fix: strip message wrapper in CLI session title generation (#7996)

Signed-off-by: Extra Small <littleshuai.bot@gmail.com>

crates/goose/src/providers/base.rs

@@ -715,9 +715,15 @@ pub trait Provider: Send + Sync {
         )
         .map_err(|e| ProviderError::ContextLengthExceeded(e.to_string()))?;
 
+        use super::cli_common::{
+            SESSION_NAME_BEGIN_MARKER, SESSION_NAME_END_MARKER, SESSION_NAME_SUFFIX,
+        };
         let user_text = format!(
-            "---BEGIN USER MESSAGES---\n{}\n---END USER MESSAGES---\n\nGenerate a short title for the above messages.",
+            "{}\n{}\n{}\n\n{}",
-            context.join("\n")
+            SESSION_NAME_BEGIN_MARKER,
+            context.join("\n"),
+            SESSION_NAME_END_MARKER,
+            SESSION_NAME_SUFFIX,
         );
         let message = Message::user().with_text(&user_text);
         let result = self

crates/goose/src/providers/cli_common.rs

@@ -3,6 +3,7 @@ use serde_json::Value;
 use super::base::{ProviderUsage, Usage};
 use super::errors::ProviderError;
 use crate::conversation::message::{Message, MessageContent};
+use crate::utils::safe_truncate;
 use rmcp::model::Role;
 
 pub(crate) fn extract_usage_tokens(usage_info: &Value) -> Usage {
@@ -32,6 +33,10 @@ pub(crate) fn error_from_event(provider_name: &str, parsed: &Value) -> ProviderE
     }
 }
 
+pub(crate) const SESSION_NAME_BEGIN_MARKER: &str = "---BEGIN USER MESSAGES---";
+pub(crate) const SESSION_NAME_END_MARKER: &str = "---END USER MESSAGES---";
+pub(crate) const SESSION_NAME_SUFFIX: &str = "Generate a short title for the above messages.";
+
 pub(crate) fn is_session_description_request(system: &str) -> bool {
     system.contains("four words or less") || system.contains("4 words or less")
 }
@@ -50,10 +55,29 @@ pub(crate) fn generate_simple_session_description(
             })
         })
         .map(|text| {
-            text.split_whitespace()
+            // Strip the wrapper added by generate_session_name so we get
+            // the actual user content.
+            let stripped = text
+                .strip_prefix(SESSION_NAME_BEGIN_MARKER)
+                .unwrap_or(text)
+                .trim_start_matches(['\n', '\r']);
+            let full_suffix = format!("{}\n\n{}", SESSION_NAME_END_MARKER, SESSION_NAME_SUFFIX);
+            let stripped = stripped
+                .strip_suffix(&full_suffix)
+                .or_else(|| stripped.strip_suffix(SESSION_NAME_END_MARKER))
+                .unwrap_or(stripped)
+                .trim();
+
+            let desc: String = stripped
+                .split_whitespace()
                 .take(4)
                 .collect::<Vec<_>>()
-                .join(" ")
+                .join(" ");
+            if desc.is_empty() {
+                "Simple task".to_string()
+            } else {
+                safe_truncate(&desc, 100)
+            }
         })
         .unwrap_or_else(|| "Simple task".to_string());