Mempalace Persistence

Community plugin — not officially maintained by the MemPalace team. Fully open source, ~200 lines of TypeScript.

An OpenCode plugin that automatically saves every conversation to MemPalace and uses stored memory to provide better, context-aware responses. Real-time, zero cron, zero external scripts.

---

How it works in 3 seconds

Without plugin	With plugin
Every session starts from scratch	The model knows who you are and what you've done
You repeat context each time	Memory is automatic
Model starts from scratch each time	Memory persists across sessions

The plugin injects relevant memories from MemPalace into every prompt (via experimental.chat.messages.transform), and saves every response back to MemPalace. A perfect feedback loop.

---

Installation

1. Plugin (saves conversations)

{
  "plugin": ["opencode-mempalace-persistence"]
}

Add this line to your ~/.config/opencode/opencode.json and restart OpenCode.

2. Identity (who you are)

Create ~/.mempalace/identity.txt:

I am [name], a [role]. I work with [technologies]. My main projects are [projects].

This file is loaded by the plugin — no need to add it to instructions in opencode.json.

3. MemPalace (if not already installed)

# Install (requires mempalace>=3.3.5 for HNSW corruption fix)
uv tool install "mempalace>=3.3.5"
# or
pipx install "mempalace>=3.3.5"

# Create palace
mempalace init ~/opencode-memory

# Configure MCP
mempalace mcp

The mempalace mcp command gives you the exact MCP setup string for your configuration.

4. Memory injection (recommended)

The plugin automatically injects your identity + relevant memories from MemPalace into every prompt. No model discipline required.

Create ~/.mempalace/plugin-config.json:

{
  "autoInjectContext": true
}

Do NOT put this in opencode.json — OpenCode's schema validation rejects unknown keys. The plugin reads its config from ~/.mempalace/plugin-config.json instead.

When enabled:

• First message: Injects your identity from ~/.mempalace/identity.txt
• Every message: Runs mempalace search and injects relevant results

AGENTS.md for this mode

Create ~/.config/opencode/AGENTS.md:

# Memory & Knowledge instructions

## CRITICAL: You MUST follow these steps BEFORE every response.

### Step 1 — Query Knowledge Graph
Call `mempalace_mempalace_kg_query` for entity "user". Then filter the returned facts — keep only those whose text contains keywords from the user's question, so irrelevant facts are excluded.

### Step 2 — Record Knowledge Graph facts

After responding, if you discovered any new facts during the conversation (decisions made, milestones reached, problems encountered, preferences expressed, emotional states), call `mempalace_mempalace_kg_add` to record them. Object must be 128 characters or fewer.

**This is mandatory** — record facts you are confident about. Prefer quality over quantity; noisy KG entries degrade retrieval over time.

### Naming reminder
All MemPalace tools use the prefix `mempalace_mempalace_*` (not `mempalace_*`). Examples:
- `mempalace_mempalace_kg_query` (NOT `mempalace_kg_query`)
- `mempalace_mempalace_kg_add`
- `mempalace_mempalace_kg_invalidate`
If you ever catch yourself typing `mempalace_kg_query`, STOP — the correct prefix is `mempalace_mempalace_`.

Complete ~/.config/opencode/opencode.json

{
  "$schema": "https://opencode.ai/config.json",
  "plugin": ["opencode-mempalace-persistence"],
  "instructions": ["AGENTS.md"],
  "mcp": {
    "mempalace": {
      "type": "local",
      "command": ["mempalace-mcp"],
      "enabled": true
    }
  }
}

Note: identity.txt is NOT listed in instructions — the plugin injects it automatically. It is also NOT in the provider block or permission block — those are optional and depend on your model setup.

5. Alternative: Model-driven memory (without autoInjectContext)

If you prefer the model to search MemPalace on its own via AGENTS.md (requires good model tool-use discipline), set autoInjectContext to false or omit the file:

{
  "autoInjectContext": false
}

AGENTS.md for this mode

Create ~/.config/opencode/AGENTS.md:

# Memory & Knowledge instructions

## CRITICAL: You MUST follow these steps BEFORE every response.

### Step 1 — Search MemPalace
Call `mempalace_mempalace_search` with the user's question or key topics as query. Get the top 5-10 most relevant memory drawers.
**This is mandatory. Never skip this step. No exceptions.**

### Step 2 — Query Knowledge Graph
Call `mempalace_mempalace_kg_query` for entity "user". Then filter the returned facts.

