedding_model.multimodal:
+        return _get_multimodal_embedder(embedding_model)
+
     if provider == "ollama":
         # Use model-level base_url if set, otherwise fall back to providers config
         base_url = embedding_model.base_url or config.providers.ollama.base_url
@@ -193,9 +225,52 @@ def get_embedder(config: AppConfig = Config) -> EmbedderWrapper:
     if provider == "vllm":
         from haiku.rag.embeddings.vllm import VLLMMultimodalEmbedder
 
-        base_url = embedding_model.base_url or "http://localhost:8000/v1"
-        if not base_url.rstrip("/").endswith("/v1"):
-            base_url = base_url.rstrip("/") + "/v1"
-        return VLLMMultimodalEmbedder(model_name, vector_dim, base_url=base_url)
+        base_url = _vllm_base_url(embedding_model.base_url)
+        return VLLMMultimodalEmbedder(
+            model_name, vector_dim, base_url=base_url, supports_images=False
+        )
 
     raise ValueError(f"Unsupported embedding provider: {provider}")
+
+
+def _vllm_base_url(base_url: str | None) -> str:
+    base_url = base_url or "http://localhost:8000/v1"
+    if not base_url.rstrip("/").endswith("/v1"):
+        base_url = base_url.rstrip("/") + "/v1"
+    return base_url
+
+
+def _get_multimodal_embedder(
+    embedding_model: "EmbeddingModelConfig",
+) -> EmbedderWrapper:
+    """Build an image-capable embedder for providers that support multimodal.
+
+    Each provider passes images in its own wire format, so the capability lives
+    in a per-provider embedder rather than a generic flag.
+    """
+    provider = embedding_model.provider
+    model_name = embedding_model.name
+    vector_dim = embedding_model.vector_dim
+
+    if provider == "vllm":
+        from haiku.rag.embeddings.vllm import VLLMMultimodalEmbedder
+
+        base_url = _vllm_base_url(embedding_model.base_url)
+        return VLLMMultimodalEmbedder(
+            model_name, vector_dim, base_url=base_url, supports_images=True
+        )
+
+    if provider == "voyageai":
+        from haiku.rag.embeddings.voyageai import VoyageMultimodalEmbedder
+
+        return VoyageMultimodalEmbedder(model_name, vector_dim)
+
+    if provider == "cohere":
+        from haiku.rag.embeddings.cohere import CohereMultimodalEmbedder
+
+        return CohereMultimodalEmbedder(model_name, vector_dim)
+
+    raise ValueError(
+        f"Provider '{provider}' does not support multimodal embedding. Set "
+        "embeddings.model.multimodal: true on a vllm, voyageai, or cohere model."
+    )

haiku_rag_slim/haiku/rag/embeddings/cohere.py

@@ -0,0 +1,66 @@
+"""Multimodal embedder backed by Cohere's ``embed`` API (``embed-v4.0``).
+
+``embed-v4.0`` maps text and images into a shared vector space. Text uses the
+``search_document``/``search_query`` input types; images are passed as base64
+data URIs with the ``image`` input type. The API key is read from the
+environment (``CO_API_KEY``) like the text-only Cohere path.
+"""
+
+from typing import TYPE_CHECKING
+
+from haiku.rag.embeddings import EmbedderWrapper, _to_data_uri
+
+if TYPE_CHECKING:
+    from PIL import Image as PILImage
+
+
+class CohereMultimodalEmbedder(EmbedderWrapper):
+    def __init__(
+        self,
+        model_name: str,
+        vector_dim: int,
+        api_key: str | None = None,
+    ):
+        super().__init__(embedder=None, vector_dim=vector_dim, supports_images=True)
+        import cohere
+
+        self._model_name = model_name
+        self._client = cohere.AsyncClientV2(api_key=api_key)
+
+    async def _embed_texts(
+        self, texts: list[str], input_type: str
+    ) -> list[list[float]]:
+        result = await self._client.embed(
+            model=self._model_name,
+            input_type=input_type,
+            texts=texts,
+            output_dimension=self._vector_dim,
+            embedding_types=["float"],
+        )
+        return _floats(result)
+
+    async def embed_query(self, text: str) -> list[float]:
+        rows = await self._embed_texts([text], "search_query")
+        return rows[0]
+
+    async def embed_documents(self, texts: list[str]) -> list[list[float]]:
+        if not texts:
+            return []
+        return await self._embed_texts(texts, "search_document")
+
+    async def embed_image(self, image: "bytes | PILImage.Image") -> list[float]:
+        result = await self._client.embed(
+            model=self._model_name,
+            input_type="image",
+            images=[_to_data_uri(image)],
+            output_dimension=self._vector_dim,
+            embedding_types=["float"],
+        )
+        return _floats(result)[0]
+
+
+def _floats(result: object) -> list[list[float]]:
+    floats = result.embeddings.float_  # type: ignore[attr-defined]  # ty: ignore[unresolved-attribute]
+    if floats is None:
+        raise ValueError("Cohere returned no float embeddings.")
+    return [list(e) for e in floats]

