From 0fb96cb139c7a17801774f2b873a2cf9af223913 Mon Sep 17 00:00:00 2001
From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com>
Date: Wed, 3 Jun 2026 16:26:01 +0000
Subject: [PATCH 01/16] Initial plan


From 26d634df6b8d2f23a977e37e78abcd02df80a209 Mon Sep 17 00:00:00 2001
From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com>
Date: Wed, 3 Jun 2026 16:34:48 +0000
Subject: [PATCH 02/16] feat(compiler): allow @encode(string) on boolean

Co-authored-by: timotheeguerin <1031227+timotheeguerin@users.noreply.github.com>
---
 packages/compiler/generated-defs/TypeSpec.ts     | 12 +++++++++++-
 packages/compiler/lib/std/decorators.tsp         | 12 +++++++++++-
 packages/compiler/src/core/messages.ts           |  2 +-
 packages/compiler/src/lib/decorators.ts          |  6 ++++--
 .../compiler/test/decorators/decorators.test.ts  | 16 +++++++++++++++-
 .../docs/standard-library/built-in-decorators.md | 13 +++++++++++--
 6 files changed, 53 insertions(+), 8 deletions(-)

diff --git a/packages/compiler/generated-defs/TypeSpec.ts b/packages/compiler/generated-defs/TypeSpec.ts
index 2f066713ac6..66b1f3e984d 100644
--- a/packages/compiler/generated-defs/TypeSpec.ts
+++ b/packages/compiler/generated-defs/TypeSpec.ts
@@ -77,7 +77,7 @@ export type MediaTypeHintDecorator = (
 /**
  * Specify how to encode the target type.
  *
- * @param encodingOrEncodeAs Known name of an encoding or a scalar type to encode as(Only for numeric types to encode as string).
+ * @param encodingOrEncodeAs Known name of an encoding or a scalar type to encode as(Only for numeric and boolean types to encode as string).
  * @param encodedAs What target type is this being encoded as. Default to string.
  * @example offsetDateTime encoded with rfc7231
  *
@@ -98,6 +98,16 @@ export type MediaTypeHintDecorator = (
  *   @encode(string) id: int64;
  * }
  * ```
+ *
+ * @example encode boolean type to string
+ *
+ * `@encode(string)` on boolean uses only `true` or `false`. Parsing is case-insensitive for those two values only.
+ *
+ * ```tsp
+ * model FeatureFlags {
+ *   @encode(string) enabled: boolean;
+ * }
+ * ```
  */
 export type EncodeDecorator = (
   context: DecoratorContext,
diff --git a/packages/compiler/lib/std/decorators.tsp b/packages/compiler/lib/std/decorators.tsp
index 0c35a010e26..dd99b403dd9 100644
--- a/packages/compiler/lib/std/decorators.tsp
+++ b/packages/compiler/lib/std/decorators.tsp
@@ -566,7 +566,7 @@ enum ArrayEncoding {
 
 /**
  * Specify how to encode the target type.
- * @param encodingOrEncodeAs Known name of an encoding or a scalar type to encode as(Only for numeric types to encode as string).
+ * @param encodingOrEncodeAs Known name of an encoding or a scalar type to encode as(Only for numeric and boolean types to encode as string).
  * @param encodedAs What target type is this being encoded as. Default to string.
  *
  * @example offsetDateTime encoded with rfc7231
@@ -590,6 +590,16 @@ enum ArrayEncoding {
  *   @encode(string) id: int64;
  * }
  * ```
+ *
+ * @example encode boolean type to string
+ *
+ * `@encode(string)` on boolean uses only `true` or `false`. Parsing is case-insensitive for those two values only.
+ *
+ * ```tsp
+ * model FeatureFlags {
+ *   @encode(string) enabled: boolean;
+ * }
+ * ```
  */
 extern dec encode(
   target: Scalar | ModelProperty,
diff --git a/packages/compiler/src/core/messages.ts b/packages/compiler/src/core/messages.ts
index 9008e0f6be6..11d8ea2c29c 100644
--- a/packages/compiler/src/core/messages.ts
+++ b/packages/compiler/src/core/messages.ts
@@ -942,7 +942,7 @@ const diagnostics = {
       wrongType: paramMessage`Encoding '${"encoding"}' cannot be used on type '${"type"}'. Expected: ${"expected"}.`,
       wrongEncodingType: paramMessage`Encoding '${"encoding"}' on type '${"type"}' is expected to be serialized as '${"expected"}' but got '${"actual"}'.`,
       wrongNumericEncodingType: paramMessage`Encoding '${"encoding"}' on type '${"type"}' is expected to be serialized as '${"expected"}' but got '${"actual"}'. Set '@encode' 2nd parameter to be of type ${"expected"}. e.g. '@encode("${"encoding"}", int32)'`,
-      firstArg: `First argument of "@encode" must be the encoding name or the string type when encoding numeric types.`,
+      firstArg: `First argument of "@encode" must be the encoding name or the string type when encoding numeric or boolean types.`,
     },
   },
 
diff --git a/packages/compiler/src/lib/decorators.ts b/packages/compiler/src/lib/decorators.ts
index 3290a9dec74..18bb45e365a 100644
--- a/packages/compiler/src/lib/decorators.ts
+++ b/packages/compiler/src/lib/decorators.ts
@@ -873,7 +873,9 @@ export type BytesKnownEncoding = "base64" | "base64url";
 export interface EncodeData {
   /**
    * Known encoding key.
-   * Can be undefined when `@encode(string)` is used on a numeric type. In that case it just means using the base10 decimal representation of the number.
+   * Can be undefined when `@encode(string)` is used on a numeric or boolean type.
+   * For numeric this means using the base10 decimal representation of the number.
+   * For boolean this means using `true` or `false`.
    */
   encoding?: DateTimeKnownEncoding | DurationKnownEncoding | BytesKnownEncoding | string;
   type: Scalar;
@@ -995,7 +997,7 @@ function validateEncodeData(context: DecoratorContext, target: Type, encodeData:
     case "base64url":
       return check(["bytes"], ["string"]);
     case undefined:
-      return check(["numeric"], ["string"]);
+      return check(["numeric", "boolean"], ["string"]);
   }
 }
 
diff --git a/packages/compiler/test/decorators/decorators.test.ts b/packages/compiler/test/decorators/decorators.test.ts
index 5a1ec399d76..1c46022acb0 100644
--- a/packages/compiler/test/decorators/decorators.test.ts
+++ b/packages/compiler/test/decorators/decorators.test.ts
@@ -665,6 +665,20 @@ describe("compiler: built-in decorators", () => {
           strictEqual(encodeData.encoding, undefined);
           strictEqual(encodeData.type.name, "string");
         });
+
+        it(`@encode(string) on boolean model property`, async () => {
+          const { prop, program } = await Tester.compile(t.code`
+            model Foo {
+              @encode(string)
+              ${t.modelProperty("prop")}: boolean;
+            }
+          `);
+
+          const encodeData = getEncode(program, prop);
+          ok(encodeData);
+          strictEqual(encodeData.encoding, undefined);
+          strictEqual(encodeData.type.name, "string");
+        });
       });
       describe("invalid", () => {
         invalidCases.forEach(([target, encoding, encodeAs, expectedCode, expectedMessage]) => {
@@ -693,7 +707,7 @@ describe("compiler: built-in decorators", () => {
           expectDiagnostics(diagnostics, {
             code: "invalid-encode",
             severity: "error",
-            message: "Encoding 'string' cannot be used on type 's'. Expected: numeric.",
+            message: "Encoding 'string' cannot be used on type 's'. Expected: numeric, boolean.",
           });
         });
       });
diff --git a/website/src/content/docs/docs/standard-library/built-in-decorators.md b/website/src/content/docs/docs/standard-library/built-in-decorators.md
index e38804062e6..c60e5132e26 100644
--- a/website/src/content/docs/docs/standard-library/built-in-decorators.md
+++ b/website/src/content/docs/docs/standard-library/built-in-decorators.md
@@ -192,7 +192,7 @@ Specify how to encode the target type.
 #### Parameters
 | Name | Type | Description |
 |------|------|-------------|
-| encodingOrEncodeAs | `Scalar` \| `valueof string \| EnumMember` | Known name of an encoding or a scalar type to encode as(Only for numeric types to encode as string). |
+| encodingOrEncodeAs | `Scalar` \| `valueof string \| EnumMember` | Known name of an encoding or a scalar type to encode as(Only for numeric and boolean types to encode as string). |
 | encodedAs | `Scalar` | What target type is this being encoded as. Default to string. |
 
