# Plugin / Extensibility / IoC > Every principle in this category is listed as a record. Page: Ontology · Principles Canonical: https://banes-lab.com/ontology#architecture-category-plugin-extensibility-ioc Listed in [Ontology · Principles](https://banes-lab.com/api/pages/ontology/principles.md), after [Streaming / Pipeline / Dataflow Processing](https://banes-lab.com/ontology/principles/architecture-category-streaming-pipeline-dataflow-processing.md) and before [Self-Healing / Recovery / Deployment Safety](https://banes-lab.com/ontology/principles/architecture-category-self-healing-recovery-deployment-safety.md). Every principle in this category is listed as a record. Each record carries its kind, its severity, the scopes it applies at and the layer it lives in, then the edge relations that join it to other records, the records that point back at it, the contracts that answer to it and the tensions it takes part in. The descriptors say how it is violated, detected, measured, repaired and enforced. Where the record carries one, an exemplar shows the shape before and after the principle is applied. Relations diagram The relations inside this category. ```mermaid flowchart LR n_plugin_architecture["Plugin Architecture"] n_extension_points["Extension Points"] n_inversion_of_control["Inversion of Control (IoC)"] n_dependency_injection["Dependency Injection"] n_service_registry["Service Registry"] n_registry_pattern["Registry Pattern"] n_service_locator_pattern["Service Locator Pattern"] n_feature_toggle["Feature Toggle"] n_plugin_architecture --> n_extension_points n_extension_points --> n_plugin_architecture n_inversion_of_control --> n_dependency_injection ``` ### Plugin Architecture - Kind: [style](https://banes-lab.com/records/kind/style.md) - Category: [Plugin / Extensibility / IoC](https://banes-lab.com/ontology/principles/architecture-category-plugin-extensibility-ioc.md) - Severity: [contextual](https://banes-lab.com/records/vocabulary/severity-contextual.md) - Scope: component, runtime, system - Layer: [Extensibility Core](https://banes-lab.com/records/layer/extensibility-core.md) Details Definition A convention of building a small core that discovers and loads plugins through declared extension points. Requires [Extension Points](https://banes-lab.com/records/architecture/extension-points.md), [Stable Interfaces](https://banes-lab.com/records/architecture/stable-interfaces.md), [Discovery](https://banes-lab.com/records/lexicon/discovery.md) Reinforces [Open/Closed Principle (OCP)](https://banes-lab.com/records/architecture/open-closed.md), [Modularity](https://banes-lab.com/records/architecture/modularity.md) Enables [Runtime Extensibility](https://banes-lab.com/records/architecture/runtime-extensibility.md) In tension with [Static Analysis](https://banes-lab.com/records/architecture/static-analysis.md), [Security](https://banes-lab.com/records/lexicon/security.md) Conflicts with [Hardcoded Extensions](https://banes-lab.com/records/lexicon/hardcoded-extensions.md) Referenced by [Runtime Discovery](https://banes-lab.com/records/architecture/runtime-discovery.md), [Runtime Extensibility](https://banes-lab.com/records/architecture/runtime-extensibility.md), [Modularity](https://banes-lab.com/records/architecture/modularity.md), [Composability](https://banes-lab.com/records/architecture/composability.md), [Replaceability](https://banes-lab.com/records/architecture/replaceability.md), [Open/Closed Principle (OCP)](https://banes-lab.com/records/architecture/open-closed.md), [Self-Describing Architecture](https://banes-lab.com/records/architecture/self-describing-architecture.md), [Extension Points](https://banes-lab.com/records/architecture/extension-points.md) Tensions [Plugin Architecture / Static Analysis](https://banes-lab.com/records/tension/plugin-architecture-static-analysis.md), [Plugin Architecture / Security](https://banes-lab.com/records/tension/plugin-architecture-security.md) Violated by core importing plugin implementations Detected by direct plugin imports, central switch for plugins Measured by plugin isolation score Refactored by Introduce SPI, Add Registry, Extract Extension Point Enforced by plugin contract tests, dependency rules Before ```typescript class FooApp { run() { new FooExport().run(); new BarExport().run(); } } ``` After ```typescript interface FooPlugin { name: string; setup(app: FooApp): void; } class FooApp { constructor(private readonly plugins: readonly FooPlugin[]) {} run() { this.plugins.forEach(plugin => plugin.setup(this)); } } ``` How it is checked Checked by plugin contract tests, dependency