A Manifesto in Four Freedoms · Est. Europe · Open Source

# You shouldn't have to choose between simple and powerful. Or between the cloud and control.

So we stopped choosing. Sandcastle is an open-source orchestrator for AI agents — define a workflow in one file, run it on any model, ship it anywhere on your own rules, and let it get sharper every run.

$pip install sandcastle-ai
workflow · live Claude
run #1,284 $0.00
7 model providers 236 workflow templates 22 step types Auto-failover EU data residency Record & replay every run Hard budget caps $0 local steps Self-hostable BSL 1.1 → Apache 2.0 in 2030 7 model providers 236 workflow templates 22 step types Auto-failover EU data residency Record & replay every run Hard budget caps $0 local steps Self-hostable BSL 1.1 → Apache 2.0 in 2030
01 The First Freedom

## Build
anything.

Complex agents from one simple file. 22 step types — parallel fan-out, conditions, loops, gates, deterministic $0 steps. Or skip the YAML entirely and describe what you want in a sentence; Sandcastle designs the workflow.

workflow.yaml
steps: - type: llm # research, in parallel fan_out: 5 - type: http # $0 — no model call - type: gate # human approval
workflow.run() idle
run #1284 0/6 steps $0.00 engine Claude
02 The Second Freedom

## Any
model.

Model-independent by design. Claude, GPT, Mistral, Gemini, Llama — or fully local. Swap providers in one line. And when one goes down, auto-failover moves to the next while you sleep.

swap one line
-model: claude-sonnet
+model: mistral-large
# failover: [gpt-4o, local/llama]
03 The Third Freedom

## Anywhere,
your rules.

Cloud, your own server, fully isolated or air-gapped, or EU-only. The same workflow, your gate. EU data residency is built in — when you enable it, every model call stays in region.

deployment / gate

- Cloud ready
- Your server (self-host)ready
- Isolated / air-gapped ready
- EU-only residency enabled

04 The Fourth Freedom

## It
learns.

It self-tunes on what succeeds and heals what fails. Every run is recorded — so you can replay your past workflows against new models and keep the winner. Smarter over time, on autopilot.

quality / per run
best-variant score 0.94
A/B per step · auto-deploy the best variant
The specifics — for the record

## No feature gates. One version. Every line above ships free.

7
Model providers — Claude, GPT, Gemini, Mistral, MiniMax, OpenRouter, local
236
Workflow templates — 118 built-in + 118 community, one-click install
22
Step types — mix AI with deterministic $0 steps
$0
Local steps cost nothing — http, code, condition, transform, notify
100%
Record & replay — every run captured for audit and re-runs
EU
Data residency — built for the EU AI Act era, audit-ready trail
Hard
Budget caps — per step and per run, stop before the invoice blows up
2030
BSL 1.1 today, converts to Apache 2.0 — self-hostable, no lock-in

The declaration ends. The build begins.

## Four freedoms. One command.

$pip install sandcastle-ai Copy
Docs ↗ PyPI ↗ GitHub ↗ What's new