diff --git a/.skills/mcc-integration-testing/SKILL.md b/.skills/mcc-integration-testing/SKILL.md
index 168b545f..6316e0b8 100644
--- a/.skills/mcc-integration-testing/SKILL.md
+++ b/.skills/mcc-integration-testing/SKILL.md
@@ -115,6 +115,43 @@ Use this for TPS, movement-cadence, or packet-cadence work:
 
 Run them against a real server with a temp config and summarize counts from the captured logs.
 
+### 4. Full inventory regression sweep
+
+Use this when touching inventory snapshots, player/container slot sync, creative inventory, item-slot serialization, packet palettes, game-mode updates, or block-use paths that open containers:
+
+```bash
+tools/run-inventory-full-sweep.sh --versions "1.21.10 1.21.11"
+```
+
+Default coverage includes:
+
+- player inventory listing and inventory discovery
+- creative give/delete
+- inventory search
+- player right/left click stack split and merge
+- player drop one and drop all
+- chest open via `useblock`
+- container listing and close
+- mirrored player slots in container windows
+- shift-click and shift-right-click transfer
+- container right/left click, cursor stack, drop one, and drop all
+- creative middle-click command path
+- log scan for packet parse failures, queue-empty crashes, unhandled exceptions, and disconnects
+
+Run the Issue #3112 repro after a passing sweep:
+
+```bash
+tools/run-inventory-full-sweep.sh --versions "1.20.4" --run-issue-script
+```
+
+The script writes `summary.tsv` under `RUN_ROOT` and per-version logs under `/tmp/mcc-debug/inventory-full-<version>/mcc-debug.log`.
+
+When a matrix has existing PASS rows, do not rerun them unless a later code change affects that row or the user asks for a full rerun. Derive remaining rows from summaries:
+
+```bash
+awk 'FNR>1 && $2=="PASS" {print $1}' /tmp/mcc-inventory-full-sweep/*/summary.tsv | sort -V | uniq
+```
+
 ## Preconditions
 
 Before running any scenario:
@@ -165,6 +202,8 @@ Optionally override the login name with the fourth argument to the config helper
   - summarize the latest full-spectrum run
 - `tools/run-creative-e2e.sh`
   - ordered creative-mode E2E regression scenario
+- `tools/run-inventory-full-sweep.sh`
+  - full inventory command/API sweep across one or more versions, with optional Issue #3112 MCCScript repro
 
 ## Evidence Discipline
 
@@ -224,3 +263,7 @@ Always summarize:
 - If a test assertion fails, inspect the real MCC output before changing the code or weakening the assertion.
 - If an older server behaves oddly on Linux, check `use-native-transport=false` in `server.properties`.
 - If a matrix row fails before producing `mcc.log` or a command transcript, treat it as a harness failure, fix the environment, and rerun that row before drawing product conclusions.
+- If creative inventory commands report "You must be in Creative gamemode" after RCON switched the player, inspect game-mode update parsing before assuming creative inventory is broken. Modern servers can update local game mode through game event reason `3`.
+- If an inventory row crashes with `Queue empty` or `Failed to process incoming packet`, inspect packet palette routing before changing inventory code. A single shifted packet ID can make a healthy inventory feature look broken.
+- For chest-open failures, separate product and harness causes. The player may be standing inside the chest or suffocating on older servers. Stand beside the chest, put a floor under the player, and retry `useblock`.
+- For shared local servers, a `Done` log line does not prove RCON is ready. Retry setup commands and verify the actual RCON port from `server.properties`.
diff --git a/.skills/mcc-version-adaptation/SKILL.md b/.skills/mcc-version-adaptation/SKILL.md
index 706399cb..c3be7c12 100644
--- a/.skills/mcc-version-adaptation/SKILL.md
+++ b/.skills/mcc-version-adaptation/SKILL.md
@@ -157,6 +157,50 @@ When packet changes are detected:
 2. Create new `PacketPaletteXXX.cs` based on the previous one, adjusting IDs
 3. Update `PacketType18Handler.cs` routing
 
