CAIN-42 · Start here

Playground

Send a real action and watch CAIN decide it, stage by stage.

Last reviewed 2026-10-01

Live   Console (signed in) · Console

What it is

Fire a real decision and watch all 17 stages.

Where it fits

Part of Start here: New to CAIN-42? Try it in two minutes, no card needed. Every CAIN-42 product runs behind the same rule: an AI agent's action is checked before it runs (identity, authority, policy, risk), decided as allow, hold for a human, or block, and recorded as signed evidence. Unknown or error never becomes allow.

Use it

• Open it https://cainstudio.online/console#/play

Live now

Checked from your browser when this page opened, not from a cached list.

Fire a real decision

Send an action through the live CAIN-42 pipeline from this page, with no account, and watch every stage decide. This is the same pipeline every product here sits behind; it runs for a throwaway demo tenant and is rate limited.

For AI engineers

Every product sits behind one decision path: your agent proposes an action with the exact arguments, CAIN runs it through identity, authority, policy, risk, trust and quorum consensus, and answers ALLOW, REQUIRE_APPROVAL or DENY with an Ed25519-signed record. A timeout, outage or unknown verdict never becomes ALLOW. A brand-new agent has no trust history, so its first actions usually come back REQUIRE_APPROVAL.

Python (zero dependencies)

pip install https://cainstudio.online/cainstudio-0.3.0-py3-none-any.whl
export CAIN_API_KEY=...   # free key: https://cainstudio.online/signup

import cainstudio

@cainstudio.guard()
def transfer(amount_usd: float, to: str) -> str:
    ...  # runs only if CAIN allows this call, with these arguments

try:
    transfer(5000, "acme")
except cainstudio.ApprovalRequired as e:
    print("held for a human:", e.approval_id)
except cainstudio.ActionBlocked as e:
    print("refused:", e.decision.reasons)
except cainstudio.CainUnavailable:
    print("CAIN unreachable: not run")   # fail-closed

See a real decision with no account

cainstudio try          # live pipeline, stage by stage
cainstudio try --list   # the other attack scenarios

MCP clients (Claude Code, Cursor)

claude mcp add --transport http cain https://cainstudio.online/mcp

More: Python SDK · TypeScript SDK · framework integrations · AI quickstart · decision signing key

Tested guarantees in this area

Every rule in these niches has its own page with its recorded result.

• Core guarantees: 377 tested invariants — Fail-closed basics that every other area relies on.
• Evidence, receipts & proofs: 928 tested invariants — Signed records that prove what happened, checkable by anyone.

Related

• Agent trust sandbox — Try CAIN on a pretend agent in your browser, no account needed.
• AI quickstart — Paste one block into your coding agent and it sets CAIN up for you.
• CAIN Studio Managed Cloud Subscriptions (Developer & Enterprise SaaS) — CAIN Studio in the cloud: a free tier, then plans that grow with you.
• Live demo: decide, enforce, prove — Watch CAIN decide, enforce and prove one real action, end to end.