# Mtg Export > Export the user's MTG Arena (MTGA) collection straight from the running game into their MTG workspace as collection/MTGA-export-.csv, then sync it. Use this skill when the user wants to export, dump, capture, back up, or refresh their MTG Arena collection / owned cards, or asks "what do I own in Arena", or wants their collection available to the deckbuilding skills (mtg-std-build / mtg-std-upgrade prefer cards you already own). It is a one-shot: it reads the owned-card list out of the live MTGA process memory (no anchor cards, no manual steps), names the cards from the local Scryfall database built by the mtg-db skill (never downloading its own card data), and writes a Moxfield-format CSV into the collection folder. The export is then pushed by invoking the mtg-sync skill afterwards (as the normal user — never from inside the export process). Works on Windows (via pymem) and macOS (via Mach APIs; needs sudo). Requires MTG Arena installed and running. - Skill: `guuse/mtg-export` (Agent Skill, multi-file: 4 files) - Install (CLI): `npx skillmds@latest add guuse/mtg-export` - Raw SKILL.md: https://api.skillmd.com/api/skills/guuse/mtg-export/raw - Safety review: pending - Works with: Claude Code, Claude.ai, OpenAI Codex - Category: Data & Analytics - Author: guuse (https://skillmd.com/u/guuse) - Updated: 2026-09-22 - Page: https://skillmd.com/skills/guuse/mtg-export --- # MTG Arena Collection Export This skill captures the user's **owned MTG Arena collection** and drops it into their [MTG workspace](../mtg-db/SKILL.md) as `collection/MTGA-export-.csv` — the exact shape the **mtg-std-build** and **mtg-std-upgrade** skills read to prefer cards the user already owns. It runs in **one shot**, with no anchor cards and no manual data entry: it reads the collection directly out of the running game's memory and translates the Arena card ids to names using the **local Scryfall database** (`mtg-db`), so it never downloads or builds its own card data. ## How it works MTG Arena keeps the owned collection in memory as a map of **`arena_id` → owned count**. The bundled scanner (`scripts/export_collection.py`) attaches to the live MTGA process, finds that map anchor-free (it keeps the largest contiguous block of valid `arena_id → count` entries, validated against the card database), and writes the result as CSV. Card names/sets come from the `arena_cards` table in `/database/cards.sqlite` (built by **mtg-db**); MTGA's own bundled card files, if present, are merged in best-effort so cards from a set newer than the database still resolve. - **Platforms:** Windows (reads memory via `pymem`) and macOS (via Mach `task_for_pid` — needs `sudo`; works for the native Steam app and CrossOver/Wine). Linux is not supported. - **Dependencies:** `numpy` (both platforms) and `pymem` (Windows only). See `scripts/requirements.txt`. These are the one exception to the repo's stdlib-only rule — reading another process's memory requires them. ## Prerequisites (tell the user, once) 1. **MTG Arena is installed and running.** 2. In-game, open the **Collection** or **Decks** tab and **scroll through the cards** for ~30s so the whole collection is loaded into memory. (If the export comes back partial or empty, this is almost always why — scroll and re-run.) 3. The **local Scryfall database exists** with the Arena map. If the database is missing or was built before this skill existed, build/refresh it first via **mtg-db** (see below). ## How to drive it (the one-shot) Three steps — ready the card data, run the exporter, then push via **mtg-sync**. The export script **does not push**; the orchestrating skill invokes mtg-sync afterwards, as the normal user, so git uses the user's SSH key and config (see *Sync* below for why this matters): 1. **Ensure the local Scryfall database exists and carries the Arena-id map** (the `arena_cards` table). Do this via the **mtg-db** skill: check its status and, if the database is missing or was built before this skill existed, refresh it (a one-time ~78 MB download, ~30 s). The deck skills auto-build this database too, so on a machine that has already built a deck it's usually present — it just needs a refresh if it predates the Arena map. 2. **Export** with the bundled script: ```bash python "${CLAUDE_SKILL_DIR}/scripts/export_collection.py" ``` It writes the CSV and prints its path to stdout. If the exporter exits with *"No Arena