gbrain/docs/integrations/embedding-providers.md

Embedding providers

GBrain ships with 16 embedding-provider recipes covering OpenAI, ZeroEntropy, Voyage, OpenRouter (single key, many hosted models), the major hosted alternatives, three local options, and a universal escape hatch (LiteLLM proxy). Run gbrain providers list to see the live registry; gbrain providers explain --json emits a machine-readable matrix for agents.

This page is the human-readable counterpart: capability per provider, env-var setup, dimensions, cost, and known constraints.

Quick start

gbrain providers list                          # see all providers
gbrain providers env <provider-id>             # see required env vars
gbrain providers test --model openai:text-embedding-3-large   # smoke-test
gbrain init --pglite --model voyage            # use a non-default provider

Init resolves your provider from env keys

As of v0.37, gbrain init --pglite auto-detects which provider to use from your env vars. With OPENAI_API_KEY set, you get OpenAI. With ZEROENTROPY_API_KEY set, you get ZeroEntropy. If multiple provider keys are set, init fires an interactive picker. If no provider keys are set in a non-TTY context (CI, Docker build), init exits 1 with a paste-ready setup hint. Explicit flags (--embedding-model, --no-embedding) always win over env detection.

The resolved provider + dimensions get persisted to ~/.gbrain/config.json atomically, so subsequent runs are deterministic across releases.

TL;DR table

Provider	env vars	default dims	cost ($/1M tokens)	local?	multimodal?
zeroentropyai	ZEROENTROPY_API_KEY	2560 (Matryoshka to 1280/640/320/...)	0.05	no	no
openai	OPENAI_API_KEY	1536	0.13	no	no
openrouter	OPENROUTER_API_KEY	1536	0.02	no	model-dependent
voyage	VOYAGE_API_KEY	1024	0.18	no	yes (voyage-multimodal-3)
google	GOOGLE_GENERATIVE_AI_API_KEY	768	0.025	no	no
azure-openai	AZURE_OPENAI_API_KEY, AZURE_OPENAI_ENDPOINT, AZURE_OPENAI_DEPLOYMENT	1536	0.13	no	no
minimax	MINIMAX_API_KEY	1536	0.07	no	no
dashscope	DASHSCOPE_API_KEY	1024	varies	no	no
zhipu	ZHIPUAI_API_KEY	1024	varies	no	no
ollama	(none — runs locally)	768	0	yes	no
llama-server	(none — runs locally)	user-set	0	yes	no
litellm	LITELLM_API_KEY (optional)	user-set	varies	yes (proxy)	no
together	TOGETHER_API_KEY	768	varies	no	no
anthropic	(no embedding model — chat only)	—	—	—	—
deepseek	(no embedding model — chat only)	—	—	—	—
groq	(no embedding model — chat only)	—	—	—	—

Note on local providers. Ollama and llama-server have no required API key, so they don't show up in env-detection auto-pick. Pick them explicitly with --embedding-model ollama:<model> to avoid silently routing to a daemon that may not be running.

If first import fails

If gbrain import fails with expected N dimensions, not M, run gbrain doctor. The output will print the exact gbrain config set ... or gbrain retrieval-upgrade command to repair the mismatch. You should not need to delete ~/.gbrain. The bug-class that historically forced rm -rf recoveries is closed as of v0.37.

The doctor distinguishes two repair paths:

• Empty brain (no embedded chunks yet) — drop and re-init at the right dim:

  gbrain init --force --pglite --embedding-model <provider>:<model> --embedding-dimensions <N>
  

