Plugin Capability — Kernel Protocol reference

Defines the standard way plugins declare their capabilities, implementations, and conformance levels to ensure interoperability across vendors.

Plugin Capability Protocol

Defines the standard way plugins declare their capabilities, implementations, and conformance levels to ensure interoperability across vendors.

Based on the Protocol-Oriented Architecture pattern similar to:

Kubernetes CRDs (Custom Resource Definitions)
OSGi Service Registry
Eclipse Extension Points

Source: packages/spec/src/kernel/plugin-capability.zod.ts

TypeScript Usage

import { CapabilityConformanceLevelSchema, ExtensionPointSchema, PluginCapabilitySchema, PluginCapabilityManifestSchema, PluginDependencySchema, PluginInterfaceSchema, ProtocolFeatureSchema, ProtocolReferenceSchema, ProtocolVersionSchema } from '@objectstack/spec/kernel';
import type { CapabilityConformanceLevel, ExtensionPoint, PluginCapability, PluginCapabilityManifest, PluginDependency, PluginInterface, ProtocolFeature, ProtocolReference, ProtocolVersion } from '@objectstack/spec/kernel';

// Validate data
const result = CapabilityConformanceLevelSchema.parse(data);

CapabilityConformanceLevel

Level of protocol conformance

Allowed Values

full
partial
experimental
deprecated

ExtensionPoint

Properties

Property	Type	Required	Description
id	`string`	✅	Unique extension point identifier
name	`string`	✅
description	`string`	optional
type	`Enum<'action' \| 'hook' \| 'widget' \| 'provider' \| 'transformer' \| 'validator' \| 'decorator'>`	✅
contract	`{ input?: string; output?: string; signature?: string }`	optional
cardinality	`Enum<'single' \| 'multiple'>`	optional (default: `"multiple"`)	Whether multiple extensions can register to this point

Nested Shape: `ExtensionPoint.contract`

Property	Type	Required	Description
input	`string`	optional	Input type/schema
output	`string`	optional	Output type/schema
signature	`string`	optional	Function signature if applicable

PluginCapability

Properties

Property	Type	Required	Description
protocol	`{ id: string; label: string; version: object; specification?: string; … }`	✅
conformance	`Enum<'full' \| 'partial' \| 'experimental' \| 'deprecated'>`	optional (default: `"full"`)	Level of protocol conformance
implementedFeatures	`string[]`	optional	List of implemented feature names
features	`{ name: string; enabled?: boolean; description?: string; sinceVersion?: string; … }[]`	optional
metadata	`Record<string, any>`	optional
certified	`boolean`	optional (default: `false`)	Has passed official conformance tests
certificationDate	`string`	optional

Nested Shape: `PluginCapability.protocol`

Property	Type	Required	Description
id	`string`	✅	Unique protocol identifier (e.g., com.objectstack.protocol.storage.v1)
label	`string`	✅
version	`{ major: integer; minor: integer; patch: integer }`	✅	Semantic version of the protocol
specification	`string`	optional	URL or path to protocol specification
description	`string`	optional

Nested Shape: `PluginCapability.features[number]`

Property	Type	Required	Description
name	`string`	✅	Feature identifier within the protocol
enabled	`boolean`	optional (default: `true`)
description	`string`	optional
sinceVersion	`string`	optional	Version when this feature was added
deprecatedSince	`string`	optional	Version when deprecated

PluginCapabilityManifest

Properties

Property	Type	Required	Description
implements	`{ protocol: object; conformance?: Enum<'full' \| 'partial' \| 'experimental' \| 'deprecated'>; implementedFeatures?: string[]; features?: object[]; … }[]`	optional	List of protocols this plugin conforms to
provides	`{ id: string; name: string; description?: string; version: object; … }[]`	optional	Services/APIs this plugin offers to others
requires	`{ pluginId: string; version: string; optional?: boolean; reason?: string; … }[]`	optional	Required plugins and their capabilities
extensionPoints	`{ id: string; name: string; description?: string; type: Enum<'action' \| 'hook' \| 'widget' \| 'provider' \| 'transformer' \| 'validator' \| 'decorator'>; … }[]`	optional	Points where other plugins can extend this plugin
extensions	`{ targetPluginId: string; extensionPointId: string; implementation: string; priority?: integer }[]`	optional	Extensions contributed to other plugins

