diff --git a/src/mcp/__tests__/command-tools.test.ts b/src/mcp/__tests__/command-tools.test.ts
index ae5ec63064..d419068de6 100644
--- a/src/mcp/__tests__/command-tools.test.ts
+++ b/src/mcp/__tests__/command-tools.test.ts
@@ -5,6 +5,7 @@ import { createCommandToolExecutor, listCommandTools } from '../command-tools.ts
 import { COMMAND_OUTPUT_SCHEMAS } from '../command-output-schemas.ts';
 import { AppError } from '../../kernel/errors.ts';
 import { NAVIGATION_COMMAND_PROJECTIONS } from '../../commands/system/navigation-projection.ts';
+import { validateAgainstSchema } from './output-schema-validator.ts';
 
 test('MCP command tool executor hides client creation behind an execution adapter', async () => {
   const client = {} as AgentDeviceClient;
@@ -379,6 +380,136 @@ test('MCP boot structuredContent is consistent with its advertised outputSchema'
   assert.deepEqual(result.structuredContent, bootResult);
 });
 
+// --- #1219 public Apple platform parity in MCP output schemas ---
+// These validate representative structured content against the COMPLETE
+// advertised schema (enums/consts and nested required fields), not just the
+// presence of required keys, and pin the negative cases the required-only check
+// silently accepted.
+
+function bootResultFor(platform: 'ios' | 'macos') {
+  return {
+    platform,
+    target: platform === 'macos' ? 'desktop' : 'mobile',
+    device: platform === 'macos' ? 'My Mac' : 'iPhone 16',
+    id: 'UDID-123',
+    kind: platform === 'macos' ? 'device' : 'simulator',
+    booted: true,
+    // Additive Apple-OS discriminant rides alongside the leaf platform.
+    appleOs: platform,
+  } as const;
+}
+
+function shutdownResultFor(platform: 'ios' | 'macos') {
+  const { platform: leaf, target, device, id, kind, appleOs } = bootResultFor(platform);
+  return {
+    platform: leaf,
+    target,
+    device,
+    id,
+    kind,
+    appleOs,
+    shutdown: { success: true, exitCode: 0, stdout: '', stderr: '' },
+  };
+}
+
+function prepareResultFor(platform: 'ios' | 'macos') {
+  return {
+    action: 'ios-runner',
+    platform,
+    deviceId: 'UDID-123',
+    deviceName: 'iPhone 16',
+    kind: 'simulator',
+    durationMs: 1200,
+    runner: {},
+    connectMs: 100,
+    healthCheckMs: 50,
+    timing: {
+      totalMs: 1200,
+      additiveParts: { connectAfterBuildMs: 100, healthCheckMs: 50 },
+      containment: { healthCheckMs: [] },
+      note: 'ok',
+    },
+    message: 'prepared',
+  };
+}
+
+test('MCP boot/shutdown schemas advertise public Apple leaves, never internal apple', () => {
+  const platformEnum = COMMAND_OUTPUT_SCHEMAS.boot.properties?.platform?.enum;
+  assert.deepEqual(platformEnum, ['ios', 'macos', 'android', 'linux', 'web']);
+  assert.equal(platformEnum?.includes('apple'), false);
+  // shutdown shares the same resolved-device header.
+  assert.deepEqual(COMMAND_OUTPUT_SCHEMAS.shutdown.properties?.platform?.enum, platformEnum);
+});
+
+test('MCP valid ios/macos boot results satisfy the complete boot schema', () => {
+  for (const platform of ['ios', 'macos'] as const) {
+    assert.deepEqual(
+      validateAgainstSchema(bootResultFor(platform), COMMAND_OUTPUT_SCHEMAS.boot),
+      [],
+    );
+  }
+});
+
+test('MCP valid ios/macos shutdown results satisfy the complete shutdown schema', () => {
+  for (const platform of ['ios', 'macos'] as const) {
+    assert.deepEqual(
+      validateAgainstSchema(shutdownResultFor(platform), COMMAND_OUTPUT_SCHEMAS.shutdown),
+      [],
+    );
+  }
+});
+
+test('MCP boot schema rejects the internal apple platform and unknown enum values', () => {
+  // Internal identity must not be advertised on the public result field.
