diff --git a/code/frameworks/angular-vite/src/client/docs/__testfixtures__/doc-model/argtypes-filtered.snapshot b/code/frameworks/angular-vite/src/client/docs/__testfixtures__/doc-model/argtypes-filtered.snapshot
index d77122d74876..6847572594bb 100644
--- a/code/frameworks/angular-vite/src/client/docs/__testfixtures__/doc-model/argtypes-filtered.snapshot
+++ b/code/frameworks/angular-vite/src/client/docs/__testfixtures__/doc-model/argtypes-filtered.snapshot
@@ -8,7 +8,7 @@
         "summary": "#345F92",
       },
       "type": {
-        "required": true,
+        "required": false,
         "summary": "string",
       },
     },
@@ -23,7 +23,7 @@
     "table": {
       "category": "outputs",
       "type": {
-        "required": true,
+        "required": false,
         "summary": "(e: string) => void",
       },
     },
@@ -56,7 +56,7 @@
     "table": {
       "category": "outputs",
       "type": {
-        "required": true,
+        "required": false,
         "summary": "(e: boolean) => void",
       },
     },
diff --git a/code/frameworks/angular-vite/src/client/docs/__testfixtures__/doc-model/argtypes.snapshot b/code/frameworks/angular-vite/src/client/docs/__testfixtures__/doc-model/argtypes.snapshot
index d77122d74876..6847572594bb 100644
--- a/code/frameworks/angular-vite/src/client/docs/__testfixtures__/doc-model/argtypes.snapshot
+++ b/code/frameworks/angular-vite/src/client/docs/__testfixtures__/doc-model/argtypes.snapshot
@@ -8,7 +8,7 @@
         "summary": "#345F92",
       },
       "type": {
-        "required": true,
+        "required": false,
         "summary": "string",
       },
     },
@@ -23,7 +23,7 @@
     "table": {
       "category": "outputs",
       "type": {
-        "required": true,
+        "required": false,
         "summary": "(e: string) => void",
       },
     },
@@ -56,7 +56,7 @@
     "table": {
       "category": "outputs",
       "type": {
-        "required": true,
+        "required": false,
         "summary": "(e: boolean) => void",
       },
     },
diff --git a/code/frameworks/angular/src/client/docs/__testfixtures__/doc-model/argtypes-filtered.snapshot b/code/frameworks/angular/src/client/docs/__testfixtures__/doc-model/argtypes-filtered.snapshot
index d77122d74876..6847572594bb 100644
--- a/code/frameworks/angular/src/client/docs/__testfixtures__/doc-model/argtypes-filtered.snapshot
+++ b/code/frameworks/angular/src/client/docs/__testfixtures__/doc-model/argtypes-filtered.snapshot
@@ -8,7 +8,7 @@
         "summary": "#345F92",
       },
       "type": {
-        "required": true,
+        "required": false,
         "summary": "string",
       },
     },
@@ -23,7 +23,7 @@
     "table": {
       "category": "outputs",
       "type": {
-        "required": true,
+        "required": false,
         "summary": "(e: string) => void",
       },
     },
@@ -56,7 +56,7 @@
     "table": {
       "category": "outputs",
       "type": {
-        "required": true,
+        "required": false,
         "summary": "(e: boolean) => void",
       },
     },
diff --git a/code/frameworks/angular/src/client/docs/__testfixtures__/doc-model/argtypes.snapshot b/code/frameworks/angular/src/client/docs/__testfixtures__/doc-model/argtypes.snapshot
index d77122d74876..6847572594bb 100644
--- a/code/frameworks/angular/src/client/docs/__testfixtures__/doc-model/argtypes.snapshot
+++ b/code/frameworks/angular/src/client/docs/__testfixtures__/doc-model/argtypes.snapshot
@@ -8,7 +8,7 @@
         "summary": "#345F92",
       },
       "type": {
-        "required": true,
+        "required": false,
         "summary": "string",
       },
     },
@@ -23,7 +23,7 @@
     "table": {
       "category": "outputs",
       "type": {
-        "required": true,
+        "required": false,
         "summary": "(e: string) => void",
       },
     },
@@ -56,7 +56,7 @@
     "table": {
       "category": "outputs",
       "type": {
-        "required": true,
+        "required": false,
         "summary": "(e: boolean) => void",
       },
     },
diff --git a/code/lib/angular-compodoc/src/compodoc-types.ts b/code/lib/angular-compodoc/src/compodoc-types.ts
index 18174cf65c17..f8fbfce51986 100644
--- a/code/lib/angular-compodoc/src/compodoc-types.ts
+++ b/code/lib/angular-compodoc/src/compodoc-types.ts
@@ -26,7 +26,17 @@ export interface Property {
   decorators?: Decorator[];
   /** Omitted by Compodoc for members it cannot type, e.g. `@HostBinding`. */
   type?: string;
-  optional: boolean;
+  /**
+   * Whether the member is TS-optional. Compodoc omits it entirely for `@Input()`-decorated
+   * properties while emitting it for signal inputs and plain class properties (compodoc#863, still
+   * open at 2.0.0), so it is absent far more often than the old non-optional declaration implied.
