feat: Phase 2 — embeddings + hybrid memory.search

Adds a small embedder sidecar (Xenova/bge-small-en-v1.5, ONNX, CPU-only)
that the web app calls inline on memory.write and memory.update, and on
demand from the new memory.search tool.

memory.search performs three candidate fetches in parallel — pgvector
cosine similarity, Postgres full-text via plainto_tsquery + ts_rank_cd,
and tag-set overlap — then fuses them with Reciprocal Rank Fusion
(k=60). Each result carries its per-source rank so the model can see
*why* a memory surfaced.

The migrator boot step gained an idempotent embedding backfill: any row
with embedding IS NULL is batched (32 at a time) through the embedder
after SQL migrations apply. Safe to run on every boot.

New tool memory.update fixes the missing edit path; centralises the
re-embed-on-content-change rule alongside write.

Stack additions:
- apps/embedder/ — Fastify server, persistent /data/models volume so the
  ~30 MB model only downloads once
- apps/web/lib/embedder.ts — typed HTTP client with batched embed +
  health probe
- packages/schemas — MemoryUpdateInput, MemorySearchInput
- docker-compose — embedder service, healthcheck, app + migrator both
  depend_on it healthy; EMBEDDER_URL promoted to a required env var

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
This commit is contained in:
2026-05-15 09:04:44 -07:00
co-authored by Claude Opus 4.7
parent e1fa1197f4
commit 9a8b504f51
12 changed files with 1523 additions and 19 deletions
+62
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# syntax=docker/dockerfile:1.7
# -----------------------------------------------------------------------------
# Embedder sidecar.
#
# Builds from the repo root: docker build -f apps/embedder/Dockerfile .
# -----------------------------------------------------------------------------
FROM node:20-alpine AS base
RUN corepack enable
WORKDIR /app
# ---------- deps ----------
FROM base AS deps
COPY package.json pnpm-workspace.yaml pnpm-lock.yaml .npmrc ./
COPY apps/embedder/package.json ./apps/embedder/
# Other workspace package.json files needed so pnpm install can resolve the
# workspace before --filter narrows things down.
COPY apps/web/package.json ./apps/web/
COPY packages/schemas/package.json ./packages/schemas/
RUN --mount=type=cache,id=pnpm,target=/root/.local/share/pnpm/store \
pnpm install --frozen-lockfile --filter @shared-memory/embedder...
# ---------- builder ----------
FROM base AS builder
COPY --from=deps /app/node_modules ./node_modules
COPY --from=deps /app/apps/embedder/node_modules ./apps/embedder/node_modules
COPY . .
# Compile TS to JS.
RUN cd apps/embedder \
&& pnpm exec tsc -p tsconfig.json --noEmit false --outDir dist
# Prune devDependencies so the runtime image only ships production deps.
RUN cd apps/embedder \
&& pnpm install --prod --frozen-lockfile --filter @shared-memory/embedder...
# ---------- runner ----------
FROM node:20-alpine AS runner
WORKDIR /app
ENV NODE_ENV=production \
PORT=8080 \
HOST=0.0.0.0 \
MODEL_CACHE_DIR=/data/models
RUN apk add --no-cache wget \
&& addgroup --system --gid 1001 nodejs \
&& adduser --system --uid 1001 --ingroup nodejs node-embedder \
&& mkdir -p /data/models \
&& chown -R node-embedder:nodejs /data
COPY --from=builder --chown=node-embedder:nodejs /app/apps/embedder/dist ./dist
COPY --from=builder --chown=node-embedder:nodejs /app/apps/embedder/node_modules ./node_modules
COPY --from=builder --chown=node-embedder:nodejs /app/apps/embedder/package.json ./package.json
USER node-embedder
EXPOSE 8080
VOLUME ["/data/models"]
HEALTHCHECK --interval=15s --timeout=5s --start-period=120s --retries=5 \
CMD wget -q -O - http://127.0.0.1:8080/health | grep -q '"ready":true' || exit 1
CMD ["node", "--enable-source-maps", "dist/index.js"]
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{
"name": "@shared-memory/embedder",
"version": "0.1.0",
"private": true,
"type": "module",
"scripts": {
"dev": "tsx watch src/index.ts",
"build": "tsc --noEmit",
"start": "node --enable-source-maps dist/index.js",
"typecheck": "tsc --noEmit"
},
"dependencies": {
"@xenova/transformers": "^2.17.2",
"fastify": "^5.2.0"
},
"devDependencies": {
"@types/node": "^22.10.2",
