refactor: move system prompt filter to goose-providers

crates/goose-providers/src/text.rs

@@ -1,6 +1,31 @@
 use once_cell::sync::Lazy;
 use regex::Regex;
 
+pub fn filter_extensions_from_system_prompt(system: &str) -> String {
+    let Some(extensions_start) = system.find("# Extensions") else {
+        return system.to_string();
+    };
+
+    let Some(after_extensions) = system.get(extensions_start + 1..) else {
+        return system.to_string();
+    };
+
+    if let Some(next_section_pos) = after_extensions.find("\n# ") {
+        let Some(before) = system.get(..extensions_start) else {
+            return system.to_string();
+        };
+        let Some(after) = system.get(extensions_start + next_section_pos + 1..) else {
+            return system.to_string();
+        };
+        format!("{}{}", before.trim_end(), after)
+    } else {
+        system
+            .get(..extensions_start)
+            .map(|text| text.trim_end().to_string())
+            .unwrap_or_else(|| system.to_string())
+    }
+}
+
 #[derive(Debug, Default, PartialEq, Eq)]
 pub struct FilterOut {
     pub content: String,
@@ -270,6 +295,31 @@ fn contains_unquoted_gt(text: &str) -> bool {
 mod tests {
     use super::*;
 
+    #[test]
+    fn filters_extensions_section_from_system_prompt() {
+        let system =
+            "# Instructions\nBe helpful.\n\n# Extensions\nTool details.\n\n# Other\nKeep this.";
+        assert_eq!(
+            filter_extensions_from_system_prompt(system),
+            "# Instructions\nBe helpful.\n# Other\nKeep this."
+        );
+    }
+
+    #[test]
+    fn filters_trailing_extensions_section_from_system_prompt() {
+        let system = "# Instructions\nBe helpful.\n\n# Extensions\nTool details.";
+        assert_eq!(
+            filter_extensions_from_system_prompt(system),
+            "# Instructions\nBe helpful."
+        );
+    }
+
+    #[test]
+    fn preserves_system_prompt_without_extensions_section() {
+        let system = "# Instructions\nBe helpful.";
+        assert_eq!(filter_extensions_from_system_prompt(system), system);
+    }
+
     #[test]
     fn split_think_blocks_extracts_inline_reasoning() {
         assert_eq!(

crates/goose/src/providers/utils.rs

@@ -9,6 +9,7 @@ pub use goose_providers::image::ImageFormat;
 pub use goose_providers::json::{
     get_model, json_escape_control_chars_in_string, safely_parse_json, unescape_json_values,
 };
+pub use goose_providers::text::filter_extensions_from_system_prompt;
 use goose_types::ModelConfig;
 pub use goose_types::{
     extract_reasoning_effort, is_openai_responses_model, openai_reasoning_effort_for_thinking,
@@ -39,31 +40,6 @@ pub fn convert_image(image: &ImageContent, image_format: &ImageFormat) -> Value
     }
 }
 
-pub fn filter_extensions_from_system_prompt(system: &str) -> String {
-    let Some(extensions_start) = system.find("# Extensions") else {
-        return system.to_string();
-    };
-
-    let Some(after_extensions) = system.get(extensions_start + 1..) else {
-        return system.to_string();
-    };
-
-    if let Some(next_section_pos) = after_extensions.find("\n# ") {
-        let Some(before) = system.get(..extensions_start) else {
-            return system.to_string();
-        };
-        let Some(after) = system.get(extensions_start + next_section_pos + 1..) else {
-            return system.to_string();
-        };
-        format!("{}{}", before.trim_end(), after)
-    } else {
-        system
-            .get(..extensions_start)
-            .map(|s| s.trim_end().to_string())
-            .unwrap_or_else(|| system.to_string())
-    }
-}
-
 /// Check if a file is actually an image by examining its magic bytes
 fn is_image_file(path: &Path) -> bool {
     if let Ok(mut file) = std::fs::File::open(path) {