embeddings-runtime Stinger

You are the playbook for embeddings-runtime-worker-bee. Every invocation produces one concrete artifact: a model or provider recommendation, an on/off decision, a model-swap plan, a batching or caching fix, a daemon-lifecycle fix, or a configuration snippet. Every claim is backed by the ground truth in references/research/ (the new provider-selection sourcing), research/ (the original Hivemind/local-daemon research trail), and, where applicable, the actual Hivemind source under src/embeddings/.

Scope in one sentence

Embedding model selection and runtime, generally: hosted providers (OpenAI, Cohere, Voyage AI) and self-hosted local models, dimension/cost/latency tradeoffs, batching, caching, and the dim-must-match-schema constraint against whichever vector store is in play. The local-daemon (nomic-embed-text-v1.5) material is one fully documented implementation of the self-hosted path, not the whole scope.

When to use this skill

Use when the user says: "which embedding model should I use", "OpenAI vs Cohere vs Voyage", "should I turn embeddings on", "swap the embedding model", "cache embeddings", "batch embedding calls", "the embed daemon is stuck", "change the embedding dimension", or "local vs hosted embeddings".

Covers choosing and calling a hosted provider (OpenAI text-embedding-3, Cohere embed-v3/v4, Voyage AI) or running a self-hosted local model (transformers.js), dimension and cost tradeoffs, batching, caching to avoid re-embedding identical text, and the dim-must-match-schema constraint against pgvector (this stack's default) or Deep Lake. The local-daemon material (nomic-embed-text-v1.5, 768-dim, q8, Unix-socket IPC) is kept as one documented self-hosted implementation.

Do NOT use for the vector column/index/schema mechanics themselves (vector-store-stinger), API key security (security-worker-bee), or PRD authorship (library-worker-bee).

Invocation modes (routing table)

Read the user's request and match to one mode. Most requests match one primary mode with one supporting mode.

Mode	Trigger phrases	Primary guide
selection	"which embedding model", "OpenAI vs Cohere vs Voyage", "local or hosted", "what should I use for embeddings"	guides/00-selection-matrix.md
hosted-openai	"text-embedding-3", "OpenAI embeddings", "dimensions parameter"	guides/hosted-01-openai.md
hosted-cohere	"embed-v4", "Cohere embeddings", "input_type", "search_document vs search_query"	guides/hosted-02-cohere.md
hosted-voyage	"Voyage AI", "voyage-4", "voyage embeddings"	guides/hosted-03-voyage.md
batching	"batch embedding calls", "rate limit", "bulk embed", "backfill embeddings"	guides/01-batching.md
caching	"cache embeddings", "avoid re-embedding", "duplicate embedding calls"	guides/02-caching.md
local-daemon-lifecycle	"embed daemon stuck", "warmup", "daemon won't start", "first embedding is slow"	guides/local-daemon-01-lifecycle.md
local-daemon-ipc	"socket protocol", "NDJSON", "client can't reach daemon", "unix socket path"	guides/local-daemon-02-ipc-protocol.md
local-daemon-model-selection	"swap the embedding model" (on the Hivemind local daemon), "nomic vs other"	guides/local-daemon-03-model-selection.md
local-daemon-quantization	"q8 vs fp32", "footprint", "quantization quality" (local daemon)	guides/local-daemon-04-quantization-and-footprint.md
local-daemon-on-vs-off	"should I turn embeddings on", "is 600MB worth it", "BM25 fallback" (Hivemind)	guides/local-daemon-05-embeddings-vs-bm25.md
local-vs-hosted-hivemind	"run embeddings locally or hosted" (Hivemind specifically)	guides/local-daemon-06-local-vs-hosted.md
schema-and-dim	"change the dimension", "dim mismatch", "schema event", "EMBEDDING_DIMS"	guides/local-daemon-07-schema-and-columns.md (Deep Lake) or vector-store-stinger (pgvector)

First action on every invocation

1. Read guides/00-principles.md, the non-negotiables that govern every output regardless of provider or runtime.
2. Match the request to the routing table above. If no store or provider has been chosen yet, start at guides/00-selection-matrix.md rather than assuming.
3. Open the relevant guide(s) before producing any output.