 #### Examples
@@ -221,6 +221,16 @@ model Pet {
 }
 ```
 
+##### encode boolean type to string
+
+`@encode(string)` on boolean uses only `true` or `false`. Parsing is case-insensitive for those two values only.
+
+```tsp
+model FeatureFlags {
+  @encode(string) enabled: boolean;
+}
+```
+
 
 ### `@encodedName` {#@encodedName}
 
@@ -1548,4 +1558,3 @@ model DogRead {
  ...Dog
 }
 ```
-

From dbd1269d0e577c11abae06642a1e3fb88ffc338c Mon Sep 17 00:00:00 2001
From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com>
Date: Wed, 3 Jun 2026 16:47:38 +0000
Subject: [PATCH 03/16] docs: simplify boolean @encode(string) wording

Co-authored-by: timotheeguerin <1031227+timotheeguerin@users.noreply.github.com>
---
 .../content/docs/docs/standard-library/built-in-decorators.md   | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/website/src/content/docs/docs/standard-library/built-in-decorators.md b/website/src/content/docs/docs/standard-library/built-in-decorators.md
index c60e5132e26..8e5054ce83f 100644
--- a/website/src/content/docs/docs/standard-library/built-in-decorators.md
+++ b/website/src/content/docs/docs/standard-library/built-in-decorators.md
@@ -223,7 +223,7 @@ model Pet {
 
 ##### encode boolean type to string
 
-`@encode(string)` on boolean uses only `true` or `false`. Parsing is case-insensitive for those two values only.
+`@encode(string)` on boolean uses only case-insensitive `true` or `false` values.
 
 ```tsp
 model FeatureFlags {

From 8237396d75a96090440fc44678b71db77cfffe5c Mon Sep 17 00:00:00 2001
From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com>
Date: Wed, 3 Jun 2026 18:04:08 +0000
Subject: [PATCH 04/16] test(http-specs): add boolean @encode(string) spector
 scenario

Co-authored-by: timotheeguerin <1031227+timotheeguerin@users.noreply.github.com>
---
 packages/http-specs/spec-summary.md           | 21 ++++++++++++++++
 .../http-specs/specs/encode/numeric/main.tsp  | 25 +++++++++++++++++++
 .../specs/encode/numeric/mockapi.ts           |  4 +++
 3 files changed, 50 insertions(+)

diff --git a/packages/http-specs/spec-summary.md b/packages/http-specs/spec-summary.md
index c623a91cc95..510a7ce5b81 100644
--- a/packages/http-specs/spec-summary.md
+++ b/packages/http-specs/spec-summary.md
@@ -1310,6 +1310,27 @@ Expected query parameter `input=120`
 Test iso8601 encode for a duration parameter.
 Expected query parameter `input=P40D`
 
+### Encode_Numeric_Property_boolAsString
+
+- Endpoint: `post /encode/numeric/property/bool`
+
+Test operation with request and response model contains property of boolean type with string encode.
+Expected request body:
+
+```json
+{
+  "value": "true"
+}
+```
+
+Expected response body:
+
+```json
+{
+  "value": "true"
+}
+```
+
 ### Encode_Numeric_Property_safeintAsString
 
 - Endpoint: `post /encode/numeric/property/safeint`
diff --git a/packages/http-specs/specs/encode/numeric/main.tsp b/packages/http-specs/specs/encode/numeric/main.tsp
index 5677d2c673c..d0fe45bdf57 100644
--- a/packages/http-specs/specs/encode/numeric/main.tsp
+++ b/packages/http-specs/specs/encode/numeric/main.tsp
@@ -40,6 +40,31 @@ namespace Property {
     value: uint8;
   }
 
+  @route("/bool")
+  @scenario
+  @scenarioDoc("""
+    Test operation with request and response model contains property of boolean type with string encode.
+    Expected request body:
+    ```json
+    {
+      "value": "true"
+    }
+    ```
+    Expected response body:
+    ```json
+    {
+      "value": "true"
+    }
+    ```
+    """)
+  @post
+  op boolAsString(@body value: BoolAsStringProperty): BoolAsStringProperty;
+
+  model BoolAsStringProperty {
+    @encode(string)
+    value: boolean;
+  }
+
   interface SendIntAsString<IntType extends integer, StringValue extends string, Payload> {
     @scenario
     @scenarioDoc(
diff --git a/packages/http-specs/specs/encode/numeric/mockapi.ts b/packages/http-specs/specs/encode/numeric/mockapi.ts
index fe5feaaed25..d18f042211e 100644
--- a/packages/http-specs/specs/encode/numeric/mockapi.ts
+++ b/packages/http-specs/specs/encode/numeric/mockapi.ts
@@ -30,3 +30,7 @@ Scenarios.Encode_Numeric_Property_uint8AsString = createTests(
   "/encode/numeric/property/uint8",
   "255",
 );
+Scenarios.Encode_Numeric_Property_boolAsString = createTests(
+  "/encode/numeric/property/bool",
+  "true",
+);

From ab2b2d1fb7e22a7352faabbcddc6bb9460dc55da Mon Sep 17 00:00:00 2001
From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com>
Date: Wed, 3 Jun 2026 18:05:26 +0000
Subject: [PATCH 05/16] test(http-specs): refine boolean encode scenario naming

Co-authored-by: timotheeguerin <1031227+timotheeguerin@users.noreply.github.com>
---
 packages/http-specs/spec-summary.md                 | 4 ++--
 packages/http-specs/specs/encode/numeric/main.tsp   | 4 ++--
 packages/http-specs/specs/encode/numeric/mockapi.ts | 2 +-
 3 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/packages/http-specs/spec-summary.md b/packages/http-specs/spec-summary.md
index 510a7ce5b81..048b1fb86ce 100644
--- a/packages/http-specs/spec-summary.md
+++ b/packages/http-specs/spec-summary.md
@@ -1312,9 +1312,9 @@ Expected query parameter `input=P40D`
 
 ### Encode_Numeric_Property_boolAsString
 
-- Endpoint: `post /encode/numeric/property/bool`
+- Endpoint: `post /encode/numeric/property/boolean`
 
-Test operation with request and response model contains property of boolean type with string encode.
+Test operation with request and response model containing a property of boolean type with string encode.
 Expected request body:
 
 ```json
diff --git a/packages/http-specs/specs/encode/numeric/main.tsp b/packages/http-specs/specs/encode/numeric/main.tsp
index d0fe45bdf57..446ff4da661 100644
--- a/packages/http-specs/specs/encode/numeric/main.tsp
+++ b/packages/http-specs/specs/encode/numeric/main.tsp
@@ -40,10 +40,10 @@ namespace Property {
     value: uint8;
   }
 
