Delx Memory MCP Server

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.

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HTTP (v2 stateless)

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

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):

{
  "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.

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What makes it different (honest)

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

Tools (15)

Session start

Reads

Mutations (require explicit_user_intent: true)

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.

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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.

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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" } }

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Storage layout

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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

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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.

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License

MIT © 2026 David Batista. Code of Conduct.