diff --git a/entrypoints/main.d.cts b/entrypoints/main.d.cts
index 94d834ba..d4fcdc16 100644
--- a/entrypoints/main.d.cts
+++ b/entrypoints/main.d.cts
@@ -1,2 +1,12 @@
-export {default} from './main.js';
-export * from './main.js';
+import type {TestFn} from '../types/test-fn.cjs';
+
+export * from '../types/assertions.cjs';
+export * from '../types/try-fn.cjs';
+export * from '../types/test-fn.cjs';
+export * from '../types/subscribable.cjs';
+
+/** Call to declare a test, or chain to declare hooks or test modifiers */
+declare const test: TestFn;
+
+/** Call to declare a test, or chain to declare hooks or test modifiers */
+export default test;
diff --git a/entrypoints/main.d.ts b/entrypoints/main.d.ts
index f12fc65b..6120bb89 100644
--- a/entrypoints/main.d.ts
+++ b/entrypoints/main.d.ts
@@ -1,12 +1,2 @@
-import type {TestFn} from '../types/test-fn.js';
-
-export * from '../types/assertions.js';
-export * from '../types/try-fn.js';
-export * from '../types/test-fn.js';
-export * from '../types/subscribable.js';
-
-/** Call to declare a test, or chain to declare hooks or test modifiers */
-declare const test: TestFn;
-
-/** Call to declare a test, or chain to declare hooks or test modifiers */
-export default test;
+export * from './main.cjs';
+export {default} from './main.cjs';
diff --git a/entrypoints/plugin.d.cts b/entrypoints/plugin.d.cts
index 83723514..24319ce2 100644
--- a/entrypoints/plugin.d.cts
+++ b/entrypoints/plugin.d.cts
@@ -1 +1,77 @@
-export * from './plugin.js'
+import type {URL} from 'node:url';
+
+export namespace SharedWorker {
+	export type ProtocolIdentifier = 'ava-4';
+
+	export type FactoryOptions = {
+		negotiateProtocol <Data = unknown>(supported: readonly ['ava-4']): Protocol<Data>;
+		// Add overloads for additional protocols.
+	};
+
+	export type Factory = (options: FactoryOptions) => void;
+
+	export type Protocol<Data = unknown> = {
+		readonly initialData: Data;
+		readonly protocol: 'ava-4';
+		broadcast: (data: Data) => BroadcastMessage<Data>;
+		ready: () => Protocol<Data>;
+		subscribe: () => AsyncIterableIterator<ReceivedMessage<Data>>;
+		testWorkers: () => AsyncIterableIterator<TestWorker<Data>>;
+	};
+
+	export type BroadcastMessage<Data = unknown> = {
+		readonly id: string;
+		replies: () => AsyncIterableIterator<ReceivedMessage<Data>>;
+	};
+
+	export type PublishedMessage<Data = unknown> = {
+		readonly id: string;
+		replies: () => AsyncIterableIterator<ReceivedMessage<Data>>;
+	};
+
+	export type ReceivedMessage<Data = unknown> = {
+		readonly data: Data;
+		readonly id: string;
+		readonly testWorker: TestWorker;
+		reply: (data: Data) => PublishedMessage<Data>;
+	};
+
+	export type TestWorker<Data = unknown> = {
+		readonly id: string;
+		readonly file: string;
+		publish: (data: Data) => PublishedMessage<Data>;
+		subscribe: () => AsyncIterableIterator<ReceivedMessage<Data>>;
+		teardown: (fn: (() => Promise<void>) | (() => void)) => () => Promise<void>;
+	};
+
+	export namespace Plugin {
+		export type RegistrationOptions<Identifier extends ProtocolIdentifier, Data = unknown> = {
+			readonly filename: string | URL;
+			readonly initialData?: Data;
+			readonly supportedProtocols: readonly Identifier[];
+			readonly teardown?: () => void;
+		};
+
+		export type Protocol<Data = unknown> = {
+			readonly available: Promise<void>;
+			readonly currentlyAvailable: boolean;
+			readonly protocol: 'ava-4';
+			publish: (data: Data) => PublishedMessage<Data>;
+			subscribe: () => AsyncIterableIterator<ReceivedMessage<Data>>;
+		};
+
+		export type PublishedMessage<Data = unknown> = {
+			readonly id: string;
+			replies: () => AsyncIterableIterator<ReceivedMessage<Data>>;
+		};
+
+		export type ReceivedMessage<Data = unknown> = {
+			readonly data: Data;
+			readonly id: string;
+			reply: (data: Data) => PublishedMessage<Data>;
+		};
+	}
+}
+
+export function registerSharedWorker<Data = unknown>(options: SharedWorker.Plugin.RegistrationOptions<'ava-4', Data>): SharedWorker.Plugin.Protocol<Data>;
+// Add overloads for additional protocols.
diff --git a/entrypoints/plugin.d.ts b/entrypoints/plugin.d.ts
index 24319ce2..e84a6643 100644
--- a/entrypoints/plugin.d.ts
+++ b/entrypoints/plugin.d.ts
@@ -1,77 +1 @@
-import type {URL} from 'node:url';
-
-export namespace SharedWorker {
-	export type ProtocolIdentifier = 'ava-4';
-
-	export type FactoryOptions = {
-		negotiateProtocol <Data = unknown>(supported: readonly ['ava-4']): Protocol<Data>;
-		// Add overloads for additional protocols.
