Persistent memory MCP server. 25 tools, BM25+MMR+OOD retrieval, CFR-21 audit, knowledge graph.
Most knowledge and memory work still happens through a UI a human drives. Cuba MCP server moves it into the conversation instead. Persistent memory MCP server. 25 tools, BM25+MMR+OOD retrieval, CFR-21 audit, knowledge graph.
Written in Rust. Backed by PostgreSQL + pgvector. 28 MCP tools (29 with CUBA_DOCS=1), 19 CLI commands, and every number below measured on a benchmark that — as of v0.12 — actually measures what it claims to. (The previous one did not. See Measured.)
The server publishes 1 tool. What each one is for:
Retrieval — Hybrid RRF fusion (k=60, Cormack 2009) over three signals — full-text, BM25 (ts_rank_cd), and pgvector HNSW — with entropy-routed weighting thatcuba-memorys on npm is all you need. Most clients run it directly, so configuration is a few lines and a restart.
Configuration is passed through the environment: DATABASE_URL, CUBA_HTTP_TOKEN, ORT_DYLIB_PATH, CUBA_RERANKER_PATH, ONNX_MODEL_PATH, CUBA_NLI_PATH. Treat anything key-shaped as a real credential — scope it to the minimum the server needs, and rotate it if it ever lands in a shared config.
Plenty of knowledge and memory servers cover similar ground. The differences that matter in practice are scope of access and how much setup stands between you and a working tool call. Cuba's toolset — Retrieval — is a fair guide to whether it matches your workflow. It is maintained by LeandroPG19; worth a glance at recent repository activity before you build anything load-bearing on it.
SyncDev reviews every entry in this directory against the project's own documentation before publishing, and revisits them as servers change.
| Tool | What it does |
|---|---|
| Retrieval | Hybrid RRF fusion (k=60, Cormack 2009) over three signals — full-text, BM25 (ts_rank_cd), and pgvector HNSW — with entropy-routed weighting that shifts from keyword-heavy to semantic as the query's Shannon entropy rises. |
{
"mcpServers": {
"cuba-memorys": {
"command": "npx",
"args": ["-y", "cuba-memorys"],
"env": {
"DATABASE_URL": "your-value",
"CUBA_HTTP_TOKEN": "your-value",
"ORT_DYLIB_PATH": "your-value",
"CUBA_RERANKER_PATH": "your-value",
"ONNX_MODEL_PATH": "your-value",
"CUBA_NLI_PATH": "your-value"
}
}
}
}Add to claude_desktop_config.json, then restart Claude Desktop.
| Variable | Description | Required |
|---|---|---|
| DATABASE_URL | Endpoint or connection string the server talks to. | Yes |
| CUBA_HTTP_TOKEN | Credential the server authenticates with. | Yes |
| ORT_DYLIB_PATH | Filesystem location the server is allowed to use. | Optional |
| CUBA_RERANKER_PATH | Filesystem location the server is allowed to use. | Optional |
| ONNX_MODEL_PATH | Filesystem location the server is allowed to use. | Optional |
| CUBA_NLI_PATH | Filesystem location the server is allowed to use. | Optional |
A knowledge graph your assistant keeps between sessions — entities, relations and observations that persist.
Kill hallucinated APIs — version-accurate, up-to-date library documentation injected straight into context.
Your workspace, on speaking terms with AI — search, read and write Notion pages and databases.
A structured scratchpad for hard problems — stepwise reasoning with revisions, branches and visible logic.
Symbol-level code navigation, refactoring and memory for coding agents — the IDE brain your assistant has been missing.
Chat with your second brain — search, read and write vault notes through the Local REST API.