### Step 3 — Record Knowledge Graph facts
After responding, call `mempalace_mempalace_kg_add` for any new facts.

### Naming reminder
All MemPalace tools use the prefix `mempalace_mempalace_*` (not `mempalace_*`).

And keep "~/.mempalace/identity.txt" in instructions in opencode.json since the plugin won't inject it.

Comparison

Feature	Auto-inject (Recommended)	Model-driven (alternative)
Memory search	Plugin injects automatically	Model calls mempalace_search
Identity	Plugin injects automatically	Via instructions: ["identity.txt"]
AGENTS.md	Minimal (KG only)	Full (search + KG)
Depends on model discipline	No	Yes

# Install (requires mempalace>=3.3.5 for HNSW corruption fix)
uv tool install "mempalace>=3.3.5"
# or
pipx install "mempalace>=3.3.5"

# Create palace
mempalace init ~/opencode-memory

# Configure MCP
mempalace mcp

The mempalace mcp command gives you the exact MCP setup string for your configuration.

---

What happens after installation (auto-inject mode)

You ask a question
  → Plugin hooks into `experimental.chat.messages.transform`
  → Injects your identity + relevant memories from MemPalace
  → Model sees context without having to search

The model responds
  → Plugin detects the response is complete
  → Saves the conversation to MemPalace (flat export, no hardcoded wings)
  → Model records KG facts via MCP tools (mandatory per AGENTS.md)

Next time you ask
  → Plugin finds the previous memory → injects it automatically
  → The cycle continues, memory grows

---

What gets saved

Every turn (question + answer) is saved as a drawer in MemPalace. No forced categorization — MemPalace's own mining handles organization. The model can optionally record KG facts (decisions, milestones, preferences) during conversation via MCP tools.

---

Architecture

                 ┌──────────────────────────────┐
                 │         OpenCode              │
                 │                               │
  User msg ─────►│  experimental.chat.messages   │
                 │  .transform hook              │
                 │    ↓                          │
                 │  Injects identity + memories  │
                 │  (autoInjectContext: true)    │
                 │    ↓                          │
                 │  Model sees context → answers │
                 │    ↓                          │
  Answer done ──►│  chat.message + session.idle  │
                 │    ↓                          │
                 │  Query OpenCode DB            │
                 │  since last sync              │
                 │    ↓                          │
                 │  Export → flat text files     │
                 │    ↓                          │
                 │  mempalace mine (async)       │
                 │  single serialized call       │
                 └──────────────────────────────┘
                            │
                            ▼
                 ┌──────────────────────────┐
                 │      MemPalace            │
                 │  ~/opencode-memory/       │
                 │  Vector DB + KG           │
                 └──────────────────────────┘
                            ▲
                            │
                 ┌──────────────────────────┐
                 │  Model (via AGENTS.md)    │
                 │  Records KG facts:       │
                 │  kg_add / kg_invalidate  │
                 └──────────────────────────┘

---

Relevant files

File	Purpose
~/.config/opencode/opencode.json	OpenCode config with plugin + MCP
~/.config/opencode/AGENTS.md	Tells the model to manage KG facts
~/.mempalace/plugin-config.json	Plugin config (autoInjectContext)
~/.mempalace/identity.txt	Your identity (injected by plugin)
~/.mempalace/config.json	MemPalace config (palace path)
~/.mempalace/knowledge_graph.sqlite3	Knowledge Graph (structured facts)
~/opencode-memory/	MemPalace vector DB (all drawers)
~/.mempalace/sync_state.json	Last sync state

---

Install from npm

{
  "plugin": ["opencode-mempalace-persistence"]
}

Local development

{
  "plugin": ["/path/to/opencode-mempalace-persistence/dist/index.js"]
}

Debug logging

export OPENCODE_MEMPALACE_DEBUG=1

When set, the plugin writes a debug log to /tmp/opencode-mempalace.log.

---

License

MIT