# Cortex — AI Project Memory & Knowledge Graph

## Overview

Cortex is a CLI tool and web server for storing, linking, and searching project knowledge as a graph of typed nodes and edges. It supports hybrid search (BM25 + vector similarity + freshness), auto-decay of stale nodes, and a web portal for visualization.

Data is stored in `.memory/cortex.db` (SQLite) in the current working directory.

---

## CLI Reference

All commands are invoked as `memory <command>`.

### `memory add <kind>`

Add a node to the knowledge graph.

| Argument / Option | Required | Description |
|---|---|---|
| `<kind>` | yes | Node kind: `memory`, `component`, `task`, `decision` |
| `-t, --title <title>` | yes | Node title |
| `-c, --content <content>` | no | Node content/description |
| `--tags <tags>` | no | Comma-separated tags |
| `--status <status>` | no | Status (e.g. `todo`, `doing`, `done`, `active`, `deprecated`) |

```bash
memory add memory -t "Auth flow design" -c "OAuth2 PKCE flow for SPA" --tags auth,security --status active
memory add task -t "Implement login page" --status todo
memory add decision -t "Use PostgreSQL" -c "Chose Postgres over MySQL for JSON support"
memory add component -t "UserService" -c "Handles user CRUD operations" --tags backend
```

### `memory query <text>`

Search the knowledge graph using natural language. Uses hybrid BM25 + vector + freshness scoring.

| Argument / Option | Required | Description |
|---|---|---|
| `<text>` | yes | Natural language search query |
| `--kind <kind>` | no | Filter by node kind |
| `--limit <n>` | no | Max results (default: 10) |
| `--format <fmt>` | no | Output format: `text` or `json` (default: `text`) |

```bash
memory query "authentication"
memory query "database decisions" --kind decision
memory query "user service" --limit 5 --format json
```

### `memory show <id>`

Show a node's full details and its connections. The `<id>` can be a full UUID or a unique prefix.

Each call to `show` updates the node's `lastAccessedAt` timestamp, which affects freshness scoring.

| Argument / Option | Required | Description |
|---|---|---|
| `<id>` | yes | Node ID or unique prefix |
| `--format <fmt>` | no | Output format: `text` or `json` (default: `text`) |

```bash
memory show abc123
memory show abc123 --format json
```

### `memory list`

List nodes in the knowledge graph.

| Option | Required | Description |
|---|---|---|
| `--kind <kind>` | no | Filter by kind |
| `--status <status>` | no | Filter by status |
| `--tags <tags>` | no | Comma-separated tags to filter |
| `--limit <n>` | no | Max results |
| `--stale` | no | Include stale/decayed nodes |
| `--format <fmt>` | no | Output format: `text` or `json` (default: `text`) |

```bash
memory list
memory list --kind task --status todo
memory list --tags auth,security
memory list --stale
memory list --format json
```

### `memory update <id>`

Update an existing node's fields.

| Argument / Option | Required | Description |
|---|---|---|
| `<id>` | yes | Node ID or unique prefix |
| `-t, --title <title>` | no | New title |
| `-c, --content <content>` | no | New content |
| `--status <status>` | no | New status |
| `--tags <tags>` | no | Replace tags (comma-separated) |
| `--stale` | no | Mark as stale |

```bash
memory update abc123 --status done
memory update abc123 -t "Updated title" -c "New content"
memory update abc123 --tags newtag1,newtag2
```

### `memory remove <id>`

Remove a node. Default is soft delete (marks as stale). Use `--hard` for permanent deletion.

| Argument / Option | Required | Description |
|---|---|---|
| `<id>` | yes | Node ID or unique prefix |
| `--hard` | no | Permanently delete instead of marking stale |

```bash
memory remove abc123
memory remove abc123 --hard
```

### `memory link <fromId> <toId>`

Create a directed edge between two nodes.

| Argument / Option | Required | Description |
|---|---|---|
| `<fromId>` | yes | Source node ID or prefix |
| `<toId>` | yes | Target node ID or prefix |
| `--type <type>` | yes | Edge type: `depends_on`, `contains`, `implements`, `blocked_by`, `subtask_of`, `relates_to`, `supersedes`, `about` |

```bash
memory link abc123 def456 --type depends_on
memory link abc123 def456 --type contains
```

### `memory graph [id]`

Visualize the knowledge graph as an ASCII tree. Optionally root at a specific node.

| Argument | Required | Description |
|---|---|---|
| `[id]` | no | Root node ID or prefix. Omit for full graph. |

```bash
memory graph
memory graph abc123
```

### `memory decay`

Run auto-decay to mark old untouched nodes as stale. Nodes whose `lastAccessedAt` exceeds the threshold are marked stale and hidden from default listings and search.

| Option | Required | Description |
|---|---|---|
| `--days <number>` | no | Max age in days before decay (default: 180) |

```bash
memory decay
memory decay --days 90
memory decay --days 0   # decay all nodes not accessed today
```

### `memory serve`

Start the Cortex Portal web server. Auto-decay runs on startup and every 24 hours.

| Option | Required | Description |
|---|---|---|
| `-p, --port <number>` | no | Port number (default: 3100) |

```bash
memory serve
memory serve --port 8080
```

---

## Node Kinds

| Kind | Purpose |
|---|---|
| `memory` | General knowledge, notes, context |
| `component` | Code components, services, modules |
| `task` | Work items, todos |
| `decision` | Architectural or design decisions |

## Edge Types

| Type | Meaning |
|---|---|
| `depends_on` | Source depends on target |
| `contains` | Source contains target |
| `implements` | Source implements target |
| `blocked_by` | Source is blocked by target |
| `subtask_of` | Source is a subtask of target |
| `relates_to` | General relationship |
| `supersedes` | Source supersedes/replaces target |
| `about` | Source is about target |

## Search Scoring

Search combines three signals:

- **BM25** (weight 0.25) — text relevance
- **Vector similarity** (weight 0.60) — semantic similarity via embeddings (requires Ollama)
- **Freshness** (weight 0.15) — exponential decay based on `lastAccessedAt`

Freshness multiplier: `e^(-0.01 * ageDays)` — half-life ~69 days. Recently accessed nodes are boosted; old untouched nodes are penalized but not zeroed.

## REST API

The web server exposes these endpoints under `/api`:

| Method | Path | Description |
|---|---|---|
| `GET` | `/api/nodes` | List nodes. Query params: `kind`, `status`, `tags`, `limit`, `includeStale` |
| `GET` | `/api/nodes/:id` | Get node + connections |
| `POST` | `/api/nodes` | Create node. Body: `{ kind, title, content?, status?, tags?, metadata? }` |
| `PATCH` | `/api/nodes/:id` | Update node. Body: `{ title?, content?, status?, tags?, metadata?, isStale? }` |
| `DELETE` | `/api/nodes/:id` | Delete node. Query param: `hard=true` for permanent delete |
| `POST` | `/api/edges` | Create edge. Body: `{ fromId, toId, type, metadata? }` |
| `DELETE` | `/api/edges/:id` | Delete edge |
| `GET` | `/api/graph` | Get full graph (nodes + edges) for visualization |
| `POST` | `/api/search` | Search. Body: `{ text, options?: { kind?, tags?, limit?, includeStale? } }` |