haiku_rag_slim/haiku/rag/embeddings/vllm.py

@@ -11,21 +11,17 @@ Models like ``Qwen/Qwen3-VL-Embedding-8B`` and ``jinaai/jina-embeddings-v4``
 ship with chat templates that map both shapes into a shared vector space.
 """
 
-import base64
-import io
 from typing import TYPE_CHECKING, Any
 
 import httpx
 
-from haiku.rag.embeddings import EmbedderWrapper
+from haiku.rag.embeddings import EmbedderWrapper, _to_data_uri
 
 if TYPE_CHECKING:
     from PIL import Image as PILImage
 
 
 class VLLMMultimodalEmbedder(EmbedderWrapper):
-    supports_images = True
-
     def __init__(
         self,
         model_name: str,
@@ -33,8 +29,11 @@ class VLLMMultimodalEmbedder(EmbedderWrapper):
         base_url: str,
         api_key: str | None = None,
         timeout: float = 60.0,
+        supports_images: bool = True,
     ):
-        super().__init__(embedder=None, vector_dim=vector_dim)
+        super().__init__(
+            embedder=None, vector_dim=vector_dim, supports_images=supports_images
+        )
         self._model_name = model_name
         self._base_url = base_url.rstrip("/")
         self._api_key = api_key
@@ -99,6 +98,11 @@ class VLLMMultimodalEmbedder(EmbedderWrapper):
         )
 
     async def embed_image(self, image: "bytes | PILImage.Image") -> list[float]:
+        if not self.supports_images:
+            raise NotImplementedError(
+                "This vLLM embedder is text-only. Set "
+                "embeddings.model.multimodal: true to embed images."
+            )
         rows = await self._post(
             {
                 "model": self._model_name,
@@ -117,20 +121,3 @@ class VLLMMultimodalEmbedder(EmbedderWrapper):
             }
         )
         return rows[0]
-
-
-def _to_data_uri(image: "bytes | PILImage.Image") -> str:
-    """Render an image as a ``data:image/png;base64,...`` URI."""
-    if isinstance(image, bytes):
-        return f"data:image/png;base64,{base64.b64encode(image).decode('ascii')}"
-
-    from PIL import Image as PILImageModule
-
-    if isinstance(image, PILImageModule.Image):
-        buf = io.BytesIO()
-        image.save(buf, format="PNG")
-        return (
-            f"data:image/png;base64,{base64.b64encode(buf.getvalue()).decode('ascii')}"
-        )
-
-    raise TypeError(f"Unsupported image type: {type(image)!r}")