• Non-empty brain — migrate cleanly with the supported reindex path:

  gbrain retrieval-upgrade --to <provider>:<model> --reindex
  

Decision tree

• Cost-sensitive, English-only: Ollama (free, local) or Voyage (paid, best quality per dollar).
• Quality-first: Voyage voyage-4-large (1024-2048 dims, ~3-4× more dense tokens than OpenAI tiktoken).
• Code-heavy brain (gstack per-worktree, source repos): Voyage voyage-code-3 (1024 default; supports 256/512/1024/2048). Tuned on programming languages. Voyage publishes head-to-head numbers showing it outperforms their general flagships on code retrieval (voyageai.com/blog). For gstack's per-worktree pglite-backed code brain, this is the right default — see Topology 3 in docs/architecture/topologies.md.
• Reranking pair: ZeroEntropy zerank-2 is the hosted default in tokenmax mode (see docs/ai-providers/zeroentropy.md). Voyage rerank-2.5 pairs cleanly with Voyage embeddings.
• Local reranking (no API spend): llama-server-reranker recipe (v0.40.6.1) — point gbrain at your own llama-server --reranking instance running Qwen3-Reranker or self-hosted ZeroEntropy weights. Same gateway.rerank() seam, $0 per call. Walkthrough in docs/ai-providers/llama-server-reranker.md.
• One key for many hosted models: OpenRouter. Set OPENROUTER_API_KEY and use openrouter:<provider>/<model> for chat against GPT-5.2, Claude 4.x, Gemini 3, DeepSeek, and dozens more without juggling per-provider keys. Embedding catalog includes OpenAI, Google, Qwen, BGE-M3.
• Enterprise compliance: Azure OpenAI (data residency + private endpoints) or self-hosted via llama-server / Ollama.
• China region: DashScope (Alibaba) or Zhipu (BigModel). DashScope's international endpoint at dashscope-intl.aliyuncs.com; override provider_base_urls.dashscope for the China endpoint.
• OSS local, full control: llama-server (llama.cpp) for any GGUF model; Ollama for the curated catalog.
• Anything else: LiteLLM proxy. Run LiteLLM in front of any provider (Bedrock, Vertex, Cohere, Jina, Fireworks, etc.) and point gbrain at it via LITELLM_BASE_URL.

Per-provider details

OpenAI

Default. Set OPENAI_API_KEY. Models: text-embedding-3-large (3072 max, 1536 default), text-embedding-3-small (1536). Matryoshka via the dimensions field — gbrain pins it from embedding_dimensions config so existing 1536-dim brains stay aligned across SDK upgrades.

Voyage AI

Best-in-class quality on the Voyage 4 family (Jan 2026 release). Set VOYAGE_API_KEY. Models: voyage-4-large, voyage-4, voyage-4-lite, voyage-4-nano, voyage-3.5, voyage-code-3 (code-tuned), voyage-finance-2, voyage-law-2, voyage-multimodal-3 (text + image).

Voyage 4 family shares an embedding space across all variants, so you can index with voyage-4-large and query with voyage-4-lite without reindexing. Dims: 256, 512, 1024, 2048. 2048 exceeds pgvector's HNSW cap of 2000 — those brains fall back to exact vector scans (still correct, just slower).

For brains that index source code (gstack's per-worktree pglite-backed code brain — see Topology 3 in docs/architecture/topologies.md), prefer voyage-code-3 over voyage-4-large. Voyage tunes it on programming languages and publishes head-to-head numbers vs their general flagships on code retrieval. Configure at install time:

gbrain init --pglite --embedding-model voyage:voyage-code-3 --embedding-dimensions 1024

To switch an existing brain, use gbrain reinit-pglite --embedding-model voyage:voyage-code-3 --embedding-dimensions 1024 (PGLite) or follow docs/embedding-migrations.md (Postgres). gbrain config set embedding_model is refused — the schema column has to resize.

gbrain reindex --code will print a recommendation when run against a brain whose configured embedding model isn't code-tuned; suppress with GBRAIN_NO_CODE_MODEL_NUDGE=1 if you've intentionally chosen another model (single-vendor procurement, compliance, etc.).

Google Gemini

Set GOOGLE_GENERATIVE_AI_API_KEY (the AI Studio public API key). Model: gemini-embedding-001. Default 768 dims; Matryoshka up to 3072. Cheap.

For GCP service-account / Vertex AI auth (production deployments), see the v0.32.x follow-up — Vertex ADC is on the roadmap.

