Allow for prompt caching to work by using baibot_conversation_start_time_utc instead of baibot_now_utc

This patch introduces a new `baibot_conversation_start_time_utc` variable which indicates the time the conversation got started. Using `baibot_now_utc` is still possible, but given that the current time is a moving target, its use is in conflict with prompt caching. Because the new `baibot_conversation_start_time_utc` prompt variable is a more reasonable default, we're now using it in all sample configs.
2024-10-03 11:48:14 +03:00
parent db9422740c
commit 85e66406dc
25 changed files with 159 additions and 25 deletions
--- a/docs/configuration/text-generation.md
+++ b/docs/configuration/text-generation.md
@@ -77,11 +77,14 @@ Prompts may contain the following **placeholder variables** which will be replac
 |---------------------------|-------------|---------|
 | `{{ baibot_name }}`       | Name of the bot as configured in the `user.name` field in the [Static configuration](./README.md#static-configuration) | `Baibot` |
 | `{{ baibot_model_id }}`   | Text-Generation model ID as configured in the [🤖 agent](../agents.md)'s configuration | `gpt-4o` |
-| `{{ baibot_now_utc }}`    | Current date and time in UTC | `2024-09-20 (Friday), 14:26:42 UTC` |
+| `{{ baibot_now_utc }}`    | Current date and time in UTC (⚠️ usage may break prompt caching - see below) | `2024-09-20 (Friday), 14:26:42 UTC` |
+| `{{ baibot_conversation_start_time_utc }}` | The date and time in UTC that the conversation started | `2024-09-20 (Friday), 14:26:42 UTC` |
+
+💡 `{{ baibot_now_utc }}` changes as time goes on, which prevents [prompt caching](https://platform.openai.com/docs/guides/prompt-caching) from working. It's better to use `{{ baibot_conversation_start_time_utc }}` in prompts, as its value doesn't change yet still orients the bot to the current date/time.

 Here's a prompt that combines some of the above variables:

-> You are a brief, but helpful bot called {{ baibot_name }} powered by the {{ baibot_model_id }} model. The date/time now is: {{ baibot_now_utc }}."
+> You are a brief, but helpful bot called {{ baibot_name }} powered by the {{ baibot_model_id }} model. The date/time of this conversation's start is: {{ baibot_conversation_start_time_utc }}."