+   */
+  optional?: boolean;
+  /**
+   * Compodoc's own requiredness flag, which is what Angular actually means by a required input.
+   * Present for signal inputs and for `@Input({ required })`; absent for a plain `@Input()`.
+   */
+  required?: boolean;
   defaultValue?: string;
   description?: Html;
   rawdescription?: string;
diff --git a/code/lib/angular-compodoc/src/extract-arg-types.test.ts b/code/lib/angular-compodoc/src/extract-arg-types.test.ts
index e295161232da..571648c4c7c8 100644
--- a/code/lib/angular-compodoc/src/extract-arg-types.test.ts
+++ b/code/lib/angular-compodoc/src/extract-arg-types.test.ts
@@ -72,3 +72,59 @@ describe('extractArgTypesFromData', () => {
     expect(() => extract('Status', { enumerations: [{ name: 'Status' }] as never })).not.toThrow();
   });
 });
+
+describe('required', () => {
+  /** Extracts a single input declared with the given pair of Compodoc flags. */
+  const requiredOf = (flags: { optional?: boolean; required?: boolean }) => {
+    const componentData = {
+      name: 'StatusComponent',
+      type: 'component',
+      inputsClass: [{ name: 'value', type: 'string', ...flags }],
+      outputsClass: [],
+      propertiesClass: [],
+      methodsClass: [],
+    } as never;
+
+    const argTypes = extractArgTypesFromData(componentData, {
+      compodocJson: jsonWith({} as never),
+      filterNonInputControls: true,
+      logger,
+      unwrapHtml: (html: unknown) => String(html),
+    });
+
+    // `required` has always been written into `table.type`, which the public ArgTypes type
+    // declares as summary/detail only, so reading it back needs an assertion.
+    return (argTypes.value.table?.type as { required?: boolean } | undefined)?.required;
+  };
+
+  // One case per shape Compodoc can emit. Which declaration produces which pair is recorded here
+  // because the pairs are not self-explanatory, and one of them is self-contradictory.
+  it('is false for a signal input with a default: `input("")`', () => {
+    expect(requiredOf({ optional: false, required: false })).toBe(false);
+  });
+
+  it('is true for `input.required<T>()`', () => {
+    expect(requiredOf({ optional: false, required: true })).toBe(true);
+  });
+
+  it('is true for `@Input({ required: true })`', () => {
+    expect(requiredOf({ optional: false, required: true })).toBe(true);
+  });
+
+  it('is false for `@Input({ required: false })`, which Compodoc reports as required and optional at once', () => {
+    // Compodoc derives `required` from the presence of the key rather than its value, so this
+    // declaration contradicts itself. Trusting `required` alone would call it required.
+    expect(requiredOf({ optional: true, required: true })).toBe(false);
+  });
+
+  it('falls back to `optional` when Compodoc omits `required`', () => {
+    expect(requiredOf({ optional: true })).toBe(false);
+    expect(requiredOf({ optional: false })).toBe(true);
+  });
+
+  it('is true for a plain `@Input()`, for which Compodoc emits neither flag (compodoc#863)', () => {
+    // The remaining upstream gap: with nothing to read, every plain decorator input reads as
+    // required. Fixing it upstream makes `optional` appear, and this case corrects itself.
+    expect(requiredOf({})).toBe(true);
+  });
+});
diff --git a/code/lib/angular-compodoc/src/extract-arg-types.ts b/code/lib/angular-compodoc/src/extract-arg-types.ts
index 3dc9395c2567..b5327dc78e73 100644
--- a/code/lib/angular-compodoc/src/extract-arg-types.ts
+++ b/code/lib/angular-compodoc/src/extract-arg-types.ts
@@ -76,6 +76,21 @@ export const isMethod = (methodOrProp: Method | Property): methodOrProp is Metho
   return (methodOrProp as Method).args !== undefined;
 };
 
+/**
+ * Whether a member must be bound, from the two flags Compodoc emits about it.
+ *
+ * `required` is the flag that matches what Angular means, but it is only trustworthy in one
+ * direction: Compodoc derives it from the presence of the `required` key in an `@Input({...})`
+ * argument rather than from its value, so `@Input({ required: false })` reports `required: true`
+ * alongside `optional: true`. Requiring both to agree keeps that case correct.
+ *
+ * `required` is absent altogether for a plain `@Input()`, which falls back to `optional` - and
+ * Compodoc omits that too (compodoc#863), so those inputs still read as required. That is the
+ * upstream gap; the moment a fixed Compodoc emits `optional`, this returns the right answer with
+ * no change here.
