If an action cannot be authorized, it cannot execute.
Yebo implements fail-closed execution control for AI agents. Every action you route through the Yebo gateway is checked against its mandate and its policy, and held for approval when the policy requires it, before anything runs. The gateway fails closed. Execution runs in dry-run mode today, so no money moves.
Three Interdependent Layers
Identity alone is not enough. Communication alone is not enough. Execution only happens after mandate validation and authorized proof.
Device-Bound Identity
Approvers authenticate with a passkey (WebAuthn), not a password: the private key is created and held by their device's authenticator, and Yebo stores only the public key. Authorization proofs are signed by the gateway's key. Per-payment device signing is live and has been exercised in production: the approver's passkey signs the exact payment (amount, payee, agent, validity window), and anyone can check it offline with yebo-verify 0.2.0.
- Passkey (WebAuthn) authentication
- Private key held by the device authenticator
- Yebo stores only the public key
Mandates
Not a permission. A deterministic, immutable authorization contract. Each mandate specifies exactly what action is authorized, for how much, with whom, under which policy, within a strict time window. Once sealed, a mandate cannot be modified. Any change requires a new mandate. The same inputs always produce the same mandate hash.
- Immutable once created
- Policy-embedded and time-bound
- Replay-resistant by design
The Cryptographic Mandate
The record of what a human approved. For a mission, the approver's passkey approves the mission's limits (capabilities, per-transaction limit, payees). The gateway then issues a time-bound mission token limited to those limits, checks every payment against them, and signs an execution receipt. A proof the gateway did not issue is refused. Execution runs in dry-run mode today, so no money moves. Per-payment device signing is live and has been exercised in production: the approver's passkey signs the exact payment (amount, payee, agent, validity window), and anyone can check it offline with yebo-verify 0.2.0.
- Your passkey approves the mission's limits
- Time-bound and scoped to those limits
- Gateway-signed receipt (ECDSA P-256)
Sentinel
The verification gate between authorization and execution on the gateway's /execute path: if any check fails, the action is blocked, with no override. Payment missions pass the gateway's mission gate instead, which enforces scope, amount, payee, expiry and approval.
FAIL-CLOSED ENFORCEMENT
If any single verification fails, the entire execution is blocked.
Every execution decision is logged. Every block is auditable. There is no silent failure mode.
Signed Transport (draft)
Y-Signal, Yebo's message protocol, is a draft signed-envelope format (sender, recipient, sequence); signature verification and replay protection are coming soon.
Y-Signal is an internal draft protocol. Gateway API traffic does not use it yet; that is coming soon.
WHAT CANNOT HAPPEN
- ✗An agent cannot forge a Yebo-signed authorization
- ✗A mandate cannot be modified after creation
- ✗A proof cannot be reused or transferred
- ✗An action routed through Yebo cannot skip the gateway's verification
- ✗An execution cannot proceed without valid proof
- ✗An audit record cannot be altered without breaking its hash chain
Yebo replaces trust with enforceable authority.
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