docs: add Claude Code plugin marketplace installation instructions to README

[back1ply]

Problem

The README doesn't document how to install this plugin via the Claude Code plugin marketplace system. Users trying /plugin marketplace install brightdata/skills or /plugin marketplace install brightdata/brightdata-plugins get silent (no content) responses because that command doesn't exist — the correct flow is multiple separate steps.

Correct installation steps

/plugin marketplace add brightdata/skills
/plugin install brightdata-plugin@brightdata-plugins
/reload-plugins

Why two steps?

• marketplace add registers the catalog (like adding an app store)
• install installs the specific plugin from that catalog
• reload-plugins activates it in the current session

The plugin name (brightdata-plugin) comes from the "name" field in .claude-plugin/marketplace.json, and the marketplace name (brightdata-plugins) comes from the top-level "name" field in that same file.

Known post-install error (unfixable by user)

After /reload-plugins, /doctor reports:

brightdata-plugin@brightdata-plugins [brightdata-plugin]: Dependency "jq@brightdata-plugins" is not installed — run `claude plugin install jq@brightdata-plugins`, or check that its marketplace is added

Following that advice fails:

Plugin "jq" not found in marketplace "brightdata-plugins"

Root cause: plugin.json declares jq (and curl) as plugin dependencies, but these are system binaries — not Claude Code plugins. The error cannot be resolved through the plugin system. See anthropics/claude-plugins-official#1571 for the full analysis.

Fix needed: Remove curl/jq from the dependencies array in .claude-plugin/plugin.json. They should remain as documented system prerequisites in the README, not plugin dependencies.

Suggestion

1. Fix plugin.json — remove system binary names from dependencies
2. Add a Claude Code Installation section to the README with the three commands above

Reference: official Anthropic docs on installing plugins.

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Discovered this via trial and error — would save future users the confusion.