diff --git a/src/fast_check/transform_dts.rs b/src/fast_check/transform_dts.rs
index beab1ae49..96b09cf6e 100644
--- a/src/fast_check/transform_dts.rs
+++ b/src/fast_check/transform_dts.rs
@@ -498,14 +498,16 @@ impl<'a> FastCheckDtsTransformer<'a> {
   }
 
   fn decl_to_type_decl(&mut self, decl: Decl) -> Option<Decl> {
+    let is_declare = self.is_top_level;
     match decl {
       Decl::Class(mut class_decl) => {
         class_decl.class.body = self.class_body_to_type(class_decl.class.body);
-        class_decl.declare = self.is_top_level;
+        class_decl.declare = is_declare;
         Some(Decl::Class(class_decl))
       }
       Decl::Fn(mut fn_decl) => {
         fn_decl.function.body = None;
+        fn_decl.declare = is_declare;
 
         for param in &mut fn_decl.function.params {
           match &mut param.pat {
@@ -570,7 +572,7 @@ impl<'a> FastCheckDtsTransformer<'a> {
         Some(Decl::Fn(fn_decl))
       }
       Decl::Var(mut var_decl) => {
-        var_decl.declare = self.is_top_level;
+        var_decl.declare = is_declare;
 
         for decl in &mut var_decl.decls {
           if let Pat::Ident(ident) = &mut decl.name {
@@ -602,7 +604,7 @@ impl<'a> FastCheckDtsTransformer<'a> {
         Some(Decl::Var(var_decl))
       }
       Decl::TsEnum(mut ts_enum) => {
-        ts_enum.declare = self.is_top_level;
+        ts_enum.declare = is_declare;
 
         for member in &mut ts_enum.members {
           if let Some(init) = &member.init {
@@ -619,7 +621,7 @@ impl<'a> FastCheckDtsTransformer<'a> {
         Some(Decl::TsEnum(ts_enum))
       }
       Decl::TsModule(mut ts_module) => {
-        ts_module.declare = self.is_top_level;
+        ts_module.declare = is_declare;
 