 ### 🌡️ Temperature Override
--- a/docs/sample-provider-configs/anthropic.yml
+++ b/docs/sample-provider-configs/anthropic.yml
@@ -2,7 +2,7 @@ base_url: https://api.anthropic.com/v1
 api_key: YOUR_API_KEY_HERE
 text_generation:
  model_id: claude-3-5-sonnet-20240620
-  prompt: "You are a brief, but helpful bot called {{ baibot_name }} powered by the {{ baibot_model_id }} model. The date/time now is: {{ baibot_now_utc }}."
+  prompt: "You are a brief, but helpful bot called {{ baibot_name }} powered by the {{ baibot_model_id }} model. The date/time of this conversation's start is: {{ baibot_conversation_start_time_utc }}."
  temperature: 1.0
  max_response_tokens: 8192
  max_context_tokens: 204800
--- a/docs/sample-provider-configs/groq.yml
+++ b/docs/sample-provider-configs/groq.yml
@@ -2,7 +2,7 @@ base_url: https://api.groq.com/openai/v1
 api_key: YOUR_API_KEY_HERE
 text_generation:
  model_id: llama3-70b-8192
-  prompt: "You are a brief, but helpful bot called {{ baibot_name }} powered by the {{ baibot_model_id }} model. The date/time now is: {{ baibot_now_utc }}."
+  prompt: "You are a brief, but helpful bot called {{ baibot_name }} powered by the {{ baibot_model_id }} model. The date/time of this conversation's start is: {{ baibot_conversation_start_time_utc }}."
  temperature: 1.0
  max_response_tokens: 4096
  max_context_tokens: 131072
--- a/docs/sample-provider-configs/localai.yml
+++ b/docs/sample-provider-configs/localai.yml
@@ -2,7 +2,7 @@ base_url: http://my-localai-self-hosted-service:8080/v1
 api_key: YOUR_API_KEY_HERE
 text_generation:
  model_id: gpt-4
-  prompt: "You are a brief, but helpful bot called {{ baibot_name }} powered by the {{ baibot_model_id }} model. The date/time now is: {{ baibot_now_utc }}."
+  prompt: "You are a brief, but helpful bot called {{ baibot_name }} powered by the {{ baibot_model_id }} model. The date/time of this conversation's start is: {{ baibot_conversation_start_time_utc }}."
  temperature: 1.0
  max_response_tokens: 4096
  max_context_tokens: 128000
--- a/docs/sample-provider-configs/mistral.yml
+++ b/docs/sample-provider-configs/mistral.yml
@@ -2,7 +2,7 @@ base_url: https://api.mistral.ai/v1
 api_key: YOUR_API_KEY_HERE
 text_generation:
  model_id: mistral-large-latest
-  prompt: "You are a brief, but helpful bot called {{ baibot_name }} powered by the {{ baibot_model_id }} model. The date/time now is: {{ baibot_now_utc }}."
+  prompt: "You are a brief, but helpful bot called {{ baibot_name }} powered by the {{ baibot_model_id }} model. The date/time of this conversation's start is: {{ baibot_conversation_start_time_utc }}."
  temperature: 1.0
  max_response_tokens: 4096
  max_context_tokens: 128000
--- a/docs/sample-provider-configs/ollama.yml
+++ b/docs/sample-provider-configs/ollama.yml
@@ -2,7 +2,7 @@ base_url: http://my-ollama-self-hosted-service:11434/v1
 api_key: YOUR_API_KEY_HERE
 text_generation:
  model_id: gemma2:2b
-  prompt: "You are a brief, but helpful bot called {{ baibot_name }} powered by the {{ baibot_model_id }} model. The date/time now is: {{ baibot_now_utc }}."
+  prompt: "You are a brief, but helpful bot called {{ baibot_name }} powered by the {{ baibot_model_id }} model. The date/time of this conversation's start is: {{ baibot_conversation_start_time_utc }}."
  temperature: 1.0
  max_response_tokens: 4096
  max_context_tokens: 128000
--- a/docs/sample-provider-configs/openai-compatible.yml
+++ b/docs/sample-provider-configs/openai-compatible.yml
@@ -2,7 +2,7 @@ base_url: ''
 api_key: YOUR_API_KEY_HERE
 text_generation:
  model_id: some-model
-  prompt: "You are a brief, but helpful bot called {{ baibot_name }} powered by the {{ baibot_model_id }} model. The date/time now is: {{ baibot_now_utc }}."
+  prompt: "You are a brief, but helpful bot called {{ baibot_name }} powered by the {{ baibot_model_id }} model. The date/time of this conversation's start is: {{ baibot_conversation_start_time_utc }}."
  temperature: 1.0
  max_response_tokens: 4096
  max_context_tokens: 128000