haiku_rag_slim/haiku/rag/embeddings/voyageai.py

@@ -0,0 +1,68 @@
+"""Multimodal embedder backed by VoyageAI's ``multimodal_embed`` endpoint.
+
+``voyage-multimodal-3`` maps text and images into a shared vector space. Text is
+embedded as single-element content lists; images are passed as ``PIL.Image``
+objects (the SDK accepts them directly). The API key is read from the
+environment (``VOYAGE_API_KEY``) like the text-only Voyage path.
+"""
+
+import io
+from typing import TYPE_CHECKING
+
+from haiku.rag.embeddings import EmbedderWrapper
+
+if TYPE_CHECKING:
+    from PIL import Image as PILImage
+
+
+class VoyageMultimodalEmbedder(EmbedderWrapper):
+    def __init__(
+        self,
+        model_name: str,
+        vector_dim: int,
+        api_key: str | None = None,
+    ):
+        super().__init__(embedder=None, vector_dim=vector_dim, supports_images=True)
+        import voyageai
+
+        self._model_name = model_name
+        self._client = voyageai.AsyncClient(api_key=api_key)
+
+    async def embed_query(self, text: str) -> list[float]:
+        result = await self._client.multimodal_embed(
+            inputs=[[text]],
+            model=self._model_name,
+            input_type="query",
+            output_dimension=self._vector_dim,
+        )
+        return list(result.embeddings[0])
+
+    async def embed_documents(self, texts: list[str]) -> list[list[float]]:
+        if not texts:
+            return []
+        result = await self._client.multimodal_embed(
+            inputs=[[text] for text in texts],
+            model=self._model_name,
+            input_type="document",
+            output_dimension=self._vector_dim,
+        )
+        return [list(e) for e in result.embeddings]
+
+    async def embed_image(self, image: "bytes | PILImage.Image") -> list[float]:
+        result = await self._client.multimodal_embed(
+            inputs=[[_to_pil(image)]],
+            model=self._model_name,
+            input_type="document",
+            output_dimension=self._vector_dim,
+        )
+        return list(result.embeddings[0])
+
+
+def _to_pil(image: "bytes | PILImage.Image") -> "PILImage.Image":
+    from PIL import Image as PILImageModule
+
+    if isinstance(image, bytes):
+        return PILImageModule.open(io.BytesIO(image))
+    if isinstance(image, PILImageModule.Image):
+        return image
+    raise TypeError(f"Unsupported image type: {type(image)!r}")

tests/test_doctor.py

@@ -49,11 +49,19 @@ VECTOR_DIM = 4
 ChunkRecord = create_chunk_model(VECTOR_DIM)
 
 
-def _config(provider: str = "ollama", name: str = "test", vector_dim: int = VECTOR_DIM):
+def _config(
+    provider: str = "ollama",
+    name: str = "test",
+    vector_dim: int = VECTOR_DIM,
+    multimodal: bool = False,
+):
     return AppConfig(
         embeddings=EmbeddingsConfig(
             model=EmbeddingModelConfig(
-                provider=provider, name=name, vector_dim=vector_dim
+                provider=provider,
+                name=name,
+                vector_dim=vector_dim,
+                multimodal=multimodal,
             )
         )
     )
@@ -312,7 +320,7 @@ async def test_image_only_document_multimodal_embedder_warns(temp_db_path):
         ],
     )
     report = await run_doctor(
-        _config(provider="vllm", name="qwen-vl"), temp_db_path, {}
+        _config(provider="vllm", name="qwen-vl", multimodal=True), temp_db_path, {}
     )
     result = _result(report, "documents_pictures_no_chunks")
     assert result.severity is Severity.WARN

tests/test_embedder.py

@@ -308,7 +308,7 @@ def _ollama_text_only_config():
 async def test_text_only_embedder_does_not_support_images():
     embedder = get_embedder(_ollama_text_only_config())
     assert embedder.supports_images is False
-    with pytest.raises(NotImplementedError, match="multimodal provider"):
+    with pytest.raises(NotImplementedError, match="multimodal"):
         await embedder.embed_image(b"\x89PNG\r\n\x1a\n")
 
 
@@ -417,6 +417,20 @@ async def test_vllm_supports_images_flag():
     assert embedder.supports_images is True
 
 
+async def test_vllm_text_only_embed_image_raises():
+    from haiku.rag.embeddings.vllm import VLLMMultimodalEmbedder
+
+    embedder = VLLMMultimodalEmbedder(
+        model_name="x",
+        vector_dim=2,
+        base_url="http://localhost:8000/v1",
+        supports_images=False,
+    )
+    assert embedder.supports_images is False
+    with pytest.raises(NotImplementedError, match="text-only"):
+        await embedder.embed_image(b"\x89PNG\r\n\x1a\n")
+
+
 async def test_vllm_connect_error_surfaces_helpful_message(monkeypatch):
     import httpx
 
@@ -630,6 +644,7 @@ async def test_vllm_get_embedder_routes_to_multimodal():
                 name="Qwen/Qwen3-VL-Embedding-2B",
                 vector_dim=2048,
                 base_url="http://my-vllm:8000/v1",
+                multimodal=True,
             )
         )
     )
@@ -638,6 +653,40 @@ async def test_vllm_get_embedder_routes_to_multimodal():
     assert embedder._base_url == "http://my-vllm:8000/v1"  # type: ignore[attr-defined]  # ty: ignore[unresolved-attribute]
 