         if let Some(body) = ts_module.body.clone() {
           ts_module.body = Some(self.transform_ts_ns_body(body));
@@ -995,7 +997,7 @@ mod tests {
       r#"export function foo(a: number): number {
   return {};
 }"#,
-      "export function foo(a: number): number;",
+      "export declare function foo(a: number): number;",
     )
     .await;
     transform_dts_test(
@@ -1003,35 +1005,35 @@ mod tests {
 export function foo(a: any): number {
   return {};
 }"#,
-      r#"export function foo(a: string): number;"#,
+      r#"export declare function foo(a: string): number;"#,
     )
     .await;
     transform_dts_test(
       r#"export function foo(a = 2): number {
   return 2;
 }"#,
-      r#"export function foo(a?: number): number;"#,
+      r#"export declare function foo(a?: number): number;"#,
     )
     .await;
     transform_dts_test(
       r#"export function foo(a: string = 2): number {
   return 2;
 }"#,
-      r#"export function foo(a?: string): number;"#,
+      r#"export declare function foo(a?: string): number;"#,
     )
     .await;
     transform_dts_test(
       r#"export function foo([a, b] = [1, 2]): number {
   return 2;
 }"#,
-      r#"export function foo([a, b]?: [number, number]): number;"#,
+      r#"export declare function foo([a, b]?: [number, number]): number;"#,
     )
     .await;
     transform_dts_test(
       r#"export function foo({a, b} = { a: 1, b: 2 }): number {
   return 2;
 }"#,
-      r#"export function foo({ a, b }?: {
+      r#"export declare function foo({ a, b }?: {
   a: number;
   b: number;
 }): number;"#,
diff --git a/src/graph.rs b/src/graph.rs
index 0b99942f4..6e1833685 100644
--- a/src/graph.rs
+++ b/src/graph.rs
@@ -5383,7 +5383,7 @@ mod tests {
     let dts = fsm.dts.unwrap();
     assert_eq!(
       dts.text.to_string().trim(),
-      "export function add(a: number, b: number): number;"
+      "export declare function add(a: number, b: number): number;"
     );
     assert!(dts.diagnostics.is_empty());
   }
diff --git a/tests/specs/graph/jsr/FastCheck_EntrypointJsWithTsDecl.txt b/tests/specs/graph/jsr/FastCheck_EntrypointJsWithTsDecl.txt
index 7973a67ed..6f1228c80 100644
--- a/tests/specs/graph/jsr/FastCheck_EntrypointJsWithTsDecl.txt
+++ b/tests/specs/graph/jsr/FastCheck_EntrypointJsWithTsDecl.txt
@@ -87,4 +87,4 @@ Fast check https://jsr.io/@scope/a/1.0.0/mod.d.ts:
   {}
   export function getRandom(): number;
   --- DTS ---
-  export function getRandom(): number;
+  export declare function getRandom(): number;
diff --git a/tests/specs/graph/jsr/FastCheck_Functions.txt b/tests/specs/graph/jsr/FastCheck_Functions.txt
index 9d216a850..a7bdddc02 100644
--- a/tests/specs/graph/jsr/FastCheck_Functions.txt
+++ b/tests/specs/graph/jsr/FastCheck_Functions.txt
@@ -184,30 +184,30 @@ Fast check https://jsr.io/@scope/a/1.0.0/mod.ts:
   export declare function declareFunc(param: string): string;
   export declare function declareFunc(param: PublicDeclareFunc): string;
   --- DTS ---
-  export function test1(): void;
-  export function test2(): number;
-  /** Some Doc **/ export function test3(param: number): number;
-  export function test4(param?: number): number;
-  export function test5<T extends PublicOther>(param?: number): T;
-  export function test6<T = PublicOther>(param?: number): T;
-  export function test7(param?: number): number;
-  export function test7(param?: number, param2?: PublicOther2): number;
-  function test8(param: number): number;
-  function test8(param: string): string;
-  function test8(param0?: any): any;
+  export declare function test1(): void;
+  export declare function test2(): number;
+  /** Some Doc **/ export declare function test3(param: number): number;
+  export declare function test4(param?: number): number;
+  export declare function test5<T extends PublicOther>(param?: number): T;
+  export declare function test6<T = PublicOther>(param?: number): T;
+  export declare function test7(param?: number): number;
+  export declare function test7(param?: number, param2?: PublicOther2): number;
+  declare function test8(param: number): number;
+  declare function test8(param: string): string;
+  declare function test8(param0?: any): any;
   export { test8 };
   export default function test9(param: number): number;
   export default function test9(param: string): string;
-  export function test10(...params: string[]): string[];
-  export function test11(options?: {
+  export declare function test10(...params: string[]): string[];
+  export declare function test11(options?: {
     copy: boolean;
   }): void;
   export interface GlobOptions {
   }
-  export function test12({}?: GlobOptions): void;
-  export function test13([]?: number[]): void;
-  export function test14(): never;
-  export function test15(): Generator<number>;
+  export declare function test12({}?: GlobOptions): void;
+  export declare function test13([]?: number[]): void;
+  export declare function test14(): never;
+  export declare function test15(): Generator<number>;
   declare class PublicOther {
   }
   declare class PublicOther2 {
diff --git a/tests/specs/graph/jsr/FastCheck_InitIdentsAndMembers.txt b/tests/specs/graph/jsr/FastCheck_InitIdentsAndMembers.txt
index 0b3495d62..d7ce0c437 100644
--- a/tests/specs/graph/jsr/FastCheck_InitIdentsAndMembers.txt
+++ b/tests/specs/graph/jsr/FastCheck_InitIdentsAndMembers.txt
@@ -167,7 +167,7 @@ Fast check https://jsr.io/@scope/b/1.0.0/mod.ts:
     export class A {
     }
   }
-  export function test(a?: any, C?: any): void;
+  export declare function test(a?: any, C?: any): void;
   --- DTS Diagnostics ---
   unable to infer type, falling back to any type
       at https://jsr.io/@scope/b/1.0.0/mod.ts@140
diff --git a/tests/specs/graph/jsr/FastCheck_Issue22829.txt b/tests/specs/graph/jsr/FastCheck_Issue22829.txt
index 06c0ef09f..a268eed48 100644
--- a/tests/specs/graph/jsr/FastCheck_Issue22829.txt
+++ b/tests/specs/graph/jsr/FastCheck_Issue22829.txt
@@ -118,8 +118,8 @@ Fast check https://jsr.io/@scope/a/1.0.0/functions.ts:
   declare abstract class Internal<T> {
     prop: T;
   }
-  function func(): void;
-  export function other_func(): void;
+  declare function func(): void;
+  export declare function other_func(): void;
   export declare const functions: {
     readonly other;
   };
diff --git a/tests/specs/graph/jsr/FastCheck_JsWithTsDecl.txt b/tests/specs/graph/jsr/FastCheck_JsWithTsDecl.txt
index 0acca050e..73f5f9f79 100644
--- a/tests/specs/graph/jsr/FastCheck_JsWithTsDecl.txt
+++ b/tests/specs/graph/jsr/FastCheck_JsWithTsDecl.txt
@@ -136,4 +136,4 @@ Fast check https://jsr.io/@scope/a/1.0.0/random.d.ts:
   {}
   export function getRandom(): number;
   --- DTS ---
-  export function getRandom(): number;
+  export declare function getRandom(): number;
diff --git a/tests/specs/graph/jsr/FastCheck_TypeAssertion.txt b/tests/specs/graph/jsr/FastCheck_TypeAssertion.txt
index 45feda660..8a3fe966b 100644
--- a/tests/specs/graph/jsr/FastCheck_TypeAssertion.txt
+++ b/tests/specs/graph/jsr/FastCheck_TypeAssertion.txt
@@ -131,7 +131,7 @@ Fast check https://jsr.io/@scope/a/1.0.0/mod.ts:
   export declare const str: "foo" & {
     __brand: "foo";
   };
-  export function createMockApp<S extends Record<string | number | symbol, any> = Record<string, any>>(state?: S): Application<S>;
+  export declare function createMockApp<S extends Record<string | number | symbol, any> = Record<string, any>>(state?: S): Application<S>;
   export declare class A {
     prop: Public1;
     constructor(prop?: Public1);