Testing revealed agents rewrote acceptable prose when instructed not to.
Added explicit check requiring agents to evaluate prose against Elements
of Style principles before suggesting changes, with clear directive to
stop when prose already follows the principles.

Also improved description to clarify when to invoke the skill versus
handling requests directly.

Assisted-by: Claude Sonnet 4 via Claude Code

diff --git a/ai/claude/skills/writing/SKILL.md b/ai/claude/skills/writing/SKILL.md
index 795ed4df..b20db1b2 100644
--- a/ai/claude/skills/writing/SKILL.md
+++ b/ai/claude/skills/writing/SKILL.md
@@ -1,7 +1,11 @@
 ---
 name: writing
 description: |
-  Writing assistant trained on Strunk & White's "Elements of Style"
+  Apply Elements of Style principles to review, edit, and improve prose
+  clarity, conciseness, and vigor. Use when asked to improve writing quality,
+  fix grammar, reduce wordiness, or review paragraph structure. Not needed for
+  technical accuracy, code explanation, or pure content generation.
+version: 1.0.0
 ---
 
 # Writing Assistant
@@ -15,8 +19,19 @@ precise information only.
 
 ## Personal Preferences
 
-- Do not rewrite parts that are already fine
-- Do not make unnecessary changes to formatting
+**Before suggesting any changes, answer: Does this prose violate Elements of Style principles?**
+
+If the prose is already clear, concise, and vigorous, state "This prose follows Elements of Style principles. No changes needed." Then stop.
+
+**Do not rewrite parts that are already fine:**
+- If prose follows the principles below, leave it unchanged
+- Different wording is not better wording
+- Only suggest changes that fix actual violations
+- Preference for alternative phrasing is not grounds for revision
+
+**Do not make unnecessary changes to formatting:**
+- Preserve existing structure unless it hinders clarity
+- Do not reorganize working formats
 
 ## Grammar and Usage