Nested Shape: `PluginCapabilityManifest.implements[number]`

Property	Type	Required	Description
protocol	`{ id: string; label: string; version: object; specification?: string; … }`	✅
conformance	`Enum<'full' \| 'partial' \| 'experimental' \| 'deprecated'>`	optional (default: `"full"`)	Level of protocol conformance
implementedFeatures	`string[]`	optional	List of implemented feature names
features	`{ name: string; enabled?: boolean; description?: string; sinceVersion?: string; … }[]`	optional
metadata	`Record<string, any>`	optional
certified	`boolean`	optional (default: `false`)	Has passed official conformance tests
certificationDate	`string`	optional

Nested Shape: `PluginCapabilityManifest.provides[number]`

Property	Type	Required	Description
id	`string`	✅	Unique interface identifier
name	`string`	✅
description	`string`	optional
version	`{ major: integer; minor: integer; patch: integer }`	✅	Semantic version of the protocol
methods	`{ name: string; description?: string; parameters?: object[]; returnType?: string; … }[]`	✅
events	`{ name: string; description?: string; payload?: string }[]`	optional
stability	`Enum<'stable' \| 'beta' \| 'alpha' \| 'experimental'>`	optional (default: `"stable"`)

Nested Shape: `PluginCapabilityManifest.requires[number]`

Property	Type	Required	Description
pluginId	`string`	✅	Required plugin identifier
version	`string`	✅	Semantic version constraint
optional	`boolean`	optional (default: `false`)
reason	`string`	optional
requiredCapabilities	`string[]`	optional	Protocol IDs the dependency must support

Nested Shape: `PluginCapabilityManifest.extensionPoints[number]`

Property	Type	Required	Description
id	`string`	✅	Unique extension point identifier
name	`string`	✅
description	`string`	optional
type	`Enum<'action' \| 'hook' \| 'widget' \| 'provider' \| 'transformer' \| 'validator' \| 'decorator'>`	✅
contract	`{ input?: string; output?: string; signature?: string }`	optional
cardinality	`Enum<'single' \| 'multiple'>`	optional (default: `"multiple"`)	Whether multiple extensions can register to this point

Nested Shape: `PluginCapabilityManifest.extensions[number]`

Property	Type	Required	Description
targetPluginId	`string`	✅	Plugin ID being extended
extensionPointId	`string`	✅	Extension point identifier
implementation	`string`	✅	Path to implementation module
priority	`integer`	optional (default: `100`)	Registration priority (lower = higher priority)

PluginDependency

Properties

Property	Type	Required	Description
pluginId	`string`	✅	Required plugin identifier
version	`string`	✅	Semantic version constraint
optional	`boolean`	optional (default: `false`)
reason	`string`	optional
requiredCapabilities	`string[]`	optional	Protocol IDs the dependency must support

PluginInterface

Properties

Property	Type	Required	Description
id	`string`	✅	Unique interface identifier
name	`string`	✅
description	`string`	optional
version	`{ major: integer; minor: integer; patch: integer }`	✅	Semantic version of the protocol
methods	`{ name: string; description?: string; parameters?: object[]; returnType?: string; … }[]`	✅
events	`{ name: string; description?: string; payload?: string }[]`	optional
stability	`Enum<'stable' \| 'beta' \| 'alpha' \| 'experimental'>`	optional (default: `"stable"`)

Nested Shape: `PluginInterface.methods[number]`

Property	Type	Required	Description
name	`string`	✅	Method name
description	`string`	optional
parameters	`{ name: string; type: string; required?: boolean; description?: string }[]`	optional
returnType	`string`	optional	Return value type
async	`boolean`	optional (default: `false`)	Whether method returns a Promise

Nested Shape: `PluginInterface.events[number]`

Property	Type	Required	Description
name	`string`	✅	Event name
description	`string`	optional
payload	`string`	optional	Event payload type

ProtocolFeature

Properties

Property	Type	Required	Description
name	`string`	✅	Feature identifier within the protocol
enabled	`boolean`	optional (default: `true`)
description	`string`	optional
sinceVersion	`string`	optional	Version when this feature was added
deprecatedSince	`string`	optional	Version when deprecated

ProtocolReference

Properties

Property	Type	Required	Description
id	`string`	✅	Unique protocol identifier (e.g., com.objectstack.protocol.storage.v1)
label	`string`	✅
version	`{ major: integer; minor: integer; patch: integer }`	✅	Semantic version of the protocol
specification	`string`	optional	URL or path to protocol specification
description	`string`	optional

ProtocolVersion

Semantic version of the protocol

Properties

Property	Type	Required
major	`integer`	✅
minor	`integer`	✅
patch	`integer`	✅

Plugin Capability — Kernel Protocol reference

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