+  assert.notDeepEqual(
+    validateAgainstSchema(
+      { ...bootResultFor('ios'), platform: 'apple' },
+      COMMAND_OUTPUT_SCHEMAS.boot,
+    ),
+    [],
+  );
+  assert.notDeepEqual(
+    validateAgainstSchema(
+      { ...bootResultFor('ios'), platform: 'windows' },
+      COMMAND_OUTPUT_SCHEMAS.boot,
+    ),
+    [],
+  );
+  // The `booted` discriminant is a const true; a false value fails the schema.
+  assert.notDeepEqual(
+    validateAgainstSchema({ ...bootResultFor('ios'), booted: false }, COMMAND_OUTPUT_SCHEMAS.boot),
+    [],
+  );
+  // A missing nested-required shutdown field (stderr) fails validation.
+  assert.notDeepEqual(
+    validateAgainstSchema(
+      { ...shutdownResultFor('ios'), shutdown: { success: true, exitCode: 0, stdout: '' } },
+      COMMAND_OUTPUT_SCHEMAS.shutdown,
+    ),
+    [],
+  );
+});
+
+test('MCP prepare schema mirrors its PublicPlatform contract', () => {
+  const platformEnum = COMMAND_OUTPUT_SCHEMAS.prepare.properties?.platform?.enum;
+  assert.deepEqual(platformEnum, ['ios', 'macos', 'android', 'linux', 'web']);
+  assert.equal(platformEnum?.includes('apple'), false);
+
+  for (const platform of ['ios', 'macos'] as const) {
+    assert.deepEqual(
+      validateAgainstSchema(prepareResultFor(platform), COMMAND_OUTPUT_SCHEMAS.prepare),
+      [],
+    );
+  }
+  assert.notDeepEqual(
+    validateAgainstSchema(
+      { ...prepareResultFor('ios'), platform: 'apple' },
+      COMMAND_OUTPUT_SCHEMAS.prepare,
+    ),
+    [],
+  );
+});
+
 test('MCP session tool exposes state-dir resolution without a daemon round-trip', async () => {
   const sessionTool = listCommandTools().find((tool) => tool.name === 'session');
   assert.ok(sessionTool);
diff --git a/src/mcp/__tests__/output-schema-validator.ts b/src/mcp/__tests__/output-schema-validator.ts
new file mode 100644
index 0000000000..8b3fcb5886
--- /dev/null
+++ b/src/mcp/__tests__/output-schema-validator.ts
@@ -0,0 +1,106 @@
+import type { JsonSchema } from '../../commands/command-contract.ts';
+
+/**
+ * A focused JSON Schema validator for the MCP `outputSchema` dialect actually
+ * used by COMMAND_OUTPUT_SCHEMAS: `type` (including union type arrays), `enum`,
+ * `const`, `required`, `properties`, `items`, and `oneOf`. It exists so the
+ * command-tools tests can validate representative structured content against the
+ * COMPLETE advertised schema — enums/consts and nested required fields — rather
+ * than only checking that required keys are present.
+ *
+ * It is intentionally NON-STRICT: unknown properties are allowed (mirroring the
+ * schemas' deliberate absence of `additionalProperties: false`, so additive
+ * fields such as `cost` validate). It is a test helper, not a schema generator.
+ */
+export function validateAgainstSchema(value: unknown, schema: JsonSchema): string[] {
+  return collectErrors(value, schema, '$');
+}
+
+/** Convenience predicate for the common "does it validate at all" assertion. */
+export function matchesSchema(value: unknown, schema: JsonSchema): boolean {
+  return collectErrors(value, schema, '$').length === 0;
+}
+
+function collectErrors(value: unknown, schema: JsonSchema, path: string): string[] {
+  if (schema.oneOf) return oneOfErrors(value, schema.oneOf, path);
+
+  const errors = [...constErrors(value, schema, path), ...enumErrors(value, schema, path)];
+
+  if (schema.type !== undefined && !matchesType(value, schema.type)) {
+    errors.push(
+      `${path}: expected type ${JSON.stringify(schema.type)}, got ${describeType(value)}`,
+    );
+    return errors;
+  }
+
+  errors.push(...objectErrors(value, schema, path), ...arrayErrors(value, schema, path));
+  return errors;
+}
+
+function oneOfErrors(value: unknown, branches: readonly JsonSchema[], path: string): string[] {
+  const matching = branches.filter((branch) => collectErrors(value, branch, path).length === 0);
+  if (matching.length === 1) return [];
+  return [`${path}: expected to match exactly one oneOf branch, matched ${matching.length}`];
+}
+
