delx-memory

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

# 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

# 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.

Wire it into your MCP client

Claude Desktop

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

{
  "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.

Hermes

See examples/hermes.md.

OpenClaw

See examples/openclaw.md.

Codex CLI

See examples/codex.toml.

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

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

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

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

MIT © 2026 David Batista