rules Population Every extension point, plugin, registration and dependency construction site Freshness A verdict stands until a plugin, a registration or the composition root changes Refusal The dependency rule, plugin contract test or banned-API rule fails a change that hardcodes an extension or hides a dependency Observation Imports from the core to plugins, construction sites and registry contents, read from source and at startup Evidence None, because the catalog states this check as a class, so a watched run belongs to each system that adopts it Authoritative side The extension contract, which every plugin conforms to while the core names no plugin Depends on [Extension Points](https://banes-lab.com/records/architecture/extension-points.md), [Stable Interfaces](https://banes-lab.com/records/architecture/stable-interfaces.md), [Discovery](https://banes-lab.com/records/lexicon/discovery.md), [Open/Closed Principle (OCP)](https://banes-lab.com/records/architecture/open-closed.md), [Modularity](https://banes-lab.com/records/architecture/modularity.md), [Runtime Extensibility](https://banes-lab.com/records/architecture/runtime-extensibility.md) Shape it refuses [Hardcoded Extensions](https://banes-lab.com/records/lexicon/hardcoded-extensions.md) ### Extension Points - Kind: [mechanism](https://banes-lab.com/records/kind/mechanism.md) - Category: [Plugin / Extensibility / IoC](https://banes-lab.com/ontology/principles/architecture-category-plugin-extensibility-ioc.md) - Severity: [recommended](https://banes-lab.com/records/vocabulary/severity-recommended.md) - Scope: framework, plugin, module - Layer: [Extensibility Core](https://banes-lab.com/records/layer/extensibility-core.md) Details Definition A mechanism that exposes named hooks or interfaces where new behavior can be added without editing the core. Requires [Stable Interfaces](https://banes-lab.com/records/architecture/stable-interfaces.md), [Contracts](https://banes-lab.com/records/lexicon/contracts.md) Reinforces [Open/Closed Principle (OCP)](https://banes-lab.com/records/architecture/open-closed.md), [Plugin Architecture](https://banes-lab.com/records/architecture/plugin-architecture.md) Enables [Third-Party Extension](https://banes-lab.com/records/lexicon/third-party-extension.md) In tension with [API Surface Growth](https://banes-lab.com/records/lexicon/api-surface-growth.md) Conflicts with [Closed Core](https://banes-lab.com/records/lexicon/closed-core.md) Referenced by [Runtime Extensibility](https://banes-lab.com/records/architecture/runtime-extensibility.md), [Open/Closed Principle (OCP)](https://banes-lab.com/records/architecture/open-closed.md), [Plugin Architecture](https://banes-lab.com/records/architecture/plugin-architecture.md) Tensions [Extension Points / API Surface Growth](https://banes-lab.com/records/tension/api-surface-growth-extension-points.md) Violated by modifying internals to add behavior Detected by repeated core edits for variants Measured by extension coverage Refactored by Add Hook, Add SPI, Extract Interface Enforced by extension tests, API review Before ```typescript function saveFoo(foo: Foo) { validateFoo(foo); fooStore.save(foo); sendFooEmail(foo); } ``` After ```typescript type FooHooks = { beforeSave: Array<(foo: Foo) => void>; afterSave: Array<(foo: Foo) => void> }; function saveFoo(foo: Foo, hooks: FooHooks) { hooks.beforeSave.forEach(hook => hook(foo)); fooStore.save(foo); hooks.afterSave.forEach(hook => hook(foo)); } ``` How it is checked Checked by extension tests, API review Population Every extension point, plugin, registration and dependency construction site Freshness A verdict stands until a plugin, a registration or the composition root changes Refusal The dependency rule, plugin contract test or banned-API rule fails a change that hardcodes an extension or hides a dependency Observation Imports from the core to plugins, construction sites and registry contents, read from source and at startup Evidence None, because the catalog states this check as a class, so a watched run belongs to each system that adopts it Authoritative side The extension contract, which every plugin conforms to while the core names no plugin Depends on [Stable Interfaces](https://banes-lab.com/records/architecture/stable-interfaces.md), [Contracts](https://banes-lab.com/records/lexicon/contracts.md), [Open/Closed Principle (OCP)](https://banes-lab.com/records/architecture/open-closed.md), [Plugin Architecture](https://banes-lab.com/records/architecture/plugin-architecture.md), [Third-Party Extension](https://banes-lab.com/records/lexicon/third-party-extension.md) Shape