 
+def test_multimodal_defaults_to_false():
+    model = EmbeddingModelConfig(provider="vllm", name="x", vector_dim=2)
+    assert model.multimodal is False
+    assert "multimodal" in model.model_dump()
+
+
+async def test_vllm_text_only_when_multimodal_unset():
+    config = AppConfig(
+        embeddings=EmbeddingsConfig(
+            model=EmbeddingModelConfig(
+                provider="vllm",
+                name="qwen3-embedding:4b",
+                vector_dim=2560,
+                base_url="http://my-vllm:8000/v1",
+            )
+        )
+    )
+    embedder = get_embedder(config)
+    assert embedder.supports_images is False
+
+
+@pytest.mark.parametrize("provider", ["ollama", "openai", "sentence-transformers"])
+async def test_multimodal_unsupported_provider_raises(provider):
+    config = AppConfig(
+        embeddings=EmbeddingsConfig(
+            model=EmbeddingModelConfig(
+                provider=provider, name="x", vector_dim=2, multimodal=True
+            )
+        )
+    )
+    with pytest.raises(ValueError, match="does not support multimodal"):
+        get_embedder(config)
+
+
 @pytest.mark.vcr()
 async def test_vllm_embed_text_and_image_end_to_end():
     """End-to-end against a real vLLM ``/v1/embeddings`` server: confirm
@@ -672,3 +721,268 @@ async def test_vllm_embed_text_and_image_end_to_end():
     image_vec = await embedder.embed_image(image)
     assert len(image_vec) == 4096
     assert any(abs(x) > 1e-6 for x in image_vec), "image embedding is all zeros"
+
+
+class _FakeVoyageResult:
+    def __init__(self, embeddings):
+        self.embeddings = embeddings
+
+
+def _fake_voyage_client(captured, embeddings):
+    class FakeAsyncClient:
+        def __init__(self, *args, **kwargs):
+            captured["init"] = kwargs
+
+        async def multimodal_embed(self, **kwargs):
+            captured.update(kwargs)
+            return _FakeVoyageResult(embeddings)
+
+    return FakeAsyncClient
+
+
+async def test_voyage_embed_documents_request_shape(monkeypatch):
+    from haiku.rag.embeddings.voyageai import VoyageMultimodalEmbedder
+
+    captured: dict = {}
+    monkeypatch.setattr(
+        "voyageai.AsyncClient",
+        _fake_voyage_client(captured, [[0.1, 0.2], [0.3, 0.4]]),
+    )
+
+    embedder = VoyageMultimodalEmbedder("voyage-multimodal-3", vector_dim=2)
+    vecs = await embedder.embed_documents(["a cat", "a dog"])
+
+    assert vecs == [[0.1, 0.2], [0.3, 0.4]]
+    assert captured["model"] == "voyage-multimodal-3"
+    assert captured["input_type"] == "document"
+    assert captured["inputs"] == [["a cat"], ["a dog"]]
+    assert captured["output_dimension"] == 2
+
+
+async def test_voyage_embed_query_request_shape(monkeypatch):
+    from haiku.rag.embeddings.voyageai import VoyageMultimodalEmbedder
+
+    captured: dict = {}
+    monkeypatch.setattr(
+        "voyageai.AsyncClient", _fake_voyage_client(captured, [[0.5, 0.6]])
+    )
+
+    embedder = VoyageMultimodalEmbedder("voyage-multimodal-3", vector_dim=2)
+    vec = await embedder.embed_query("find the cat")
+
+    assert vec == [0.5, 0.6]
+    assert captured["model"] == "voyage-multimodal-3"
+    assert captured["input_type"] == "query"
+    assert captured["inputs"] == [["find the cat"]]
+
+
+async def test_voyage_embed_image_passes_pil(monkeypatch):
+    from PIL import Image
+
+    from haiku.rag.embeddings.voyageai import VoyageMultimodalEmbedder
+
+    captured: dict = {}
+    monkeypatch.setattr(
+        "voyageai.AsyncClient", _fake_voyage_client(captured, [[0.7, 0.8]])
+    )
+
+    embedder = VoyageMultimodalEmbedder("voyage-multimodal-3", vector_dim=2)
