lighterpack-mcp

An MCP server that lets AI agents create and manage LighterPack packing lists — add gear, track weights, organize categories, and share lists, all through natural conversation.

Unofficial. This project is not affiliated with or endorsed by LighterPack. It talks to LighterPack's own web API (the same one lighterpack.com's browser client uses) — see Architecture below.

What is this?

LighterPack is a free tool backpackers and travelers use to plan and share packing lists — tracking item weights, prices, and categories to optimize what they bring. This MCP server exposes LighterPack's list/category/item model as ~35 tools, so an MCP-compatible AI agent (Claude Desktop, Claude Code, etc.) can build and edit packing lists on your behalf: "Create a 3-day backpacking list with a Shelter category containing my tent and rain jacket, mark the jacket as worn, and give me a share link."

Quick start

Requires Node.js ≥20 and a LighterPack account.

npx lighterpack-mcp

Add it to your MCP client's config (example for Claude Desktop, claude_desktop_config.json):

{
  "mcpServers": {
    "lighterpack": {
      "command": "npx",
      "args": ["-y", "lighterpack-mcp"],
      "env": {
        "LIGHTERPACK_USERNAME": "your-username",
        "LIGHTERPACK_PASSWORD": "your-password"
      }
    }
  }
}

Configuration

| Env var | Required | Default | Description | |---|---|---|---| | LIGHTERPACK_USERNAME | Yes | — | Your LighterPack account username. | | LIGHTERPACK_PASSWORD | Yes | — | Your LighterPack account password. | | LIGHTERPACK_BASE_URL | No | https://lighterpack.com | Point at a self-hosted LighterPack instance (it's open source too). |

One account per server instance — there's no tool to switch accounts mid-session, by design.

Tool reference

Weights are always in grams at the tool boundary (weight / weightUnit inputs, weightGrams outputs), regardless of what unit LighterPack's own UI happens to display. Internally LighterPack always stores weight in milligrams, so nothing is lost either way.

Library / account

| Tool | Description | |---|---| | get_account_info | Signed-in username plus list/category/item counts and library-wide settings. | | refresh_library | Force a re-fetch from LighterPack, discarding the local cache. | | set_total_unit | Unit LighterPack's UI uses to display list totals. | | set_item_unit | Default unit LighterPack's UI pre-fills for new items. | | set_currency_symbol | Currency symbol shown next to prices (1-4 chars). |

Lists

| Tool | Description | |---|---| | create_list | Create a new, empty packing list. | | list_lists | Summary of every list (name, category count, totals). | | get_list | Full detail for one list: categories, items, computed totals. | | rename_list | Rename a list. | | set_list_description | Set a list's description. | | set_list_optional_fields | Toggle optional columns: images, price, worn, consumable, list description, pack weight. | | copy_list | Duplicate a list (categories copied, items shared with the original). | | delete_list | Delete a list (fails if it's the only one). | | generate_share_link | Mint a public read-only share link (lighterpack.com/r/<code>). |

Categories

| Tool | Description | |---|---| | add_category | Add a category to a list. | | rename_category | Rename a category. | | set_category_color | Set or clear a category's swatch color. | | remove_category | Remove a category (fails on a list's last category unless force). | | reorder_categories | Set a list's category display order. |

Items

| Tool | Description | |---|---| | add_item_to_category | Add a new item to a category, or link an existing item (shared item). | | update_item | Patch name, description, price, weight, link, or image URL. | | remove_item_from_category | Unlink an item from one category (keeps the item elsewhere). | | delete_item | Delete an item everywhere it's referenced. Cannot be undone. | | fork_item | Detach a shared item into an independent copy for one list. | | set_item_image_url | Point an item at an external image URL. | | upload_item_image | Upload a local/binary photo (JPEG/PNG/WebP, 5MB max) and attach it. |

Item flags (per category placement)

| Tool | Description | |---|---| | set_item_quantity | Set exact quantity. | | increment_item_quantity / decrement_item_quantity | Adjust quantity by N (floored at 0). | | set_item_worn | Mark worn/not worn (auto-clears consumable — they're mutually exclusive). | | set_item_consumable | Mark consumable/not consumable (auto-clears worn). | | set_item_star | Set the favorite/priority level: 0 (none) to 3 — LighterPack's star is a 3-level rating, not a plain flag. |

Batch / composite

| Tool | Description | |---|---| | add_items_batch | Add several items to one category in a single save round-trip. | | create_list_with_items | Scaffold a whole list — categories and items — in one call. | | batch_update_items | Apply field and/or flag edits across many items in one call. |

Deliberately out of scope: account registration/deletion, password/email changes, and password recovery — high-risk, low-value for an agent to hold.

Architecture

LighterPack has no granular REST API — there's no "create list" or "add item" endpoint. Instead, a user's entire library (every list, category, and item) is a single JSON document, synced via POST /saveLibrary with an optimistic-concurrency token (sync_token). This server's SyncEngine is the one place that fetch → mutate → save cycle is implemented: every tool call runs a small mutation against a cached, cloned copy of the library and persists it, retrying once if another writer (e.g. your browser tab) saved in between. See mutations.ts for the business rules (worn/consumable exclusivity, id sequencing, shared items, etc.), ported from LighterPack's own open-source client.

Limitations

• No realtime push — if you (or someone else) edits the list on lighterpack.com while an agent session is open, call refresh_library to pick up the change.
• One LighterPack account per server instance.
• Account creation/deletion and credential changes are intentionally not exposed as tools.

Contributing

Contributions are welcome! See CONTRIBUTING.md for dev setup, testing, and how to add a new tool.

License

MIT