-  @route("/bool")
+  @route("/boolean")
   @scenario
   @scenarioDoc("""
-    Test operation with request and response model contains property of boolean type with string encode.
+    Test operation with request and response model containing a property of boolean type with string encode.
     Expected request body:
     ```json
     {
diff --git a/packages/http-specs/specs/encode/numeric/mockapi.ts b/packages/http-specs/specs/encode/numeric/mockapi.ts
index d18f042211e..38818f6deb9 100644
--- a/packages/http-specs/specs/encode/numeric/mockapi.ts
+++ b/packages/http-specs/specs/encode/numeric/mockapi.ts
@@ -31,6 +31,6 @@ Scenarios.Encode_Numeric_Property_uint8AsString = createTests(
   "255",
 );
 Scenarios.Encode_Numeric_Property_boolAsString = createTests(
-  "/encode/numeric/property/bool",
+  "/encode/numeric/property/boolean",
   "true",
 );

From 2e01d673e2b00610b91271b12da96ca92cc758d9 Mon Sep 17 00:00:00 2001
From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com>
Date: Wed, 3 Jun 2026 18:06:25 +0000
Subject: [PATCH 06/16] test(http-specs): clarify boolean string encode route

Co-authored-by: timotheeguerin <1031227+timotheeguerin@users.noreply.github.com>
---
 packages/http-specs/spec-summary.md                 | 2 +-
 packages/http-specs/specs/encode/numeric/main.tsp   | 2 +-
 packages/http-specs/specs/encode/numeric/mockapi.ts | 2 +-
 3 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/packages/http-specs/spec-summary.md b/packages/http-specs/spec-summary.md
index 048b1fb86ce..66ebdccfb9e 100644
--- a/packages/http-specs/spec-summary.md
+++ b/packages/http-specs/spec-summary.md
@@ -1312,7 +1312,7 @@ Expected query parameter `input=P40D`
 
 ### Encode_Numeric_Property_boolAsString
 
-- Endpoint: `post /encode/numeric/property/boolean`
+- Endpoint: `post /encode/numeric/property/bool-as-string`
 
 Test operation with request and response model containing a property of boolean type with string encode.
 Expected request body:
diff --git a/packages/http-specs/specs/encode/numeric/main.tsp b/packages/http-specs/specs/encode/numeric/main.tsp
index 446ff4da661..c39e35486a1 100644
--- a/packages/http-specs/specs/encode/numeric/main.tsp
+++ b/packages/http-specs/specs/encode/numeric/main.tsp
@@ -40,7 +40,7 @@ namespace Property {
     value: uint8;
   }
 
-  @route("/boolean")
+  @route("/bool-as-string")
   @scenario
   @scenarioDoc("""
     Test operation with request and response model containing a property of boolean type with string encode.
diff --git a/packages/http-specs/specs/encode/numeric/mockapi.ts b/packages/http-specs/specs/encode/numeric/mockapi.ts
index 38818f6deb9..8de224d65d3 100644
--- a/packages/http-specs/specs/encode/numeric/mockapi.ts
+++ b/packages/http-specs/specs/encode/numeric/mockapi.ts
@@ -31,6 +31,6 @@ Scenarios.Encode_Numeric_Property_uint8AsString = createTests(
   "255",
 );
 Scenarios.Encode_Numeric_Property_boolAsString = createTests(
-  "/encode/numeric/property/boolean",
+  "/encode/numeric/property/bool-as-string",
   "true",
 );

From 1f88780b529d1d3fca0cdf16366b03e3bd9036ea Mon Sep 17 00:00:00 2001
From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com>
Date: Wed, 3 Jun 2026 18:07:59 +0000
Subject: [PATCH 07/16] test(http-specs): move boolean encode scenario to
 encode/boolean

Co-authored-by: timotheeguerin <1031227+timotheeguerin@users.noreply.github.com>
---
 packages/http-specs/spec-summary.md           | 42 +++++++++----------
 .../http-specs/specs/encode/boolean/main.tsp  | 37 ++++++++++++++++
 .../specs/encode/boolean/mockapi.ts           | 20 +++++++++
 .../http-specs/specs/encode/numeric/main.tsp  | 25 -----------
 .../specs/encode/numeric/mockapi.ts           |  4 --
 5 files changed, 78 insertions(+), 50 deletions(-)
 create mode 100644 packages/http-specs/specs/encode/boolean/main.tsp
 create mode 100644 packages/http-specs/specs/encode/boolean/mockapi.ts

