diff --git a/src/channels/discord.rs b/src/channels/discord.rs
index fd5fe37..b9e4da6 100644
--- a/src/channels/discord.rs
+++ b/src/channels/discord.rs
@@ -87,13 +87,23 @@ impl Channel for DiscordChannel {
         let url = format!("https://discord.com/api/v10/channels/{channel_id}/messages");
         let body = json!({ "content": message });
 
-        self.client
+        let resp = self
+            .client
             .post(&url)
             .header("Authorization", format!("Bot {}", self.bot_token))
             .json(&body)
             .send()
             .await?;
 
+        if !resp.status().is_success() {
+            let status = resp.status();
+            let err = resp
+                .text()
+                .await
+                .unwrap_or_else(|e| format!("<failed to read response body: {e}>"));
+            anyhow::bail!("Discord send message failed ({status}): {err}");
+        }
+
         Ok(())
     }
 
diff --git a/src/channels/slack.rs b/src/channels/slack.rs
index d8b35cb..5a18cc3 100644
--- a/src/channels/slack.rs
+++ b/src/channels/slack.rs
@@ -58,13 +58,34 @@ impl Channel for SlackChannel {
             "text": message
         });
 
-        self.client
+        let resp = self
+            .client
             .post("https://slack.com/api/chat.postMessage")
             .bearer_auth(&self.bot_token)
             .json(&body)
             .send()
             .await?;
 
+        let status = resp.status();
+        let body = resp
+            .text()
+            .await
+            .unwrap_or_else(|e| format!("<failed to read response body: {e}>"));
+
+        if !status.is_success() {
+            anyhow::bail!("Slack chat.postMessage failed ({status}): {body}");
+        }
+
+        // Slack returns 200 for most app-level errors; check JSON "ok" field
+        let parsed: serde_json::Value = serde_json::from_str(&body).unwrap_or_default();
+        if parsed.get("ok") == Some(&serde_json::Value::Bool(false)) {
+            let err = parsed
+                .get("error")
+                .and_then(|e| e.as_str())
+                .unwrap_or("unknown");
+            anyhow::bail!("Slack chat.postMessage failed: {err}");
+        }
+
         Ok(())
     }
 
diff --git a/src/channels/telegram.rs b/src/channels/telegram.rs
index 1f9b202..49ff843 100644
--- a/src/channels/telegram.rs
+++ b/src/channels/telegram.rs
@@ -376,12 +376,22 @@ impl Channel for TelegramChannel {
             "parse_mode": "Markdown"
         });
 
-        self.client
+        let resp = self
+            .client
             .post(self.api_url("sendMessage"))
             .json(&body)
             .send()
             .await?;
 
+        if !resp.status().is_success() {
+            let status = resp.status();
+            let err = resp
+                .text()
+                .await
+                .unwrap_or_else(|e| format!("<failed to read response body: {e}>"));
+            anyhow::bail!("Telegram sendMessage failed ({status}): {err}");
+        }
+
         Ok(())
     }
 
diff --git a/src/util.rs b/src/util.rs
index 077ccad..9a218e7 100644
--- a/src/util.rs
+++ b/src/util.rs
@@ -1,4 +1,4 @@
-//! Utility functions for ZeroClaw.
+//! Utility functions for `ZeroClaw`.
 //!
 //! This module contains reusable helper functions used across the codebase.
 
@@ -58,7 +58,10 @@ mod tests {
     fn test_truncate_ascii_with_truncation() {
         // ASCII string longer than limit - truncates
         assert_eq!(truncate_with_ellipsis("hello world", 5), "hello...");
-        assert_eq!(truncate_with_ellipsis("This is a long message", 10), "This is a...");
+        assert_eq!(
+            truncate_with_ellipsis("This is a long message", 10),
+            "This is a..."
+        );
     }
 
     #[test]