th-memory-mcp

th-memory-mcp

Long-term memory MCP server for OpenCode — stores preferences, lessons, and usage history in a single local SQLite file (100% local, no external API) so the AI can "remember and adapt" to the user through context-based learning.

Status: v2.2.0 — a temporal, conflict-aware, hybrid-retrieval memory engine. 16 MCP tools, 20 passing test suites. Non-destructive schema migration from v1 (all v1 data preserved). New in v2: lifecycle states, temporal validity, conflict/dedup resolution with USER/SESSION/PROJECT/GLOBAL scope, hybrid FTS+vector retrieval (RRF), memory graph, get_context assembly, periodic consolidation, and link_memory / merge_memory / update_memory / import_memory / extract_memories.

Requirements

• Node.js >= 20 — the server uses Node-only APIs (the better-sqlite3 native build and import.meta.url resolution) and the MCP SDK requires a modern runtime. CI tests on Node 20.x and 22.x.
• npm — to install dependencies and run the build/test scripts (npm install, npm run build, npm test).
• OpenCode — the host that loads this MCP server and the auto-capture plugin. Any build supporting MCP over stdio + plugins works; the plugin runs on OpenCode's bundled Bun runtime.
• OS: Windows / macOS / Linux — the server is cross-platform (Node). The auto-capture plugin runs wherever OpenCode's Bun runtime runs. Windows note: MEMORY_DB_PATH is easiest to set with setx; on macOS/Linux use export in your shell profile.

No external services, accounts, or API keys are required — everything lives in a single local SQLite file.

Quick Start

Fastest path: after cloning, run npm run quickstart — it builds, wires opencode.json, deploys the plugin, and sets MEMORY_DB_PATH for you in one command. The steps below show exactly what it does (use them if you prefer manual control).

Install via npm (alternative): install the server globally with npm install -g th-memory-mcp (or run it on demand with npx th-memory-mcp), then point the mcp command in opencode.json to th-memory-mcp instead of the built dist/index.js. The auto-capture plugin still comes from this repo (copy src/plugin/learning-capture.ts as described in step 4 below).

# 1. Clone and build
git clone https://github.com/worakorn-prince/th-memory-mcp.git
cd th-memory-mcp
npm install
npm run build

# 2. Share one DB between the server and the plugin
#    Windows (PowerShell):
setx MEMORY_DB_PATH "$PWD/data/memory.db"
#    macOS / Linux (add to your shell profile, e.g. ~/.zshrc):
# export MEMORY_DB_PATH="$PWD/data/memory.db"

• Merge this into your ~/.config/opencode/opencode.json (replace <REPO> with the absolute clone path):

{
  "instructions": ["<REPO>/AGENTS.memory.example.md"],
  "mcp": {
    "memory": {
      "type": "local",
      "command": ["node", "<REPO>/dist/index.js"],
      "enabled": true,
      "environment": { "MEMORY_DB_PATH": "<REPO>/data/memory.db" }
    }
  }
}

• (Optional) Auto-capture: copy src/plugin/learning-capture.ts → ~/.config/opencode/plugins/
• Restart OpenCode
• Try it: "Remember that I prefer pnpm" → new session → "What package manager do I prefer?"

Architecture

OpenCode ──┬─ Plugin learning-capture (Bun)  ── auto-captures prompts/tool/error into DB
            │                                   └─ injects profile back into context on compaction
             └─ MCP th-memory-mcp (Node.js stdio)  ── 16 tools read/write the same SQLite DB
                                                      ▲
                               Global instructions (memory-protocol.md) teach the AI to use the tools

See ARCHITECTURE_v2.md for the full architecture spec.

Why th-memory-mcp?

LLMs don't remember you between sessions — every new chat starts blank. th-memory-mcp gives your AI a private, local long-term memory:

• Context-based learning, not fine-tuning — it captures your preferences, corrections, and habits, then recalls them into context next time. Same mechanism as the memory features of leading AI products, without sending any data off your machine.
• 100% local & private — a single SQLite file, no cloud, no external API. Secrets are filtered before anything is stored.
• Low overhead — each tool call is capped (latency < 10 ms, bounded output size) and the AI only queries memory when it's actually useful, so it never bloats your context.
• Resilient — every tool degrades gracefully; if the DB is unavailable the AI keeps working instead of crashing.
• Open & extensible — MIT licensed, 16 documented tools, a rule-based distill, and an auto-capture plugin you can adapt.