-	};
-
-	export type Factory = (options: FactoryOptions) => void;
-
-	export type Protocol<Data = unknown> = {
-		readonly initialData: Data;
-		readonly protocol: 'ava-4';
-		broadcast: (data: Data) => BroadcastMessage<Data>;
-		ready: () => Protocol<Data>;
-		subscribe: () => AsyncIterableIterator<ReceivedMessage<Data>>;
-		testWorkers: () => AsyncIterableIterator<TestWorker<Data>>;
-	};
-
-	export type BroadcastMessage<Data = unknown> = {
-		readonly id: string;
-		replies: () => AsyncIterableIterator<ReceivedMessage<Data>>;
-	};
-
-	export type PublishedMessage<Data = unknown> = {
-		readonly id: string;
-		replies: () => AsyncIterableIterator<ReceivedMessage<Data>>;
-	};
-
-	export type ReceivedMessage<Data = unknown> = {
-		readonly data: Data;
-		readonly id: string;
-		readonly testWorker: TestWorker;
-		reply: (data: Data) => PublishedMessage<Data>;
-	};
-
-	export type TestWorker<Data = unknown> = {
-		readonly id: string;
-		readonly file: string;
-		publish: (data: Data) => PublishedMessage<Data>;
-		subscribe: () => AsyncIterableIterator<ReceivedMessage<Data>>;
-		teardown: (fn: (() => Promise<void>) | (() => void)) => () => Promise<void>;
-	};
-
-	export namespace Plugin {
-		export type RegistrationOptions<Identifier extends ProtocolIdentifier, Data = unknown> = {
-			readonly filename: string | URL;
-			readonly initialData?: Data;
-			readonly supportedProtocols: readonly Identifier[];
-			readonly teardown?: () => void;
-		};
-
-		export type Protocol<Data = unknown> = {
-			readonly available: Promise<void>;
-			readonly currentlyAvailable: boolean;
-			readonly protocol: 'ava-4';
-			publish: (data: Data) => PublishedMessage<Data>;
-			subscribe: () => AsyncIterableIterator<ReceivedMessage<Data>>;
-		};
-
-		export type PublishedMessage<Data = unknown> = {
-			readonly id: string;
-			replies: () => AsyncIterableIterator<ReceivedMessage<Data>>;
-		};
-
-		export type ReceivedMessage<Data = unknown> = {
-			readonly data: Data;
-			readonly id: string;
-			reply: (data: Data) => PublishedMessage<Data>;
-		};
-	}
-}
-
-export function registerSharedWorker<Data = unknown>(options: SharedWorker.Plugin.RegistrationOptions<'ava-4', Data>): SharedWorker.Plugin.Protocol<Data>;
-// Add overloads for additional protocols.
+export type * from './plugin.cjs';
diff --git a/index.d.ts b/index.d.ts
new file mode 100644
index 00000000..66c0e85d
--- /dev/null
+++ b/index.d.ts
@@ -0,0 +1,4 @@
+// For compatibility with resolution algorithms other than Node16.
+
+export * from './entrypoints/main.cjs';
+export {default} from './entrypoints/main.cjs';
diff --git a/package.json b/package.json
index 5f40bd5d..eea1e896 100644
--- a/package.json
+++ b/package.json
@@ -42,7 +42,8 @@
 	"files": [
 		"entrypoints",
 		"lib",
-		"types"
+		"types",
+		"*.d.ts"
 	],
 	"keywords": [
 		"🦄",
diff --git a/plugin.d.ts b/plugin.d.ts
new file mode 100644
index 00000000..a1524f2c
--- /dev/null
+++ b/plugin.d.ts
@@ -0,0 +1,3 @@
+// For compatibility with resolution algorithms other than Node16.
+
+export * from './entrypoints/plugin.cjs';
diff --git a/types/assertions.d.ts b/types/assertions.d.cts
similarity index 100%
rename from types/assertions.d.ts
rename to types/assertions.d.cts
diff --git a/types/subscribable.d.ts b/types/subscribable.d.cts
similarity index 100%
rename from types/subscribable.d.ts
rename to types/subscribable.d.cts
diff --git a/types/test-fn.d.ts b/types/test-fn.d.cts
similarity index 98%
rename from types/test-fn.d.ts
rename to types/test-fn.d.cts
index f58a5d2c..8eb16785 100644
--- a/types/test-fn.d.ts
+++ b/types/test-fn.d.cts
@@ -1,6 +1,6 @@
-import type {Assertions} from './assertions.js';
-import type {Subscribable} from './subscribable.js';
-import type {TryFn} from './try-fn.js';
+import type {Assertions} from './assertions.cjs';
+import type {Subscribable} from './subscribable.cjs';
+import type {TryFn} from './try-fn.cjs';
 
 /** The `t` value passed to test & hook implementations. */
 export type ExecutionContext<Context = unknown> = {
diff --git a/types/try-fn.d.ts b/types/try-fn.d.cts
similarity index 96%
rename from types/try-fn.d.ts
rename to types/try-fn.d.cts
index f1381d82..802c834d 100644
--- a/types/try-fn.d.ts
+++ b/types/try-fn.d.cts
@@ -1,4 +1,4 @@
-import type {Implementation} from './test-fn.js';
+import type {Implementation} from './test-fn.cjs';
 
 export type CommitDiscardOptions = {
 	/**