feat(discord): add mention_only config for @-mention trigger (#529)

When mention_only is true, the bot only responds to messages that
@-mention the bot. Other messages in the guild are silently ignored.
Also strips the bot mention from content before processing.

Co-authored-by: Will Sarg <12886992+willsarg@users.noreply.github.com>

src/channels/discord.rs

@@ -11,6 +11,7 @@ pub struct DiscordChannel {
     guild_id: Option<String>,
     allowed_users: Vec<String>,
     listen_to_bots: bool,
+    mention_only: bool,
     client: reqwest::Client,
     typing_handle: std::sync::Mutex<Option<tokio::task::JoinHandle<()>>>,
 }
@@ -21,12 +22,14 @@ impl DiscordChannel {
         guild_id: Option<String>,
         allowed_users: Vec<String>,
         listen_to_bots: bool,
+        mention_only: bool,
     ) -> Self {
         Self {
             bot_token,
             guild_id,
             allowed_users,
             listen_to_bots,
+            mention_only,
             client: reqwest::Client::new(),
             typing_handle: std::sync::Mutex::new(None),
         }
@@ -343,6 +346,22 @@ impl Channel for DiscordChannel {
                         continue;
                     }
 
+                    // Skip messages that don't @-mention the bot (when mention_only is enabled)
+                    if self.mention_only {
+                        let mention_tag = format!("<@{bot_user_id}>");
+                        if !content.contains(&mention_tag) {
+                            continue;
+                        }
+                    }
+
+                    // Strip the bot mention from content so the agent sees clean text
+                    let clean_content = if self.mention_only {
+                        let mention_tag = format!("<@{bot_user_id}>");
+                        content.replace(&mention_tag, "").trim().to_string()
+                    } else {
+                        content.to_string()
+                    };
+
                     let message_id = d.get("id").and_then(|i| i.as_str()).unwrap_or("");
                     let channel_id = d.get("channel_id").and_then(|c| c.as_str()).unwrap_or("").to_string();
 
@@ -354,7 +373,7 @@ impl Channel for DiscordChannel {
                         },
                         sender: author_id.to_string(),
                         reply_to: channel_id.clone(),
-                        content: content.to_string(),
+                        content: clean_content,
                         channel: "discord".to_string(),
                         timestamp: std::time::SystemTime::now()
                             .duration_since(std::time::UNIX_EPOCH)
@@ -424,7 +443,7 @@ mod tests {
 
     #[test]
     fn discord_channel_name() {
-        let ch = DiscordChannel::new("fake".into(), None, vec![], false);
+        let ch = DiscordChannel::new("fake".into(), None, vec![], false, false);
         assert_eq!(ch.name(), "discord");
     }
 
@@ -445,21 +464,27 @@ mod tests {
 
     #[test]
     fn empty_allowlist_denies_everyone() {
-        let ch = DiscordChannel::new("fake".into(), None, vec![], false);
+        let ch = DiscordChannel::new("fake".into(), None, vec![], false, false);
         assert!(!ch.is_user_allowed("12345"));
         assert!(!ch.is_user_allowed("anyone"));
     }
 
     #[test]
     fn wildcard_allows_everyone() {
-        let ch = DiscordChannel::new("fake".into(), None, vec!["*".into()], false);
+        let ch = DiscordChannel::new("fake".into(), None, vec!["*".into()], false, false);
         assert!(ch.is_user_allowed("12345"));
         assert!(ch.is_user_allowed("anyone"));
     }
 
     #[test]
     fn specific_allowlist_filters() {
-        let ch = DiscordChannel::new("fake".into(), None, vec!["111".into(), "222".into()], false);
+        let ch = DiscordChannel::new(
+            "fake".into(),
+            None,
+            vec!["111".into(), "222".into()],
+            false,
+            false,
+        );
         assert!(ch.is_user_allowed("111"));
         assert!(ch.is_user_allowed("222"));
         assert!(!ch.is_user_allowed("333"));
@@ -468,7 +493,7 @@ mod tests {
 
     #[test]
     fn allowlist_is_exact_match_not_substring() {
-        let ch = DiscordChannel::new("fake".into(), None, vec!["111".into()], false);
+        let ch = DiscordChannel::new("fake".into(), None, vec!["111".into()], false, false);
         assert!(!ch.is_user_allowed("1111"));
         assert!(!ch.is_user_allowed("11"));
         assert!(!ch.is_user_allowed("0111"));
@@ -476,20 +501,26 @@ mod tests {
 
     #[test]
     fn allowlist_empty_string_user_id() {
-        let ch = DiscordChannel::new("fake".into(), None, vec!["111".into()], false);
+        let ch = DiscordChannel::new("fake".into(), None, vec!["111".into()], false, false);
         assert!(!ch.is_user_allowed(""));
     }
 
     #[test]
     fn allowlist_with_wildcard_and_specific() {
-        let ch = DiscordChannel::new("fake".into(), None, vec!["111".into(), "*".into()], false);
+        let ch = DiscordChannel::new(
+            "fake".into(),
+            None,
+            vec!["111".into(), "*".into()],
+            false,
+            false,
+        );
         assert!(ch.is_user_allowed("111"));
         assert!(ch.is_user_allowed("anyone_else"));
     }
 
