feat(ios): add Talk voice directive hint toggle (#18250)

* feat(ios): add Talk voice directive hint toggle

* docs(changelog): credit voice directive hint slice

---------

Co-authored-by: Mariano Belinky <mariano@mb-server-643.local>

apps/shared/OpenClawKit/Sources/OpenClawKit/TalkPromptBuilder.swift

@@ -1,10 +1,19 @@
 public enum TalkPromptBuilder: Sendable {
-    public static func build(transcript: String, interruptedAtSeconds: Double?) -> String {
+    public static func build(
+        transcript: String,
+        interruptedAtSeconds: Double?,
+        includeVoiceDirectiveHint: Bool = true
+    ) -> String {
         var lines: [String] = [
             "Talk Mode active. Reply in a concise, spoken tone.",
-            "You may optionally prefix the response with JSON (first line) to set ElevenLabs voice (id or alias), e.g. {\"voice\":\"<id>\",\"once\":true}.",
         ]
 
+        if includeVoiceDirectiveHint {
+            lines.append(
+                "You may optionally prefix the response with JSON (first line) to set ElevenLabs voice (id or alias), e.g. {\"voice\":\"<id>\",\"once\":true}."
+            )
+        }
+
         if let interruptedAtSeconds {
             let formatted = String(format: "%.1f", interruptedAtSeconds)
             lines.append("Assistant speech interrupted at \(formatted)s.")

apps/shared/OpenClawKit/Tests/OpenClawKitTests/TalkPromptBuilderTests.swift

@@ -12,4 +12,18 @@ final class TalkPromptBuilderTests: XCTestCase {
         let prompt = TalkPromptBuilder.build(transcript: "Hi", interruptedAtSeconds: 1.234)
         XCTAssertTrue(prompt.contains("Assistant speech interrupted at 1.2s."))
     }
+
+    func testBuildIncludesVoiceDirectiveHintByDefault() {
+        let prompt = TalkPromptBuilder.build(transcript: "Hello", interruptedAtSeconds: nil)
+        XCTAssertTrue(prompt.contains("ElevenLabs voice"))
+    }
+
+    func testBuildExcludesVoiceDirectiveHintWhenDisabled() {
+        let prompt = TalkPromptBuilder.build(
+            transcript: "Hello",
+            interruptedAtSeconds: nil,
+            includeVoiceDirectiveHint: false)
+        XCTAssertFalse(prompt.contains("ElevenLabs voice"))
+        XCTAssertTrue(prompt.contains("Talk Mode active."))
+    }
 }