it refuses [Closed Core](https://banes-lab.com/records/lexicon/closed-core.md) ### Inversion of Control (IoC) - Kind: [principle](https://banes-lab.com/records/kind/principle.md) - Category: [Plugin / Extensibility / IoC](https://banes-lab.com/ontology/principles/architecture-category-plugin-extensibility-ioc.md) - Severity: [recommended](https://banes-lab.com/records/vocabulary/severity-recommended.md) - Scope: framework, runtime, component - Layer: [Extensibility Core](https://banes-lab.com/records/layer/extensibility-core.md) Details Definition A design rule that a framework or composition root owns object creation and control flow, and application code supplies the parts it calls. Requires [Abstraction](https://banes-lab.com/records/architecture/abstraction.md), [Composition Root](https://banes-lab.com/records/lexicon/composition-root.md) Reinforces [Dependency Inversion Principle (DIP)](https://banes-lab.com/records/architecture/dependency-inversion.md), [Dependency Injection](https://banes-lab.com/records/architecture/dependency-injection.md) Enables [Framework Control Flow](https://banes-lab.com/records/lexicon/framework-control-flow.md), [Plugins](https://banes-lab.com/records/lexicon/plugins.md) In tension with [Traceability](https://banes-lab.com/records/architecture/traceability.md) Conflicts with [Direct Control Ownership](https://banes-lab.com/records/lexicon/direct-control-ownership.md) Tensions [Inversion of Control (IoC) / Traceability](https://banes-lab.com/records/tension/inversion-of-control-ioc-traceability.md) Violated by application manually controlling framework-owned lifecycle Detected by scattered object lifecycle construction Measured by composition centralization Refactored by Introduce Container, Extract Composition Root Enforced by lifecycle rules Before ```typescript class FooJob { run() { const store = new SqlFooStore(); return store.save(makeFoo()); } } ``` After ```typescript class FooJob { constructor(private readonly make: () => Foo, private readonly store: FooStore) {} run() { return this.store.save(this.make()); } } container.run(FooJob); ``` How it is checked Checked by lifecycle rules Population Every extension point, plugin, registration and dependency construction site Freshness A verdict stands until a plugin, a registration or the composition root changes Refusal The dependency rule, plugin contract test or banned-API rule fails a change that hardcodes an extension or hides a dependency Observation Imports from the core to plugins, construction sites and registry contents, read from source and at startup Evidence None, because the catalog states this check as a class, so a watched run belongs to each system that adopts it Authoritative side The extension contract, which every plugin conforms to while the core names no plugin Depends on [Abstraction](https://banes-lab.com/records/architecture/abstraction.md), [Composition Root](https://banes-lab.com/records/lexicon/composition-root.md), [Dependency Inversion Principle (DIP)](https://banes-lab.com/records/architecture/dependency-inversion.md), [Dependency Injection](https://banes-lab.com/records/architecture/dependency-injection.md), [Framework Control Flow](https://banes-lab.com/records/lexicon/framework-control-flow.md), [Plugins](https://banes-lab.com/records/lexicon/plugins.md) Shape it refuses [Direct Control Ownership](https://banes-lab.com/records/lexicon/direct-control-ownership.md) ### Dependency Injection - Kind: [pattern](https://banes-lab.com/records/kind/pattern.md) - Category: [Plugin / Extensibility / IoC](https://banes-lab.com/ontology/principles/architecture-category-plugin-extensibility-ioc.md) - Severity: [recommended](https://banes-lab.com/records/vocabulary/severity-recommended.md) - Scope: class, module, component - Layer: [Extensibility Core](https://banes-lab.com/records/layer/extensibility-core.md) Details Definition A design pattern that passes an object its dependencies from outside, usually through its constructor. Requires [Abstraction](https://banes-lab.com/records/architecture/abstraction.md), [Composition Root](https://banes-lab.com/records/lexicon/composition-root.md) Reinforces [Dependency Inversion Principle (DIP)](https://banes-lab.com/records/architecture/dependency-inversion.md), [Testability](https://banes-lab.com/records/architecture/testability.md) Enables [Mocking](https://banes-lab.com/records/lexicon/mocking.md), [Replaceability](https://banes-lab.com/records/architecture/replaceability.md) In tension with [Constructor Complexity](https://banes-lab.com/records/lexicon/constructor-complexity.md) Conflicts