+function constErrors(value: unknown, schema: JsonSchema, path: string): string[] {
+  if (!('const' in schema) || value === schema.const) return [];
+  return [`${path}: expected const ${JSON.stringify(schema.const)}, got ${JSON.stringify(value)}`];
+}
+
+function enumErrors(value: unknown, schema: JsonSchema, path: string): string[] {
+  if (!schema.enum || schema.enum.includes(value)) return [];
+  return [`${path}: ${JSON.stringify(value)} is not one of ${JSON.stringify(schema.enum)}`];
+}
+
+function objectErrors(value: unknown, schema: JsonSchema, path: string): string[] {
+  if (!isPlainObject(value)) return [];
+  const errors: string[] = [];
+  for (const key of schema.required ?? []) {
+    if (!(key in value)) errors.push(`${path}.${key}: missing required property`);
+  }
+  for (const [key, propSchema] of Object.entries(schema.properties ?? {})) {
+    if (key in value) errors.push(...collectErrors(value[key], propSchema, `${path}.${key}`));
+  }
+  return errors;
+}
+
+function arrayErrors(value: unknown, schema: JsonSchema, path: string): string[] {
+  if (!Array.isArray(value) || !schema.items) return [];
+  const items = schema.items;
+  return value.flatMap((item, index) => collectErrors(item, items, `${path}[${index}]`));
+}
+
+function matchesType(value: unknown, type: string | readonly string[]): boolean {
+  const types = Array.isArray(type) ? type : [type];
+  return types.some((candidate) => matchesSingleType(value, candidate));
+}
+
+function matchesSingleType(value: unknown, type: string): boolean {
+  switch (type) {
+    case 'object':
+      return isPlainObject(value);
+    case 'array':
+      return Array.isArray(value);
+    case 'string':
+      return typeof value === 'string';
+    case 'number':
+      return typeof value === 'number';
+    case 'boolean':
+      return typeof value === 'boolean';
+    case 'null':
+      return value === null;
+    default:
+      return false;
+  }
+}
+
+function describeType(value: unknown): string {
+  if (value === null) return 'null';
+  if (Array.isArray(value)) return 'array';
+  return typeof value;
+}
+
+function isPlainObject(value: unknown): value is Record<string, unknown> {
+  return typeof value === 'object' && value !== null && !Array.isArray(value);
+}
diff --git a/src/mcp/command-output-schemas.ts b/src/mcp/command-output-schemas.ts
index 9de05dbad6..625d0f6ddf 100644
--- a/src/mcp/command-output-schemas.ts
+++ b/src/mcp/command-output-schemas.ts
@@ -3,7 +3,7 @@ import { projectedSystemCommandOutputSchemas } from '../commands/system/index.ts
 import type { CommandResultMap } from '../core/command-descriptor/command-result.ts';
 import { booleanSchema, looseObjectSchema, stringSchema } from '../commands/command-input.ts';
 import { SESSION_SURFACES } from '../contracts/session-surface.ts';
-import { DEVICE_TARGETS, PLATFORMS } from '../kernel/device.ts';
+import { DEVICE_TARGETS, PUBLIC_PLATFORMS } from '../kernel/device.ts';
 
 /**
  * Registry of per-command MCP `outputSchema`s, keyed by the daemon command
@@ -260,7 +260,9 @@ const settleObservationSchema: JsonSchema = objectSchema(
 
 // boot / shutdown share the resolved-device header (src/contracts/device.ts).
 const deviceHeaderProperties: Record<string, JsonSchema> = {
-  platform: enumSchema(PLATFORMS),
+  // Public leaf vocabulary (ios | macos | android | linux | web): boot/shutdown
+  // emit publicPlatformString, never the internal `apple` platform.
+  platform: enumSchema(PUBLIC_PLATFORMS),
   target: enumSchema(DEVICE_TARGETS),
   device: stringSchema('Human-readable device name.'),
   id: stringSchema('Stable device id.'),
@@ -353,7 +355,8 @@ export const COMMAND_OUTPUT_SCHEMAS = {
   prepare: objectSchema(
     {
       action: constSchema('ios-runner'),
-      platform: enumSchema(PLATFORMS),
+      // PublicPlatform leaf, mirroring PrepareCommandResult (src/contracts/prepare.ts).
+      platform: enumSchema(PUBLIC_PLATFORMS),
       deviceId: stringSchema(),
       deviceName: stringSchema(),
       kind: enumSchema(DEVICE_KINDS),