Persistent, project-local memory for AI coding agents.
---
Most coding agents lose critical decisions between sessions: architecture invariants, API contracts, rejected patterns, and setup quirks. OpenContext solves context loss through a lightweight Model Context Protocol (MCP) server that lets agents read and mutate durable markdown files inside `.opencontext/`.
No vector databases, no cloud subscriptions, and no hidden state. Memory is plain markdown tracked directly in Git.
---
### Quickstart
Run the MCP server directly without installation via `npx`:
```bash
npx -y opencontext-mcp
```
### One-Command Setup
Scaffold OpenContext in the current project interactively:
```bash
npx -y opencontext-mcp init
```
`init` walks you through the setup (enabling OpenCode and Claude Code integration) and generates everything you need:
- `.opencontext/` — directory that holds your context topic files
- `.opencontext.json` — configuration template
- `opencode.json` — MCP server entry for OpenCode
- `.mcp.json` — MCP server entry for Claude Code
- `AGENTS.md` / `CLAUDE.md` — workflow reminders for your agents
The `init` command takes no arguments: it always runs in the current directory, prompts interactively, and never overwrites an existing config.
### Client Setup
#### OpenCode
Add OpenContext to your project MCP configuration (`opencode.json`) — or let `opencontext-mcp init` do it for you:
```json
{
"mcp": {
"opencontext": {
"type": "local",
"command": ["npx", "-y", "opencontext-mcp"],
"enabled": true
}
}
}
```
#### Cursor / Claude Desktop / Windsurf
Add OpenContext to your MCP settings file (`claude_desktop_config.json` or Cursor MCP settings):
```json
{
"mcpServers": {
"opencontext": {
"command": "npx",
"args": ["-y", "opencontext-mcp"]
}
}
}
```
---
### Remote Access (HTTP)
Expose the MCP server over the network with the Streamable HTTP transport. The endpoint URL is printed to stderr on startup.
```bash
# Plain HTTP on 127.0.0.1:3032 (default)
opencontext-mcp --http
# Custom port / bind to all interfaces
opencontext-mcp server --http --port 8787 --host 0.0.0.0
```
The server listens at `http://:/mcp` (stateless Streamable HTTP — one request at a time, no sessions). `GET /` returns basic server info, handy for a browser health check.
---
### Core Tools
| Tool | Parameters | Description |
| --- | --- | --- |
| `read_context` | `topic?` *(optional string)* | Reads a specific context topic, or returns the lightweight topic index (~100 tokens) if omitted. |
| `save_context` | `topic` *(string)*, `content` *(string)* | Writes or mutates markdown memory inside `.opencontext/.md` with built-in write guards and symlink protections. |
| `delete_context` | `topic` *(string)* | Removes an obsolete topic file and automatically rebuilds the topic index. |
---
### ADR Lifecycle & Frontmatter
Topics support optional YAML frontmatter to track lifecycle status — useful when architectural decisions evolve and old context should be visible but clearly flagged as outdated.
````markdown
---
description: OAuth2 + PKCE authentication flow
status: active
supersedes: auth_v1
---
# Authentication v2
Migrated from JWT to OAuth2 with PKCE.
````
**Supported frontmatter keys:**
| Key | Values | Description |
| --- | --- | --- |
| `description` | string | Short summary used in the auto-generated index. |
| `status` | `active` \| `deprecated` \| `superseded` | Lifecycle status. Defaults to `active` when omitted. |
| `supersedes` | string | Topic name this topic replaces *(set on the newer topic)*. |
| `superseded_by` | string | Topic name that replaced this one *(set on the older topic)*. |
Non-active topics automatically receive `[DEPRECATED]` or `[SUPERSEDED]` badges in the auto-generated `index.md`, along with cross-references showing which topic replaced or was replaced.
---
### Agent Workflows
Instruct your agents to automatically leverage project context. Add this snippet to your `.cursorrules`, `CLAUDE.md`, or system prompt:
```markdown
Before making structural code changes, run `read_context` to inspect existing project topics and architectural decisions.
Whenever a new architectural convention, database schema, or API rule is established or refactored, call `save_context` with a concise, topic-scoped markdown summary. Use YAML frontmatter (status, supersedes) when updating conventions to track lifecycle changes.
When a topic becomes obsolete, call `delete_context` to remove it. For deprecated topics that should remain visible, set status: deprecated or status: superseded in the frontmatter instead of deleting.
```
---
### Configuration
Customize storage paths and security boundaries with an optional `.opencontext.json` file in your repository root (plain JSON — comments are not supported):
```json
{
"path": ".opencontext",
"readOnly": false,
"autoIndex": true,
"guard": {
"enabled": true,
"maxFileSizeKb": 50,
"strictPatternCheck": true
}
}
```
---
### Local Development
```bash
# Clone and install dependencies
git clone [https://github.com/slxca/opencontext.git](https://github.com/slxca/opencontext.git)
cd opencontext
pnpm install
# Build & run tests
pnpm build
pnpm test
```
---
### Documentation
For advanced setup guides, guard parameters, and agent prompt templates, visit **[opencntx.dev/docs](https://www.google.com/search?q=https://opencntx.dev/docs)**.
### Contributing
Contributions are welcome. Please ensure all unit tests and typechecks pass before submitting a pull request:
```bash
pnpm typecheck && pnpm test
```