"tsx": "^4.19.2",
"typescript": "^5.7.2"
}
}
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/**
* Embedder sidecar — loads a small ONNX model once at boot and serves
* mean-pooled, L2-normalized sentence embeddings over HTTP.
*
* Endpoints:
* GET /health → { status, ready, model, dim }
* POST /embed → { vectors: number[][] } given { texts: string[] }
*
* Used by the web app's memory.write / memory.update / memory.search and
* by the migrator's one-shot backfill step.
*/
import Fastify from "fastify";
import { pipeline, env as txEnv } from "@xenova/transformers";
// Persist the downloaded model on a named docker volume so subsequent
// boots don't re-fetch ~30 MB.
txEnv.cacheDir = process.env.MODEL_CACHE_DIR ?? "/data/models";
txEnv.allowLocalModels = true;
txEnv.allowRemoteModels = true;
const MODEL_NAME = process.env.EMBEDDING_MODEL ?? "Xenova/bge-small-en-v1.5";
const EXPECTED_DIM = Number.parseInt(process.env.EMBEDDING_DIM ?? "384", 10);
const PORT = Number.parseInt(process.env.PORT ?? "8080", 10);
const HOST = process.env.HOST ?? "0.0.0.0";
// The pipeline()'s return type is a giant union covering every task; we
// only use feature-extraction, so a narrower call signature is much easier
// to work with than the upstream typing.
interface FeatureExtractor {
(
texts: string[],
options: { pooling: "mean" | "cls"; normalize: boolean },
): Promise<{ tolist: () => number[] | number[][] }>;
}
let extractor: FeatureExtractor | null = null;
async function loadModel() {
const start = Date.now();
console.log(`[embedder] loading ${MODEL_NAME}`);
// Quantized=true is the @xenova default and is fast enough; flip via env if
// we ever need the full-precision model.
extractor = (await pipeline("feature-extraction", MODEL_NAME, {
quantized: process.env.EMBEDDER_QUANTIZED !== "false",
})) as unknown as FeatureExtractor;
console.log(`[embedder] model ready in ${Date.now() - start}ms`);
}
const app = Fastify({
logger: { level: process.env.LOG_LEVEL ?? "info" },
bodyLimit: 5 * 1024 * 1024, // 5 MB — generous for batched embeds
});
app.get("/health", async () => ({
status: "ok",
ready: extractor !== null,
model: MODEL_NAME,
dim: EXPECTED_DIM,
}));
interface EmbedRequest {
texts: string[];
}
app.post("/embed", async (req, reply) => {
if (!extractor) {
return reply.code(503).send({ error: "model not loaded yet" });
}
const body = req.body as EmbedRequest | null;
if (!body || !Array.isArray(body.texts)) {
return reply.code(400).send({ error: "body must be { texts: string[] }" });
}
if (body.texts.length === 0) {
return { vectors: [] };
}
if (body.texts.length > 256) {
return reply.code(400).send({ error: "max 256 texts per request" });
}
if (body.texts.some((t) => typeof t !== "string")) {
return reply.code(400).send({ error: "every entry in texts must be a string" });
}
// Mean-pool the per-token hidden states and L2-normalize so cosine sim
// matches the inner-product distance we'll feed into pgvector.
const output = await extractor(body.texts, {
pooling: "mean",
normalize: true,
});
// Transformers.js returns a Tensor; .tolist() gives nested JS arrays.
// For batches the shape is [batch, dim]; for a single input the wrapper
// may collapse to [dim] — defensively re-wrap.
const raw = output.tolist();
const vectors: number[][] = Array.isArray(raw[0])
? (raw as number[][])
: [raw as number[]];
// Sanity-check the dimension once at runtime — catches a model swap that
// wasn't accompanied by an EMBEDDING_DIM bump.
if (vectors[0] && vectors[0].length !== EXPECTED_DIM) {
return reply.code(500).send({
error: `model produced dim=${vectors[0].length}, expected ${EXPECTED_DIM}`,
});
}
return { vectors };
});
async function start() {
await loadModel();
await app.listen({ host: HOST, port: PORT });
console.log(`[embedder] listening on http://${HOST}:${PORT}`);
}
start().catch((err) => {
console.error("[embedder] startup failed:", err);
process.exit(1);
});
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{
"extends": "../../tsconfig.base.json",
"compilerOptions": {
"rootDir": "./src",
"outDir": "./dist",
"noEmit": false,
"declaration": false,
"module": "ESNext",
"moduleResolution": "Bundler",
"lib": ["ES2022"]
},
"include": ["src/**/*.ts"]
}