Folder layout

embeddings-runtime-stinger/
├── SKILL.md                                     (this file, master index)
├── guides/
│   ├── 00-principles.md                         (stack-neutral non-negotiables, severity rubric, cross-Bee handoffs)
│   ├── 00-selection-matrix.md                   (hosted vs self-hosted; OpenAI vs Cohere vs Voyage; quick decision table)
│   ├── 01-batching.md                           (batch sizing, rate limits/backoff, discounted async batch lanes)
│   ├── 02-caching.md                            (cache key design, TTL vs event-driven invalidation, cold-start/single-flight)
│   ├── hosted-01-openai.md                      (text-embedding-3-small/large: dims, pricing, dimensions param, no input_type)
│   ├── hosted-02-cohere.md                      (embed-v3/v4: required input_type, output_dimension, embedding_types)
│   ├── hosted-03-voyage.md                      (voyage-4 family: input_type, Matryoshka + quantization, open-weight voyage-4-nano)
│   ├── local-daemon-01-lifecycle.md             (self-hosted: warmup, batching, shared install, crash recovery)
│   ├── local-daemon-02-ipc-protocol.md          (self-hosted: Unix-socket NDJSON protocol; framing; handshake; failure modes)
│   ├── local-daemon-03-model-selection.md       (self-hosted: Hivemind-scoped model rubric, worked example of 00-selection-matrix)
│   ├── local-daemon-04-quantization-and-footprint.md (self-hosted: q8 vs fp16/fp32 weight quantization for the CPU daemon)
│   ├── local-daemon-05-embeddings-vs-bm25.md     (self-hosted: the on-vs-off decision; BM25/ILIKE lexical fallback)
│   ├── local-daemon-06-local-vs-hosted.md        (self-hosted: Hivemind-specific worked example of local vs hosted)
│   └── local-daemon-07-schema-and-columns.md     (self-hosted: EMBEDDING_DIMS=768; FLOAT4[] columns; Deep Lake schema event)
├── examples/
│   ├── daemon-warmup-and-ipc.md                 (warm the local daemon, send a batch over the socket, read NDJSON back)
│   ├── embedding-model-comparison.md            (filled-in model comparison scoped to Hivemind recall)
│   └── enable-embeddings-workflow.md            (turn HIVEMIND_EMBEDDINGS + HIVEMIND_SEMANTIC_SEARCH on end-to-end)
├── templates/
│   ├── embedding-model-swap-plan.md             (the model/dim swap plan covering the schema migration)
│   └── dim-migration-checklist.md               (step-by-step dim-change checklist with the schema-heal handoff)
├── reports/
│   └── README.md                                (describes how past recommendation/audit reports accumulate)
├── references/
│   └── research/
│       ├── distilled-embeddings-runtime.md      (synthesis of the hosted-provider + batching/caching sourcing below)
│       └── raw/                                 (9 archived sources: OpenAI, Cohere, Voyage, transformers.js, caching, batching)
└── research/                                    (the original Hivemind/local-daemon research trail, unchanged)
    ├── research-plan.md
    ├── research-summary.md
    ├── index.md
    ├── internal/
    │   └── command-brief-notes.md
    └── external/
        ├── nomic-embed-text-v1.5.md
        ├── q8-quantization-tradeoffs.md
        ├── transformers-js-runtime.md
        ├── deeplake-vector-columns.md
        ├── embedding-model-landscape.md
        └── local-vs-hosted-embeddings.md

Canonical defaults

Two default tables: one for the self-hosted local-daemon implementation (unchanged from the original Hivemind scope), one for hosted-provider selection on this repo's general stack.

Self-hosted local-daemon defaults (Hivemind implementation)

Decision	Recommended default	Rationale
Embeddings engine	@huggingface/transformers ^3 (optional dep)	Pure JS/WASM runtime; runs in-process via a daemon; no native build needed
Embedding model	nomic-ai/nomic-embed-text-v1.5	Strong retrieval quality at 768 dim; the dim the Hivemind schema is built around
Quantization	q8	Best footprint/latency/quality balance for CPU inference; ~600MB on-disk install
Dimension	768 (EMBEDDING_DIMS)	Locked to the Deep Lake FLOAT4[] columns; changing it is a schema event
Default state	OFF	HIVEMIND_EMBEDDINGS and HIVEMIND_SEMANTIC_SEARCH both off; recall falls back to BM25/ILIKE
Daemon transport	Unix-socket NDJSON IPC	protocol.ts + client.ts; one warm process, batched requests

See guides/local-daemon-*.md for the full detail.

Hosted-provider defaults (general, this repo's stack)

Decision	Recommended default	Rationale
Starting point	A hosted provider (OpenAI or Voyage)	Zero ops burden, minutes to first call; see guides/00-selection-matrix.md
Provider to start with	OpenAI text-embedding-3-small	Simple symmetric call shape (no input_type discipline to get wrong), competitive pricing
Move to self-hosted when	A measured high-volume, predictable workload makes per-token cost a real line item, or text cannot leave the machine	Not a hunch; see the escape-hatch framing in guides/00-selection-matrix.md
Dimension	Match the target column, prefer Matryoshka truncation over a different model	All three hosted providers and nomic-embed-text-v1.5 support request-time or post-hoc truncation
Batching	Batch to the provider's per-call limit for bulk work; use the discounted async batch lane for backfills	Network round-trip, not inference, dominates embedding-call latency
Caching	Always, for any pipeline that re-processes overlapping content	Embeddings are a pure function of (model, version, text); caching is safe and close to free to add

Severity rubric

Used to classify findings when auditing an existing embeddings setup, on any provider or runtime. Full version in guides/00-principles.md; summary:

• Must-fix: embedding dimension does not match the target column/collection width; embeddings written with one model then queried as if from another; a dimension change shipped without the schema migration path; a hosted-provider asymmetric input_type (Cohere search_document/search_query, Voyage document/query) used inconsistently between write and query paths.
• Should-refactor: embeddings turned on with no measured recall lift over the lexical fallback; a self-hosted daemon spawned per-request instead of warmed once; a hosted API called per-item instead of batched; no embedding cache on a pipeline that repeatedly re-processes overlapping content; quantization or footprint heavier than justified.
• Style / nice-to-have: no crash-recovery or retry handling on the embedding call path; warmup or rate-limit backoff not surfaced as an expected cost; model or provider choice undocumented.

Cross-Bee handoffs

Surface these explicitly rather than attempting them inline:

• vector-store-stinger / vector-store-worker-bee for the actual schema/column mechanics when a dimension change forces a migration (pgvector column resize on this repo's default stack, or Deep Lake schema-heal on a Hivemind-style project). This Bee decides the dimension and writes the swap plan; vector-store-worker-bee executes the schema event.
• security-worker-bee if a hosted embedding provider is considered and an API key or data-egress review is needed.
• library-worker-bee for PRD authorship when turning embeddings on, or a model/provider swap, needs to be documented as a feature requirement.

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Part of The Hive, curated by Mario Aldayuz a.k.a @thenotoriousllama.