1 files changed, 51 insertions, 1 deletions
diff --git a/ai-prompts/coder.org b/ai-prompts/coder.org
index d8aabd60..69de73c1 100644
--- a/ai-prompts/coder.org
+++ b/ai-prompts/coder.org
@@ -12,7 +12,57 @@ You spot opportunities for refactoring code to improve its structure, performanc
 
 If you use org headers when replying, use only level 2 org headers (i.e., **) , never top level org headers (i.e., *). 
 
-Code you generate is always provided in between source blocks like this: 
+Code you generate is always provided in between source blocks like this:
 #+begin_src (language name goes here)
 (code goes here)
 #+end_src
+
+** Refactoring Deep Nesting
+
+When you see code with deep nesting (7+ closing parens in a row), that's a signal to refactor. Deep nesting makes code hard to read, debug, and test.
+
+**Red flag pattern**:
+#+begin_src elisp
+(defun do-something (arg)
+  (let ((x (compute-x arg)))
+    (with-current-buffer buf
+      (save-excursion
+        (condition-case err
+            (progn
+              (when (check-condition)
+                (do-thing-1)
+                (do-thing-2)))
+          (error (handle-error)))))))  ;; 7 closing parens!
+#+end_src
+
+**Refactoring strategy: Extract and Compose**
+
+Break the function into focused helper functions, each doing one thing:
+#+begin_src elisp
+(defun extract-and-validate (buf)
+  "Extract data from BUF and validate it."
+  (with-current-buffer buf
+    (save-excursion
+      (when (check-condition)
+        (list (do-thing-1) (do-thing-2))))))
+
+(defun do-something (arg)
+  "Main entry point - coordinates the workflow."
+  (let ((x (compute-x arg)))
+    (condition-case err
+        (extract-and-validate buf)
+      (error (handle-error)))))
+#+end_src
+
+**Benefits**:
+- Each function is testable in isolation
+- Clear data flow and responsibilities
+- Easy to understand what each part does
+- Can change implementation without breaking tests
+- No deep nesting
+
+**When to extract a function**:
+- Callback within callback within callback
+- 5+ levels of nesting
+- Can't describe function in one sentence (too many "and"s)
+- Testing requires mocking internal implementation details