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[ARTICLE · art-29768] src=shivvr.nuts.services ↗ pub= topic=ai-tools verified=true sentiment=· neutral

Show HN: Shivvr – Ephemeral semantic embedding and cognitive agent service

Shivvr, an ephemeral semantic embedding and cognitive agent service, launched on Show HN, offering chunking, embedding with GTR-T5-base, hybrid FST-BM25 search, and turn-based agent reasoning via Model Context Protocol (MCP). The service supports zero-config integration with Claude Code, Antigravity, and Codex, and provides per-agent orthogonal matrix rotation on embeddings for encryption.

read4 min views1 publishedJun 16, 2026

Ephemeral semantic embedding & cognitive agent service.

Chunk text. Embed with GTR-T5-base. Search via hybrid FST-BM25 vector rank fusion. Stream turn-based cognitive agent reasoning via native Model Context Protocol (MCP).

Sentence-boundary chunking + GTR-T5-base embeddings (768d). Stores in RwLock<HashMap> — pure ephemeral compute.

RRF blending dense vectors and sparse lexical indices. FST dictionary scanning provides microsecond safe query guardrails and intent-entity score boosting.

Turn-based agent loop with integrated memory search, document ingestion, session indexing, and sandboxed command execution. Powered by OpenAI/Anthropic.

Complete Model Context Protocol HTTP/SSE server endpoint (/mcp/sse

) allowing immediate, zero-config integration with Claude Code, Antigravity, and Codex.

Per-agent orthogonal matrix rotation on embeddings. Cosine similarity preserved under encryption. Keys are in-memory only.

organize

role uses GTR-T5-base (768d). retrieve

role uses OpenAI text-embedding-ada-002 (1536d) — pass your own key or set server-side.

Method Endpoint Description
GET /health Status, model info, live counts
GET /mcp/sse MCP Server SSE handshake
POST /mcp/message MCP Server JSON-RPC message router
POST /sessions/:id/agent/chat Stream non-blocking GhostAgent cognitive turns (SSE)
POST /sessions/:id/ingest Chunk + embed text into session
GET /sessions/:id/search?q=... Semantic search (supports RRF hybrid & lexical_only )
GET /sessions/:id Session metadata
DELETE /sessions/:id Delete session
GET /temp List temp stores with TTL
POST /temp/:name/ingest Ingest into temp store (2 hr TTL)
GET /temp/:name/search?q=... Search temp store
DELETE /temp/:name Delete temp store
POST /agent/:id/register Register per-agent orthogonal key
POST /agent/:id/encrypt Encrypt embeddings
POST /agent/:id/decrypt Decrypt embeddings
POST /invert Reconstruct text from embedding vector
curl -X POST https://shivvr.nuts.services/sessions/my-session/ingest \
  -H "Content-Type: application/json" \
  -d '{"text": "Supreme Raven is protected by Known Opossum.", "source": "vault_specs"}'

curl -i -X POST http://localhost:8085/sessions/my-session/agent/chat \
  -H "Content-Type: application/json" \
  -d '{"message": "Who protects the Supreme Raven?"}'

curl "http://localhost:8085/sessions/my-session/search?q=Known+Opossum&hybrid=true"

curl "http://localhost:8085/sessions/my-session/search?q=Opossum&lexical_only=true"

nemesis8 mcp add http://localhost:8085/mcp/sse
Param Default Description
q required Query text
n 5 Number of results
hybrid false Blend semantic vectors + BM25 scores (Reciprocal Rank Fusion)
lexical_only false Bypass vector embedder, execute pure BM25 search
guardrail true Enable FST toxic term scanning and automatic query blocking
role organize organize (768d local) or retrieve (1536d OpenAI)
time_weight 0.0 Blend semantic + recency score (0–1)
decay_halflife_hours 168 Recency decay half-life in hours
include_nearby false Return temporally adjacent chunks
agent_id Agent ID for encrypted search
openai_api_key Per-request OpenAI key for retrieve role (overrides server key)
Variable Default Description
PORT 8080 Listen port
MODEL_PATH models/gtr-t5-base.onnx GTR-T5-base ONNX embedder
TOKENIZER_PATH models/tokenizer.json Tokenizer
OPENAI_API_KEY Enables OpenAI completions and retrieve embeddings
ANTHROPIC_API_KEY Enables Anthropic completions and GhostAgent loops
NUTS_AUTH_JWKS_URL Enable auth (open dev mode if unset)
NUTS_AUTH_VALIDATE_URL https://auth.nuts.services/api/validate API token validation endpoint
Layer Choice
Runtime Rust + Tokio + axum
Cognition GhostAgent cognitive RAG turn loop (OpenAI / Anthropic compat)
MCP Server HTTP/SSE JSON-RPC 2.0 Model Context Protocol transport layer
Hybrid Index Tantivy FST deterministic phrase engine + BM25F field indexer
Embedding GTR-T5-base (768d) via ONNX Runtime 2.0 — local, required
Storage Ephemeral RwLock<HashMap> — no disk, no volume mounts
GPU CUDA 12.6 via ort EP on Cloud Run L4 — CPU fallback automatic
Inversion vec2text gtr-base (projection + T5 enc/dec) — optional
── more in #ai-tools 4 stories · sorted by recency
── more on @shivvr 3 stories trending now
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