Works with other harnesses

th-memory-mcp is a standard MCP server, so the 9 tools run anywhere MCP-over-stdio is supported. Full auto-capture (background prompt/tool/error capture + profile injection) needs a hook runtime — OpenCode has it built in; Claude Code gets it via our hooks bridge; Codex and Cursor use the tools manually (no hook runtime yet).

Feature	OpenCode	Claude Code	Qwen Code	Codex	Cursor
16 MCP tools	✅	✅	✅	✅	✅
Auto-capture (background)	✅ plugin	✅ hooks	⚠️ adapter	❌ manual	❌ Rules
Profile injection	✅ compaction	✅ UserPromptSubmit	❌ get_profile	❌ get_profile	❌ get_profile
Local semantic search	✅ (v2.0)	✅ (v2.0)	✅ (v2.0)	✅ (v2.0)	✅ (v2.0)

• Claude Code: see CLAUDE_CODE_HOOKS.md — drop-in hooks replicate the OpenCode plugin (capture + profile injection on UserPromptSubmit/PreCompact, rule-based distill on SessionEnd).
• Qwen Code: see QWEN_SETUP.md — MCP works fully; hooks use the Gemini-CLI schema so auto-capture needs a small adapter.
• Codex: see CODEX_SETUP.md
• Cursor: see CURSOR_SETUP.md

All harnesses share one SQLite file via MEMORY_DB_PATH, so memory captured anywhere is readable everywhere.

Highlights

• Structured memory — preferences with confidence scoring plus dedicated lesson records (situation → mistake → correction) for capturing corrections, not just flat facts.
• Lifecycle & temporal — every memory has a lifecycle state (active/stale/superseded/archived), confidence/importance/salience scoring, per-type decay, and validity intervals so the AI can reason about point-in-time truth and supersession chains.
• Conflict-aware — duplicate detection, contradiction detection, and update/supersession resolution preserve both sides of ambiguous evidence instead of silently overwriting.
• Hybrid retrieval — get_context blends FTS5 keyword search with a dependency-free local vector embedding (RRF fusion + scoring), then assembles a token-budgeted context with optional memory-graph expansion.
• Consolidation — periodic clustering of similar memories into derived memories with full provenance (derived_from links).
• First-class Thai / i18n — Thai-aware tokenization in distill; the AI accepts Thai and English interchangeably.
• Private by default — a single local SQLite file, no cloud, no API keys, with secret lines (api_key=, password:, token) filtered before storage.
• Cross-harness — runs on OpenCode, Claude Code, Codex, and Cursor sharing one DB; auto-capture + profile injection via OpenCode plugin or Claude hooks.
• Lightweight & resilient — Node + better-sqlite3, no extra native extensions; every tool degrades gracefully so the AI keeps working if the DB is unavailable.

Scripts

Command	Description
npm run build	compile TypeScript → dist/
npm start	run the MCP server (stdio) from dist/index.js
npm run distill	rule-based distill: interactions → profile sections + prune old data (env RETENTION_DAYS default 30)
npm test	full suite: capture, distill, lifecycle, temporal, conflict, retrieval, graph, context, consolidation, benchmark, security, tools_v21, smoke, e2e_transport, retrieval_benchmark, recall_regression, scope, profile, entity_extraction, conflict_benchmark
node test/capture.test.mjs	test capture-core (filter secrets, dedupe, truncate, insert SQL)
node test/distill.test.mjs	test distill-core (Thai tokenize, stats, profile sections, prune)
node test/lifecycle.test.mjs	test lifecycle engine (states, decay, supersession)
node test/temporal.test.mjs	test temporal model (validity, historical retrieval)
node test/conflict.test.mjs	test conflict & dedup resolution
node test/retrieval.test.mjs	test hybrid FTS+vector+RRF retrieval
node test/graph.test.mjs	test memory graph (entities, relations, traversal)
node test/context.test.mjs	test context assembly + token budgeting
node test/consolidation.test.mjs	test clustering + derived memories
node test/benchmark.test.mjs	latency benchmark over 300 memories
node test/security.test.mjs	injection / safety checks
node test/smoke.mjs	end-to-end smoke test over JSON-RPC (16 tools)

