KYE Protocol™·KYE PDP™
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Policy Decision Point™

Deterministic five-stage decision pipeline. Authority → Purpose → Consumption → Rules → Decision. Called by kye-gateway via service binding on every action a KYE-bound system takes.

v1.0.0 · protocol kye.pdp.v1 · constitution §14 · p99 ≤ 30 ms

Determinism guarantee. Same request + same policy_set_compilation_seal = bit-identical decision_id. No wall-clock reads, no retries, no external network calls inside the engines. The decision is a pure function of its signed inputs — replayable years later by anyone with the public keys.

The five-stage pipeline

Each stage is a separate KYE engine, locked by constitution §14. Stages run in order; any stage may emit a stop with a sealed reason.

  1. 1 Authority Authority Engine Walks the delegation chain. Confirms the caller is empowered to act on the principal's behalf. Empty chain = stop.
  2. 2 Purpose Purpose Engine Matches the request to an active Purpose Permission™. Scope, freshness, on-behalf-of. Out-of-scope = stop on principle.
  3. 3 Consumption Consumption Engine A mandate is bounded by spend, not only by time. Checks this action against the quota grants bounding the delegation — a live delegation with no headroom left still stops.
  4. 4 Rules Rules Engine Evaluates the policy_set against the (verified) input. No wall-clock, no I/O. Pure function over canonical JSON.
  5. 5 Decide Decision Engine Composes the verdict: allow · require_approval · deny + obligations. Returns the bit-identical kye.decision.record.v1.

Engines hosted

All five engines share one Worker cold-start budget. No fan-out per stage; one decision = one round trip.

Authority EnginePurpose EngineRules EngineDecision Engine

Specifications

Latency p99
≤ 30 ms
Cold start
≤ 50 ms
Determinism
pure(request, seal)
Output
kye.decision.record.v1
Caller
kye-gateway (service binding)
Bindings
KYE_DB · AI_GATEWAY

Routes

POST
/decide
Run a decision through the four-stage pipeline. Body: { request, policy_set_id }. Returns: kye.decision.record.v1.
GET
/
Service descriptor.
GET
/health
Liveness probe.
GET
/openapi
OpenAPI 3.1 contract.

Compliance evidence

Constitution §21. Every decision carries the policy_set seal + the engine versions + the public key id; auditors verify offline.