diff --git a/packages/http-specs/spec-summary.md b/packages/http-specs/spec-summary.md
index 66ebdccfb9e..1541210fdfa 100644
--- a/packages/http-specs/spec-summary.md
+++ b/packages/http-specs/spec-summary.md
@@ -369,6 +369,27 @@ Expected response body:
 }
 ```
 
+### Encode_Boolean_Property_boolAsString
+
+- Endpoint: `post /encode/boolean/property/bool-as-string`
+
+Test operation with request and response model containing a property of boolean type with string encode.
+Expected request body:
+
+```json
+{
+  "value": "true"
+}
+```
+
+Expected response body:
+
+```json
+{
+  "value": "true"
+}
+```
+
 ### Encode_Bytes_Header_base64
 
 - Endpoint: `get /encode/bytes/header/base64`
@@ -1310,27 +1331,6 @@ Expected query parameter `input=120`
 Test iso8601 encode for a duration parameter.
 Expected query parameter `input=P40D`
 
-### Encode_Numeric_Property_boolAsString
-
-- Endpoint: `post /encode/numeric/property/bool-as-string`
-
-Test operation with request and response model containing a property of boolean type with string encode.
-Expected request body:
-
-```json
-{
-  "value": "true"
-}
-```
-
-Expected response body:
-
-```json
-{
-  "value": "true"
-}
-```
-
 ### Encode_Numeric_Property_safeintAsString
 
 - Endpoint: `post /encode/numeric/property/safeint`
diff --git a/packages/http-specs/specs/encode/boolean/main.tsp b/packages/http-specs/specs/encode/boolean/main.tsp
new file mode 100644
index 00000000000..72ae77b8e94
--- /dev/null
+++ b/packages/http-specs/specs/encode/boolean/main.tsp
@@ -0,0 +1,37 @@
+import "@typespec/http";
+import "@typespec/spector";
+
+using Http;
+using Spector;
+
+@doc("Test for encode decorator on boolean.")
+@scenarioService("/encode/boolean")
+namespace Encode.Boolean;
+
+@route("/property")
+namespace Property {
+  @route("/bool-as-string")
+  @scenario
+  @scenarioDoc("""
+    Test operation with request and response model containing a property of boolean type with string encode.
+    Expected request body:
+    ```json
+    {
+      "value": "true"
+    }
+    ```
+    Expected response body:
+    ```json
+    {
+      "value": "true"
+    }
+    ```
+    """)
+  @post
+  op boolAsString(@body value: BoolAsStringProperty): BoolAsStringProperty;
+
+  model BoolAsStringProperty {
+    @encode(string)
+    value: boolean;
+  }
+}
diff --git a/packages/http-specs/specs/encode/boolean/mockapi.ts b/packages/http-specs/specs/encode/boolean/mockapi.ts
new file mode 100644
index 00000000000..89a41d5d23e
--- /dev/null
+++ b/packages/http-specs/specs/encode/boolean/mockapi.ts
@@ -0,0 +1,20 @@
+import { json, passOnSuccess, ScenarioMockApi } from "@typespec/spec-api";
+
+export const Scenarios: Record<string, ScenarioMockApi> = {};
+
+Scenarios.Encode_Boolean_Property_boolAsString = passOnSuccess({
+  uri: "/encode/boolean/property/bool-as-string",
+  method: "post",
+  request: {
+    body: json({
+      value: "true",
+    }),
+  },
+  response: {
+    status: 200,
+    body: json({
+      value: "true",
+    }),
+  },
+  kind: "MockApiDefinition",
+});
diff --git a/packages/http-specs/specs/encode/numeric/main.tsp b/packages/http-specs/specs/encode/numeric/main.tsp
index c39e35486a1..5677d2c673c 100644
--- a/packages/http-specs/specs/encode/numeric/main.tsp
+++ b/packages/http-specs/specs/encode/numeric/main.tsp
@@ -40,31 +40,6 @@ namespace Property {
     value: uint8;
   }
 
-  @route("/bool-as-string")
-  @scenario
-  @scenarioDoc("""
-    Test operation with request and response model containing a property of boolean type with string encode.
-    Expected request body:
-    ```json
-    {
-      "value": "true"
-    }
-    ```
-    Expected response body:
-    ```json
-    {
-      "value": "true"
-    }
-    ```
-    """)
-  @post
-  op boolAsString(@body value: BoolAsStringProperty): BoolAsStringProperty;
-
-  model BoolAsStringProperty {
-    @encode(string)
-    value: boolean;
-  }
-
   interface SendIntAsString<IntType extends integer, StringValue extends string, Payload> {
     @scenario
     @scenarioDoc(
diff --git a/packages/http-specs/specs/encode/numeric/mockapi.ts b/packages/http-specs/specs/encode/numeric/mockapi.ts
index 8de224d65d3..fe5feaaed25 100644
--- a/packages/http-specs/specs/encode/numeric/mockapi.ts
+++ b/packages/http-specs/specs/encode/numeric/mockapi.ts
@@ -30,7 +30,3 @@ Scenarios.Encode_Numeric_Property_uint8AsString = createTests(
   "/encode/numeric/property/uint8",
   "255",
 );
-Scenarios.Encode_Numeric_Property_boolAsString = createTests(
-  "/encode/numeric/property/bool-as-string",
-  "true",
-);

From d0152901776a4e3b42aa4eba08423a4d3faebb1b Mon Sep 17 00:00:00 2001
From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com>
Date: Wed, 3 Jun 2026 18:17:00 +0000
Subject: [PATCH 08/16] Address encode boolean docs and scenario feedback

Co-authored-by: timotheeguerin <1031227+timotheeguerin@users.noreply.github.com>
---
 packages/compiler/generated-defs/TypeSpec.ts  |  2 +-
 packages/compiler/lib/std/decorators.tsp      |  2 +-
 packages/http-specs/spec-summary.md           | 67 ++++++++++++++++++-
 .../http-specs/specs/encode/boolean/main.tsp  | 64 ++++++++++++------
 .../specs/encode/boolean/mockapi.ts           | 51 +++++++++-----
 .../standard-library/built-in-decorators.md   |  2 +-
 6 files changed, 147 insertions(+), 41 deletions(-)

diff --git a/packages/compiler/generated-defs/TypeSpec.ts b/packages/compiler/generated-defs/TypeSpec.ts
index 66b1f3e984d..d93788afbeb 100644
--- a/packages/compiler/generated-defs/TypeSpec.ts
+++ b/packages/compiler/generated-defs/TypeSpec.ts
@@ -101,7 +101,7 @@ export type MediaTypeHintDecorator = (
  *
  * @example encode boolean type to string
  *
- * `@encode(string)` on boolean uses only `true` or `false`. Parsing is case-insensitive for those two values only.
+ * `@encode(string)` on boolean uses case-insensitive `true` / `false` values.
  *
  * ```tsp
  * model FeatureFlags {
diff --git a/packages/compiler/lib/std/decorators.tsp b/packages/compiler/lib/std/decorators.tsp
index dd99b403dd9..fed9f685237 100644
--- a/packages/compiler/lib/std/decorators.tsp
+++ b/packages/compiler/lib/std/decorators.tsp
@@ -593,7 +593,7 @@ enum ArrayEncoding {
  *
  * @example encode boolean type to string
  *
- * `@encode(string)` on boolean uses only `true` or `false`. Parsing is case-insensitive for those two values only.
+ * `@encode(string)` on boolean uses case-insensitive `true` / `false` values.
  *
  * ```tsp
  * model FeatureFlags {
diff --git a/packages/http-specs/spec-summary.md b/packages/http-specs/spec-summary.md
index 1541210fdfa..17e173563c2 100644
--- a/packages/http-specs/spec-summary.md
+++ b/packages/http-specs/spec-summary.md
@@ -369,9 +369,51 @@ Expected response body:
 }
 ```
 
-### Encode_Boolean_Property_boolAsString
+### Encode_Boolean_Property_falseLower
 
-- Endpoint: `post /encode/boolean/property/bool-as-string`
+- Endpoint: `post /encode/boolean/property/false-lower`
+
+Test operation with request and response model containing a property of boolean type with string encode.
+Expected request body:
+
+```json
+{
+  "value": "false"
+}
+```
+
+Expected response body:
+
+```json
+{
+  "value": "false"
+}
+```
+
+### Encode_Boolean_Property_falseMixed
+
+- Endpoint: `post /encode/boolean/property/false-mixed`
+
+Test operation with request and response model containing a property of boolean type with string encode.
+Expected request body:
+
+```json
+{
+  "value": "FaLsE"
+}
+```
+
+Expected response body:
+
+```json
+{
+  "value": "FaLsE"
+}
+```
+
+### Encode_Boolean_Property_trueLower
+
+- Endpoint: `post /encode/boolean/property/true-lower`
 