Tools (16)

Tool	Description
remember	upsert preference (category+key) — re-saving the same key increases confidence by 0.1 (cap 1.0)
recall	search preferences + lessons (FTS5) + recent matching interactions. Use before starting a new task
get_profile	user profile overview: profile sections + top preferences + 5 most recent lessons
save_lesson	record a lesson learned from a correction (situation / mistake / correction)
search_history	search past user prompts by keyword (200-char snippets per row)
forget	delete one memory row (preference/lesson/interaction) by id (+type prevents cross-table id clash)
memory_stats	memory statistics: counts by kind, DB size, oldest/newest interaction, profile sections
get_recent_interactions	list recent raw interactions (filter by kind) — feedstock for Smart Distill
export_memory	export memory to JSON under data/exports/ only (filename auto-sanitized)
get_context	assemble relevant memories for the current task via hybrid retrieval (+ optional graph expansion) with token budgeting
consolidate	cluster similar memories via embedding similarity; optionally create derived/consolidated memories linked via derived_from
link_memory	create a typed relationship between two memories in the graph (supports/contradicts/supersedes/derived_from/related_to/caused_by/depends_on)
merge_memory	merge a duplicate/near-duplicate into a canonical memory (source becomes superseded, provenance in metadata.merged_from)
update_memory	update mutable fields in place, or create a superseding memory when content changes (set supersede=false to edit in place)
import_memory	import memories from JSON (validates type, dedupes against existing, never overwrites blindly); dry-run by default, apply=true to insert
extract_memories	scan recent captured interactions for memory-intent phrases and propose memory candidates (deterministic, no LLM); dry-run by default, apply=true to create (source=captured)

Install with OpenCode

• Merge the mcp section from opencode.example.json into your opencode.json (global or project-level)
  • Important: set MEMORY_DB_PATH to the SAME database file for both the server and the plugin (the example uses <ABSOLUTE_PATH>/th-memory-mcp/data/memory.db), otherwise the auto-capture plugin writes to a different DB than the one the AI reads
  • How to set it (pick one):
    • define it in the mcp environment (see example) — covers the MCP server only
    • or set it as a system/user-level environment variable (e.g. setx MEMORY_DB_PATH "D:/path/to/memory.db" on Windows) — covers both server and plugin, since the plugin runs in the same process as OpenCode
• Attach the global memory rules — add to opencode.json:

  "instructions": ["C:/Users/<user>/.config/opencode/memory-protocol.md"]
  

  (example rule content is in AGENTS.memory.example.md — can be attached at project level instead)
• (Optional) Deploy the auto-capture plugin: copy src/plugin/learning-capture.ts → ~/.config/opencode/plugins/learning-capture.ts
• Restart OpenCode (config loads at startup only)
• Test: "Remember that I prefer pnpm" → open a new session and ask back

Daily usage

The AI accepts both Thai and English interchangeably — you can switch languages at any time without warning.

Example command	Tool / effect
"Remember that..."	remember — save a preference
"Summarize memory" / "distill memory"	Smart Distill — AI reads get_recent_interactions, finds patterns, and saves insights itself
"How is my memory?" / "memory status"	memory_stats
"Export memory" / "backup memory"	export_memory
"Search history..."	search_history
"Forget..."	forget

Long-term care: run npm run distill occasionally to summarize stats and prune interactions older than 30 days.

data/ structure

data/
├── memory.db          # SQLite (WAL mode) — main DB (+ .db-wal, .db-shm)
└── exports/           # JSON files from export_memory (writeable only in this dir)

• DB path can be overridden via the MEMORY_DB_PATH env var
• everything in data/ is git-ignored