--- a/docs/sample-provider-configs/openai.yml
+++ b/docs/sample-provider-configs/openai.yml
@@ -2,7 +2,7 @@ base_url: https://api.openai.com/v1
 api_key: YOUR_API_KEY_HERE
 text_generation:
  model_id: gpt-4o
-  prompt: "You are a brief, but helpful bot called {{ baibot_name }} powered by the {{ baibot_model_id }} model. The date/time now is: {{ baibot_now_utc }}."
+  prompt: "You are a brief, but helpful bot called {{ baibot_name }} powered by the {{ baibot_model_id }} model. The date/time of this conversation's start is: {{ baibot_conversation_start_time_utc }}."
  temperature: 1.0
  max_response_tokens: 16384
  max_context_tokens: 128000
--- a/docs/sample-provider-configs/openrouter.yml
+++ b/docs/sample-provider-configs/openrouter.yml
@@ -2,7 +2,7 @@ base_url: https://openrouter.ai/api/v1
 api_key: YOUR_API_KEY_HERE
 text_generation:
  model_id: mattshumer/reflection-70b:free
-  prompt: "You are a brief, but helpful bot called {{ baibot_name }} powered by the {{ baibot_model_id }} model. The date/time now is: {{ baibot_now_utc }}."
+  prompt: "You are a brief, but helpful bot called {{ baibot_name }} powered by the {{ baibot_model_id }} model. The date/time of this conversation's start is: {{ baibot_conversation_start_time_utc }}."
  temperature: 1.0
  max_response_tokens: 2048
  max_context_tokens: 8192
--- a/docs/sample-provider-configs/together-ai.yml
+++ b/docs/sample-provider-configs/together-ai.yml
@@ -2,7 +2,7 @@ base_url: https://api.together.xyz/v1
 api_key: YOUR_API_KEY_HERE
 text_generation:
  model_id: meta-llama/Meta-Llama-3.1-405B-Instruct-Turbo
-  prompt: "You are a brief, but helpful bot called {{ baibot_name }} powered by the {{ baibot_model_id }} model. The date/time now is: {{ baibot_now_utc }}."
+  prompt: "You are a brief, but helpful bot called {{ baibot_name }} powered by the {{ baibot_model_id }} model. The date/time of this conversation's start is: {{ baibot_conversation_start_time_utc }}."
  temperature: 1.0
  max_response_tokens: 2048
  max_context_tokens: 8192
--- a/etc/app/config.yml.dist
+++ b/etc/app/config.yml.dist
@@ -73,7 +73,7 @@ agents:
    #     api_key: ""
    #     text_generation:
    #       model_id: gpt-4o
-    #       prompt: "You are a brief, but helpful bot called {{ baibot_name }} powered by the {{ baibot_model_id }} model. The date/time now is: {{ baibot_now_utc }}."
+    #       prompt: "You are a brief, but helpful bot called {{ baibot_name }} powered by the {{ baibot_model_id }} model. The date/time of this conversation's start is: {{ baibot_conversation_start_time_utc }}."
    #       temperature: 1.0
    #       max_response_tokens: 16384
    #       max_context_tokens: 128000
@@ -97,7 +97,7 @@ agents:
    #     api_key: null
    #     text_generation:
    #       model_id: gpt-4
-    #       prompt: "You are a brief, but helpful bot called {{ baibot_name }} powered by the {{ baibot_model_id }} model. The date/time now is: {{ baibot_now_utc }}."
+    #       prompt: "You are a brief, but helpful bot called {{ baibot_name }} powered by the {{ baibot_model_id }} model. The date/time of this conversation's start is: {{ baibot_conversation_start_time_utc }}."
    #       temperature: 1.0
    #       max_response_tokens: 16384
    #       max_context_tokens: 128000
@@ -122,7 +122,7 @@ agents:
    #     api_key: null
    #     text_generation:
    #       model_id: "gemma2:2b"
-    #       prompt: "You are a brief, but helpful bot called {{ baibot_name }} powered by the {{ baibot_model_id }} model. The date/time now is: {{ baibot_now_utc }}."
+    #       prompt: "You are a brief, but helpful bot called {{ baibot_name }} powered by the {{ baibot_model_id }} model. The date/time of this conversation's start is: {{ baibot_conversation_start_time_utc }}."
    #       temperature: 1.0
    #       max_response_tokens: 4096
    #       max_context_tokens: 128000
--- a/src/agent/mod.rs
+++ b/src/agent/mod.rs
@@ -21,5 +21,5 @@ pub use provider::{AgentProvider, AgentProviderInfo, ControllerTrait};
 pub use purpose::AgentPurpose;