with [Hardcoded Instantiation](https://banes-lab.com/records/lexicon/hardcoded-instantiation.md), [Ambient Context](https://banes-lab.com/records/architecture/ambient-context.md) Referenced by [Interface-Based Design](https://banes-lab.com/records/architecture/interface-based-design.md), [Dependency Inversion Principle (DIP)](https://banes-lab.com/records/architecture/dependency-inversion.md), [Singleton Pattern](https://banes-lab.com/records/architecture/singleton-pattern.md), [Inversion of Control (IoC)](https://banes-lab.com/records/architecture/inversion-of-control.md) Tensions [Dependency Injection / Constructor Complexity](https://banes-lab.com/records/tension/constructor-complexity-dependency-injection.md) Distinct from [Adapter Pattern](https://banes-lab.com/records/architecture/adapter-pattern.md): Dependency injection supplies a dependency from outside, while an adapter makes an incompatible interface fit the one expected. Distinct from [Composition Root](https://banes-lab.com/records/lexicon/composition-root.md): Dependency injection is passing dependencies in, while the composition root is the one place where they are wired. Distinct from [Ports and Adapters](https://banes-lab.com/records/lexicon/ports-and-adapters.md): Dependency injection is how one object receives its dependencies, while ports and adapters is how a whole core is isolated from its technologies. Distinct from [Singleton Pattern](https://banes-lab.com/records/architecture/singleton-pattern.md): Dependency injection passes a dependency in, while a singleton is reached through a global access point. Violated by newing dependencies inside business logic Detected by direct construction of external dependencies Measured by injected dependency ratio Refactored by Inject Constructor Parameter, Add Factory Enforced by lint rules, dependency review Before ```typescript class FooService { private readonly clock = new SystemClock(); private readonly store = new SqlFooStore(); } ``` After ```typescript class FooService { constructor(private readonly clock: Clock, private readonly store: FooStore) {} } ``` How it is checked Checked by lint rules, dependency review Population Every extension point, plugin, registration and dependency construction site Freshness A verdict stands until a plugin, a registration or the composition root changes Refusal The dependency rule, plugin contract test or banned-API rule fails a change that hardcodes an extension or hides a dependency Observation Imports from the core to plugins, construction sites and registry contents, read from source and at startup Evidence None, because the catalog states this check as a class, so a watched run belongs to each system that adopts it Authoritative side The extension contract, which every plugin conforms to while the core names no plugin Depends on [Abstraction](https://banes-lab.com/records/architecture/abstraction.md), [Composition Root](https://banes-lab.com/records/lexicon/composition-root.md), [Dependency Inversion Principle (DIP)](https://banes-lab.com/records/architecture/dependency-inversion.md), [Testability](https://banes-lab.com/records/architecture/testability.md), [Mocking](https://banes-lab.com/records/lexicon/mocking.md), [Replaceability](https://banes-lab.com/records/architecture/replaceability.md) Shape it refuses [Hardcoded Instantiation](https://banes-lab.com/records/lexicon/hardcoded-instantiation.md), [Ambient Context](https://banes-lab.com/records/architecture/ambient-context.md) ### Service Registry - Kind: [mechanism](https://banes-lab.com/records/kind/mechanism.md) - Category: [Plugin / Extensibility / IoC](https://banes-lab.com/ontology/principles/architecture-category-plugin-extensibility-ioc.md) - Severity: [contextual](https://banes-lab.com/records/vocabulary/severity-contextual.md) - Scope: runtime, service, plugin - Layer: [Extensibility Core](https://banes-lab.com/records/layer/extensibility-core.md) Details Definition A mechanism where services or plugins register under a key and are resolved by that key at runtime. Requires [Registration Protocol](https://banes-lab.com/records/lexicon/registration-protocol.md) Reinforces [Discovery](https://banes-lab.com/records/lexicon/discovery.md), [Dynamic Binding](https://banes-lab.com/records/architecture/dynamic-binding.md) Enables [Dynamic Resolution](https://banes-lab.com/records/lexicon/dynamic-resolution.md) In tension with [Registry Availability](https://banes-lab.com/records/lexicon/registry-availability.md) Conflicts with [Hardcoded Lookup](https://banes-lab.com/records/lexicon/hardcoded-lookup.md) Referenced