OpenCode MemPalace Plugin

Persistent memory for OpenCode with hidden retrieval, autosave, and a safe MemPalace wrapper tool.

Русская версия

OpenCode plugin for hidden retrieval and autosave with MemPalace through a local Python adapter.

• OpenCode: https://opencode.ai
• MemPalace: https://github.com/milla-jovovich/mempalace

What it does

• injects hidden retrieval hints before normal answers
• marks autosave on session lifecycle events
• exposes one safe memory tool: mempalace_memory
• routes memory through enforced user/project scopes
• applies privacy filtering before writes
• logs to both OpenCode logs and a local file

Architecture

flowchart TD
    U[User message] --> OC[OpenCode turn]
    OC --> EV[Plugin hooks]
    EV --> RET[Hidden retrieval instruction]
    EV --> AS[Autosave pending on idle/compaction]
    RET --> LLM[Model]
    AS --> LLM
    LLM --> TOOL[mempalace_memory]
    TOOL --> ADAPTER[Python adapter]
    ADAPTER --> MP[MemPalace backend]
    MP --> ADAPTER
    ADAPTER --> TOOL
    TOOL --> LLM

Loading

Installation

Add to opencode.json:

{
  "plugin": ["@rvboris/opencode-mempalace"]
}

OpenCode installs plugin dependencies automatically.

Local development

For source loading:

{
  "$schema": "https://opencode.ai/config.json",
  "plugin": [
    "file:///ABSOLUTE/PATH/TO/mempalace-autosave/plugin/index.ts"
  ]
}

The plugin itself does not require the MemPalace MCP server. It uses the bundled Python adapter.

Prerequisites

• Python 3.9+
• MemPalace installed and initialized

pip install mempalace
mempalace init <dir>
mempalace mine <dir>

Build

npm run build

This builds TypeScript into dist/ and copies the adapter to dist/bridge/.

Configuration

Environment variables:

• MEMPALACE_AUTOSAVE_ENABLED
• MEMPALACE_RETRIEVAL_ENABLED
• MEMPALACE_KEYWORD_SAVE_ENABLED
• MEMPALACE_PRIVACY_REDACTION_ENABLED
• MEMPALACE_MAX_INJECTED_ITEMS
• MEMPALACE_RETRIEVAL_QUERY_LIMIT
• MEMPALACE_AUTOSAVE_LOG_FILE
• MEMPALACE_ADAPTER_PYTHON
• MEMPALACE_USER_WING_PREFIX
• MEMPALACE_PROJECT_WING_PREFIX

Optional config file: ~/.config/opencode/mempalace.jsonc

{
  "autosaveEnabled": true,
  "retrievalEnabled": true,
  "keywordSaveEnabled": true,
  "maxInjectedItems": 6,
  "retrievalQueryLimit": 5,
  "keywordPatterns": ["remember", "save this", "don't forget", "note that"],
  "privacyRedactionEnabled": true,
  "userWingPrefix": "wing_user",
  "projectWingPrefix": "wing_project"
}

Runtime behavior

Retrieval

On normal user turns the plugin can inject hidden retrieval guidance so the model searches existing memory before answering.

Autosave

On session.idle and session.compacted, the plugin marks autosave as pending. The actual write happens on the next model turn through mempalace_memory.

Safe wrapper tool

The model should use only:

• mempalace_memory

Direct mutation tools are blocked:

• mempalace_add_drawer
• mempalace_kg_add
• mempalace_diary_write
• matching mcp-router_* variants

Scope policy

User scope

• wing: ${MEMPALACE_USER_WING_PREFIX}_profile
• rooms: preferences, workflow, communication

Use for:

• response preferences
• personal workflow habits
• cross-project conventions

Project scope

• wing: ${MEMPALACE_PROJECT_WING_PREFIX}_${slug(projectName)}
• rooms: architecture, workflow, decisions, bugs, setup

Use for:

• repo-specific setup
• architecture decisions
• build/test commands
• bug/solution patterns

Examples

Save a user preference

mempalace_memory
  mode: save
  scope: user
  room: preferences
  content: Prefers concise responses and numbered steps.

Save a project decision

mempalace_memory
  mode: save
  scope: project
  room: decisions
  content: Use Bun for builds and tests; avoid npm.

Add KG fact

mempalace_memory
  mode: kg_add
  scope: project
  subject: my-repo
  predicate: uses
  object: bun

Search memory

mempalace_memory
  mode: search
  scope: user
  room: preferences
  query: user name
  limit: 3

Privacy

• supports <private>...</private> blocks
• redacts common secrets before writes
• refuses to save fully private content

Logging

Logs are written to:

• OpenCode built-in logger
• file log: ~/.mempalace/opencode_autosave.log

For debugging:

opencode --log-level DEBUG

Notes

• no visible autosave chat messages
• no OpenCode tool-to-tool calls
• adapter uses stdin/stdout streaming
• package is publishable as a standard OpenCode plugin