+    import io
+
+    buf = io.BytesIO()
+    Image.new("RGB", (4, 4), "red").save(buf, format="PNG")
+    vec = await embedder.embed_image(buf.getvalue())
+
+    assert vec == [0.7, 0.8]
+    assert captured["model"] == "voyage-multimodal-3"
+    inputs = captured["inputs"]
+    assert len(inputs) == 1 and len(inputs[0]) == 1
+    assert isinstance(inputs[0][0], Image.Image)
+    assert captured["input_type"] == "document"
+
+
+async def test_voyage_embed_documents_empty_list_skips_request(monkeypatch):
+    from haiku.rag.embeddings.voyageai import VoyageMultimodalEmbedder
+
+    captured: dict = {}
+    monkeypatch.setattr("voyageai.AsyncClient", _fake_voyage_client(captured, []))
+
+    embedder = VoyageMultimodalEmbedder("voyage-multimodal-3", vector_dim=2)
+    assert await embedder.embed_documents([]) == []
+    assert "inputs" not in captured
+
+
+async def test_voyage_get_embedder_routes_to_multimodal(monkeypatch):
+    monkeypatch.setattr("voyageai.AsyncClient", _fake_voyage_client({}, []))
+    from haiku.rag.embeddings.voyageai import VoyageMultimodalEmbedder
+
+    config = AppConfig(
+        embeddings=EmbeddingsConfig(
+            model=EmbeddingModelConfig(
+                provider="voyageai",
+                name="voyage-multimodal-3",
+                vector_dim=1024,
+                multimodal=True,
+            )
+        )
+    )
+    embedder = get_embedder(config)
+    assert isinstance(embedder, VoyageMultimodalEmbedder)
+    assert embedder.supports_images is True
+
+
+@pytest.mark.vcr()
+async def test_voyage_embed_text_and_image_end_to_end():
+    """End-to-end against the real VoyageAI ``multimodal_embed`` API: text and
+    image inputs return embeddings of the configured dimension in a shared
+    vector space. To re-record, set ``VOYAGE_API_KEY`` and run with
+    ``--record-mode=rewrite``."""
+    from PIL import Image
+
+    from haiku.rag.embeddings.voyageai import VoyageMultimodalEmbedder
+
+    embedder = VoyageMultimodalEmbedder("voyage-multimodal-3", vector_dim=1024)
+
+    text_vec = await embedder.embed_query("a photo of a red square")
+    assert len(text_vec) == 1024
+    assert any(abs(x) > 1e-6 for x in text_vec), "text embedding is all zeros"
+
+    text_batch = await embedder.embed_documents(["hello world", "another doc"])
+    assert len(text_batch) == 2
+    assert all(len(v) == 1024 for v in text_batch)
+
+    image_vec = await embedder.embed_image(Image.new("RGB", (64, 64), (255, 0, 0)))
+    assert len(image_vec) == 1024
+    assert any(abs(x) > 1e-6 for x in image_vec), "image embedding is all zeros"
+
+
+class _FakeCohereEmbeddings:
+    def __init__(self, float_):
+        self.float_ = float_
+
+
+class _FakeCohereResult:
+    def __init__(self, float_):
+        self.embeddings = _FakeCohereEmbeddings(float_)
+
+
+def _fake_cohere_client(captured, float_):
+    class FakeAsyncClientV2:
+        def __init__(self, *args, **kwargs):
+            captured["init"] = kwargs
+
+        async def embed(self, **kwargs):
+            captured.update(kwargs)
+            return _FakeCohereResult(float_)
+
+    return FakeAsyncClientV2
+
+
+async def test_cohere_embed_documents_request_shape(monkeypatch):
+    from haiku.rag.embeddings.cohere import CohereMultimodalEmbedder
+
+    captured: dict = {}
+    monkeypatch.setattr(
+        "cohere.AsyncClientV2", _fake_cohere_client(captured, [[0.1, 0.2], [0.3, 0.4]])
+    )
+
+    embedder = CohereMultimodalEmbedder("embed-v4.0", vector_dim=2)
+    vecs = await embedder.embed_documents(["a cat", "a dog"])
+
+    assert vecs == [[0.1, 0.2], [0.3, 0.4]]