 Test operation with request and response model containing a property of boolean type with string encode.
 Expected request body:
@@ -390,6 +432,27 @@ Expected response body:
 }
 ```
 
+### Encode_Boolean_Property_trueUpper
+
+- Endpoint: `post /encode/boolean/property/true-upper`
+
+Test operation with request and response model containing a property of boolean type with string encode.
+Expected request body:
+
+```json
+{
+  "value": "TRUE"
+}
+```
+
+Expected response body:
+
+```json
+{
+  "value": "TRUE"
+}
+```
+
 ### Encode_Bytes_Header_base64
 
 - Endpoint: `get /encode/bytes/header/base64`
diff --git a/packages/http-specs/specs/encode/boolean/main.tsp b/packages/http-specs/specs/encode/boolean/main.tsp
index 72ae77b8e94..0a4771271cd 100644
--- a/packages/http-specs/specs/encode/boolean/main.tsp
+++ b/packages/http-specs/specs/encode/boolean/main.tsp
@@ -10,28 +10,52 @@ namespace Encode.Boolean;
 
 @route("/property")
 namespace Property {
-  @route("/bool-as-string")
-  @scenario
-  @scenarioDoc("""
-    Test operation with request and response model containing a property of boolean type with string encode.
-    Expected request body:
-    ```json
-    {
-      "value": "true"
-    }
-    ```
-    Expected response body:
-    ```json
-    {
-      "value": "true"
-    }
-    ```
-    """)
-  @post
-  op boolAsString(@body value: BoolAsStringProperty): BoolAsStringProperty;
-
   model BoolAsStringProperty {
     @encode(string)
     value: boolean;
   }
+
+  alias SendBoolTrueLower = SendBoolAsString<"true">;
+
+  @route("/true-lower")
+  op trueLower is SendBoolTrueLower.sendBoolAsString;
+
+  alias SendBoolFalseLower = SendBoolAsString<"false">;
+
+  @route("/false-lower")
+  op falseLower is SendBoolFalseLower.sendBoolAsString;
+
+  alias SendBoolTrueUpper = SendBoolAsString<"TRUE">;
+
+  @route("/true-upper")
+  op trueUpper is SendBoolTrueUpper.sendBoolAsString;
+
+  alias SendBoolFalseMixed = SendBoolAsString<"FaLsE">;
+
+  @route("/false-mixed")
+  op falseMixed is SendBoolFalseMixed.sendBoolAsString;
+
+  interface SendBoolAsString<StringValue extends string> {
+    @scenario
+    @scenarioDoc(
+      """
+        Test operation with request and response model containing a property of boolean type with string encode.
+        Expected request body:
+        ```json
+        {
+          "value": "{value}"
+        }
+        ```
+        Expected response body:
+        ```json
+        {
+          "value": "{value}"
+        }
+        ```
+        """,
+      { value: StringValue }
+    )
+    @post
+    sendBoolAsString(@body value: BoolAsStringProperty): BoolAsStringProperty;
+  }
 }
diff --git a/packages/http-specs/specs/encode/boolean/mockapi.ts b/packages/http-specs/specs/encode/boolean/mockapi.ts
index 89a41d5d23e..5a430256cd3 100644
--- a/packages/http-specs/specs/encode/boolean/mockapi.ts
+++ b/packages/http-specs/specs/encode/boolean/mockapi.ts
@@ -2,19 +2,38 @@ import { json, passOnSuccess, ScenarioMockApi } from "@typespec/spec-api";
 
 export const Scenarios: Record<string, ScenarioMockApi> = {};
 
-Scenarios.Encode_Boolean_Property_boolAsString = passOnSuccess({
-  uri: "/encode/boolean/property/bool-as-string",
-  method: "post",
-  request: {
-    body: json({
-      value: "true",
-    }),
-  },
-  response: {
-    status: 200,
-    body: json({
-      value: "true",
-    }),
-  },
-  kind: "MockApiDefinition",
-});
+function createBodyServerTests(uri: string, value: string) {
+  return passOnSuccess({
+    uri,
+    method: "post",
+    request: {
+      body: json({
+        value,
+      }),
+    },
+    response: {
+      status: 200,
+      body: json({
+        value,
+      }),
+    },
+    kind: "MockApiDefinition",
+  });
+}
+
+Scenarios.Encode_Boolean_Property_trueLower = createBodyServerTests(
+  "/encode/boolean/property/true-lower",
+  "true",
+);
+Scenarios.Encode_Boolean_Property_falseLower = createBodyServerTests(
+  "/encode/boolean/property/false-lower",
+  "false",
+);
+Scenarios.Encode_Boolean_Property_trueUpper = createBodyServerTests(
+  "/encode/boolean/property/true-upper",
+  "TRUE",
+);
+Scenarios.Encode_Boolean_Property_falseMixed = createBodyServerTests(
+  "/encode/boolean/property/false-mixed",
+  "FaLsE",
+);
diff --git a/website/src/content/docs/docs/standard-library/built-in-decorators.md b/website/src/content/docs/docs/standard-library/built-in-decorators.md
index 8e5054ce83f..d5827c149b9 100644
--- a/website/src/content/docs/docs/standard-library/built-in-decorators.md
+++ b/website/src/content/docs/docs/standard-library/built-in-decorators.md
@@ -223,7 +223,7 @@ model Pet {
 
 ##### encode boolean type to string
 
-`@encode(string)` on boolean uses only case-insensitive `true` or `false` values.
+`@encode(string)` on boolean uses case-insensitive `true` / `false` values.
 
 ```tsp
 model FeatureFlags {

From 888a49e8881b07a7ff4c1db1f914d4bfb3e0dad5 Mon Sep 17 00:00:00 2001
From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com>
Date: Wed, 3 Jun 2026 18:23:32 +0000
Subject: [PATCH 09/16] test(http-specs): use doc comment in boolean encode
 spec

Co-authored-by: timotheeguerin <1031227+timotheeguerin@users.noreply.github.com>
---
 packages/http-specs/specs/encode/boolean/main.tsp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/packages/http-specs/specs/encode/boolean/main.tsp b/packages/http-specs/specs/encode/boolean/main.tsp
index 0a4771271cd..d0b146d17a9 100644
--- a/packages/http-specs/specs/encode/boolean/main.tsp
+++ b/packages/http-specs/specs/encode/boolean/main.tsp
@@ -4,7 +4,7 @@ import "@typespec/spector";
 using Http;
 using Spector;
 
-@doc("Test for encode decorator on boolean.")
+/** Test for encode decorator on boolean. */
 @scenarioService("/encode/boolean")
 namespace Encode.Boolean;
 

From 397cbd1cf4ababba5167b00287a84c7ad4a1da20 Mon Sep 17 00:00:00 2001
From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com>
Date: Wed, 3 Jun 2026 18:39:26 +0000
Subject: [PATCH 10/16] test(http-specs): accept case-insensitive boolean
 request casing

Co-authored-by: timotheeguerin <1031227+timotheeguerin@users.noreply.github.com>
---
 .../specs/encode/boolean/mockapi.ts           | 27 ++++++++++++++++---
 1 file changed, 23 insertions(+), 4 deletions(-)

diff --git a/packages/http-specs/specs/encode/boolean/mockapi.ts b/packages/http-specs/specs/encode/boolean/mockapi.ts
index 5a430256cd3..fac2bee83ec 100644
--- a/packages/http-specs/specs/encode/boolean/mockapi.ts
+++ b/packages/http-specs/specs/encode/boolean/mockapi.ts
@@ -1,20 +1,35 @@
-import { json, passOnSuccess, ScenarioMockApi } from "@typespec/spec-api";
+import { createMatcher, err, json, ok, passOnSuccess, ScenarioMockApi } from "@typespec/spec-api";
 
 export const Scenarios: Record<string, ScenarioMockApi> = {};
 
-function createBodyServerTests(uri: string, value: string) {
+function createCaseInsensitiveBooleanMatcher(value: boolean) {
+  const normalized = String(value);
+  return createMatcher<string>({
+    check: (actual) => {
+      if (typeof actual !== "string") {
+        return err(`Expected string "${normalized}" but got ${typeof actual}`);
+      }
+      return actual.toLowerCase() === normalized
+        ? ok()
+        : err(`Expected case-insensitive "${normalized}" but got "${actual}"`);
+    },
+    serialize: () => normalized,
+  });
+}
+
+function createBodyServerTests(uri: string, responseValue: string, requestValue: boolean) {
   return passOnSuccess({
     uri,
     method: "post",
     request: {
       body: json({
-        value,
+        value: createCaseInsensitiveBooleanMatcher(requestValue),
       }),
     },
     response: {
       status: 200,
       body: json({
-        value,
+        value: responseValue,
       }),
     },
     kind: "MockApiDefinition",
@@ -24,16 +39,20 @@ function createBodyServerTests(uri: string, value: string) {
 Scenarios.Encode_Boolean_Property_trueLower = createBodyServerTests(
   "/encode/boolean/property/true-lower",
   "true",
+  true,
 );
 Scenarios.Encode_Boolean_Property_falseLower = createBodyServerTests(
   "/encode/boolean/property/false-lower",
   "false",
+  false,
 );
 Scenarios.Encode_Boolean_Property_trueUpper = createBodyServerTests(
   "/encode/boolean/property/true-upper",
   "TRUE",
+  true,
 );
 Scenarios.Encode_Boolean_Property_falseMixed = createBodyServerTests(
   "/encode/boolean/property/false-mixed",
   "FaLsE",
+  false,
 );

