Concepts

ECP (Execution Control Protocol) centers on three runtime ideas: a portable workflow, a host environment, and an operational Ecp instance. A workflow is a reasoned approach, captured — you design it once and run it many times, placing each step where it belongs on the determinism spectrum.

Workflow

A workflow is a portable graph of steps. You author it with the Fluent API or as JSON.

import { workflow, step } from "@executioncontrolprotocol/core"

export default workflow("Echo test")
  .run([
    step("@executioncontrolprotocol/test.echo", "Echo")
      .with({ value: "hello" })
      .as("echo"),
  ])

Canonical manifests use:

{
  "schema": "@executioncontrolprotocol.workflow",
  "version": "1.0"
}

Workflows should stay portable: no host secrets, no environment-only helpers in the graph. Use ref() to read prior step state.

Workflow contract

The contract is separate from steps. Same verbs in Fluent and JSON:

Field	Role
`.accepts()` / `workflow.accepts`	JSON Schema for run input. Property names seed state (`ref("prompt")`).
`.returns()` / `workflow.returns`	JSON Schema for public output (`result.output`). Property names are top-level state keys (typically a step `.as()`).

ecp.run(..., { input }) validates accepts before execute. The Graph Editor shows Inputs / Outputs from those schemas — they are projections, not dummy capabilities. See Fluent API and Schemas.

Environment

An environment binds what can run a workflow: runtime, extensions, policies, harnesses, and secrets access on the host.

import { environment, extension } from "@executioncontrolprotocol/node"
import "@executioncontrolprotocol/core/testing"

export default (await environment("dev")).withExtensions([
  extension("@executioncontrolprotocol/test").with({}),
])

Lifecycle (simplified): configure → bind extensions → environment:ready → runs may emit environment:beforeRun → ecp.terminate() ends the session.

Ecp instance

Call await env.init() to get an Ecp instance. Operational APIs live here — not on the environment builder:

run, validate, describe, search
encode, decode, patch
invoke (when used by hosts/harnesses)
terminate

const ecp = await env.init()
await ecp.run(manifest)
await ecp.terminate()

Definitions, bindings, invocations

Concept	Example
Definition	Extension package calls `defineExtension` + `catalogExtension` on load
Binding	`extension("@executioncontrolprotocol/format-toon").with({})` in an environment
Invocation	`step("@executioncontrolprotocol/memory.search", "…").with({…}).as("signals")`

IDs use @namespace/name for extensions and @namespace/name.capability for capabilities.

State and refs

.as("echo") writes step output into run state. Later steps read it with ref("echo.field") (stored as $ref paths under state). Optional mode controls how state is written.

Hosts

Host	Typical entry
Node	`@executioncontrolprotocol/node` + CLI
Browser	`@executioncontrolprotocol/browser` (apps bind harnesses/providers)
MCP	`@executioncontrolprotocol/mcp` adapter around an `Ecp`

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Concepts

Concepts

Workflow

Workflow contract

Environment

Ecp instance

Definitions, bindings, invocations

State and refs

Hosts

Next steps

​Concepts

​Workflow

​Workflow contract

​Environment

​Ecp instance

​Definitions, bindings, invocations

​State and refs

​Hosts

​Next steps

Concepts

Workflow

Workflow contract

Environment

Ecp instance

Definitions, bindings, invocations

State and refs

Hosts

Next steps