card map in the Scryfall database"*, the database predates this skill: refresh it via **mtg-db** and re-run. 3. **Push** by invoking the **mtg-sync** skill (best-effort — see *Sync* below). ### macOS: the scan needs root On macOS, reading game memory requires root. Plain `sudo` needs a TTY, which a non-interactive agent shell doesn't have (`sudo: a terminal is required to read the password`). Use the bundled **askpass helper** so `sudo -A` pops a native, secure macOS password dialog instead — the user types the password into a GUI prompt, with no terminal and nothing in the transcript: ```bash SUDO_ASKPASS="${CLAUDE_SKILL_DIR}/scripts/macos-askpass.sh" \ sudo -A python3 "${CLAUDE_SKILL_DIR}/scripts/export_collection.py" ``` (If you'd rather type the password in a terminal, the plain `sudo python3 …export_collection.py` form still works when run interactively, e.g. via the `! ` prefix in Claude Code.) When run under `sudo`, the script **chowns the written CSV back to the invoking user** (via `SUDO_UID`/`SUDO_GID`), so exports never land root-owned and the later mtg-sync push can stage them cleanly. (When installed via the plugin marketplace, `${CLAUDE_SKILL_DIR}` resolves to this skill's directory. The script locates the shared `mtg_scryfall` library itself, so a manually-copied layout works too as long as the skills sit side by side.) ### Flags ``` --db PATH Use an explicit cards.sqlite (default: the resolved workspace database). --out-dir DIR Write the CSV somewhere other than /collection/. --process NAME Override the MTGA process name (default: MTGA.exe / MTGA / mtga). ``` The script prints progress to **stderr** and the single written CSV path to **stdout**. Exit codes: `0` success · `2` setup/dependency problem (numpy missing, no Arena map in the DB) · `3` could not locate the collection (game not running, or cards not loaded — scroll and retry). ## Output - **`/collection/MTGA-export-.csv`** — Moxfield-format CSV with the columns `Count, Name, Edition, Condition, Language, Foil, Tag` (Condition `Near Mint`, Language `English`). One row per (name, set), counts summed. This is exactly what the Arena deckbuilding skills look for under `collection/`. The workspace is resolved the usual way: **`$MTG_HOME` → nearest `.mtg/` → `./.mtg/`** (see the mtg-db and mtg-sync skills). Point `MTG_HOME` at a synced `mtg-data` repo and the export lands there directly. ## Sync (run after every export) Once the CSV is written, push it by invoking the **mtg-sync** skill — committing and pushing the collection so it's available on the user's other machines and to the deckbuilding skills. **The export script never pushes itself.** On macOS the scan runs under `sudo`, and a git push from inside that process would run as **root** — which has neither the user's SSH key nor their git identity, so the push fails with `Permission denied (publickey)`. Running mtg-sync separately, **as the normal user**, sidesteps that entirely. This push is **best-effort**, exactly like the deck skills' push step: if the workspace isn't a git repo, `git` isn't installed, or the network is down, mtg-sync reports it in one line and the CSV still sits in the local workspace to be pushed later — the export itself still succeeded, and the deckbuilding skills read the CSV from the local workspace regardless. ## Troubleshooting - **"Collection not found" / partial export** → MTGA wasn't fully loaded. Open the Collection/Decks tab, scroll through the whole collection, then re-run. - **macOS "Cannot access game memory"** → re-run under `sudo`. From a non-interactive shell use the askpass helper (`SUDO_ASKPASS=…/macos-askpass.sh sudo -A python3 …`) so the password prompt is a GUI dialog rather than a TTY; see *macOS: the scan needs root* above. - **`sudo: a terminal is required to read the password`** → you ran plain `sudo` from a shell with no TTY. Use the `sudo -A` + `SUDO_ASKPASS` form above. - **Windows permission error** → run the terminal as Administrator. - **"No Arena card map in the Scryfall database"** → the database predates this skill (or is missing). Run `mtg-db` with `--refresh` to rebuild it with the `arena_cards` table. - **macOS process not found** → ensure MTGA is open (Steam or CrossOver); the scanner looks for `MTGA`, `MTGA.exe`, and `mtga`. Override with `--process` if needed. - **Unsupported platform** → only Windows and macOS can be scanned; Linux is not supported.