diff --git a/CLAUDE.md b/CLAUDE.md
index 4cc3268..34382bc 100644
--- a/CLAUDE.md
+++ b/CLAUDE.md
@@ -28,7 +28,7 @@ pip install arxiv requests beautifulsoup4
 ## Key conventions
 
 - Skills follow the [Agent Skills specification](https://agentskills.io/specification). Each skill directory contains a `SKILL.md` with YAML frontmatter. Required fields: `name` (1–64 chars, lowercase alphanumeric + hyphens, no leading/trailing/consecutive hyphens, must match the parent directory name) and `description` (1–1024 chars, describes both what the skill does and when to use it). Recognized optional fields: `license`, `compatibility`, `metadata`, `allowed-tools`. All skills in this repo set `license: Apache-2.0`.
-- Skill authoring follows the [best practices](https://agentskills.io/skill-creation/best-practices) and [description guidance](https://agentskills.io/skill-creation/optimizing-descriptions):
+- Skill authoring follows the [best practices](https://agentskills.io/skill-creation/best-practices), [description guidance](https://agentskills.io/skill-creation/optimizing-descriptions), and Anthropic's [Complete Guide to Building Skills for Claude](https://resources.anthropic.com/hubfs/The-Complete-Guide-to-Building-Skill-for-Claude.pdf):
   - Keep `SKILL.md` under 500 lines / ~5000 tokens; use `references/` for detail loaded on demand, and tell the agent *when* to load each reference file.
   - Spend context wisely: add what the agent lacks, omit what it knows. Provide a clear default rather than a menu of options.
   - Match instruction specificity to task fragility — be prescriptive for fragile/destructive operations, descriptive (with the *why*) for flexible ones.