Architecture

Overview

OpenSail is an AI-powered platform for building, running, and sharing agents, full-stack apps, scheduled jobs, webhook handlers, and MCP tools. The system is modular: the same orchestrator drives desktop, Docker, and Kubernetes modes by swapping task queue, pub/sub, database, and container backends behind protocols. This page explains how the components fit together, how data flows at runtime, and how the security model is enforced.

High-level diagram

Component layers

Frontend
Desktop shell
Orchestrator
Agent runner

Module	Source	Notes
App shell	`app/src/App.tsx`	React 19 router
API client	`app/src/lib/api.ts`	SSE + fetch wrapper
Editor	Monaco	code + diff view
Chat	`app/src/components/chat/`	agent message stream
Architecture Panel	React Flow	authors `.tesslate/config.json`
Kanban	drag-and-drop board

Tauri v2 Rust shell wraps a PyInstaller-frozen FastAPI sidecar. See desktop/src-tauri/ and desktop/sidecar/.

Per-launch bearer token minted on startup
SQLite database under OPENSAIL_HOME
System tray keeps the sidecar alive when the window closes
Stronghold stores long-lived tsk_ pairing keys
Deep-link handler for OAuth pairing callbacks

Module	Purpose
`main.py`	Middleware, router mounting, CORS, CSRF
`config.py`	Pydantic settings (env reader)
`models.py`	45+ SQLAlchemy models
`routers/`	REST endpoints (projects, chat, billing, apps, etc.)
`services/`	Business logic
`agent/`	Legacy inline agent (still used in cloud path)
`worker.py`	ARQ worker entrypoint

packages/tesslate-agent is the primary agent runner used by both desktop and cloud workers. It provides:

A tool registry (read/write, edit, bash, session, web search, fetch, skill loader, kanban, schedule, project control)
Progressive persistence: every AgentStep is written as it happens
Context compaction: older messages roll up via a cheap summarizer
Approval gates: tools can require human approval via permission policies
Cost and iteration caps (AGENT_MAX_COST, AGENT_MAX_ITERATIONS)

Deployment modes

Mode	Database	Queue	Pub/sub	Containers	Best for
Desktop	SQLite (aiosqlite)	asyncio + apscheduler	in-process	subprocess / docker / remote k8s	Single user
Docker	Postgres	ARQ on Redis	Redis Streams	Docker Compose	Dev, small teams
Kubernetes	Postgres (cloud: RDS)	ARQ on Redis	Redis Streams	per-project namespaces	Multi-tenant prod

All three are selected by DEPLOYMENT_MODE and wired via factories in orchestrator/app/services/.

Three-tier compute model

The AI agent does not need a full Kubernetes pod every time it reads a file. OpenSail separates operations by cost:

Tier	What runs here	Backend	Wake time
Tier 0	File ops, web calls, agent reasoning	In-process in the worker (FileOps gRPC to CSI)	Near zero
Tier 1	Shell commands	Warm ephemeral containers from a pool	Sub-second
Tier 2	Full dev environment: multi-container project, live preview, deploys	K8s namespace with multiple Deployments	On demand, hibernates when idle

About 99% of agent operations run on Tier 0 or Tier 1. Tier 2 is only needed when the user is actively working in the workspace or the agent needs to run the full stack. Hibernation is volume-level: a project snapshot captures the entire btrfs subvolume, then the namespace is torn down. Restore re-hydrates from CAS and brings all containers back together.

Storage: btrfs CSI and Volume Hub

User project data lives on btrfs subvolumes managed by a two-layer system.

btrfs CSI driver
Volume Hub
Orchestrator client

Location: services/btrfs-csi/.Runs as a DaemonSet. Responsibilities:

Create btrfs subvolumes (instant snapshot-clone from templates)
FileOps gRPC for agent Tier 0 file operations
NodeOps gRPC for template builds
S3 sync via CAS (content-addressed storage)
Per-node garbage collection

Location: services/btrfs-csi/pkg/volumehub/.Single-pod storageless orchestrator. Responsibilities:

Track volume ownership and cache placement
Pick the best node for each project
Coordinate peer-transfer when a volume migrates nodes
Trigger S3 sync on hibernation
Expose gRPC (CreateVolume, DeleteVolume, EnsureCached, TriggerSync, CreateServiceVolume, VolumeStatus)

Thin async client at orchestrator/app/services/volume_manager.py (calls hub via hub_client.py). The orchestrator never touches btrfs directly.Lifecycle:

Create: Hub picks a node, driver creates the subvolume
Compute: pod scheduled on cache_node, hostPath-mount
Hibernate: S3 sync triggered, pod removed, volume cached on node
Restore: EnsureCached tries fast local path, then peer-transfer, then S3 restore
Timeline: up to 5 K8s VolumeSnapshots per project

Agent runner integration

The orchestrator enqueues an AgentTaskPayload built from project state, chat history, git status, and TESSLATE.md. The ARQ worker picks up the task and runs the tesslate-agent loop.