 pub(super) fn default_prompt() -> &'static str {
-    "You are a brief, but helpful bot called {{ baibot_name }} powered by the {{ baibot_model_id }} model. The date/time now is: {{ baibot_now_utc }}."
+    "You are a brief, but helpful bot called {{ baibot_name }} powered by the {{ baibot_model_id }} model. The date/time of this conversation's start is: {{ baibot_conversation_start_time_utc }}."
 }
--- a/src/agent/provider/anthropic/controller.rs
+++ b/src/agent/provider/anthropic/controller.rs
@@ -72,6 +72,7 @@ impl ControllerTrait for Controller {
        let messages = vec![LLMMessage {
            author: LLMAuthor::User,
            message_text: "Hello!".to_string(),
+            timestamp: chrono::Utc::now(),
        }];

        let conversation = LLMConversation { messages };
@@ -108,6 +109,7 @@ impl ControllerTrait for Controller {
            Some(LLMMessage {
                author: LLMAuthor::Prompt,
                message_text: prompt_text,
+                timestamp: chrono::Utc::now(),
            })
        };

--- a/src/agent/provider/entity/text_generation/prompt_variables.rs
+++ b/src/agent/provider/entity/text_generation/prompt_variables.rs
@@ -7,17 +7,33 @@ pub struct TextGenerationPromptVariables {

 impl Default for TextGenerationPromptVariables {
    fn default() -> Self {
-        Self::new("unnamed", "unknown-model", Utc::now())
+        let now = Utc::now();
+        Self::new("unnamed", "unknown-model", now, Some(now))
    }
 }

 impl TextGenerationPromptVariables {
-    pub fn new(bot_name: &str, model_id: &str, utc_time: DateTime<Utc>) -> Self {
+    pub fn new(
+        bot_name: &str,
+        model_id: &str,
+        now_time: DateTime<Utc>,
+        conversation_start_time: Option<DateTime<Utc>>,
+    ) -> Self {
        let mut map = HashMap::new();

        map.insert("baibot_name".to_string(), bot_name.to_string());
        map.insert("baibot_model_id".to_string(), model_id.to_string());
-        map.insert("baibot_now_utc".to_string(), format_utc_time(utc_time));
+        map.insert("baibot_now_utc".to_string(), format_utc_time(now_time));
+
+        let baibot_conversation_start_time_utc = match conversation_start_time {
+            Some(conversation_start_time) => format_utc_time(conversation_start_time),
+            None => "unknown".to_string(),
+        };
+
+        map.insert(
+            "baibot_conversation_start_time_utc".to_string(),
+            baibot_conversation_start_time_utc,
+        );

        Self { map }
    }
@@ -52,7 +68,18 @@ mod tests {
            .with_nanosecond(250000000)
            .unwrap();

-        let variables = TextGenerationPromptVariables::new("baibot", "gpt-4o", now_utc);
+        let conversation_start_time_utc = Utc
+            .with_ymd_and_hms(2024, 9, 19, 18, 34, 15)
+            .unwrap()
+            .with_nanosecond(250000000)
+            .unwrap();
+
+        let variables = TextGenerationPromptVariables::new(
+            "baibot",
+            "gpt-4o",
+            now_utc,
+            Some(conversation_start_time_utc),
+        );

        assert_eq!(
            variables.map.get("baibot_name"),
@@ -66,9 +93,13 @@ mod tests {
            variables.map.get("baibot_now_utc"),
            Some(&format_utc_time(now_utc))
        );
+        assert_eq!(
+            variables.map.get("baibot_conversation_start_time_utc"),
+            Some(&format_utc_time(conversation_start_time_utc))
+        );

-        let prompt = "Hello, I'm {{ baibot_name }} using {{ baibot_model_id }}. The date/time now is {{ baibot_now_utc }}.";
-        let expected = "Hello, I'm baibot using gpt-4o. The date/time now is 2024-09-20 (Friday), 18:34:15 UTC.";
+        let prompt = "Hello, I'm {{ baibot_name }} using {{ baibot_model_id }}. The date/time now is {{ baibot_now_utc }} and this conversation started at {{ baibot_conversation_start_time_utc }}.";
+        let expected = "Hello, I'm baibot using gpt-4o. The date/time now is 2024-09-20 (Friday), 18:34:15 UTC and this conversation started at 2024-09-19 (Thursday), 18:34:15 UTC.";

        assert_eq!(variables.format(prompt), expected);
    }
--- a/src/agent/provider/openai/controller.rs
+++ b/src/agent/provider/openai/controller.rs
@@ -63,6 +63,7 @@ impl ControllerTrait for Controller {
        let messages = vec![LLMMessage {
            author: LLMAuthor::User,
            message_text: "Hello!".to_string(),
+            timestamp: chrono::Utc::now(),
        }];

        let conversation = LLMConversation { messages };
@@ -99,6 +100,7 @@ impl ControllerTrait for Controller {
            Some(LLMMessage {
                author: LLMAuthor::Prompt,
                message_text: prompt_text,
+                timestamp: chrono::Utc::now(),
            })
        };

--- a/src/agent/provider/openai_compat/controller.rs
+++ b/src/agent/provider/openai_compat/controller.rs
@@ -61,6 +61,7 @@ impl ControllerTrait for Controller {
        let messages = vec![LLMMessage {
            author: LLMAuthor::User,
            message_text: "Hello!".to_string(),
+            timestamp: chrono::Utc::now(),
        }];

        let conversation = LLMConversation { messages };
@@ -97,6 +98,7 @@ impl ControllerTrait for Controller {
            Some(LLMMessage {
                author: LLMAuthor::Prompt,
                message_text: prompt_text,
+                timestamp: chrono::Utc::now(),
            })
        };

--- a/src/controller/chat_completion/mod.rs
+++ b/src/controller/chat_completion/mod.rs
@@ -492,6 +492,7 @@ async fn handle_stage_text_generation(
            .text_generation_model_id()
            .unwrap_or("unknown-model".to_owned()),
        chrono::Utc::now(),
+        conversation.start_time(),
    );

    let params = TextGenerationParams {
--- a/src/controller/image/prompt.rs
+++ b/src/controller/image/prompt.rs
@@ -46,6 +46,8 @@ mod tests {