OpenRouter

Single OpenAI-compatible API for fan-out to OpenAI, Anthropic, Google, DeepSeek, Meta Llama, Qwen, and dozens of other hosted providers. One key, many models. Set OPENROUTER_API_KEY and use openrouter:<provider>/<model> (e.g. openrouter:openai/gpt-5.2, openrouter:anthropic/claude-sonnet-4.6).

Embedding: openai/text-embedding-3-small (1536d default, Matryoshka shrink to 512/768/1024). OR's embedding catalog also includes text-embedding-3-large, google/gemini-embedding-2-preview, qwen/qwen3-embedding-8b, bge-m3 — opt in via --embedding-model openrouter:<id>. Pricing matches the upstream provider (OR adds a small markup).

Chat: every chat model OR proxies works through /v1/chat/completions. The recipe lists 8 curated entry points (GPT-5.2 family, Claude 4.5/4.6/4.7, Gemini 3 Flash Preview, DeepSeek); any other OR catalog ID also works. Tool-calling envelope is supported by the OR endpoint, but per-model capability varies — check https://openrouter.ai/models before counting on tools for a specific slug.

Optional env:

• OPENROUTER_BASE_URL — point at a self-hosted OR-compatible proxy.
• OPENROUTER_REFERER (default https://gbrain.ai) and OPENROUTER_TITLE (default gbrain) — attribution headers for OR's leaderboard. Forks running gbrain inside a different agent stack (OpenClaw deployments etc.) should set these so their traffic gets attributed to them, not gbrain.

Subagent loops: gbrain's subagent infrastructure hard-pins to Anthropic-direct (stable tool_use_id across crashes/replays). OR-routed Anthropic is rejected at submit time regardless of the recipe flag. If you want the price/availability story OR offers for tool-calling, use it for chat only and keep an Anthropic key for subagent work.

Azure OpenAI

Enterprise OpenAI behind Azure tenancy. Required env: AZURE_OPENAI_API_KEY, AZURE_OPENAI_ENDPOINT (e.g. https://my-resource.openai.azure.com), AZURE_OPENAI_DEPLOYMENT (the deployment name from your Azure portal). Optional: AZURE_OPENAI_API_VERSION (defaults to 2024-10-21).

Unlike vanilla OpenAI, Azure uses api-key: header (not Authorization: Bearer) and a templated URL with ?api-version= query param — gbrain handles both via the recipe's resolveAuth + resolveOpenAICompatConfig overrides.

Models: text-embedding-3-large, text-embedding-3-small, text-embedding-ada-002 (your Azure deployment must serve the requested model).

MiniMax (海螺AI)

Set MINIMAX_API_KEY. Optional MINIMAX_GROUP_ID for org-scoped accounts. Model: embo-01 (1536 dims).

MiniMax's API takes a type: 'db' | 'query' field for asymmetric retrieval. v0.32 routes everything as type='db' (symmetric retrieval — same vector space for indexing and queries). Asymmetric query support is a v0.32.x follow-up.

DashScope (Alibaba)

Set DASHSCOPE_API_KEY. International endpoint at dashscope-intl.aliyuncs.com by default; override provider_base_urls.dashscope for the China endpoint. Models: text-embedding-v3 (current; Matryoshka 64-1024 dims), text-embedding-v2.

CJK-dominant content tokenizes denser than OpenAI tiktoken; gbrain declares chars_per_token: 2 so the batch pre-split leaves headroom.

Zhipu AI (BigModel)

Set ZHIPUAI_API_KEY. Models: embedding-3 (current; Matryoshka 256-2048 dims), embedding-2. v0.32 default is 1024 (HNSW-compatible). The 2048-dim option works but falls into the exact-scan branch (see Voyage 4 Large note above).

Ollama (local)

No env required — Ollama runs unauthenticated locally. Optional OLLAMA_BASE_URL (default http://localhost:11434/v1) and OLLAMA_API_KEY (for auth-enabled deployments).