+Use scriptable comparisons instead of eyeballing long packet tables. The packet ID is the registration index in `GameProtocols.java`:
+
+```bash
+python3 - <<'PY'
+import re
+for ver in ["1.21.10", "1.21.11", "26.1"]:
+    path=f"MinecraftOfficial/{ver}-decompiled/net/minecraft/network/protocol/game/GameProtocols.java"
+    text=open(path).read()
+    start=text.index("CLIENTBOUND_TEMPLATE")
+    names=[m.group(1) for m in re.finditer(r"\.addPacket\(([^,]+),", text[start:])]
+    print("==", ver, len(names))
+    for i, name in enumerate(names):
+        print(f"0x{i:02X}", name)
+PY
+```
+
+For focused diffs:
+
+```bash
+python3 - <<'PY'
+import re
+def packets(ver, marker):
+    text=open(f"MinecraftOfficial/{ver}-decompiled/net/minecraft/network/protocol/game/GameProtocols.java").read()
+    start=text.index(marker)
+    return [m.group(1) for m in re.finditer(r"\.addPacket\(([^,]+),", text[start:])]
+left, right = "1.21.10", "1.21.11"
+a, b = packets(left, "CLIENTBOUND_TEMPLATE"), packets(right, "CLIENTBOUND_TEMPLATE")
+for i in range(max(len(a), len(b))):
+    x = a[i] if i < len(a) else "<none>"
+    y = b[i] if i < len(b) else "<none>"
+    if x != y:
+        print(f"0x{i:02X}: {left}={x} | {right}={y}")
+PY
+```
+
+Do the same for `SERVERBOUND_TEMPLATE`. Clientbound and serverbound can change independently. Do not inherit a newer palette just because one side looks similar. For example, `1.21.11` used the same play packet order as `1.21.9/1.21.10` for the tested inventory path, while `26.1` had additional shifts.
+
+Known packet lessons:
+
+- `1.9`, `1.9.1`, and `1.9.2` need their own packet palette. They are not safe to route through the later 1.9.x palette.
+- Pure `1.19` serverbound IDs differ from later 1.19.x. Do not put `MessageAcknowledgment` at `0x03`; pure 1.19 has `ChatCommand` at `0x03`, `ChatMessage` at `0x04`, and `ChatPreview` at `0x05`.
+- A wrong packet palette often appears as unrelated inventory failure: creative give/delete disconnects, `Queue empty`, or `Failed to process incoming packet`.
+- Game event reason `3` is `CHANGE_GAME_MODE`. If RCON changed the player to creative but MCC still refuses creative inventory commands, inspect `ChangeGameState` handling.
+
 ## Step 5: Check Variant Encoding Changes
 
 For entity types that use variant serializers (Cat, Wolf, Frog, Painting), check if the codec changed between versions by inspecting:
@@ -186,6 +230,17 @@ Compare key packet codec classes between versions. Known changes:
 
 When in doubt, compare the relevant packet class (e.g. `ClientboundAddEntityPacket.java`) between versions.
 
+## Step 7.1: Check JoinGame and Respawn Formats
+
+JoinGame and Respawn are high-risk because dimension fields changed several times:
+
+- `1.16` and `1.16.1`: dimension type/name handling uses string identifiers in places where later versions do not.
+- `1.16.2` through `1.18.2`: dimension type can be an NBT compound in JoinGame/Respawn.
+- `1.19+`: dimension type commonly moves back to identifiers.
+- `1.20.6+`: registry-driven IDs appear in more fields.
+
+When a version joins but terrain, inventory, or later packets look misaligned, inspect JoinGame/Respawn first. A single wrong dimension-field read leaves unread bytes in the packet and can make the next packet look broken.
+
 ## Step 8: Update Block Collision Shapes (Physics Engine)
 
 MCC's physics engine uses block collision shape data from PrismarineJS `minecraft-data` to perform accurate AABB collision detection (stored in `MinecraftClient/Physics/BlockShapeData.json`, embedded as a resource).
diff --git a/tools/README.md b/tools/README.md
index be83c64d..87a65480 100644
--- a/tools/README.md
+++ b/tools/README.md
@@ -26,6 +26,32 @@ mcc-publish --rid linux-x64
 
 Keep shared servers running by default. Do not stop or reset them unless the user explicitly asks for that, or you need to switch server versions.
 
