diff --git a/docs/skill-creation/best-practices.mdx b/docs/skill-creation/best-practices.mdx
index 1040592..33d228d 100644
--- a/docs/skill-creation/best-practices.mdx
+++ b/docs/skill-creation/best-practices.mdx
@@ -162,6 +162,28 @@ This doesn't mean skills can't include specific details — output format templa
 
 These are reusable techniques for structuring skill content. Not every skill needs all of them — use the ones that fit your task.
 
+### Gotchas sections
+
+The highest-value content in many skills is a list of gotchas — environment-specific facts that defy reasonable assumptions. These aren't general advice ("handle errors appropriately") but concrete corrections to mistakes the agent will make without being told otherwise:
+
+````markdown
+## Gotchas
+
+- The `users` table uses soft deletes. Queries must include
+  `WHERE deleted_at IS NULL` or results will include deactivated accounts.
+- The user ID is `user_id` in the database, `uid` in the auth service,
+  and `accountId` in the billing API. All three refer to the same value.
+- The `/health` endpoint returns 200 as long as the web server is running,
+  even if the database connection is down. Use `/ready` to check full
+  service health.
+````
+
+Keep gotchas in `SKILL.md` where the agent reads them before encountering the situation. A separate reference file works if you tell the agent when to load it, but for non-obvious issues, the agent may not recognize the trigger.
+
+<Tip>
+When an agent makes a mistake you have to correct, add the correction to the gotchas section. This is one of the most direct ways to improve a skill iteratively (see [Refine with real execution](#refine-with-real-execution)).
+</Tip>
+
 ### Templates for output format
 
 When you need the agent to produce output in a specific format, provide a template. This is more reliable than describing the format in prose, because agents pattern-match well against concrete structures. Short templates can live inline in `SKILL.md`; for longer templates, or templates only needed in certain cases, store them in `assets/` and reference them from `SKILL.md` so they only load when needed.