by [Service Discovery](https://banes-lab.com/records/architecture/service-discovery.md) Tensions [Service Registry / Registry Availability](https://banes-lab.com/records/tension/registry-availability-service-registry.md) Distinct from [Health Checks](https://banes-lab.com/records/architecture/health-checks.md): A service registry resolves a key to a registered service, while health checks report whether an instance is ready to serve. Violated by manual endpoint/plugin lookup Detected by static lookup tables Measured by registry coverage Refactored by Register Service, Add Discovery Client Enforced by startup checks, [health checks](https://banes-lab.com/records/architecture/health-checks.md) Before ```typescript const fooService = new FooService(new SqlFooStore()); const barService = new BarService(new SqlBarStore()); ``` After ```typescript const services = new ServiceRegistry(); services.register("FooStore", () => new SqlFooStore()); services.register("FooService", r => new FooService(r.resolve("FooStore"))); ``` How it is checked Checked by startup checks, health checks Population Every extension point, plugin, registration and dependency construction site Freshness A verdict stands until a plugin, a registration or the composition root changes Refusal The dependency rule, plugin contract test or banned-API rule fails a change that hardcodes an extension or hides a dependency Observation Imports from the core to plugins, construction sites and registry contents, read from source and at startup Evidence None, because the catalog states this check as a class, so a watched run belongs to each system that adopts it Authoritative side The extension contract, which every plugin conforms to while the core names no plugin Depends on [Registration Protocol](https://banes-lab.com/records/lexicon/registration-protocol.md), [Discovery](https://banes-lab.com/records/lexicon/discovery.md), [Dynamic Binding](https://banes-lab.com/records/architecture/dynamic-binding.md), [Dynamic Resolution](https://banes-lab.com/records/lexicon/dynamic-resolution.md) Shape it refuses [Hardcoded Lookup](https://banes-lab.com/records/lexicon/hardcoded-lookup.md) ### Registry Pattern - Kind: [pattern](https://banes-lab.com/records/kind/pattern.md) - Category: [Plugin / Extensibility / IoC](https://banes-lab.com/ontology/principles/architecture-category-plugin-extensibility-ioc.md) - Severity: [contextual](https://banes-lab.com/records/vocabulary/severity-contextual.md) - Scope: runtime, module, plugin - Layer: [Extensibility Core](https://banes-lab.com/records/layer/extensibility-core.md) Details Definition A design pattern that replaces a conditional over kinds with a keyed table that each kind registers itself into. Requires [Keyed Registration](https://banes-lab.com/records/lexicon/keyed-registration.md) Reinforces [Discovery](https://banes-lab.com/records/lexicon/discovery.md), [Factory Pattern](https://banes-lab.com/records/architecture/factory-pattern.md) Enables [Dynamic Lookup](https://banes-lab.com/records/lexicon/dynamic-lookup.md) In tension with [Global State](https://banes-lab.com/records/lexicon/global-state.md) Conflicts with [Direct Reference](https://banes-lab.com/records/lexicon/direct-reference.md) Tensions [Registry Pattern / Global State](https://banes-lab.com/records/tension/global-state-registry-pattern.md) Distinct from [Factory Pattern](https://banes-lab.com/records/architecture/factory-pattern.md): A registry replaces a conditional over kinds with a keyed table, while a factory owns how one object and its defaults are built. Violated by ungoverned global registry Detected by mutable global maps without lifecycle Measured by registry consistency Refactored by Encapsulate Registry, Add Typed Keys Enforced by registry validation Before ```typescript function makeFoo(kind: string) { if (kind === "foo") return new Foo1(); if (kind === "bar") return new Bar(); throw new Error("unknown kind"); } ``` After ```typescript type FooFactory = () => Foo; const registry = new Map(); export const registerFoo = (kind: string, factory: FooFactory) => registry.set(kind, factory); export const makeFoo = (kind: string) => registry.get(kind)?.