delx-memory

Local-first persistent memory MCP server. One shared SQLite store any MCP-speaking agent (Claude Desktop, Cursor, Hermes, OpenClaw, Codex) can read and write — so context survives across sessions AND across tools.

Why

Every chat client has its own ephemeral context. Quit the tab → preferences gone. Switch from Claude Desktop to Cursor → starting from scratch. Pin a side project in Hermes → invisible to the next agent.

delx-memory is a tiny MCP server that exposes a single shared SQLite file as a key/value memory layer. Any client that speaks MCP can read and write the same memory file → real continuity, real cross-tool context.

15 tools — discovery + handoff + batch ops + FTS5 search + mutations gated by intent.
SQLite at ~/.delx-memory/db.sqlite (0700 dir, 0600 file).
Secret-blocking: refuses to store credential-shaped keys or values.
TTL support (lazy expiry on read).
Tags + prefix filters + FTS5 full-text search (bm25 ranking, stemming, diacritic folding; LIKE fallback if FTS5 is unavailable).
Mutations require explicit_user_intent: true so over-eager agents can't silently rewrite your context.
Zero telemetry. Zero phone-home. The file is yours.

Multi-agent namespaces

bash

# Agent A
DELX_MEMORY_NAMESPACE=claude npx -y delx-memory

# Agent B (same machine, isolated keys)
DELX_MEMORY_NAMESPACE=cursor npx -y delx-memory

Keys are stored as namespace::key. Omit the env var for a single global store (default).

Footprint / lightweight mode

Default transport is lite: tools-only MCP over stdio without loading the MCP SDK (biggest RSS win for always-on agents).
Full SDK surface (prompts + resources): delx-memory --sdk or DELX_MEMORY_TRANSPORT=sdk.
Optional HTTP: delx-memory --http (Express + SDK; still loopback by default).
DELX_MEMORY_LEAN=1 applies to the SDK path only (skip prompts/resources).
doctor --json reports rss_kb. Dominant remaining cost is Node + native better-sqlite3 (no embeddings).

Community measurements (custom transport vs SDK) pointed at the SDK tree as the main overhead — see issue #7.

Install + run

bash

# Run once (npx will download + boot)
npx -y delx-memory doctor

# Or install globally
npm install -g delx-memory
delx-memory doctor

The doctor command checks Node version, DB writability, and file permissions, then prints next steps.

HTTP (v2 stateless)

Default is stdio. Optional Streamable HTTP — no session id, JSON responses, loopback only:

Terminal

npx -y delx-memory --http
# GET  http://127.0.0.1:3030/health
# POST http://127.0.0.1:3030/mcp   (sessionless)

Env: DELX_MEMORY_HOST, DELX_MEMORY_PORT, DELX_MEMORY_TRANSPORT=http.

Wire it into your MCP client

Claude Desktop

Add to ~/Library/Application Support/Claude/claude_desktop_config.json (macOS):

config.json

{
  "mcpServers": {
    "delx-memory": {
      "command": "npx",
      "args": ["-y", "delx-memory"]
    }
  }
}

Then restart Claude Desktop. See examples/claude-desktop.json.

Cursor

Add to ~/.cursor/mcp.json. See examples/cursor.json.

What makes it different (honest)

	delx-memory	Typical cloud memory	Graph memory MCP
Data leaves your machine	No	Yes	Usually no
Multi-client same store	Yes (one SQLite)	Account-bound	Process-local
Agent mutation safety	`explicit_user_intent`	Varies	Rare
Secret storage	Hard-refused	Often allowed	Often allowed
Default RSS path	Lite (no MCP SDK)	N/A	Full stack
Multi-agent isolation	`DELX_MEMORY_NAMESPACE`	Tenants	Manual
Search	FTS5 bm25	Embeddings (cost/leak)	Graph walk

Not a vector DB. Not a second brain SaaS. Local continuity for agents that already have a model.

Tools (15)

Session start

Tool	Purpose
`memory_handoff`	One-call resume brief: stats + recent keys (optional values). Prefer this at session start.
`memory_agent_manifest`	Machine install/ops contract for agents.
`memory_connection_status` / `memory_stats`	Readiness + store size.
`memory_capabilities` / `memory_data_inventory`	Self-description for agents.

Reads

Tool	Purpose
`memory_list`	Keys only; filters: `prefix`, `tag`, `since` (delta sync).
`memory_get` / `memory_get_many`	Exact key or batch (max 50).
`memory_search`	FTS5 bm25 (+ LIKE fallback). See search quickstart.

Mutations (require `explicit_user_intent: true`)

Tool	Purpose
`memory_set` / `memory_set_batch`	Upsert one key or up to 50 in one transaction.
`memory_forget` / `memory_forget_by_tag`	Delete one key or by tag.
`memory_export`	Dump JSON / JSONL / Markdown.