From 5df2924991266be0fc8115fed65ceffa60f083c3 Mon Sep 17 00:00:00 2001
From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com>
Date: Fri, 5 Jun 2026 15:59:38 +0000
Subject: [PATCH 11/16] feat(spec-api): add case-insensitive boolean string
 matcher

Co-authored-by: timotheeguerin <1031227+timotheeguerin@users.noreply.github.com>
---
 .../specs/encode/boolean/mockapi.ts           | 19 +------
 packages/spec-api/src/matchers/boolean.ts     | 28 ++++++++++
 packages/spec-api/src/matchers/index.ts       | 11 ++++
 .../spec-api/test/matchers/boolean.test.ts    | 54 +++++++++++++++++++
 4 files changed, 95 insertions(+), 17 deletions(-)
 create mode 100644 packages/spec-api/src/matchers/boolean.ts
 create mode 100644 packages/spec-api/test/matchers/boolean.test.ts

diff --git a/packages/http-specs/specs/encode/boolean/mockapi.ts b/packages/http-specs/specs/encode/boolean/mockapi.ts
index fac2bee83ec..641d09f7783 100644
--- a/packages/http-specs/specs/encode/boolean/mockapi.ts
+++ b/packages/http-specs/specs/encode/boolean/mockapi.ts
@@ -1,29 +1,14 @@
-import { createMatcher, err, json, ok, passOnSuccess, ScenarioMockApi } from "@typespec/spec-api";
+import { json, match, passOnSuccess, ScenarioMockApi } from "@typespec/spec-api";
 
 export const Scenarios: Record<string, ScenarioMockApi> = {};
 
-function createCaseInsensitiveBooleanMatcher(value: boolean) {
-  const normalized = String(value);
-  return createMatcher<string>({
-    check: (actual) => {
-      if (typeof actual !== "string") {
-        return err(`Expected string "${normalized}" but got ${typeof actual}`);
-      }
-      return actual.toLowerCase() === normalized
-        ? ok()
-        : err(`Expected case-insensitive "${normalized}" but got "${actual}"`);
-    },
-    serialize: () => normalized,
-  });
-}
-
 function createBodyServerTests(uri: string, responseValue: string, requestValue: boolean) {
   return passOnSuccess({
     uri,
     method: "post",
     request: {
       body: json({
-        value: createCaseInsensitiveBooleanMatcher(requestValue),
+        value: match.boolean.caseInsensitiveString(requestValue),
       }),
     },
     response: {
diff --git a/packages/spec-api/src/matchers/boolean.ts b/packages/spec-api/src/matchers/boolean.ts
new file mode 100644
index 00000000000..2f16df33083
--- /dev/null
+++ b/packages/spec-api/src/matchers/boolean.ts
@@ -0,0 +1,28 @@
+import { createMatcher, err, type MockValueMatcher, ok } from "../match-engine.js";
+
+export const booleanMatcher = {
+  caseInsensitiveString(value: boolean): MockValueMatcher<string> {
+    const normalized = String(value);
+    return createMatcher({
+      check(actual: unknown) {
+        if (typeof actual !== "string") {
+          return err(
+            `match.boolean.caseInsensitiveString: expected a string but got ${typeof actual} (${JSON.stringify(actual)})`,
+          );
+        }
+        if (actual.toLowerCase() !== normalized) {
+          return err(
+            `match.boolean.caseInsensitiveString: expected case-insensitive "${normalized}" but got "${actual}"`,
+          );
+        }
+        return ok();
+      },
+      serialize() {
+        return normalized;
+      },
+      toString() {
+        return `match.boolean.caseInsensitiveString(${normalized})`;
+      },
+    });
+  },
+};
diff --git a/packages/spec-api/src/matchers/index.ts b/packages/spec-api/src/matchers/index.ts
index 054a5bb5c3e..3b4b229228e 100644
--- a/packages/spec-api/src/matchers/index.ts
+++ b/packages/spec-api/src/matchers/index.ts
@@ -1,3 +1,4 @@
+import { booleanMatcher } from "./boolean.js";
 import { dateTimeMatcher } from "./datetime.js";
 import { baseUrlMatcher } from "./local-url.js";
 
@@ -18,6 +19,16 @@ export { dateTimeMatcher } from "./datetime.js";
  * Namespace for built-in matchers.
  */
 export const match = {
+  /**
+   * Matchers for comparing boolean values encoded as strings.
+   *
+   * @example
+   * ```ts
+   * match.boolean.caseInsensitiveString(true)
+   * ```
+   */
+  boolean: booleanMatcher,
+
   /**
    * Matchers for comparing datetime values semantically.
    * Validates that the actual value is in the correct format and represents
diff --git a/packages/spec-api/test/matchers/boolean.test.ts b/packages/spec-api/test/matchers/boolean.test.ts
new file mode 100644
index 00000000000..21a9889f5b6
--- /dev/null
+++ b/packages/spec-api/test/matchers/boolean.test.ts
@@ -0,0 +1,54 @@
+import { describe, expect, it } from "vitest";
+import { isMatcher } from "../../src/match-engine.js";
+import { match } from "../../src/matchers/index.js";
+import { expectFail, expectPass } from "./matcher-test-utils.js";
+
+describe("match.boolean.caseInsensitiveString()", () => {
+  it("should be identified by isMatcher", () => {
+    expect(isMatcher(match.boolean.caseInsensitiveString(true))).toBe(true);
+  });
+
+  describe("check()", () => {
+    it("should match lower-case true", () => {
+      expectPass(match.boolean.caseInsensitiveString(true).check("true"));
+    });
+
+    it("should match upper-case true", () => {
+      expectPass(match.boolean.caseInsensitiveString(true).check("TRUE"));
+    });
+
+    it("should match mixed-case false", () => {
+      expectPass(match.boolean.caseInsensitiveString(false).check("FaLsE"));
+    });
+
+    it("should reject the opposite boolean value", () => {
+      expectFail(match.boolean.caseInsensitiveString(true).check("false"), 'expected case-insensitive "true"');
+    });
+
+    it("should reject non-string values", () => {
+      expectFail(
+        match.boolean.caseInsensitiveString(true).check(true),
+        "expected a string but got boolean",
+      );
+      expectFail(
+        match.boolean.caseInsensitiveString(false).check(null),
+        "expected a string but got object",
+      );
+    });
+  });
+
+  describe("serialize()", () => {
+    it("should serialize to canonical lowercase value", () => {
+      expect(match.boolean.caseInsensitiveString(true).serialize()).toBe("true");
+      expect(match.boolean.caseInsensitiveString(false).serialize()).toBe("false");
+    });
+  });
+
+  describe("toString()", () => {
+    it("should return a descriptive string", () => {
+      expect(match.boolean.caseInsensitiveString(true).toString()).toBe(
+        "match.boolean.caseInsensitiveString(true)",
+      );
+    });
+  });
+});

From 4c3aba625149aa75be20c7ad674caec47af8a257 Mon Sep 17 00:00:00 2001
From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com>
Date: Fri, 5 Jun 2026 16:27:24 +0000
Subject: [PATCH 12/16] refactor(spec-api): generalize case-insensitive string
 matcher

