# btmsg Reference

btmsg is the inter-agent messaging system for Agents Orchestrator. It enables
management agents (Tier 1) and project agents (Tier 2) to communicate via direct
messages and broadcast channels.

## Overview

btmsg uses a shared SQLite database at `~/.local/share/agor/btmsg.db`. Both the
Python CLI tools (used by agents) and the Rust backend (Tauri app) access the
same database concurrently. WAL mode and a 5-second busy timeout handle
contention.

Agents must register before sending or receiving messages. Registration creates
an entry in the `agents` table with the agent's ID, name, role, group, and tier.

## Database schema

### agents

| Column | Type | Description |
|--------|------|-------------|
| `id` | TEXT PK | Unique agent identifier |
| `name` | TEXT | Display name |
| `role` | TEXT | Agent role (manager, architect, tester, reviewer, or project) |
| `group_id` | TEXT | Group this agent belongs to |
| `tier` | INTEGER | 1 = management, 2 = project |
| `model` | TEXT | Model identifier (nullable) |
| `status` | TEXT | Current status (active, sleeping, stopped) |

### messages

| Column | Type | Description |
|--------|------|-------------|
| `id` | TEXT PK | UUID |
| `from_agent` | TEXT FK | Sender agent ID |
| `to_agent` | TEXT FK | Recipient agent ID |
| `content` | TEXT | Message body |
| `read` | INTEGER | 0 = unread, 1 = read |
| `reply_to` | TEXT | Parent message ID (nullable, for threading) |
| `sender_group_id` | TEXT | Sender's group ID (nullable, added by migration) |
| `created_at` | TEXT | ISO timestamp |

### channels

| Column | Type | Description |
|--------|------|-------------|
| `id` | TEXT PK | Channel identifier |
| `name` | TEXT | Channel name (e.g. `#review-queue`) |
| `group_id` | TEXT | Group this channel belongs to |
| `created_by` | TEXT FK | Agent that created the channel |
| `created_at` | TEXT | ISO timestamp |

### contacts

ACL table controlling which agents can see and message each other.

### heartbeats

Liveness tracking. Agents send periodic heartbeats; the health store uses these
to detect stalled agents.

### dead_letter_queue

Messages that could not be delivered (recipient not found, agent stopped).
Surfaced in the agent health monitoring UI.

### audit_log

Records agent actions for compliance and debugging. Entries include agent ID,
action type, target, and timestamp.

### seen_messages

Per-message read tracking with session-level granularity.

| Column | Type | Description |
|--------|------|-------------|
| `session_id` | TEXT | Reading session identifier |
| `message_id` | TEXT FK | Message that was seen |
| `seen_at` | INTEGER | Unix timestamp |

Primary key: `(session_id, message_id)`. This enables per-message acknowledgment
rather than bulk "mark all read" operations.

## CLI usage

The `btmsg` CLI is a Python script installed at `~/.local/bin/btmsg`. Agents
invoke it via shell commands in their sessions. The `BTMSG_AGENT_ID` environment
variable identifies the calling agent.

### Register an agent

```bash
btmsg register --id mgr-1 --name "Manager" --role manager \
  --group my-team --tier 1
```

### Send a direct message

```bash
btmsg send --to architect-1 --content "Review the auth module architecture"
```

### Send to a channel

```bash
btmsg channel-post --channel review-queue \
  --content "Task T-42 moved to review"
```

### Read unread messages

```bash
btmsg read
```

Returns all unread messages for the agent identified by `BTMSG_AGENT_ID`.

### List channels

```bash
btmsg channels
```

### Send a heartbeat

```bash
btmsg heartbeat
```

Updates the agent's liveness timestamp. The health store marks agents as stalled
if no heartbeat arrives within the configured `stallThresholdMin`.

### Mark messages as seen

```bash
btmsg ack --message-id <uuid>
```

Records an entry in `seen_messages` for per-message tracking.

## Role permissions

Agent capabilities depend on their role:

| Capability | Manager | Architect | Tester | Reviewer | Project |
|------------|---------|-----------|--------|----------|---------|
| Send DMs | Yes | Yes | Yes | Yes | Yes |
| Read own DMs | Yes | Yes | Yes | Yes | Yes |
| Post to channels | Yes | Yes | Yes | Yes | Yes |
| Create channels | Yes | No | No | No | No |
| Delete messages | Yes | No | No | No | No |
| List all agents | Yes | Yes | Yes | Yes | Read-only |
| Update agent status | Yes | No | No | No | No |

The Manager role has full CRUD on all btmsg resources. Other roles can read
messages addressed to them and post to channels.

## Rust backend integration

The Tauri backend reads btmsg data via `src-tauri/src/btmsg.rs`. Key functions:

- `get_agents(group_id)` -- List agents with unread counts
- `unread_count(agent_id)` -- Unread message count
- `unread_messages(agent_id)` -- Full unread message list with sender metadata
- `get_feed(group_id)` -- Recent messages across the group
- `get_channels(group_id)` -- List channels with member counts
- `get_channel_messages(channel_id)` -- Messages in a channel

All queries use named column access (`row.get("column_name")`) and return
`#[serde(rename_all = "camelCase")]` structs for direct JSON serialization to the
frontend.

## Frontend

The frontend accesses btmsg through `src/lib/adapters/btmsg-bridge.ts`, which
wraps Tauri IPC commands. The CommsTab component in ProjectBox displays messages
and channels for management agents.

## Review queue integration

When a task transitions to `review` status via bttask, the system auto-posts a
notification to the `#review-queue` channel. The `ensure_review_channels`
function creates `#review-queue` and `#review-log` idempotently. See
[bttask reference](ref-bttask.md) for details.