    #[test]
    fn test_build_prompt() {
+        let timestamp = chrono::Utc::now();
+
        let test_cases = vec![
            // Simple case
            TestCase {
@@ -59,6 +61,7 @@ mod tests {
                messages: vec![Message {
                    author: Author::User,
                    message_text: "Must be blue".to_owned(),
+                    timestamp,
                }],
                expected_prompt: "Generate a picture of a dog\nOther criteria:\n- Must be blue",
            },
@@ -68,14 +71,17 @@ mod tests {
                messages: vec![Message {
                    author: Author::User,
                    message_text: "Must be blue".to_owned(),
+                    timestamp,
                },
                Message {
                    author: Author::Assistant,
                    message_text: "Whatever".to_owned(),
+                    timestamp,
                },
                Message {
                    author: Author::User,
                    message_text: "Must be 3-legged.\nMust be flying.".to_owned(),
+                    timestamp,
                }],
                expected_prompt: "Generate a picture of an elephant\nOther criteria:\n- Must be blue\n- Must be 3-legged.. Must be flying.",
            },
@@ -85,18 +91,22 @@ mod tests {
                messages: vec![Message {
                    author: Author::User,
                    message_text: "Must be blue".to_owned(),
+                    timestamp,
                },
                Message {
                    author: Author::Assistant,
                    message_text: "Whatever".to_owned(),
+                    timestamp,
                },
                Message {
                    author: Author::User,
                    message_text: "Again".to_owned(),
+                    timestamp,
                },
                Message {
                    author: Author::User,
                    message_text: "again".to_owned(),
+                    timestamp,
                }],
                expected_prompt: "Generate a picture of a grizzly bear\nOther criteria:\n- Must be blue",
            },
--- a/src/conversation/llm/entity.rs
+++ b/src/conversation/llm/entity.rs
@@ -1,3 +1,5 @@
+use chrono::{DateTime, Utc};
+
 #[derive(Debug, Clone, PartialEq)]
 pub enum Author {
    Prompt,
@@ -9,6 +11,7 @@ pub enum Author {
 pub struct Message {
    pub author: Author,
    pub message_text: String,
+    pub timestamp: DateTime<Utc>,
 }

 #[derive(Debug)]
@@ -52,39 +55,59 @@ impl Conversation {
            messages: new_messages,
        }
    }
+
+    pub fn start_time(&self) -> Option<DateTime<Utc>> {
+        self.messages.first().map(|message| message.timestamp)
+    }
 }

 #[cfg(test)]
 mod tests {
    use super::*;
+    use chrono::{TimeZone, Utc};

    #[test]
    fn combine_consecutive_messages() {
+        let timestamp_1 = Utc.with_ymd_and_hms(2024, 9, 20, 18, 34, 15).unwrap();
+
+        let timestamp_2 = Utc.with_ymd_and_hms(2024, 9, 21, 18, 34, 15).unwrap();
+
+        let timestamp_3 = Utc.with_ymd_and_hms(2024, 9, 22, 18, 34, 15).unwrap();
+
        let conversation = Conversation {
            messages: vec![
+                // User's turn
                Message {
                    author: Author::User,
                    message_text: "Hello".to_string(),
+                    timestamp: timestamp_1,
                },
                Message {
                    author: Author::User,
                    message_text: "How are you?".to_string(),
+                    timestamp: timestamp_2,
                },
                Message {
                    author: Author::User,
                    message_text: "I'm OK, btw.".to_string(),
+                    timestamp: timestamp_3,
                },
+                // Assistant's turn
                Message {
                    author: Author::Assistant,
                    message_text: "Hi there!".to_string(),
+                    timestamp: timestamp_2,
                },
                Message {
                    author: Author::Assistant,
                    message_text: "I'm doing well, thank you.".to_string(),
+                    timestamp: timestamp_3,
                },
+                // User's turn
                Message {
                    author: Author::User,
                    message_text: "That's great!".to_string(),
+                    timestamp: timestamp_3,
                },
            ],
        };
@@ -97,12 +120,17 @@ mod tests {
            conversation.messages[0].message_text,
            "Hello\nHow are you?\nI'm OK, btw."
        );
+        assert_eq!(conversation.messages[0].timestamp, timestamp_1);
+
        assert_eq!(conversation.messages[1].author, Author::Assistant);
        assert_eq!(
            conversation.messages[1].message_text,
            "Hi there!\nI'm doing well, thank you."
        );
+        assert_eq!(conversation.messages[1].timestamp, timestamp_2);
+
        assert_eq!(conversation.messages[2].author, Author::User);
        assert_eq!(conversation.messages[2].message_text, "That's great!");
+        assert_eq!(conversation.messages[2].timestamp, timestamp_3);
    }
 }
--- a/src/conversation/llm/tests.rs
+++ b/src/conversation/llm/tests.rs
@@ -15,6 +15,7 @@ fn test_messages_by_the_bot_are_identified_correctly() {
        message_type: super::super::matrix::MatrixMessageType::Text,
        message_text: "Hello!".to_owned(),
        mentioned_users: vec![],
+        timestamp: chrono::Utc::now(),
    };

