Build with KYE

Build authority-aware apps with KYE.

KYE Protocol is not just a specification — it's a build surface. Runtime Authority API, three SDKs, an MCP server, a connector framework, signed webhooks, Decision Maps, and evidence packs. Add delegated authority, state-aware decisions, and replayable proof to AI agents, payment flows, checkout, wallets, IAM, SIEM, GRC, and enterprise workflows.

Open contracts. Paid operations.

Six surfaces

Pick the surface that fits your stack.

What you can build

Six high-leverage starters — and 15 more.

These are the products with the strongest pull from regulated buyers right now. Each composes from the surfaces above.

  • P1KYE Checkout Guard — for merchants and commerce platforms. Detect agent-backed checkout flows and verify whether the agent is allowed to buy this basket from this merchant using this instrument under the customer's limits. Composes: Runtime API + Webhooks + Evidence Packs.
  • P2KYE Payment Authority Gateway — for banks, issuers, IPGs, MPGs, PSPs, agentic-payment platforms. Verify delegated payment authority before the gateway processes the transaction. Composes: Runtime API + Payments connector + Evidence Packs.
  • P3KYE MCP Server — for agent developers and internal AI platforms. Expose KYE authority objects, schemas, decisions, and evidence to MCP clients safely. Composes: MCP Server + Read-only tools + Gated decision tools.
  • P4KYE CISO Console — for security and risk teams. View every agent, credential, capability, delegation, state, and revocation path. Composes: Authority Graph + Webhooks + Audit chain.
  • P5KYE Evidence Viewer — for auditors and regulators. Replay decisions, verify evidence packs offline with public keys, map events to controls. Composes: Evidence Packs + OSCAL projection + Decision Maps.
  • P6KYE Partner Toolkit — for consultants, audit firms, SIs. Run authority mapping, readiness checks, conformance prep, pilot scoping. Composes: Readiness API + Conformance pack + Decision Maps.

Other strong starters: agent purchasing apps · agent marketplace trust layers · wallet authority consoles · open-banking delegated-authority apps · enterprise service-account authority maps · GRC evidence automation · SIEM authority-signal feeds · certification portals · tool-governance gateways · capability registries · sector profiles for healthcare / custody / telco / federal.

Runtime Authority API

One call, before the action executes.

The decision endpoint is the single most important surface. Your app asks; KYE answers in milliseconds.

POST /v1/runtime/authorize
{
  "actor_entity_id":     "kye:entity:agent:shopping_agent_456",
  "principal_entity_id": "kye:entity:person:customer_123",
  "subject":             "kye:capability:payment_action:card_purchase",
  "resource":            { "merchant_id": "M-7104", "amount": 9999, "currency": "GBP" },
  "scope":               { "instrument": "kye:card_token:tok_abc..." },
  "policy_decision_id":  "kye:dec:01HX..."
}

→
{
  "decision":  "allow_with_constraints",
  "reason":    "scope_within_attenuated_authority",
  "obligations": [ { "type": "audit.emit", ... }, { "type": "redaction.required", ... } ],
  "stop_conditions": [ "actor.stop_signal", "delegation.revoked", "scope.attenuated" ],
  "evidence_refs":   [ "kye:evidence-pack:01HX..." ],
  "decision_map_ref": "kye:decision_map:01HX..."
}

Eight decision codes are stable across versions: allow, allow_with_constraints, require_approval, require_step_up, require_human_review, require_recovery, quarantine, deny. Map to your own code-set via the conformance pack.

Three SDKs

Same surface in TypeScript, Python, and Go.

Each SDK ships: schema types · local validators · decision client · signing helpers · evidence-pack builder · taxonomy resolver · metadata classifier · graph traversal client · decision-map renderer · webhook verifier · idempotency helper · replay client.

KYE MCP Server

Make KYE available to MCP-compatible agents.

Expose KYE schemas, dictionaries, authority checks, Decision Maps, and evidence packs through a controlled MCP interface — while production enforcement stays in the KYE Runtime Gateway, never in MCP.

The boundary: MCP is a developer / agent integration surface. The Runtime Gateway is the enforcement surface. Don't conflate.

Connector Framework

Plug KYE into the systems you already run.

A canonical connector manifest schema, 14 connector categories, and a hub for discovery. Open contracts — commercial runtime.

paymentsPayments & commerceIPG · MPG · payment gateway · checkout · shopping cart · card-token · wallet · open banking · merchant-risk · chargeback / dispute
smart_toyAI & agent runtimeMCP · agent runtime · tool gateway · capability registry · model registry · prompt registry · workflow
keyIdentity & accessOAuth/OIDC · SAML · SCIM · SPIFFE/SPIRE · IAM · PAM · passkey · credential issuer
policyPolicy & governanceOPA · Cerbos · AWS Cedar · GRC · control mapping · certification · self-audit
manage_searchSecurity & observabilitySIEM · SOAR · Splunk · Microsoft Sentinel · Datadog · CloudWatch · Kafka · EventBridge · webhook
badgeVerificationKYC provider · KYB provider · KYA provider · agent passport · credential verification
OSS / paid split

Open contracts. Paid operations.

Open source · Apache 2.0KYE Cloud · commercial
Schemas & dictionariesEvery entity / authority / decision / event / connector-manifest schema; reason codes; taxonomiesSector-specific event packs and connector packs
SDKsTypeScript / Python / Go — schema types, validators, signing helpers, webhook verifier, evidence-pack builderSDK-bundled telemetry, advanced replay, hosted SDK distribution
MCP serverSkeleton + read-only tools + decision tools (gated)Hosted MCP server, multi-tenant, audit-bound, SLA-backed
ConnectorsManifest schema, conformance tests, sample IPG / checkout / MCP connectors, local test harnessManaged Connector Hub, enterprise connector engine, regulated-sector connector packs, BYOC / on-prem installer
Reference runtimeReference Gateway: PEP middleware, embedded ePDP, conformance runnerManaged runtime gateway, decision engine, state engine, graph engine, signal bus, evidence engine
Operator UISaaS dashboard, Decision Map UI, Authority Graph UI, Evidence Pack Pro, replay console, blast-radius event trace
Conformance38 black-box fixtures, test vectorsContinuous conformance monitoring, certification workflow, partner registry

Why this split? The contract has to be open or KYE Protocol isn't a protocol — partners and developers must be able to implement, integrate, and verify without depending on a hosted service. The runtime engine that scales decisions and signal delivery, manages multi-tenant operations, computes downstream impact, and ships connectors with SLAs is the operational moat — and it sits behind a paid layer.

Adjacent reading

Where to go next.