Co-authored-by: timotheeguerin <1031227+timotheeguerin@users.noreply.github.com>
---
 .../specs/encode/boolean/mockapi.ts           |  2 +-
 packages/spec-api/src/matchers/boolean.ts     | 28 ----------
 packages/spec-api/src/matchers/index.ts       | 13 ++---
 packages/spec-api/src/matchers/string.ts      | 28 ++++++++++
 .../spec-api/test/matchers/boolean.test.ts    | 54 -------------------
 .../spec-api/test/matchers/string.test.ts     | 48 +++++++++++++++++
 6 files changed, 80 insertions(+), 93 deletions(-)
 delete mode 100644 packages/spec-api/src/matchers/boolean.ts
 create mode 100644 packages/spec-api/src/matchers/string.ts
 delete mode 100644 packages/spec-api/test/matchers/boolean.test.ts
 create mode 100644 packages/spec-api/test/matchers/string.test.ts

diff --git a/packages/http-specs/specs/encode/boolean/mockapi.ts b/packages/http-specs/specs/encode/boolean/mockapi.ts
index 641d09f7783..590645176d3 100644
--- a/packages/http-specs/specs/encode/boolean/mockapi.ts
+++ b/packages/http-specs/specs/encode/boolean/mockapi.ts
@@ -8,7 +8,7 @@ function createBodyServerTests(uri: string, responseValue: string, requestValue:
     method: "post",
     request: {
       body: json({
-        value: match.boolean.caseInsensitiveString(requestValue),
+        value: match.string.caseInsensitive(String(requestValue)),
       }),
     },
     response: {
diff --git a/packages/spec-api/src/matchers/boolean.ts b/packages/spec-api/src/matchers/boolean.ts
deleted file mode 100644
index 2f16df33083..00000000000
--- a/packages/spec-api/src/matchers/boolean.ts
+++ /dev/null
@@ -1,28 +0,0 @@
-import { createMatcher, err, type MockValueMatcher, ok } from "../match-engine.js";
-
-export const booleanMatcher = {
-  caseInsensitiveString(value: boolean): MockValueMatcher<string> {
-    const normalized = String(value);
-    return createMatcher({
-      check(actual: unknown) {
-        if (typeof actual !== "string") {
-          return err(
-            `match.boolean.caseInsensitiveString: expected a string but got ${typeof actual} (${JSON.stringify(actual)})`,
-          );
-        }
-        if (actual.toLowerCase() !== normalized) {
-          return err(
-            `match.boolean.caseInsensitiveString: expected case-insensitive "${normalized}" but got "${actual}"`,
-          );
-        }
-        return ok();
-      },
-      serialize() {
-        return normalized;
-      },
-      toString() {
-        return `match.boolean.caseInsensitiveString(${normalized})`;
-      },
-    });
-  },
-};
diff --git a/packages/spec-api/src/matchers/index.ts b/packages/spec-api/src/matchers/index.ts
index 3b4b229228e..c28fbf7d986 100644
--- a/packages/spec-api/src/matchers/index.ts
+++ b/packages/spec-api/src/matchers/index.ts
@@ -1,6 +1,6 @@
-import { booleanMatcher } from "./boolean.js";
 import { dateTimeMatcher } from "./datetime.js";
 import { baseUrlMatcher } from "./local-url.js";
+import { stringMatcher } from "./string.js";
 
 export {
   createMatcher,
@@ -19,15 +19,8 @@ export { dateTimeMatcher } from "./datetime.js";
  * Namespace for built-in matchers.
  */
 export const match = {
-  /**
-   * Matchers for comparing boolean values encoded as strings.
-   *
-   * @example
-   * ```ts
-   * match.boolean.caseInsensitiveString(true)
-   * ```
-   */
-  boolean: booleanMatcher,
+  /** Matchers for comparing string values. */
+  string: stringMatcher,
 
   /**
    * Matchers for comparing datetime values semantically.
diff --git a/packages/spec-api/src/matchers/string.ts b/packages/spec-api/src/matchers/string.ts
new file mode 100644
index 00000000000..322ac3cafea
--- /dev/null
+++ b/packages/spec-api/src/matchers/string.ts
@@ -0,0 +1,28 @@
+import { createMatcher, err, type MockValueMatcher, ok } from "../match-engine.js";
+
+export const stringMatcher = {
+  caseInsensitive(value: string): MockValueMatcher<string> {
+    const normalized = value.toLowerCase();
+    return createMatcher({
+      check(actual: unknown) {
+        if (typeof actual !== "string") {
+          return err(
+            `match.string.caseInsensitive: expected a string but got ${typeof actual}`,
+          );
+        }
+        if (actual.toLowerCase() !== normalized) {
+          return err(
+            `match.string.caseInsensitive: expected case-insensitive "${value}" but got "${actual}"`,
+          );
+        }
+        return ok();
+      },
+      serialize() {
+        return value;
+      },
+      toString() {
+        return `match.string.caseInsensitive("${value}")`;
+      },
+    });
+  },
+};
diff --git a/packages/spec-api/test/matchers/boolean.test.ts b/packages/spec-api/test/matchers/boolean.test.ts
deleted file mode 100644
index 21a9889f5b6..00000000000
--- a/packages/spec-api/test/matchers/boolean.test.ts
+++ /dev/null
@@ -1,54 +0,0 @@
-import { describe, expect, it } from "vitest";
-import { isMatcher } from "../../src/match-engine.js";
-import { match } from "../../src/matchers/index.js";
-import { expectFail, expectPass } from "./matcher-test-utils.js";
-
-describe("match.boolean.caseInsensitiveString()", () => {
-  it("should be identified by isMatcher", () => {
-    expect(isMatcher(match.boolean.caseInsensitiveString(true))).toBe(true);
-  });
-
-  describe("check()", () => {
-    it("should match lower-case true", () => {
-      expectPass(match.boolean.caseInsensitiveString(true).check("true"));
-    });
-
-    it("should match upper-case true", () => {
-      expectPass(match.boolean.caseInsensitiveString(true).check("TRUE"));
-    });
-
-    it("should match mixed-case false", () => {
-      expectPass(match.boolean.caseInsensitiveString(false).check("FaLsE"));
-    });
-
-    it("should reject the opposite boolean value", () => {
-      expectFail(match.boolean.caseInsensitiveString(true).check("false"), 'expected case-insensitive "true"');
-    });
-
-    it("should reject non-string values", () => {
-      expectFail(
-        match.boolean.caseInsensitiveString(true).check(true),
-        "expected a string but got boolean",
-      );
-      expectFail(
-        match.boolean.caseInsensitiveString(false).check(null),
-        "expected a string but got object",
-      );
-    });
-  });
-
-  describe("serialize()", () => {
-    it("should serialize to canonical lowercase value", () => {
-      expect(match.boolean.caseInsensitiveString(true).serialize()).toBe("true");
-      expect(match.boolean.caseInsensitiveString(false).serialize()).toBe("false");
-    });
-  });
-
-  describe("toString()", () => {
-    it("should return a descriptive string", () => {
-      expect(match.boolean.caseInsensitiveString(true).toString()).toBe(
-        "match.boolean.caseInsensitiveString(true)",
-      );
-    });
-  });
-});
diff --git a/packages/spec-api/test/matchers/string.test.ts b/packages/spec-api/test/matchers/string.test.ts
new file mode 100644
index 00000000000..046818de0de
--- /dev/null
+++ b/packages/spec-api/test/matchers/string.test.ts
@@ -0,0 +1,48 @@
+import { describe, expect, it } from "vitest";
+import { isMatcher } from "../../src/match-engine.js";
+import { match } from "../../src/matchers/index.js";
+import { expectFail, expectPass } from "./matcher-test-utils.js";
+
+describe("match.string.caseInsensitive()", () => {
+  it("should be identified by isMatcher", () => {
+    expect(isMatcher(match.string.caseInsensitive("true"))).toBe(true);
+  });
+
+  describe("check()", () => {
+    it("should match lower-case true", () => {
+      expectPass(match.string.caseInsensitive("true").check("true"));
+    });
+
+    it("should match upper-case true", () => {
+      expectPass(match.string.caseInsensitive("true").check("TRUE"));
+    });
+
+    it("should match mixed-case false", () => {
+      expectPass(match.string.caseInsensitive("false").check("FaLsE"));
+    });
+
+    it("should reject a different string value", () => {
+      expectFail(match.string.caseInsensitive("true").check("false"), 'expected case-insensitive "true"');
+    });
+
+    it("should reject non-string values", () => {
+      expectFail(match.string.caseInsensitive("true").check(true), "expected a string but got boolean");
+      expectFail(match.string.caseInsensitive("false").check(null), "expected a string but got object");
+    });
+  });
+
+  describe("serialize()", () => {
+    it("should serialize the original value", () => {
+      expect(match.string.caseInsensitive("TrUe").serialize()).toBe("TrUe");
+      expect(match.string.caseInsensitive("FALSE").serialize()).toBe("FALSE");
+    });
+  });
+
+  describe("toString()", () => {
+    it("should return a descriptive string", () => {
+      expect(match.string.caseInsensitive("true").toString()).toBe(
+        'match.string.caseInsensitive("true")',
+      );
+    });
+  });
+});