    let llm_message = convert_matrix_message_to_llm_message(&matrix_message, &bot_user_id).unwrap();
@@ -39,6 +40,7 @@ fn test_notice_messages_by_bot_with_speech_to_text_prefix_are_cleaned_up_and_con
        message_type: super::super::matrix::MatrixMessageType::Notice,
        message_text,
        mentioned_users: vec![],
+        timestamp: chrono::Utc::now(),
    };

    let llm_message = convert_matrix_message_to_llm_message(&matrix_message, &bot_user_id).unwrap();
@@ -62,6 +64,7 @@ fn test_notice_error_messages_by_bot_are_ignored() {
        message_type: super::super::matrix::MatrixMessageType::Notice,
        message_text,
        mentioned_users: vec![],
+        timestamp: chrono::Utc::now(),
    };

    let llm_message = convert_matrix_message_to_llm_message(&matrix_message, &bot_user_id);
@@ -86,6 +89,7 @@ fn test_other_notice_messages_by_the_bot_are_ignored() {
        message_type: super::super::matrix::MatrixMessageType::Notice,
        message_text: message_text.to_owned(),
        mentioned_users: vec![],
+        timestamp: chrono::Utc::now(),
    };

    let llm_message = convert_matrix_message_to_llm_message(&matrix_message, &bot_user_id);
--- a/src/conversation/llm/tokenization.rs
+++ b/src/conversation/llm/tokenization.rs
@@ -86,6 +86,7 @@ pub mod test {
        let message = super::Message {
            author: super::Author::User,
            message_text: "Hello there!".to_owned(),
+            timestamp: chrono::Utc::now(),
        };

        let tokens = super::calculate_token_size_for_message(&bpe, model, &message);
@@ -104,6 +105,7 @@ pub mod test {
        let prompt = super::Message {
            author: super::Author::Prompt,
            message_text: "You are a bot!".to_owned(),
+            timestamp: chrono::Utc::now(),
        };
        let prompt_length = 10;

@@ -117,6 +119,7 @@ pub mod test {
        let first = super::Message {
            author: super::Author::User,
            message_text: "Hello there!".to_owned(),
+            timestamp: chrono::Utc::now(),
        };
        let first_length = 8;

@@ -130,6 +133,7 @@ pub mod test {
        let second = super::Message {
            author: super::Author::Assistant,
            message_text: "Hello!".to_owned(),
+            timestamp: chrono::Utc::now(),
        };
        let second_length = 7;

@@ -144,6 +148,7 @@ pub mod test {
            author: super::Author::User,
            message_text: "This is the 3rd message in this conversation. It shall be preserved."
                .to_owned(),
+            timestamp: chrono::Utc::now(),
        };
        let third_length = 21;

@@ -157,6 +162,7 @@ pub mod test {
        let forth = super::Message {
            author: super::Author::Assistant,
            message_text: "This is yet another message that shall be preserved.".to_owned(),
+            timestamp: chrono::Utc::now(),
        };
        let forth_length = 15;

@@ -201,6 +207,7 @@ pub mod test {
        let prompt = super::Message {
            author: super::Author::User,
            message_text: "あなたはボットです。".to_owned(),
+            timestamp: chrono::Utc::now(),
        };
        let prompt_length = 14;

@@ -214,6 +221,7 @@ pub mod test {
        let first = super::Message {
            author: super::Author::User,
            message_text: "こんにちは!".to_owned(),
+            timestamp: chrono::Utc::now(),
        };
        let first_length = 7;