     #[test]
     fn allowlist_case_sensitive() {
-        let ch = DiscordChannel::new("fake".into(), None, vec!["ABC".into()], false);
+        let ch = DiscordChannel::new("fake".into(), None, vec!["ABC".into()], false, false);
         assert!(ch.is_user_allowed("ABC"));
         assert!(!ch.is_user_allowed("abc"));
         assert!(!ch.is_user_allowed("Abc"));
@@ -664,14 +695,14 @@ mod tests {
 
     #[test]
     fn typing_handle_starts_as_none() {
-        let ch = DiscordChannel::new("fake".into(), None, vec![], false);
+        let ch = DiscordChannel::new("fake".into(), None, vec![], false, false);
         let guard = ch.typing_handle.lock().unwrap();
         assert!(guard.is_none());
     }
 
     #[tokio::test]
     async fn start_typing_sets_handle() {
-        let ch = DiscordChannel::new("fake".into(), None, vec![], false);
+        let ch = DiscordChannel::new("fake".into(), None, vec![], false, false);
         let _ = ch.start_typing("123456").await;
         let guard = ch.typing_handle.lock().unwrap();
         assert!(guard.is_some());
@@ -679,7 +710,7 @@ mod tests {
 
     #[tokio::test]
     async fn stop_typing_clears_handle() {
-        let ch = DiscordChannel::new("fake".into(), None, vec![], false);
+        let ch = DiscordChannel::new("fake".into(), None, vec![], false, false);
         let _ = ch.start_typing("123456").await;
         let _ = ch.stop_typing("123456").await;
         let guard = ch.typing_handle.lock().unwrap();
@@ -688,14 +719,14 @@ mod tests {
 
     #[tokio::test]
     async fn stop_typing_is_idempotent() {
-        let ch = DiscordChannel::new("fake".into(), None, vec![], false);
+        let ch = DiscordChannel::new("fake".into(), None, vec![], false, false);
         assert!(ch.stop_typing("123456").await.is_ok());
         assert!(ch.stop_typing("123456").await.is_ok());
     }
 
     #[tokio::test]
     async fn start_typing_replaces_existing_task() {
-        let ch = DiscordChannel::new("fake".into(), None, vec![], false);
+        let ch = DiscordChannel::new("fake".into(), None, vec![], false, false);
         let _ = ch.start_typing("111").await;
         let _ = ch.start_typing("222").await;
         let guard = ch.typing_handle.lock().unwrap();

src/channels/mod.rs

@@ -620,6 +620,7 @@ pub async fn doctor_channels(config: Config) -> Result<()> {
                 dc.guild_id.clone(),
                 dc.allowed_users.clone(),
                 dc.listen_to_bots,
+                dc.mention_only,
             )),
         ));
     }
@@ -906,6 +907,7 @@ pub async fn start_channels(config: Config) -> Result<()> {
             dc.guild_id.clone(),
             dc.allowed_users.clone(),
             dc.listen_to_bots,
+            dc.mention_only,
         )));
     }
 

src/config/mod.rs

@@ -37,6 +37,7 @@ mod tests {
             guild_id: Some("123".into()),
             allowed_users: vec![],
             listen_to_bots: false,
+            mention_only: false,
         };
 
         let lark = LarkConfig {

src/config/schema.rs

@@ -1319,6 +1319,10 @@ pub struct DiscordConfig {
     /// The bot still ignores its own messages to prevent feedback loops.
     #[serde(default)]
     pub listen_to_bots: bool,
+    /// When true, only respond to messages that @-mention the bot.
+    /// Other messages in the guild are silently ignored.
+    #[serde(default)]
+    pub mention_only: bool,
 }
 
 #[derive(Debug, Clone, Serialize, Deserialize)]
@@ -2392,6 +2396,7 @@ tool_dispatcher = "xml"
             guild_id: Some("12345".into()),
             allowed_users: vec![],
             listen_to_bots: false,
+            mention_only: false,
         };
         let json = serde_json::to_string(&dc).unwrap();
         let parsed: DiscordConfig = serde_json::from_str(&json).unwrap();
@@ -2406,6 +2411,7 @@ tool_dispatcher = "xml"
             guild_id: None,
             allowed_users: vec![],
             listen_to_bots: false,
+            mention_only: false,
         };
         let json = serde_json::to_string(&dc).unwrap();
         let parsed: DiscordConfig = serde_json::from_str(&json).unwrap();

src/cron/scheduler.rs

@@ -245,6 +245,7 @@ async fn deliver_if_configured(config: &Config, job: &CronJob, output: &str) ->
                 dc.guild_id.clone(),
                 dc.allowed_users.clone(),
                 dc.listen_to_bots,
+                dc.mention_only,
             );
             channel.send(output, target).await?;
         }

src/onboard/wizard.rs

@@ -2586,6 +2586,7 @@ fn setup_channels() -> Result<ChannelsConfig> {
                     guild_id: if guild.is_empty() { None } else { Some(guild) },
                     allowed_users,
                     listen_to_bots: false,
+                    mention_only: false,
                 });
             }
             2 => {