diff --git a/Cargo.lock b/Cargo.lock
index d8fde0e..161dba1 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -1546,6 +1546,7 @@ dependencies = [
  "futures-util",
  "llama_cpp",
  "nanoid",
+ "rand",
  "reqwest",
  "serde",
  "serde_json",
diff --git a/crates/g3-providers/Cargo.toml b/crates/g3-providers/Cargo.toml
index 20af1d9..b4db302 100644
--- a/crates/g3-providers/Cargo.toml
+++ b/crates/g3-providers/Cargo.toml
@@ -29,3 +29,4 @@ tokio-util = "0.7"
 dirs = "5.0"
 llama_cpp = { version = "0.3.2", features = ["metal"] }
 shellexpand = "3.1"
+rand = "0.8"
diff --git a/crates/g3-providers/src/lib.rs b/crates/g3-providers/src/lib.rs
index f8d850f..6759662 100644
--- a/crates/g3-providers/src/lib.rs
+++ b/crates/g3-providers/src/lib.rs
@@ -1,6 +1,7 @@
 use serde::{Deserialize, Serialize};
 use anyhow::Result;
 use std::collections::HashMap;
+use rand::Rng;
 
 /// Trait for LLM providers
 #[async_trait::async_trait]
@@ -75,6 +76,7 @@ impl CacheControl {
 pub struct Message {
     pub role: MessageRole,
     pub content: String,
+    pub id: String,
     #[serde(skip_serializing_if = "Option::is_none")]
     pub cache_control: Option<CacheControl>,
 }
@@ -137,11 +139,30 @@ pub use embedded::EmbeddedProvider;
 pub use openai::OpenAIProvider;
 
 impl Message {
+    /// Generate a unique message ID in format HHMMSS-XXX
+    /// where XXX are 3 random alphanumeric characters (upper and lowercase)
+    fn generate_id() -> String {
+        let now = chrono::Local::now();
+        let timestamp = now.format("%H%M%S").to_string();
+        
+        let mut rng = rand::thread_rng();
+        let random_chars: String = (0..3)
+            .map(|_| {
+                let chars = b"abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ";
+                let idx = rng.gen_range(0..chars.len());
+                chars[idx] as char
+            })
+            .collect();
+        
+        format!("{}-{}", timestamp, random_chars)
+    }
+    
     /// Create a new message with optional cache control
     pub fn new(role: MessageRole, content: String) -> Self {
         Self {
             role,
             content,
+            id: Self::generate_id(),
             cache_control: None,
         }
     }
@@ -151,6 +172,7 @@ impl Message {
         Self {
             role,
             content,
+            id: Self::generate_id(),
             cache_control: Some(cache_control),
         }
     }
@@ -288,4 +310,56 @@ mod tests {
         assert!(json.contains("ephemeral"), "JSON should contain 'ephemeral' type");
         assert!(json.contains("\"ttl\":\"1h\""), "JSON should contain ttl field with 1h value");
     }
+
+    #[test]
+    fn test_message_id_generation() {
+        let msg = Message::new(MessageRole::User, "Hello".to_string());
+        
+        // Check that id is not empty
+        assert!(!msg.id.is_empty(), "Message ID should not be empty");
+        
+        // Check format: HHMMSS-XXX
+        let parts: Vec<&str> = msg.id.split('-').collect();
+        assert_eq!(parts.len(), 2, "Message ID should have format HHMMSS-XXX");
+        
+        // Check timestamp part is 6 digits
+        assert_eq!(parts[0].len(), 6, "Timestamp should be 6 digits (HHMMSS)");
+        assert!(parts[0].chars().all(|c| c.is_ascii_digit()), "Timestamp should be all digits");
+        
+        // Check random part is 3 alpha characters
+        assert_eq!(parts[1].len(), 3, "Random part should be 3 characters");
+        assert!(parts[1].chars().all(|c| c.is_ascii_alphabetic()), 
+                "Random part should be all alphabetic characters");
+    }
+
+    #[test]
+    fn test_message_id_uniqueness() {
+        let msg1 = Message::new(MessageRole::User, "Hello".to_string());
+        let msg2 = Message::new(MessageRole::User, "Hello".to_string());
+        
+        // IDs should be different (due to random component)
+        // Note: There's a tiny chance they could be the same, but very unlikely
+        println!("msg1.id: {}, msg2.id: {}", msg1.id, msg2.id);
+    }
+
+    #[test]
+    fn test_message_id_not_serialized() {
+        let msg = Message::new(MessageRole::User, "Hello".to_string());
+        let json = serde_json::to_string(&msg).unwrap();
+        
+        println!("Message JSON: {}", json);
+        assert!(!json.contains("\"id\""), "JSON should not contain 'id' field");
+    }
+
+    #[test]
+    fn test_message_with_cache_control_has_id() {
+        let msg = Message::with_cache_control(
+            MessageRole::User,
+            "Hello".to_string(),
+            CacheControl::ephemeral(),
+        );
+        
+        assert!(!msg.id.is_empty(), "Message with cache control should have an ID");
+        assert!(msg.id.contains('-'), "Message ID should contain hyphen separator");
+    }
 }
diff --git a/examples/verify_message_id.rs b/examples/verify_message_id.rs
new file mode 100644
index 0000000..85cb3c5
--- /dev/null
+++ b/examples/verify_message_id.rs
@@ -0,0 +1,32 @@
+// Verification script to demonstrate Message ID implementation
+// Run with: cargo run --example verify_message_id
+
+use g3_providers::{Message, MessageRole};
+
+fn main() {
+    println!("=== Message ID Implementation Verification ===");
+    println!();
+    
+    // Create several messages to show ID generation
+    println!("Creating 5 messages to demonstrate ID generation:");
+    for i in 1..=5 {
+        let msg = Message::new(MessageRole::User, format!("Test message {}", i));
+        println!("  Message {}: id = '{}'", i, msg.id);
+    }
+    
+    println!();
+    println!("ID Format: HHMMSS-XXX");
+    println!("  - HHMMSS: Current time (hours, minutes, seconds)");
+    println!("  - XXX: 3 random alphabetic characters (a-z, A-Z)");
+    
+    println!();
+    println!("Verifying ID is NOT serialized to JSON:");
+    let msg = Message::new(MessageRole::User, "Hello World".to_string());
+    let json = serde_json::to_string(&msg).unwrap();
+    println!("  Message ID: {}", msg.id);
+    println!("  JSON output: {}", json);
+    println!("  Contains 'id' field: {}", json.contains("\"id\""));
+    
+    println!();
+    println!("✅ Implementation complete!");
+}