+### Full inventory regression sweep
+
+Use `tools/run-inventory-full-sweep.sh` when changing inventory, container, item-slot serialization, packet palettes, game-mode handling, or block-use behavior. It runs MCC against real local servers with temporary configs and checks player inventory, creative give/delete, search, click, drop, chest container, mirrored player slots, and crash markers.
+
+```bash
+# Focused retest
+tools/run-inventory-full-sweep.sh --versions "1.21.10 1.21.11"
+
+# Full default major-version sweep
+tools/run-inventory-full-sweep.sh
+
+# Run the Issue #3112 mirrored-player-inventory script after a passing sweep
+tools/run-inventory-full-sweep.sh --versions "1.20.4" --run-issue-script
+```
+
+Useful environment overrides:
+
+```bash
+RUN_ROOT=/tmp/my-inventory-run \
+MCC_SERVERS=/path/to/servers \
+STOP_ON_FAIL=1 \
+tools/run-inventory-full-sweep.sh --versions "1.19 1.20.4"
+```
+
+The script writes `summary.tsv` under `RUN_ROOT`. Per-version MCC logs are under `/tmp/mcc-debug/inventory-full-<version>/mcc-debug.log`, and command output blocks are saved next to the summary.
+
 ### tmpfs build mode
 
 ```bash
diff --git a/tools/run-inventory-full-sweep.sh b/tools/run-inventory-full-sweep.sh
new file mode 100755
index 00000000..ea98846e
--- /dev/null
+++ b/tools/run-inventory-full-sweep.sh
@@ -0,0 +1,673 @@
+#!/usr/bin/env bash
+set -u -o pipefail
+
+SCRIPT_SELF="${BASH_SOURCE[0]}"
+while [[ -L "$SCRIPT_SELF" ]]; do
+    SCRIPT_DIRNAME="$(cd -P "$(dirname "$SCRIPT_SELF")" >/dev/null 2>&1 && pwd)"
+    SCRIPT_SELF="$(readlink "$SCRIPT_SELF")"
+    [[ "$SCRIPT_SELF" != /* ]] && SCRIPT_SELF="$SCRIPT_DIRNAME/$SCRIPT_SELF"
+done
+REPO_ROOT="$(cd -P "$(dirname "$SCRIPT_SELF")/.." >/dev/null 2>&1 && pwd)"
+SCRIPT_DIR="$REPO_ROOT/.skills/mcc-integration-testing/scripts"
+RUN_ROOT="${RUN_ROOT:-/tmp/mcc-inventory-full-sweep/$(date +%Y%m%d-%H%M%S)}"
+VERSIONS="${VERSIONS_OVERRIDE:-1.8 1.9 1.10 1.11 1.12 1.13 1.14 1.15 1.16 1.17 1.18 1.19 1.20 1.21 26.1}"
+RUN_ISSUE_SCRIPT="${RUN_ISSUE_SCRIPT:-0}"
+ISSUE_VERSION="${ISSUE_VERSION:-1.20.4}"
+STOP_ON_FAIL="${STOP_ON_FAIL:-1}"
+
+usage() {
+    cat <<'USAGE'
+Usage: tools/run-inventory-full-sweep.sh [options]
+
+Runs MCC inventory command/API coverage against real local Minecraft servers.
+The matrix is sequential because mc-* tmux sessions are shared state.
+
+Options:
+  --versions "1.20.4 1.21.11"  Space-separated versions to test.
+  --run-issue-script           Run the Issue #3112 MCCScript repro after a passing sweep.
+  --issue-version VERSION      Version for the Issue #3112 repro. Default: 1.20.4.
+  --keep-going                 Continue after failures.
+  --stop-on-fail               Stop on first failure. Default.
+  -h, --help                   Show this help.
+
+Environment overrides:
+  VERSIONS_OVERRIDE, RUN_ROOT, RUN_ISSUE_SCRIPT, ISSUE_VERSION, STOP_ON_FAIL,