@@ -227,6 +235,7 @@ pub mod test {
        let second = super::Message {
            author: super::Author::Assistant,
            message_text: "こんにちは。今日は元気ですか。".to_owned(),
+            timestamp: chrono::Utc::now(),
        };
        let second_length = 15;

@@ -240,6 +249,7 @@ pub mod test {
        let third = super::Message {
            author: super::Author::User,
            message_text: "これは第3のメッセージなので、保存されます。".to_owned(),
+            timestamp: chrono::Utc::now(),
        };
        let third_length = 22;

@@ -253,6 +263,7 @@ pub mod test {
        let forth = super::Message {
            author: super::Author::Assistant,
            message_text: "これはもう一つの保存されますメッセージです。".to_owned(),
+            timestamp: chrono::Utc::now(),
        };
        let forth_length = 21;

--- a/src/conversation/llm/utils.rs
+++ b/src/conversation/llm/utils.rs
@@ -17,19 +17,30 @@ pub fn convert_matrix_message_to_llm_message(

 fn convert_bot_message(matrix_message: &MatrixMessage) -> Option<Message> {
    match matrix_message.message_type {
-        MatrixMessageType::Text => convert_bot_text_message(&matrix_message.message_text),
-        MatrixMessageType::Notice => convert_bot_notice_message(&matrix_message.message_text),
+        MatrixMessageType::Text => {
+            convert_bot_text_message(&matrix_message.message_text, &matrix_message.timestamp)
+        }
+        MatrixMessageType::Notice => {
+            convert_bot_notice_message(&matrix_message.message_text, &matrix_message.timestamp)
+        }
    }
 }

-fn convert_bot_text_message(text: &str) -> Option<Message> {
+fn convert_bot_text_message(
+    text: &str,
+    timestamp: &chrono::DateTime<chrono::Utc>,
+) -> Option<Message> {
    Some(Message {
        author: Author::Assistant,
        message_text: text.to_owned(),
+        timestamp: timestamp.to_owned(),
    })
 }

-fn convert_bot_notice_message(text: &str) -> Option<Message> {
+fn convert_bot_notice_message(
+    text: &str,
+    timestamp: &chrono::DateTime<chrono::Utc>,
+) -> Option<Message> {
    // Notice messages sent by the bot are usually transcriptions of previous messages sent by the user.
    // Such transcriptions are prefixed with an emoji and blockquoted.
    // If we find a notice that doesn't match this pattern, we skip it.
@@ -42,6 +53,7 @@ fn convert_bot_notice_message(text: &str) -> Option<Message> {
        return Some(Message {
            author: Author::User,
            message_text: text.to_owned(),
+            timestamp: timestamp.to_owned(),
        });
    }

@@ -52,5 +64,6 @@ fn convert_user_message(matrix_message: &MatrixMessage) -> Option<Message> {
    Some(Message {
        author: Author::User,
        message_text: matrix_message.message_text.clone(),
+        timestamp: matrix_message.timestamp.to_owned(),
    })
 }
--- a/src/conversation/matrix/entity.rs
+++ b/src/conversation/matrix/entity.rs
@@ -1,3 +1,4 @@
+use chrono::{DateTime, Utc};
 use regex::Regex;

 use mxlink::matrix_sdk::ruma::OwnedUserId;
@@ -8,6 +9,7 @@ pub struct MatrixMessage {
    pub message_type: MatrixMessageType,
    pub message_text: String,
    pub mentioned_users: Vec<OwnedUserId>,
+    pub timestamp: DateTime<Utc>,
 }

 #[derive(Clone)]
--- a/src/conversation/matrix/utils/mod.rs
+++ b/src/conversation/matrix/utils/mod.rs
@@ -234,6 +234,13 @@ pub fn convert_matrix_native_event_to_matrix_message(
        text
    };

+    let timestamp = chrono::DateTime::<chrono::Utc>::from(
+        matrix_native_event
+            .origin_server_ts()
+            .to_system_time()
+            .unwrap_or_else(std::time::SystemTime::now),
+    );
+
    let mentioned_users = room_message
        .mentions
        .map(|m| m.user_ids.iter().map(|u| u.to_owned()).collect())
@@ -248,6 +255,7 @@ pub fn convert_matrix_native_event_to_matrix_message(
        },
        message_text: text,
        mentioned_users,
+        timestamp,
    })
 }

