Architecture Overview — Escepine Docs

Escepine is a standalone execution plane: it sits between declarative workflow definitions and the agents and tools that execute them, and it owns everything between — dispatch, state, checkpointing, policy enforcement, verification, compensation, and audit. The authoring surface is the SOP; everything below it is the plane's responsibility.

System map

request
  │
  ▼
Intent Matching & Search ......... request → candidate SOP
  │
  ▼
Core Execution Engine ............ dispatch loop · per-step pipeline
  ├──▶ Policy Gateway ............ Cedar ALLOW/DENY before every tool call
  ├──▶ MCP sandbox ............... ephemeral execution containers
  ├──▶ HITL gates ................ pause · escalate · park · resume
  │
  ▼
Evidence Ledger .................. every event, as it happens
  │
  ▼
Control Plane .................... canvas renders the event stream;
                                    signals return to the engine

Services

Service	Owns	Failure isolation
Core Execution Engine	SOP parsing, dispatch loop, per-step pipeline, checkpoints, budgets	Engine failure halts the workflow; no step executes without it
Policy Gateway	Cedar evaluation before every EXECUTION step	Unavailable gateway fails closed — no tool call proceeds
Telemetry & Evidence Ledger	Event emission and the append-only audit trail	A step does not commit past an unrecorded event
Control Plane & Observability	Live canvas, bidirectional signal channel, per-step inspection	Canvas outage stops nothing; HITL gates stay parked until signals return
Context Orchestrator	Context assembly and retrieval ahead of and during execution	Missing context halts the dependent step — nothing plans on absent inputs
Intent Matching & Search	Mapping requests to candidate SOPs ahead of execution	No match, no run — nothing starts half-executed

Data flow

Stage	What happens
1	A request arrives; intent matching selects the SOP
2	The engine ingests and validates the DAG — structural violations are rejected before any execution
3	The dispatch loop releases each step whose dependencies are complete
4	The step runs the engine pipeline: gates, execution, verification
5	Events land in the Evidence Ledger as they happen
6	The Control Plane renders the canvas from the stream; HITL signals flow back
7	Terminal artifacts hydrate into downstream steps

Guarantees inherited by every workflow

Guarantee	Mechanism	Evidence
Every side effect is policy-checked	Cedar evaluation before EXECUTION	`policy_eval` per call
Every output is verified before commit	Verifier gate	`verification` verdict and critique
Every committed step can be rolled back	Saga compensations	`compensation` events, reverse order
Every retry is bounded	Budget hierarchy	Escalation and regeneration events
Every run is reconstructible	Checksum-chained Evidence Ledger	Full event trail
Every long run is resumable	Checkpoints	Checkpoint records

Is / is not

Escepine is	Escepine is not
An execution plane: dispatch, state, enforcement, audit	An agent framework — it does not reason; it governs reasoning steps
Governance-native: guarantees are runtime properties	An LLM provider
Deployed inside your perimeter	A hosted SaaS
White-glove delivered	A self-serve library