() ?? fail(`unknown ${kind}`); ``` How it is checked Checked by registry validation Population Every extension point, plugin, registration and dependency construction site Freshness A verdict stands until a plugin, a registration or the composition root changes Refusal The dependency rule, plugin contract test or banned-API rule fails a change that hardcodes an extension or hides a dependency Observation Imports from the core to plugins, construction sites and registry contents, read from source and at startup Evidence None, because the catalog states this check as a class, so a watched run belongs to each system that adopts it Authoritative side The extension contract, which every plugin conforms to while the core names no plugin Depends on [Keyed Registration](https://banes-lab.com/records/lexicon/keyed-registration.md), [Discovery](https://banes-lab.com/records/lexicon/discovery.md), [Factory Pattern](https://banes-lab.com/records/architecture/factory-pattern.md), [Dynamic Lookup](https://banes-lab.com/records/lexicon/dynamic-lookup.md) Shape it refuses [Direct Reference](https://banes-lab.com/records/lexicon/direct-reference.md) ### Service Locator Pattern - Kind: [pattern](https://banes-lab.com/records/kind/pattern.md) - Category: [Plugin / Extensibility / IoC](https://banes-lab.com/ontology/principles/architecture-category-plugin-extensibility-ioc.md) - Severity: [discouraged](https://banes-lab.com/records/vocabulary/severity-discouraged.md) - Scope: runtime, dependency access - Layer: [Extensibility Core](https://banes-lab.com/records/layer/extensibility-core.md) Details Definition A design pattern in which code fetches its dependencies from a global registry at the point of use. Requires [Registry](https://banes-lab.com/records/lexicon/registry.md) Reinforces [Runtime Lookup](https://banes-lab.com/records/lexicon/runtime-lookup.md) Enables [Late Resolution](https://banes-lab.com/records/lexicon/late-resolution.md) In tension with [Testability](https://banes-lab.com/records/architecture/testability.md), [Dependency Inversion Principle (DIP)](https://banes-lab.com/records/architecture/dependency-inversion.md), [Explicit Dependencies](https://banes-lab.com/records/lexicon/explicit-dependencies.md) Conflicts with none Tensions [Service Locator Pattern / Testability](https://banes-lab.com/records/tension/service-locator-pattern-testability.md), [Service Locator Pattern / Dependency Inversion Principle (DIP)](https://banes-lab.com/records/tension/dependency-inversion-principle-dip-service-locator-pattern.md), [Service Locator Pattern / Explicit Dependencies](https://banes-lab.com/records/tension/explicit-dependencies-service-locator-pattern.md) Violated by hidden dependencies through global locator Detected by service locator calls inside domain logic Measured by hidden dependency count Refactored by Replace with Dependency Injection Enforced by banned API rules Before ```typescript class FooController { save(foo: Foo) { const store = serviceLocator.resolve("FooStore"); return store.save(foo); } } ``` After ```typescript class FooController { constructor(private readonly store: FooStore) {} save(foo: Foo) { return this.store.save(foo); } } ``` How it is checked Checked by banned API rules Population Every extension point, plugin, registration and dependency construction site Freshness A verdict stands until a plugin, a registration or the composition root changes Refusal The dependency rule, plugin contract test or banned-API rule fails a change that hardcodes an extension or hides a dependency Observation Imports from the core to plugins, construction sites and registry contents, read from source and at startup Evidence None, because the catalog states this check as a class, so a watched run belongs to each system that adopts it Authoritative side The extension contract, which every plugin conforms to while the core names no plugin Depends on [Registry](https://banes-lab.com/records/lexicon/registry.md), [Runtime Lookup](https://banes-lab.com/records/lexicon/runtime-lookup.md), [Late Resolution](https://banes-lab.com/records/lexicon/late-resolution.md) Shape it refuses Not answered ### Feature Toggle - Kind: [mechanism](https://banes-lab.com/records/kind/mechanism.md) - Category: [Plugin / Extensibility / IoC](https://banes-lab.com/ontology/principles/architecture-category-plugin-extensibility-ioc.md) - Severity: [contextual](https://banes-lab.com/records/vocabulary/severity-contextual.md) - Scope: application, release, runtime - Layer: [Extensibility Core](https://banes-lab.com/records/layer/extensibility-core.md) Details Definition A mechanism that switches a code path on or off at runtime from externally held flag state, so a release can happen without a deploy. Requires [Externalized Flag State](https://banes-lab.com/records/lexicon/externalized-flag-state.md) Reinforces [Continuous Delivery](https://banes-lab.com/records/lexicon/continuous-delivery.md), [Runtime