--- a/src/conversation/matrix/utils/tests.rs
+++ b/src/conversation/matrix/utils/tests.rs
@@ -1,3 +1,5 @@
+use chrono::{TimeZone, Utc};
+
 use mxlink::matrix_sdk::ruma::OwnedUserId;

 use crate::conversation::matrix::{
@@ -11,11 +13,14 @@ fn is_message_from_allowed_sender() {
    let allowed_user_id = OwnedUserId::try_from("@user.someone:example.com").unwrap();
    let unallowed_user_id = OwnedUserId::try_from("@another:example.com").unwrap();

+    let timestamp = Utc.with_ymd_and_hms(2024, 9, 20, 18, 34, 15).unwrap();
+
    let bot_message = MatrixMessage {
        sender_id: bot_user_id.to_owned(),
        message_type: MatrixMessageType::Text,
        message_text: "Hello!".to_owned(),
        mentioned_users: vec![],
+        timestamp,
    };

    let allowed_user_message = MatrixMessage {
@@ -23,6 +28,7 @@ fn is_message_from_allowed_sender() {
        message_type: MatrixMessageType::Text,
        message_text: "Hello!".to_owned(),
        mentioned_users: vec![],
+        timestamp,
    };

    let unallowed_user_message = MatrixMessage {
@@ -30,6 +36,7 @@ fn is_message_from_allowed_sender() {
        message_type: MatrixMessageType::Text,
        message_text: "Hello!".to_owned(),
        mentioned_users: vec![],
+        timestamp,
    };

    let parsed_regex = match mxidwc::parse_pattern("@user.*:example.com") {
@@ -77,11 +84,14 @@ async fn process_matrix_messages() {
    let allowed_user_id = OwnedUserId::try_from("@user.someone:example.com").unwrap();
    let unallowed_user_id = OwnedUserId::try_from("@another:example.com").unwrap();

+    let timestamp = Utc.with_ymd_and_hms(2024, 9, 20, 18, 34, 15).unwrap();
+
    let allowed_user_message = MatrixMessage {
        sender_id: allowed_user_id.to_owned(),
        message_type: MatrixMessageType::Text,
        message_text: "Hello from the user!".to_owned(),
        mentioned_users: vec![],
+        timestamp,
    };

    let allowed_user_message_with_prefix = MatrixMessage {
@@ -89,6 +99,7 @@ async fn process_matrix_messages() {
        message_type: MatrixMessageType::Text,
        message_text: "!bai Hello from the user!".to_owned(),
        mentioned_users: vec![],
+        timestamp,
    };

    let allowed_user_message_with_prefix_no_space = MatrixMessage {
@@ -96,6 +107,7 @@ async fn process_matrix_messages() {
        message_type: MatrixMessageType::Text,
        message_text: "!baiHello from the user!".to_owned(),
        mentioned_users: vec![],
+        timestamp,
    };

    let allowed_user_message_with_prefix_full_width_space = MatrixMessage {
@@ -103,6 +115,7 @@ async fn process_matrix_messages() {
        message_type: MatrixMessageType::Text,
        message_text: "!bai　Hello from the user!".to_owned(),
        mentioned_users: vec![],
+        timestamp,
    };

    let bot_message = MatrixMessage {
@@ -110,6 +123,7 @@ async fn process_matrix_messages() {
        message_type: MatrixMessageType::Text,
        message_text: "Hello from the bot!".to_owned(),
        mentioned_users: vec![],
+        timestamp,
    };

    let allowed_user_message_with_bot_mention = MatrixMessage {
@@ -117,6 +131,7 @@ async fn process_matrix_messages() {
        message_type: MatrixMessageType::Text,
        message_text: "@baibot: Hello from the user!".to_owned(),
        mentioned_users: vec![bot_user_id.to_owned()],
+        timestamp,
    };

    // The message text is the same as above - it mentions the bot, but the actually-mentioned user is another user.
@@ -125,6 +140,7 @@ async fn process_matrix_messages() {
        message_type: MatrixMessageType::Text,
        message_text: allowed_user_message_with_bot_mention.message_text.clone(),
        mentioned_users: vec![allowed_user_id.to_owned()],
+        timestamp,
    };

    let unallowed_user_message = MatrixMessage {
@@ -132,6 +148,7 @@ async fn process_matrix_messages() {
        message_type: MatrixMessageType::Text,
        message_text: "Hello from an unallowed user!".to_owned(),
        mentioned_users: vec![],
+        timestamp,
    };

    let parsed_regex = match mxidwc::parse_pattern("@user.*:example.com") {