[FEATURE] Add custom skills to session via CLI arg

Preflight Checklist

• [x] I have searched existing requests and this feature hasn't been requested yet
• [x] This is a single feature request (not multiple features)

Problem Statement

I can already add --plugin-dir <dir>, --agents <json>, and --mcp-config <configs> via the CLI to customize basically everything else I want to customize via the CLI, but I can't add skills the same way.

This presents an issue to me because I use wrapper scripts to launch claude with different options at different times, and currently the only thing I can't elegantly do is include skills based on different contexts.

This feature would also just add consistency to the CLI, making it so ~everything that can be customized via the filesystem can be customized via CLI flags as well.

Proposed Solution

I'd like to be able to run claude --skills <json> the same way I can run claude --agents <json>

Then in my custom wrapper scripts I could just call this flag with the agent(s) I want active in that session

Alternative Solutions

Currently I work around this by creating custom plugins containing my skills and then include them with --plugin-dir, but its definitely more difficult / less flexible to do this

Priority

Medium - Would be very helpful

Feature Category

CLI commands and flags

Use Case Example

_No response_

Additional Context

_No response_