feat: add --plugins-dir flag to load plugins from custom directories

[csmith49]

Summary

Add a --plugins-dir CLI flag similar to Claude Code's --plugin-dir flag, allowing users to load plugins (skills) from custom directories for the current session only.

Changes

New Features

• New --plugins-dir flag (repeatable) to specify plugin directories
• Plugins are loaded additively, supplementing default plugin locations (not replacing them)
• Support for both specific plugin directories and directories containing multiple plugins
• Graceful handling of nonexistent or invalid paths with warnings
• Deduplication of skills with the same name

Usage Examples

openhands --plugins-dir ./my-plugin        # Load single plugin
openhands --plugins-dir ./plugins          # Load all plugins in directory  
openhands --plugins-dir ./p1 --plugins-dir ./p2  # Load multiple

Implementation Details

The flag is passed through the full call chain:

entrypoint -> textual_app -> runner_factory -> conversation_runner
  -> setup -> agent_store -> agent_context

New module openhands_cli/plugins.py handles loading skills from custom directories using the SDK's load_skills_from_dir function.

Testing

• Added comprehensive tests in tests/test_plugins_dir.py:
  • CLI argument parsing tests
  • Plugin loading tests for various scenarios (empty dir, nonexistent path, valid skills, deduplication)

Verification Commands Run

make lint           # ✅ All checks passed
make test           # ✅ 1286 passed
uv run pytest tests/test_plugins_dir.py -v  # ✅ 9 passed

Help Output

--plugins-dir DIR     Load plugins (skills) from directories for this
                      session only (repeatable). Can specify a directory
                      containing plugins or a specific plugin directory.

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This PR was created by an AI assistant (OpenHands) on behalf of the user.

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🚀 Try this PR

uvx --python 3.12 git+https://github.com/OpenHands/OpenHands-CLI.git@feature/plugins-dir-flag

[github-actions]

Coverage Report •

File	Stmts	Miss	Cover	Missing
openhands_cli
entrypoint.py	123	45	63%	32, 52–53, 56, 59, 61–62, 64–65, 68, 70, 72, 76, 81, 83–84, 133, 135–136, 139–143, 146–147, 149, 151, 161, 163–165, 167, 169–171, 174, 176, 180, 189, 191–193, 210, 258
plugins.py	61	8	86%	110–112, 115, 132, 136–138
setup.py	45	9	80%	70–73, 78–81, 89
openhands_cli/argparsers
main_parser.py	33	0	100%
util.py	11	0	100%
openhands_cli/stores
agent_store.py	190	25	86%	98, 116, 119, 158, 271–272, 275, 296, 437, 439–440, 442, 444, 486–487, 489, 496, 503, 505, 514, 517–518, 521–522, 524
openhands_cli/tui
textual_app.py	217	49	77%	124, 263–264, 269, 272, 277, 288, 290–292, 312–313, 320, 328, 334, 338, 343–345, 383, 389, 446, 448, 480, 483, 498, 501, 503–504, 517–519, 521–527, 531, 539–540, 579, 581, 616, 637, 692–693, 723
openhands_cli/tui/core
conversation_runner.py	98	39	60%	100–102, 109, 111, 122, 128, 154, 161–162, 165–167, 177, 185, 187–190, 198, 201–202, 206, 213, 217–218, 223, 225, 231–232, 237, 239, 241, 248, 251, 256, 258, 270–271
runner_factory.py	30	0	100%
TOTAL	6703	921	86%