Every mutation refuses to run unless the caller passes explicit_user_intent: true. The intent: an agent that decides on its own to update memory must show its work. The user can see the flag in the tool call and reject it if they didn't ask.

Privacy contract (read this)

delx-memory is NOT a secrets manager. Use macOS Keychain / gnome-keyring / Windows Credential Manager for those.

What we refuse to store:

Keys matching: oauth, token, secret, password, cookie, refresh, api_key, api-key, apikey, bearer, credential, session_id (case-insensitive).
Values matching credential shapes:
- JWT tokens (eyJ…)
- Bearer <token> headers
- Stripe sk_live_… / sk_test_…
- Slack xoxb-… / xoxp-… / etc.
- GitHub github_pat_… / ghp_… / gho_… / ghs_… / ghr_…
- OpenAI / Anthropic sk-… (with realistic length)
- AWS access keys AKIA…
- Authorization: <scheme> <token> strings
Nested objects are walked recursively — a nested field named refresh_token (even with an empty value) is rejected.

What stays local:

The DB file lives at ~/.delx-memory/db.sqlite.
Directory is created with mode 0700; file with mode 0600. (Best effort on Windows / WSL / non-POSIX filesystems.)
Nothing is uploaded. No telemetry. No phone-home.

What we do NOT promise:

Other users of the same machine (root, your sudo-using housemate) can read the file. Use full-disk encryption (FileVault, BitLocker, LUKS) if that matters.
TTL is best-effort. Expired rows are deleted lazily on next read; SQLite doesn't VACUUM automatically, so freed pages may sit on disk. For sensitive ephemera, treat the DB file like any other unencrypted dotfile.
No durability promise. Back up ~/.delx-memory/db.sqlite like any other dotfile if you care about losing it.

Example session

Code

agent> memory_stats({})
→ { total_keys: 0, db_path: "/Users/me/.delx-memory/db.sqlite", … }

user> Remember that I prefer concise responses in pt-BR.

agent> memory_set({
  key: "user_preferences",
  value: { language: "pt-BR", verbosity: "concise" },
  tags: ["profile", "preferences"],
  explicit_user_intent: true
})
→ { action: "created", key: "user_preferences", … }

# … new chat, possibly different tool …

agent> memory_list({ tag: "preferences" })
→ [{ key: "user_preferences", updated_at: … }]

agent> memory_get({ key: "user_preferences" })
→ { found: true, value: { language: "pt-BR", verbosity: "concise" } }

Storage layout


Default path	`~/.delx-memory/db.sqlite`
Override	`DELX_MEMORY_PATH` env var
Directory mode	`0700`
File mode	`0600`
Schema	`memory(key PRIMARY KEY, value, created_at, updated_at, ttl_expires_at, tags, metadata)`
Indexes	partial index on `ttl_expires_at`, plus `tags`, `updated_at`
Per-value cap	64 KB (JSON-serialized)
Per-key cap	512 chars

CLI

Code

delx-memory                Start MCP stdio server
delx-memory --http         Start local HTTP MCP server (127.0.0.1:3030)
delx-memory setup          Print MCP client config snippets
delx-memory setup --json   Print as JSON
delx-memory doctor         Health check + next steps
delx-memory doctor --json  Health check as JSON
delx-memory version        Print version

Environment

Var	Default	Purpose
`DELX_MEMORY_PATH`	`~/.delx-memory/db.sqlite`	DB file location
`DELX_MEMORY_TRANSPORT`	`stdio`	`stdio` or `http`
`DELX_MEMORY_HOST`	`127.0.0.1`	HTTP host
`DELX_MEMORY_PORT`	`3030`	HTTP port
`DELX_MEMORY_ALLOWED_ORIGIN`	`http://HOST:PORT`	CORS origin

Development

bash

git clone https://github.com/davidmosiah/delx-memory
cd delx-memory
npm install
npm test         # typecheck + build + smoke + secret-detector + ttl + tag-delete + metadata

See AGENTS.md for repo conventions, SECURITY.md for the security model and reporting policy, and CONTRIBUTING.md for PR rules.

License

Skill or MCP

Same package, two doors. MCP registers tools on stdio/HTTP. The skill can drive the same tools through the CLI when the client has no MCP:

Terminal

npx -y delx-memory call memory_connection_status --json '{}'

Copy skill/SKILL.md into your agent skills dir.

delx-memory

Why

Multi-agent namespaces

Footprint / lightweight mode

Install + run

HTTP (v2 stateless)

Wire it into your MCP client

Claude Desktop

Cursor

Hermes

OpenClaw

Codex CLI

What makes it different (honest)

Tools (15)

Session start

Reads

Mutations (require explicit_user_intent: true)

Privacy contract (read this)

Example session

Storage layout

CLI

Environment

Development

License

Skill or MCP

Mutations (require `explicit_user_intent: true`)