+ */
+const isRequired = (item: Property): boolean => (item.required ?? true) && !item.optional;
+
 export const checkValidComponentOrDirective = (component: Component | Directive) => {
   if (!component.name) {
     throw new Error(`Invalid component ${JSON.stringify(component)}`);
@@ -371,7 +386,7 @@ export const extractArgTypesFromData = (
           category: section,
           type: {
             summary: isMethod(item) ? displaySignature(item) : item.type,
-            required: isMethod(item) ? false : !item.optional,
+            required: isMethod(item) ? false : isRequired(item as Property),
           },
           defaultValue: { summary: defaultValue },
         },
@@ -400,7 +415,10 @@ export const extractArgTypesFromData = (
         category: 'outputs',
         type: {
           summary: `(e: ${item.type}) => void`,
-          required: !item.optional,
+          // An output is never required to bind, and a real output says so via Compodoc's own
+          // flag. This one is synthesized, so it has to say so itself rather than inheriting the
+          // requiredness of the model input it derives from.
+          required: false,
         },
       },
     };
diff --git a/code/lib/docgen-harness/src/angular/__testfixtures__/signal-io/argtypes-filtered.snapshot b/code/lib/docgen-harness/src/angular/__testfixtures__/signal-io/argtypes-filtered.snapshot
index d5fa9719674a..06ae30f4ff63 100644
--- a/code/lib/docgen-harness/src/angular/__testfixtures__/signal-io/argtypes-filtered.snapshot
+++ b/code/lib/docgen-harness/src/angular/__testfixtures__/signal-io/argtypes-filtered.snapshot
@@ -27,7 +27,7 @@
         "summary": false,
       },
       "type": {
-        "required": true,
+        "required": false,
         "summary": "boolean",
       },
     },
@@ -45,7 +45,7 @@
         "summary": 1,
       },
       "type": {
-        "required": true,
+        "required": false,
         "summary": "number",
       },
     },
@@ -63,7 +63,7 @@ Visible caption next to the control.",
         "summary": "",
       },
       "type": {
-        "required": true,
+        "required": false,
         "summary": "string",
       },
     },
diff --git a/code/lib/docgen-harness/src/angular/__testfixtures__/signal-io/argtypes.snapshot b/code/lib/docgen-harness/src/angular/__testfixtures__/signal-io/argtypes.snapshot
index d1d2ddf3535a..be0e98ae35c2 100644
--- a/code/lib/docgen-harness/src/angular/__testfixtures__/signal-io/argtypes.snapshot
+++ b/code/lib/docgen-harness/src/angular/__testfixtures__/signal-io/argtypes.snapshot
@@ -27,7 +27,7 @@
         "summary": false,
       },
       "type": {
-        "required": true,
+        "required": false,
         "summary": "boolean",
       },
     },
@@ -45,7 +45,7 @@
         "summary": 1,
       },
       "type": {
-        "required": true,
+        "required": false,
         "summary": "number",
       },
     },
@@ -63,7 +63,7 @@ Visible caption next to the control.",
         "summary": "",
       },
       "type": {
-        "required": true,
+        "required": false,
         "summary": "string",
       },
     },
@@ -82,7 +82,7 @@ Visible caption next to the control.",
         "summary": false,
       },
       "type": {
-        "required": true,
+        "required": false,
         "summary": "boolean",
       },
     },
diff --git a/code/lib/docgen-harness/src/angular/__testfixtures__/signal-model/argtypes-filtered.snapshot b/code/lib/docgen-harness/src/angular/__testfixtures__/signal-model/argtypes-filtered.snapshot
index 9fe2f82109f3..93023348f9cf 100644
--- a/code/lib/docgen-harness/src/angular/__testfixtures__/signal-model/argtypes-filtered.snapshot
+++ b/code/lib/docgen-harness/src/angular/__testfixtures__/signal-model/argtypes-filtered.snapshot
@@ -25,7 +25,7 @@
     "table": {
       "category": "outputs",
       "type": {
-        "required": true,
+        "required": false,
         "summary": "(e: boolean) => void",
       },
     },
@@ -44,7 +44,7 @@ Current text value of the field.",
         "summary": "start",
       },
       "type": {
-        "required": true,
+        "required": false,
         "summary": "string",
       },
     },
@@ -60,7 +60,7 @@ Current text value of the field.",
     "table": {
       "category": "outputs",
       "type": {
-        "required": true,
+        "required": false,
         "summary": "(e: string) => void",
       },
     },
diff --git a/code/lib/docgen-harness/src/angular/__testfixtures__/signal-model/argtypes.snapshot b/code/lib/docgen-harness/src/angular/__testfixtures__/signal-model/argtypes.snapshot
index 9fe2f82109f3..93023348f9cf 100644
--- a/code/lib/docgen-harness/src/angular/__testfixtures__/signal-model/argtypes.snapshot
+++ b/code/lib/docgen-harness/src/angular/__testfixtures__/signal-model/argtypes.snapshot
@@ -25,7 +25,7 @@
     "table": {
       "category": "outputs",
       "type": {
-        "required": true,
+        "required": false,
         "summary": "(e: boolean) => void",
       },
     },
@@ -44,7 +44,7 @@ Current text value of the field.",
         "summary": "start",
       },
       "type": {
-        "required": true,
+        "required": false,
         "summary": "string",
       },
     },
@@ -60,7 +60,7 @@ Current text value of the field.",
     "table": {
       "category": "outputs",
       "type": {
-        "required": true,
+        "required": false,
         "summary": "(e: string) => void",
       },
     },