Extensibility](https://banes-lab.com/records/architecture/runtime-extensibility.md) Enables [Decoupled Deploy and Release](https://banes-lab.com/records/lexicon/decoupled-deploy-and-release.md), [Gradual Rollout](https://banes-lab.com/records/lexicon/gradual-rollout.md) In tension with [Flag Debt](https://banes-lab.com/records/lexicon/flag-debt.md) Conflicts with [Hardcoded Branch Constant](https://banes-lab.com/records/lexicon/hardcoded-branch-constant.md) Tensions [Feature Toggle / Flag Debt](https://banes-lab.com/records/tension/feature-toggle-flag-debt.md) Violated by release paths gated by a hardcoded boolean constant Detected by compile-time flags requiring redeploy to flip Measured by redeploys per behavior change Refactored by Introduce Runtime Feature Flags Enforced by release review Before ```typescript if (NEW_FOO_FLOW_ENABLED) runNewFooFlow(); else runOldFooFlow(); ``` After ```typescript if (featureFlags.enabled("new-foo-flow", { user, percentage: 10 })) runNewFooFlow(); else runOldFooFlow(); ``` How it is checked Checked by release review Population Every extension point, plugin, registration and dependency construction site Freshness A verdict stands until a plugin, a registration or the composition root changes Refusal The dependency rule, plugin contract test or banned-API rule fails a change that hardcodes an extension or hides a dependency Observation Imports from the core to plugins, construction sites and registry contents, read from source and at startup Evidence None, because the catalog states this check as a class, so a watched run belongs to each system that adopts it Authoritative side The extension contract, which every plugin conforms to while the core names no plugin Depends on [Externalized Flag State](https://banes-lab.com/records/lexicon/externalized-flag-state.md), [Continuous Delivery](https://banes-lab.com/records/lexicon/continuous-delivery.md), [Runtime Extensibility](https://banes-lab.com/records/architecture/runtime-extensibility.md), [Decoupled Deploy and Release](https://banes-lab.com/records/lexicon/decoupled-deploy-and-release.md), [Gradual Rollout](https://banes-lab.com/records/lexicon/gradual-rollout.md) Shape it refuses [Hardcoded Branch Constant](https://banes-lab.com/records/lexicon/hardcoded-branch-constant.md) ## Links to - [style](https://banes-lab.com/records/kind/style.md) - [contextual](https://banes-lab.com/records/vocabulary/severity-contextual.md) - [Extensibility Core](https://banes-lab.com/records/layer/extensibility-core.md) - [Extension Points](https://banes-lab.com/records/architecture/extension-points.md) - [Stable Interfaces](https://banes-lab.com/records/architecture/stable-interfaces.md) - [Discovery](https://banes-lab.com/records/lexicon/discovery.md) - [Open/Closed Principle](https://banes-lab.com/records/architecture/open-closed.md) - [Modularity](https://banes-lab.com/records/architecture/modularity.md) - [Runtime Extensibility](https://banes-lab.com/records/architecture/runtime-extensibility.md) - [Static Analysis](https://banes-lab.com/records/architecture/static-analysis.md) - [Security](https://banes-lab.com/records/lexicon/security.md) - [Hardcoded Extensions](https://banes-lab.com/records/lexicon/hardcoded-extensions.md) - [Runtime Discovery](https://banes-lab.com/records/architecture/runtime-discovery.md) - [Composability](https://banes-lab.com/records/architecture/composability.md) - [Replaceability](https://banes-lab.com/records/architecture/replaceability.md) - [Self-Describing Architecture](https://banes-lab.com/records/architecture/self-describing-architecture.md) - [Plugin Architecture / Static Analysis](https://banes-lab.com/records/tension/plugin-architecture-static-analysis.md) - [Plugin Architecture / Security](https://banes-lab.com/records/tension/plugin-architecture-security.md) - [mechanism](https://banes-lab.com/records/kind/mechanism.md) - [recommended](https://banes-lab.com/records/vocabulary/severity-recommended.md) - [Contracts](https://banes-lab.com/records/lexicon/contracts.md) - [Plugin Architecture](https://banes-lab.com/records/architecture/plugin-architecture.md) - [Third-Party Extension](https://banes-lab.com/records/lexicon/third-party-extension.md) - [API Surface Growth](https://banes-lab.com/records/lexicon/api-surface-growth.md) - [Closed Core](https://banes-lab.com/records/lexicon/closed-core.md) - [Extension Points / API Surface Growth](https://banes-lab.com/records/tension/api-surface-growth-extension-points.md) - [principle](https://banes-lab.com/records/kind/principle.md) - [Abstraction](https://banes-lab.com/records/architecture/abstraction.md) - [Composition