What
A built-in "skill" (a packaged set of instructions Claude Code can load for a task) related to browser use used to ship as a compiled script file (ctbrowser.mjs). It now ships as a SKILL.md file instead, written in markdown, matching the format used by other bundled skills.
Why
This is a packaging change to how the skill is stored and shipped, bringing it in line with the format other skills already use.
Names in the bundleSKILL.md
The entry above is what we published on the day. These lines were added later, as Anthropic's own pages caught up, and they sit beside the original rather than replacing it.
Confirmed since
Anthropic's documentation has since written up SKILL.md, on Let Claude coordinate ongoing work with Projects.
* Skills, subagents, and commands: commit them to a repository you added to the project, for example a skill at `.claude/skills/<skill-name>/SKILL.md`. Each cloud thread clones every repository in the project and loads `.claude/skills/`, `…claude-projects see the edit
One source agreesOne thing we can check says the same as this entry.
Anthropic's documentation agrees
Anthropic's documentation has since written up SKILL.md, on Let Claude coordinate ongoing work with Projects.