Create default gooseignore file when missing

Signed-off-by: Matt Joyce <matt.joyce@gmail.com>

Author: mattjoyce

crates/goose-mcp/src/developer/rmcp_developer.rs

@@ -121,6 +121,8 @@ pub struct PromptArgumentTemplate {
 // Embeds the prompts directory to the build
 static PROMPTS_DIR: Dir = include_dir!("$CARGO_MANIFEST_DIR/src/developer/prompts");
 
+const DEFAULT_GOOSEIGNORE_CONTENT: &str = "**/.env\n**/.env.*\n**/secrets.*\n";
+
 /// Loads prompt files from the embedded PROMPTS_DIR and returns a HashMap of prompts.
 /// Ensures that each prompt name is unique.
 fn load_prompt_files() -> HashMap<String, Prompt> {
@@ -1295,12 +1297,34 @@ impl DeveloperServer {
             .map(|strategy| strategy.config_dir().join(".gooseignore"))
             .ok();
 
-        let has_local_ignore = local_ignore_path.is_file();
+        let mut has_local_ignore = local_ignore_path.is_file();
         let has_global_ignore = global_ignore_path
             .as_ref()
             .map(|p| p.is_file())
             .unwrap_or(false);
 
+        if !has_local_ignore && !has_global_ignore {
+            match std::fs::write(&local_ignore_path, DEFAULT_GOOSEIGNORE_CONTENT) {
+                Ok(_) => {
+                    has_local_ignore = true;
+                }
+                Err(err) => {
+                    tracing::warn!(
+                        "Failed to create default .gooseignore at {}: {}",
+                        local_ignore_path.display(),
+                        err
+                    );
+
+                    for pattern in DEFAULT_GOOSEIGNORE_CONTENT.lines() {
+                        if pattern.is_empty() {
+                            continue;
+                        }
+                        let _ = builder.add_line(None, pattern);
+                    }
+                }
+            }
+        }
+
         if has_global_ignore {
             let _ = builder.add(global_ignore_path.as_ref().unwrap());
         }
@@ -1309,12 +1333,6 @@ impl DeveloperServer {
             let _ = builder.add(&local_ignore_path);
         }
 
-        if !has_local_ignore && !has_global_ignore {
-            let _ = builder.add_line(None, "**/.env");
-            let _ = builder.add_line(None, "**/.env.*");
-            let _ = builder.add_line(None, "**/secrets.*");
-        }
-
         builder.build().expect("Failed to build ignore patterns")
     }
 
@@ -3236,6 +3254,14 @@ mod tests {
         // Don't create any ignore files
         let server = create_test_server();
 
+        let gooseignore_path = temp_dir.path().join(".gooseignore");
+        assert!(
+            gooseignore_path.exists(),
+            ".gooseignore should be created by default"
+        );
+        let default_contents = fs::read_to_string(gooseignore_path).unwrap();
+        assert_eq!(default_contents, DEFAULT_GOOSEIGNORE_CONTENT);
+
         // Default patterns should be used
         assert!(
             server.is_ignored(Path::new(".env")),