diff --git a/plugin/skills/spike/SKILL.md b/plugin/skills/spike/SKILL.md
index 537eb1b..45de101 100644
--- a/plugin/skills/spike/SKILL.md
+++ b/plugin/skills/spike/SKILL.md
@@ -1,6 +1,6 @@
 ---
 description: Find Faultline error groups that have been active recently, ranked by occurrence count.
-argument-hint: [duration like 1h, 4h, 1d — default 1h]
+argument-hint: "[duration like 1h, 4h, 1d — default 1h]"
 ---
 
 Surface error groups that are firing right now.
diff --git a/plugin/skills/stats/SKILL.md b/plugin/skills/stats/SKILL.md
index b92d54f..476bae7 100644
--- a/plugin/skills/stats/SKILL.md
+++ b/plugin/skills/stats/SKILL.md
@@ -1,6 +1,6 @@
 ---
 description: Show time-bucketed error occurrence counts for the Faultline instance.
-argument-hint: [period]
+argument-hint: "[period]"
 ---
 
 Show error volume over a time window using the `error_stats` MCP tool.
diff --git a/plugin/skills/trace/SKILL.md b/plugin/skills/trace/SKILL.md
index ef4b05f..24e00f3 100644
--- a/plugin/skills/trace/SKILL.md
+++ b/plugin/skills/trace/SKILL.md
@@ -1,6 +1,6 @@
 ---
 description: Inspect Faultline APM traces — slow endpoints or a specific request's span breakdown.
-argument-hint: [endpoint | trace-id]
+argument-hint: "[endpoint | trace-id]"
 ---
 
 Investigate APM traces using `list_traces` and `get_trace`.