TypeScript — @decionis/shield
Node.js, server agents, and browser-safe sandbox.
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API documentation
Agent spending authorization
Let your app ask before it spends. Add user-controlled spending permissions to apps and AI agents with a few lines of code. Decionis Shield is the consumer spending surface of the protocol: the user sets the limits, your agent asks before it spends.
Quickstart — your first spending decision
Your app wants to spend. Shield decides whether it has permission. No policy graphs, signature plumbing, or enterprise organization model is required for first success.
$ npm install @decionis/shieldimport { ShieldClient } from "@decionis/shield";
const shield = new ShieldClient(); // sandbox by default
const decision = await shield.authorize({
amount: 89,
currency: "USD",
purpose: "Book hotel",
merchant: "Hilton"
});
if (decision.allowed) await execute();Sandbox by default — no real money
ShieldKit 0.1.0 is public. npm artifacts are verified before every release. The client starts in sandbox mode, so the first decision costs nothing and moves nothing.
The three verdicts
Every authorization resolves to exactly one of three answers.
| Verdict | Meaning | Your application's behavior |
|---|---|---|
| ALLOW | This exact action is authorized now. | Execute once and preserve the decision ID. |
| ASK | The user must approve. | Hold. Execute only after a later ALLOW. |
| BLOCK | The action is not authorized. | Stop. Do not execute. |
Handle ASK correctly
Approval is a hold, never a soft allow. Shield orchestrates Presence when the user's rules require human approval. Your application waits for a final ALLOW bound to the same action.
switch (decision.verdict) {
case "ALLOW":
await execute();
break;
case "ASK": {
const final = await shield.requestApproval(decision.decisionId);
if (final.verdict === "ALLOW") await execute();
break;
}
case "BLOCK":
await cancel();
}Deterministic sandbox
Understand Shield from one command. Every fixture is labelled sandbox evidence, replays deterministically, and cannot authorize real execution.
npx @decionis/shield-demo --all| Scenario | Verdict |
|---|---|
| Normal purchase | ALLOW |
| Purchase above automatic limit | ASK |
| Subscription below threshold | ALLOW |
| Subscription price increase | ASK |
| Unknown autonomous agent | BLOCK |
| Agent exceeds weekly allowance | BLOCK |
| Expired spending permission | BLOCK |
Choose your surface
One authorization contract, four ways in.
Swift — ShieldKit
iOS and macOS with native async/await types.
REST — POST /v1/shield/authorize
One contract for any trusted backend.
MCP — shield.request_purchase
Consumer-friendly tools for agent runtimes.
Enforcement boundary and product hierarchy
Applications must request Shield authorization before executing the consequential action.
Posture — what Shield does and does not control
Shield deterministically controls Shield-integrated execution. Observed activity and sandbox simulations must be labelled as such. Shield does not universally intercept arbitrary card or bank transactions.
Where this sits
Decionis Protocol is enterprise execution authority. Presence is human authorization and verification. Shield is consumer, app, and agent spending authority — the surface this page documents.
Build a Shield-compatible spender
Start in sandbox, handle ASK correctly, inspect the dossier, then complete production identity and compatibility validation.
The consumer product this authorizes against is Decionis Shield (App Store); the wider developer surface lives at the Decionis developer hub.