Extensions

Extensions add capabilities to an ECP (Execution Control Protocol) environment: model providers, formats, memory, secrets, and more.

Catalog and bind

Extension packages should call catalogExtension(def) at module load so string ids resolve:

import "@executioncontrolprotocol/format-toon"
import { extension } from "@executioncontrolprotocol/node"

extension("@executioncontrolprotocol/format-toon").with({})

Prefer npm package name === extension id (for example @executioncontrolprotocol/format-toon). ensureBoundExtensionsRegistered() runs automatically before encode, decode, describe, and run when using the core environment path — you typically do not need a separate register step for cataloged packages.

Definitions vs invocations

Layer	API
Define	`defineExtension(ns, name).withCapabilities([...]).build()`
Catalog	`catalogExtension(def)` on package load
Bind	`extension("@scope/name").with({…})` in an environment
Invoke	`step("@scope/name.capability", "Label").with({…})`

Package boundaries

Extensions depend on @executioncontrolprotocol/types and @executioncontrolprotocol/core (plus focused third-party libs). They must not import:

@executioncontrolprotocol/node
@executioncontrolprotocol/browser
@executioncontrolprotocol/cli
@executioncontrolprotocol/mcp

Hosts wrap core; extensions stay portable.

First-party and vendor

Protocol/platform extensions live in the ECP monorepo (formats, providers such as Ollama and Chrome AI, memory, secrets, …). Vendor integrations (fal, Slack, image-sharp, Adobe, …) ship from the sibling executioncontrolprotocol-extensions repository. In-repo testing stub:

import "@executioncontrolprotocol/core/testing"
extension("@executioncontrolprotocol/test").with({})

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Extensions

Extensions

Catalog and bind

Definitions vs invocations

Package boundaries

First-party and vendor

Next steps

​Extensions

​Catalog and bind

​Definitions vs invocations

​Package boundaries

​First-party and vendor

​Next steps

Extensions

Catalog and bind

Definitions vs invocations

Package boundaries

First-party and vendor

Next steps