@memextend/opencode

OpenCode adapter for memextend - Memory extension for AI coding agents

Status: ⚠️ Experimental/Untested - This adapter was developed based on OpenCode's MCP documentation but has not been tested in a production OpenCode environment. Community feedback and contributions are welcome!

This adapter provides memextend integration for OpenCode by Anomaly, an open-source AI coding agent.

Features

• MCP (Model Context Protocol) server for mid-session memory operations
• Search through past work and decisions
• Save important context and patterns
• Store global preferences across projects
• Semantic search using vector embeddings

Requirements

• Node.js 18+
• OpenCode installed (npm i -g opencode-ai)
• memextend CLI initialized (memextend init)

Installation

# Install the adapter
npm install @memextend/opencode

# Or if using the memextend monorepo
pnpm install
pnpm build

Configuration

Option 1: Global Configuration

Add memextend to your global OpenCode configuration at ~/.config/opencode/opencode.json:

{
  "$schema": "https://opencode.ai/config.json",
  "mcp": {
    "memextend": {
      "type": "local",
      "command": ["node", "/path/to/node_modules/@memextend/opencode/dist/mcp/server.cjs"],
      "enabled": true
    }
  }
}

Option 2: Project-Local Configuration

Add to your project's opencode.json:

{
  "$schema": "https://opencode.ai/config.json",
  "mcp": {
    "memextend": {
      "type": "local",
      "command": ["node", "./node_modules/@memextend/opencode/dist/mcp/server.cjs"],
      "enabled": true
    }
  }
}

Option 3: Using npx

If you have the package installed globally, you can reference it directly:

{
  "$schema": "https://opencode.ai/config.json",
  "mcp": {
    "memextend": {
      "type": "local",
      "command": ["npx", "@memextend/opencode", "mcp"],
      "enabled": true
    }
  }
}

Finding the Server Path

To find the correct path for your installation:

# If installed globally
npm root -g
# Then append: /@memextend/opencode/dist/mcp/server.cjs

# If installed locally in a project
npm root
# Then append: /@memextend/opencode/dist/mcp/server.cjs

Available MCP Tools

Once configured, the following tools are available in your OpenCode sessions:

memextend_search

Search through your memories using semantic and full-text search.

Use: Search for "authentication flow" or "Redis caching decisions"

memextend_save

Save a memory for the current project.

Use: Save important decisions, patterns, or context for future reference

memextend_save_global

Save a global preference or fact that applies across all projects.

Use: Save coding style preferences, common patterns, or personal facts
Types: preference, pattern, fact

memextend_forget

Delete a specific memory by ID.

Use: Remove outdated or incorrect memories

memextend_status

Get memextend status and memory statistics.

Use: Check how many memories are stored, database location, etc.

memextend_context

Get relevant context for the current session.

Use: Retrieve recent memories, global preferences, and semantically related past work

Usage Examples

After configuring memextend in your opencode.json, start OpenCode in your project:

opencode

Then interact with memextend through natural language:

> Search my memories for authentication patterns

> Save this as a memory: We decided to use JWT tokens with 24-hour expiry for API authentication

> Remember globally that I prefer TypeScript with strict mode enabled

> What context do you have about this project?

> Show me the memextend status

Agent Instructions

To give your agent memory guidance, copy the included AGENTS.md file to your project root or global config:

# Project-level (recommended)
cp node_modules/@memextend/opencode/AGENTS.md AGENTS.md

# Or global
cp node_modules/@memextend/opencode/AGENTS.md ~/.config/opencode/AGENTS.md

OpenCode automatically loads AGENTS.md files and includes them in the agent's context. The file contains instructions for when to search and save memories.

Note: OpenCode also falls back to CLAUDE.md if no AGENTS.md exists, so if you already have ~/.claude/CLAUDE.md from Claude Code, it will work automatically.

How It Works

1. MCP Integration: OpenCode connects to the memextend MCP server via stdio
2. Tool Discovery: OpenCode discovers the memextend tools at startup
3. Semantic Search: Memories are embedded using the Nomic embed model for semantic search
4. Hybrid Search: Combines vector similarity with full-text search for best results
5. Persistent Storage: Memories are stored in SQLite with sqlite-vec for vectors

Configuration Reference

OpenCode MCP Config

interface MCPConfig {
  type: 'local' | 'remote';  // 'local' for stdio servers
  command?: string[];         // Command and arguments to run
  environment?: Record<string, string>;  // Environment variables
  enabled?: boolean;          // Enable/disable the server
  timeout?: number;           // Request timeout in ms
}

memextend Config (~/.memextend/config.json)

{
  "retrieval": {
    "autoInject": true,
    "maxMemories": 10,
    "recentDays": 7,
    "includeGlobal": true
  },
  "capture": {
    "tools": ["Edit", "Write", "Bash", "Task"],
    "skipTools": ["Read", "Glob", "Grep"],
    "maxContentLength": 2000
  }
}

Differences from Claude Code Adapter

| Feature | Claude Code | OpenCode | |---------|-------------|----------| | Hook System | Native hooks (SessionStart, Stop) | No native hooks | | Auto Context Injection | Yes (via SessionStart hook) | Manual via memextend_context | | Auto Memory Capture | Yes (via Stop hook) | Manual via memextend_save | | MCP Support | Yes | Yes | | Mid-Session Tools | Yes | Yes |

Since OpenCode does not have a native hook system like Claude Code, automatic context injection and memory capture are not available. Instead, users should:

1. Use memextend_context at the start of a session to get relevant memories
2. Explicitly save important information using memextend_save or memextend_save_global

Troubleshooting

MCP Server Not Found

If OpenCode cannot find the memextend MCP server:

1. Verify the path in your config is correct
2. Ensure the package is built: npm run build
3. Check Node.js is in your PATH

No Memories Found

If searches return no results:

1. Run memextend init to initialize the database
2. Verify memextend is working: memextend status
3. Save some test memories first

Permission Errors

If you see permission errors:

1. Ensure memextend directories exist: ~/.memextend/
2. Check write permissions on the database files

Development

# Build the adapter
npm run build

# Run tests
npm test

# Build only the MCP server bundle
npm run build:bundle

Related

• memextend - Main memextend project
• OpenCode - OpenCode by Anomaly
• MCP Specification - Model Context Protocol

License

MIT - Copyright (c) 2026 ZodTTD LLC