Root](https://banes-lab.com/records/lexicon/composition-root.md) - [Dependency Inversion Principle](https://banes-lab.com/records/architecture/dependency-inversion.md) - [Dependency Injection](https://banes-lab.com/records/architecture/dependency-injection.md) - [Framework Control Flow](https://banes-lab.com/records/lexicon/framework-control-flow.md) - [Plugins](https://banes-lab.com/records/lexicon/plugins.md) - [Traceability](https://banes-lab.com/records/architecture/traceability.md) - [Direct Control Ownership](https://banes-lab.com/records/lexicon/direct-control-ownership.md) - [Inversion of Control (IoC) / Traceability](https://banes-lab.com/records/tension/inversion-of-control-ioc-traceability.md) - [pattern](https://banes-lab.com/records/kind/pattern.md) - [Testability](https://banes-lab.com/records/architecture/testability.md) - [Mocking](https://banes-lab.com/records/lexicon/mocking.md) - [Constructor Complexity](https://banes-lab.com/records/lexicon/constructor-complexity.md) - [Hardcoded Instantiation](https://banes-lab.com/records/lexicon/hardcoded-instantiation.md) - [Ambient Context](https://banes-lab.com/records/architecture/ambient-context.md) - [Interface-Based Design](https://banes-lab.com/records/architecture/interface-based-design.md) - [Singleton Pattern](https://banes-lab.com/records/architecture/singleton-pattern.md) - [Inversion of Control](https://banes-lab.com/records/architecture/inversion-of-control.md) - [Dependency Injection / Constructor Complexity](https://banes-lab.com/records/tension/constructor-complexity-dependency-injection.md) - [Adapter Pattern](https://banes-lab.com/records/architecture/adapter-pattern.md) - [Ports and Adapters](https://banes-lab.com/records/lexicon/ports-and-adapters.md) - [Registration Protocol](https://banes-lab.com/records/lexicon/registration-protocol.md) - [Dynamic Binding](https://banes-lab.com/records/architecture/dynamic-binding.md) - [Dynamic Resolution](https://banes-lab.com/records/lexicon/dynamic-resolution.md) - [Registry Availability](https://banes-lab.com/records/lexicon/registry-availability.md) - [Hardcoded Lookup](https://banes-lab.com/records/lexicon/hardcoded-lookup.md) - [Service Discovery](https://banes-lab.com/records/architecture/service-discovery.md) - [Service Registry / Registry Availability](https://banes-lab.com/records/tension/registry-availability-service-registry.md) - [Health Checks](https://banes-lab.com/records/architecture/health-checks.md) - [Keyed Registration](https://banes-lab.com/records/lexicon/keyed-registration.md) - [Factory Pattern](https://banes-lab.com/records/architecture/factory-pattern.md) - [Dynamic Lookup](https://banes-lab.com/records/lexicon/dynamic-lookup.md) - [Global State](https://banes-lab.com/records/lexicon/global-state.md) - [Direct Reference](https://banes-lab.com/records/lexicon/direct-reference.md) - [Registry Pattern / Global State](https://banes-lab.com/records/tension/global-state-registry-pattern.md) - [discouraged](https://banes-lab.com/records/vocabulary/severity-discouraged.md) - [Registry](https://banes-lab.com/records/lexicon/registry.md) - [Runtime Lookup](https://banes-lab.com/records/lexicon/runtime-lookup.md) - [Late Resolution](https://banes-lab.com/records/lexicon/late-resolution.md) - [Explicit Dependencies](https://banes-lab.com/records/lexicon/explicit-dependencies.md) - [Service Locator Pattern / Testability](https://banes-lab.com/records/tension/service-locator-pattern-testability.md) - [Service Locator Pattern / Dependency Inversion Principle (DIP)](https://banes-lab.com/records/tension/dependency-inversion-principle-dip-service-locator-pattern.md) - [Service Locator Pattern / Explicit Dependencies](https://banes-lab.com/records/tension/explicit-dependencies-service-locator-pattern.md) - [Externalized Flag State](https://banes-lab.com/records/lexicon/externalized-flag-state.md) - [Continuous Delivery](https://banes-lab.com/records/lexicon/continuous-delivery.md) - [Decoupled Deploy and Release](https://banes-lab.com/records/lexicon/decoupled-deploy-and-release.md) - [Gradual Rollout](https://banes-lab.com/records/lexicon/gradual-rollout.md) - [Flag Debt](https://banes-lab.com/records/lexicon/flag-debt.md) - [Hardcoded Branch Constant](https://banes-lab.com/records/lexicon/hardcoded-branch-constant.md) - [Feature Toggle / Flag Debt](https://banes-lab.com/records/tension/feature-toggle-flag-debt.md) ## Linked from - [The layer topology](https://banes-lab.com/ontology/schema/the-layer-topology.md) - [The membership](https://banes-lab.com/ontology/schema/the-membership.md)