Acquire lock

Redis-based distributed lock prevents concurrent runs on the same project.

Loop

Each iteration: run the agent, persist AgentStep rows, publish events to the Redis Stream, check for a cancellation signal.

Stream to client

The API router subscribes to the stream and forwards events over SSE or WebSocket. The client renders steps in real time.

Finalize

On completion: write the final Message, release the lock, optionally fire a webhook for external agent callers.

Progressive persistence means pods can die, browsers can close, and the session is resumable.

Apps subsystem

An app on OpenSail is a versioned, immutable, manifest-described bundle produced from a workspace. Models:

Model	Role
`MarketplaceApp`	Identity anchor (slug, creator, category, state)
`AppVersion`	Immutable version with manifest, CAS bundle address, approval state
`AppInstance`	Per-user install with wallet mix and update policy
`AppSubmission`	Staged approval pipeline row (stage0 → stage3 → approved)
`YankRequest`	Unpublish flow; critical severity requires two admins
`AppBundle`	Curated pack of AppVersions

Services: installer.py, publisher.py, submissions.py, yanks.py, runtime.py, stage1_scanner.py, stage2_sandbox.py. See the Publishing Apps guide.

Channels and gateway

Messaging integrations live under orchestrator/app/services/channels/ with the Gateway v2 runner at services/gateway/runner.py. Platforms: Telegram, Slack, Discord, WhatsApp, Signal, CLI. Identity pairing links platform accounts to OpenSail users. Schedules (cron + timezone) deliver agent output to any configured channel. See Communication gateways.

Security model

Layer	Enforcement
Transport	HTTPS in production; Traefik or NGINX Ingress
Session	JWT with short-lived access + refresh rotation
CSRF	Double-submit cookie with `X-CSRF-Token` header
Passwords	bcrypt
Secrets at rest	Fernet encryption via `SECRET_KEY`-derived key (`CHANNEL_ENCRYPTION_KEY`, `DEPLOYMENT_ENCRYPTION_KEY`)
RBAC	`Team`, `TeamMembership` (admin/editor/viewer), `ProjectMembership` override, `AuditLog`
Network isolation (K8s)	`NamespacePerProject` + `NetworkPolicy` enforcing zero cross-project traffic
Agent capabilities	`.tesslate/permissions.json` gates shell, network, git push, file writes; approval prompts for `ask` policies

Every significant action writes to the append-only AuditLog, keyed by team and project.

Next steps

Configuration

All environment variables with defaults.

Deployment

Path-by-path production guides.

Data flow

Request lifecycle, agent execution, container lifecycle.

Container orchestration

Three-tier compute, PVC lifecycle, snapshots.

Get Started

Install and Run

Core Concepts

Working with Projects

Agents and Skills

Ship and Share

Self-Hosting

Developer Guide

Overview

High-level diagram

Component layers

Deployment modes

Three-tier compute model

Storage: btrfs CSI and Volume Hub

Agent runner integration

Apps subsystem

Channels and gateway

Security model

Next steps

Configuration

Deployment

Data flow

Container orchestration

Get Started

Install and Run

Core Concepts

Working with Projects

Agents and Skills

Ship and Share

Self-Hosting

Developer Guide

Documentation Index

​Overview

​High-level diagram

​Component layers

​Deployment modes

​Three-tier compute model

​Storage: btrfs CSI and Volume Hub

​Agent runner integration

​Apps subsystem

​Channels and gateway

​Security model

​Next steps

Configuration

Deployment

Data flow

Container orchestration

Overview

High-level diagram

Component layers

Deployment modes

Three-tier compute model

Storage: btrfs CSI and Volume Hub

Agent runner integration

Apps subsystem

Channels and gateway

Security model

Next steps