From 8cfc9132f26dd47c7fcb3c1dd3d6f40ea8ba8ed3 Mon Sep 17 00:00:00 2001
From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com>
Date: Fri, 5 Jun 2026 16:28:12 +0000
Subject: [PATCH 13/16] chore(spec-api): simplify string matcher error messages

Co-authored-by: timotheeguerin <1031227+timotheeguerin@users.noreply.github.com>
---
 packages/spec-api/src/matchers/string.ts | 8 ++------
 1 file changed, 2 insertions(+), 6 deletions(-)

diff --git a/packages/spec-api/src/matchers/string.ts b/packages/spec-api/src/matchers/string.ts
index 322ac3cafea..a2b2908e79c 100644
--- a/packages/spec-api/src/matchers/string.ts
+++ b/packages/spec-api/src/matchers/string.ts
@@ -6,14 +6,10 @@ export const stringMatcher = {
     return createMatcher({
       check(actual: unknown) {
         if (typeof actual !== "string") {
-          return err(
-            `match.string.caseInsensitive: expected a string but got ${typeof actual}`,
-          );
+          return err(`expected a string but got ${typeof actual}`);
         }
         if (actual.toLowerCase() !== normalized) {
-          return err(
-            `match.string.caseInsensitive: expected case-insensitive "${value}" but got "${actual}"`,
-          );
+          return err(`expected case-insensitive "${value}" but got "${actual}"`);
         }
         return ok();
       },

From f095d136ad90a204035d1d46ddfbfe06e65ad573 Mon Sep 17 00:00:00 2001
From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com>
Date: Fri, 5 Jun 2026 17:08:25 +0000
Subject: [PATCH 14/16] chore(compiler): regenerate generated defs

Co-authored-by: timotheeguerin <1031227+timotheeguerin@users.noreply.github.com>
---
 packages/compiler/generated-defs/TypeSpec.ts | 1 -
 1 file changed, 1 deletion(-)

diff --git a/packages/compiler/generated-defs/TypeSpec.ts b/packages/compiler/generated-defs/TypeSpec.ts
index d93788afbeb..0fa7f3838e6 100644
--- a/packages/compiler/generated-defs/TypeSpec.ts
+++ b/packages/compiler/generated-defs/TypeSpec.ts
@@ -98,7 +98,6 @@ export type MediaTypeHintDecorator = (
  *   @encode(string) id: int64;
  * }
  * ```
- *
  * @example encode boolean type to string
  *
  * `@encode(string)` on boolean uses case-insensitive `true` / `false` values.

From 7d5c39165ea17d975613e56a463d577f689ffe72 Mon Sep 17 00:00:00 2001
From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com>
Date: Fri, 5 Jun 2026 17:16:13 +0000
Subject: [PATCH 15/16] style: format boolean encode spec and string matcher
 tests

Co-authored-by: timotheeguerin <1031227+timotheeguerin@users.noreply.github.com>
---
 packages/http-specs/specs/encode/boolean/main.tsp |  4 +++-
 packages/spec-api/test/matchers/string.test.ts    | 15 ++++++++++++---
 2 files changed, 15 insertions(+), 4 deletions(-)

diff --git a/packages/http-specs/specs/encode/boolean/main.tsp b/packages/http-specs/specs/encode/boolean/main.tsp
index d0b146d17a9..9d4eba49d28 100644
--- a/packages/http-specs/specs/encode/boolean/main.tsp
+++ b/packages/http-specs/specs/encode/boolean/main.tsp
@@ -53,7 +53,9 @@ namespace Property {
         }
         ```
         """,
-      { value: StringValue }
+      {
+        value: StringValue,
+      }
     )
     @post
     sendBoolAsString(@body value: BoolAsStringProperty): BoolAsStringProperty;
diff --git a/packages/spec-api/test/matchers/string.test.ts b/packages/spec-api/test/matchers/string.test.ts
index 046818de0de..2d48d48a5da 100644
--- a/packages/spec-api/test/matchers/string.test.ts
+++ b/packages/spec-api/test/matchers/string.test.ts
@@ -22,12 +22,21 @@ describe("match.string.caseInsensitive()", () => {
     });
 
     it("should reject a different string value", () => {
-      expectFail(match.string.caseInsensitive("true").check("false"), 'expected case-insensitive "true"');
+      expectFail(
+        match.string.caseInsensitive("true").check("false"),
+        'expected case-insensitive "true"',
+      );
     });
 
     it("should reject non-string values", () => {
-      expectFail(match.string.caseInsensitive("true").check(true), "expected a string but got boolean");
-      expectFail(match.string.caseInsensitive("false").check(null), "expected a string but got object");
+      expectFail(
+        match.string.caseInsensitive("true").check(true),
+        "expected a string but got boolean",
+      );
+      expectFail(
+        match.string.caseInsensitive("false").check(null),
+        "expected a string but got object",
+      );
     });
   });
 

From c58089fe42977cca0d30f45bfb9c80679ea48d07 Mon Sep 17 00:00:00 2001
From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com>
Date: Fri, 5 Jun 2026 17:26:11 +0000
Subject: [PATCH 16/16] chore: add chronus changelog entries for encode boolean
 updates

Co-authored-by: timotheeguerin <1031227+timotheeguerin@users.noreply.github.com>
---
 ...t-encode-string-boolean-changelog-2026-6-5-17-25-0.md | 9 +++++++++
 1 file changed, 9 insertions(+)
 create mode 100644 .chronus/changes/copilot-encode-string-boolean-changelog-2026-6-5-17-25-0.md

diff --git a/.chronus/changes/copilot-encode-string-boolean-changelog-2026-6-5-17-25-0.md b/.chronus/changes/copilot-encode-string-boolean-changelog-2026-6-5-17-25-0.md
new file mode 100644
index 00000000000..316436bef04
--- /dev/null
+++ b/.chronus/changes/copilot-encode-string-boolean-changelog-2026-6-5-17-25-0.md
@@ -0,0 +1,9 @@
+---
+changeKind: feature
+packages:
+  - "@typespec/compiler"
+  - "@typespec/spec-api"
+  - "@typespec/http-specs"
+---
+
+Allow `@encode(string)` on boolean targets, define case-insensitive `true`/`false` string semantics, and add shared case-insensitive string matcher support with encode/boolean Spector coverage.