[FEATURE] npx-style ephemeral skill execution from remote URL/registry

Problem Statement

Currently, skills must be installed as SKILL.md files in ~/.claude/skills/ or .claude/skills/ before they can be used. There's no way to try out or run a skill once without persisting it to the filesystem. For one-off tasks or evaluating community skills, this creates unnecessary friction: install → use → manually delete.

Proposed Solution

An npx-style mechanism to run a skill ephemerally from a remote source (URL, gist, registry) without saving it locally. For example:

claude skill run https://gist.github.com/.../SKILL.md
claude --skill <url-or-package-ref>

The skill would be fetched, loaded for the current session only, and discarded afterward. No files written to disk.

Alternative Solutions

• Paste skill instructions directly into chat (works but loses structured metadata like allowed-tools, description)
• Install to filesystem, use, then manually rm -rf the skill directory
• #46308 proposes path-based invocation for local files, which helps but still requires the file on disk
• #41068 covers on-demand loading but focuses on performance, not ephemeral usage

Priority

Medium - Would be very helpful

Feature Category

CLI commands and flags