[DOCS] Environment variables docs missing `CLAUDE_CODE_PLUGIN_SEED_DIR`

Documentation Type

Missing documentation (feature not documented)

Documentation Location

https://code.claude.com/docs/en/env-vars

Section/Topic

Plugin seeding for headless/plugin installation workflows

Current Documentation

No documentation currently exists for CLAUDE_CODE_PLUGIN_SEED_DIR.

The environment variable reference does not list it, and the headless guide does not explain how seeded plugin directories interact with programmatic plugin installation.

What's Wrong or Missing?

Claude Code v2.1.77 release notes mention headless mode plugin installation composing correctly with CLAUDE_CODE_PLUGIN_SEED_DIR, which confirms that this is a supported environment variable and workflow.

Users currently have no reference docs for what the variable does, when to set it, or how it behaves in headless/plugin installation flows.

Suggested Improvement

Add CLAUDE_CODE_PLUGIN_SEED_DIR to the env-vars page and cross-reference it from headless/plugin docs.

Suggested coverage:

• what directory the variable points to
• what "seeded" plugins are used for
• how it interacts with headless mode plugin installation
• any precedence or merge behavior if plugins are also installed by other mechanisms

Impact

Medium - Makes feature difficult to understand

Additional Context

Affected Pages:

| Page | Context |
|------|---------|
| https://code.claude.com/docs/en/env-vars | Missing the CLAUDE_CODE_PLUGIN_SEED_DIR environment variable entirely |
| https://code.claude.com/docs/en/headless | Closest code.claude.com page for programmatic/headless plugin installation behavior |

Total scope: 2 pages affected

Source: Claude Code v2.1.77 release notes

Exact release entry:

Improved headless mode plugin installation to compose correctly with CLAUDE_CODE_PLUGIN_SEED_DIR