+    assert captured["model"] == "embed-v4.0"
+    assert captured["input_type"] == "search_document"
+    assert captured["texts"] == ["a cat", "a dog"]
+    assert captured["output_dimension"] == 2
+    assert captured["embedding_types"] == ["float"]
+
+
+async def test_cohere_embed_query_request_shape(monkeypatch):
+    from haiku.rag.embeddings.cohere import CohereMultimodalEmbedder
+
+    captured: dict = {}
+    monkeypatch.setattr(
+        "cohere.AsyncClientV2", _fake_cohere_client(captured, [[0.5, 0.6]])
+    )
+
+    embedder = CohereMultimodalEmbedder("embed-v4.0", vector_dim=2)
+    vec = await embedder.embed_query("find the cat")
+
+    assert vec == [0.5, 0.6]
+    assert captured["model"] == "embed-v4.0"
+    assert captured["input_type"] == "search_query"
+    assert captured["texts"] == ["find the cat"]
+
+
+async def test_cohere_embed_image_uses_image_input_type(monkeypatch):
+    from haiku.rag.embeddings.cohere import CohereMultimodalEmbedder
+
+    captured: dict = {}
+    monkeypatch.setattr(
+        "cohere.AsyncClientV2", _fake_cohere_client(captured, [[0.7, 0.8]])
+    )
+
+    embedder = CohereMultimodalEmbedder("embed-v4.0", vector_dim=2)
+    vec = await embedder.embed_image(b"\x89PNG\r\n\x1a\nfake")
+
+    assert vec == [0.7, 0.8]
+    assert captured["model"] == "embed-v4.0"
+    assert captured["input_type"] == "image"
+    images = captured["images"]
+    assert len(images) == 1
+    assert images[0].startswith("data:image/png;base64,")
+
+
+async def test_cohere_embed_documents_empty_list_skips_request(monkeypatch):
+    from haiku.rag.embeddings.cohere import CohereMultimodalEmbedder
+
+    captured: dict = {}
+    monkeypatch.setattr("cohere.AsyncClientV2", _fake_cohere_client(captured, []))
+
+    embedder = CohereMultimodalEmbedder("embed-v4.0", vector_dim=2)
+    assert await embedder.embed_documents([]) == []
+    assert "texts" not in captured
+
+
+async def test_cohere_get_embedder_routes_to_multimodal(monkeypatch):
+    monkeypatch.setattr("cohere.AsyncClientV2", _fake_cohere_client({}, []))
+    from haiku.rag.embeddings.cohere import CohereMultimodalEmbedder
+
+    config = AppConfig(
+        embeddings=EmbeddingsConfig(
+            model=EmbeddingModelConfig(
+                provider="cohere",
+                name="embed-v4.0",
+                vector_dim=1536,
+                multimodal=True,
+            )
+        )
+    )
+    embedder = get_embedder(config)
+    assert isinstance(embedder, CohereMultimodalEmbedder)
+    assert embedder.supports_images is True
+
+
+@pytest.mark.vcr()
+async def test_cohere_embed_text_and_image_end_to_end():
+    """End-to-end against the real Cohere ``embed`` API (``embed-v4.0``): text
+    and image inputs return embeddings of the configured dimension in a shared
+    vector space. To re-record, set ``CO_API_KEY`` and run with
+    ``--record-mode=rewrite``."""
+    from PIL import Image
+
+    from haiku.rag.embeddings.cohere import CohereMultimodalEmbedder
+
+    embedder = CohereMultimodalEmbedder("embed-v4.0", vector_dim=1536)
+
+    text_vec = await embedder.embed_query("a photo of a red square")
+    assert len(text_vec) == 1536
+    assert any(abs(x) > 1e-6 for x in text_vec), "text embedding is all zeros"
+
+    text_batch = await embedder.embed_documents(["hello world", "another doc"])
+    assert len(text_batch) == 2
+    assert all(len(v) == 1536 for v in text_batch)
+
+    image_vec = await embedder.embed_image(Image.new("RGB", (64, 64), (255, 0, 0)))
+    assert len(image_vec) == 1536
+    assert any(abs(x) > 1e-6 for x in image_vec), "image embedding is all zeros"