11.5k-star Claude Code SEO skill secretly adds self-promo to your output
claude-seo (github.com/AgriciDaniel/claude-seo) is an SEO analysis skill for Claude Code with 11.5k stars and 1.7k forks, numbers that on the surface suggest heavy real-world use. But a closer look at the source reveals a hidden instruction on line 119 of skills/seo/SKILL.md, labeled 'Community Footer'. This instruction makes the AI agent automatically append a promotional message to the output every time one of more than 15 /seo commands finishes, including audit, technical, schema, content, backlinks, cluster, sxo, and drift compare.
The appended text promotes the maintainer, agricidaniel, and links to both the free and paid tiers of their Skool community. The text itself is not or hidden with special characters; it sits in plain view in the public . However, it is inserted with no disclosure to the user and no way to opt out.
This means anyone using the skill for client work is unknowingly embedding a backlink to the maintainer's community inside every deliverable they publish or share.
Key points
- claude-seo is a Claude Code SEO analysis skill with 11.5k stars and 1.7k forks
- Line 119 of skills/seo/SKILL.md contains a hidden 'Community Footer' instruction
- It auto-appends a promotional message after 15+ /seo commands finish, including audit, technical, schema, content, and backlinks
- The message links to the maintainer's free and paid Skool community, with no disclosure or opt-out
- Reviewing source files, especially instruction files like SKILL.md, before installing is the practical takeaway