diff --git a/ai-tutors/lesson-04-your-first-skill.md b/ai-tutors/lesson-04-your-first-skill.md
index 3ae36696..e7cfd470 100644
--- a/ai-tutors/lesson-04-your-first-skill.md
+++ b/ai-tutors/lesson-04-your-first-skill.md
@@ -496,9 +496,15 @@ Apache-2.0 licensed.
 >   patterns that hold the data-not-instructions and sandbox principles in every
 >   skill you write. Covers the injection-flag idiom, the privacy gate, and the
 >   draft-before-post shape.
+> - **Debugging a skill (debugging-skills.md)** — step 6: reading the audit log,
+>   reproducing failures with the eval harness, and isolating prompt vs tool vs
+>   model problems when a skill does not behave as expected.
+> - **Writing portable skills (portable-skills.md)** — step 7: authoring skills
+>   that work for any project and any model, using placeholders and capability
+>   floors so your skill does not break when the project or model changes.
 > - **Eval-driven development (eval-driven-development.md)** — step 8: how to judge
 >   output that can vary, with worked examples from real Magpie skills. Your skill
->   is not finished until it has an eval suite, so read step 5 first and then this.
+>   is not finished until it has an eval suite, so read steps 5–7 first and then this.
 > - **Agentic and autonomous work (agentic-work.md)** — step 9: once a skill is
 >   written, tested, and safe, this is how you let it run without watching every step.
 >