Recipe ships with nomic-embed-text (768d, recommended), mxbai-embed-large (1024d), all-minilm (384d). gbrain providers test --model ollama:nomic-embed-text smoke-tests the local install.

llama-server (local, llama.cpp)

llama.cpp's llama-server --embeddings endpoint. No env required. Optional LLAMA_SERVER_BASE_URL (default http://localhost:8080/v1) and LLAMA_SERVER_API_KEY.

User-driven models: launch llama-server with --model <gguf-path> --embeddings, then run gbrain init --embedding-model llama-server:<your-id> --embedding-dimensions <N>. The recipe refuses the implicit shorthand --model llama-server because there's no canonical first model.

LiteLLM proxy (universal escape hatch)

Run LiteLLM in front of any provider — Bedrock, Vertex, Cohere, Jina, Fireworks, OctoAI, etc. The proxy normalizes everything to the OpenAI-compatible API; gbrain points at the proxy via LITELLM_BASE_URL and proxies the call.

This is the catch-all for "my provider isn't in the list above." Set up LiteLLM, then gbrain init --embedding-model litellm:<your-model-id> --embedding-dimensions <N>.

Choosing dimensions

Three numbers matter:

1. Provider's native dims: each model has a "true" output dim (e.g. OpenAI text-embedding-3-large is 3072 native).
2. Matryoshka reductions: most modern providers let you request a smaller vector via the dimensions field.
3. HNSW cap: pgvector's HNSW index supports up to 2000 dims. Brains above that fall back to exact vector scans (slower but correct; gbrain handles the SQL automatically via chunkEmbeddingIndexSql in src/core/vector-index.ts).

For most users: stay at 1024 or 1536. Bigger isn't better below the noise floor; smaller saves disk + RAM with marginal recall loss on Matryoshka providers.

My provider isn't listed

Four options:

1. Use OpenRouter when the provider/model is available through OR's OpenAI-compatible API (covers most hosted chat models + a growing embedding catalog).
2. Use LiteLLM proxy (above) — the universal escape hatch. Works for 100+ providers.
3. Open a feature request at github.com/garrytan/gbrain/issues with the provider's API docs URL and a setup snippet. Recipes are ~30-40 lines of TypeScript.
4. Submit a recipe: clone, copy src/core/ai/recipes/voyage.ts as the gold-standard openai-compat template, register in src/core/ai/recipes/index.ts, add a per-recipe smoke test under test/ai/recipe-<name>.test.ts. The recipe contract test (test/ai/recipes-contract.test.ts) and IRON RULE regression test pin the structural invariants.

Switching providers on an existing brain

Embedding dimensions are baked into the schema at gbrain init time. As of v0.37.11.0, gbrain config set embedding_model and gbrain config set embedding_dimensions are refused — the schema column has to resize alongside the config, and config set only touches the config row.

The supported paths:

• PGLite (default install): gbrain reinit-pglite --embedding-model <provider>:<model> --embedding-dimensions <N> — one-command wipe-and-reinit that preserves every other config field (chat model, expansion model, API keys), backs up the prior brain to <path>.bak, runs gbrain init with the new flags, and re-syncs your brain repo. Add --no-sync to skip the resync, --yes to skip the TTY confirmation, --json for scripts.
• Postgres (Supabase / self-hosted): follow the SQL recipe in docs/embedding-migrations.md (drop the HNSW index, ALTER COLUMN TYPE, clear stale embeddings, recreate the index conditionally, then gbrain init --supabase --embedding-model X --embedding-dimensions N to update the file plane and re-embed).

gbrain doctor 8c "alternative_providers" surfaces unconfigured providers whose env is already set — useful when you've configured OpenAI but also have e.g. VOYAGE_API_KEY exported and want to know you can switch without extra setup.

gbrain doctor 8c "alternative_providers" surfaces unconfigured providers whose env is already set — useful when you've configured OpenAI but also have e.g. VOYAGE_API_KEY exported and want to know you can switch without extra setup.