+  MCC_SERVERS.
+
+Examples:
+  tools/run-inventory-full-sweep.sh --versions "1.21.10 1.21.11"
+  RUN_ISSUE_SCRIPT=1 tools/run-inventory-full-sweep.sh --versions "1.20.4"
+USAGE
+}
+
+while [[ $# -gt 0 ]]; do
+    case "$1" in
+        --versions)
+            VERSIONS="$2"
+            shift 2
+            ;;
+        --run-issue-script)
+            RUN_ISSUE_SCRIPT=1
+            shift
+            ;;
+        --issue-version)
+            ISSUE_VERSION="$2"
+            shift 2
+            ;;
+        --keep-going)
+            STOP_ON_FAIL=0
+            shift
+            ;;
+        --stop-on-fail)
+            STOP_ON_FAIL=1
+            shift
+            ;;
+        -h|--help)
+            usage
+            exit 0
+            ;;
+        *)
+            echo "Unknown option: $1" >&2
+            usage >&2
+            exit 2
+            ;;
+    esac
+done
+
+source "$REPO_ROOT/tools/mcc-env.sh"
+source "$SCRIPT_DIR/common.sh"
+
+mkdir -p "$RUN_ROOT"
+SUMMARY="$RUN_ROOT/summary.tsv"
+printf 'target\tstatus\tdetail\tlog\n' > "$SUMMARY"
+
+wait_for_file_pattern_local() {
+    local file="$1"
+    local pattern="$2"
+    local timeout="${3:-10}"
+    local end=$((SECONDS + timeout))
+    while (( SECONDS < end )); do
+        if [[ -f "$file" ]] && grep -Eq "$pattern" "$file"; then
+            return 0
+        fi
+        sleep 0.2
+    done
+    return 1
+}
+
+sanitize_version() {
+    printf '%s' "$1" | tr '.-' '__'
+}
+
+server_target_for() {
+    local version="$1"
+    local dir
+    if [[ -d "${MCC_SERVERS:-}/$version-Vanilla" ]]; then
+        printf '%s-Vanilla' "$version"
+    elif [[ -d "$REPO_ROOT/MinecraftOfficial/downloads/$version" ]]; then
+        printf '%s' "$version"
+    else
+        printf '%s-Vanilla' "$version"
+    fi
+}
+
+server_dir_for() {
+    local target="$1"
+    local root="${MCC_SERVERS:-$REPO_ROOT/MinecraftOfficial/downloads}"
+    printf '%s/%s\n' "$root" "$target"
+}
+
+rcon_port_for() {
+    local target="$1"
+    local props
+    props="$(server_dir_for "$target")/server.properties"
+    if [[ -f "$props" ]]; then
+        local port_line
+        port_line="$(grep -E '^rcon\.port=' "$props" | tail -n 1 || true)"
+        if [[ -n "$port_line" ]]; then
+            printf '%s\n' "${port_line#rcon.port=}"
+            return 0
+        fi
+    fi
+    printf '25575\n'
+}
+
+run_rcon() {
+    local port="$1"
+    local command="$2"
+    local attempt
+    for attempt in 1 2 3 4 5; do
+        if mc-rcon "$command" "$port" >/dev/null 2>&1; then
+            return 0
+        fi
+        sleep 1
+    done
+    return 1
+}
+
+run_rcon_or_detail() {
+    local port="$1"
+    local cmd="$2"
+    if run_rcon "$port" "$cmd"; then
+        return 0
+    fi
+    FAIL_DETAIL="rcon failed: $cmd"
+    return 1
+}
+
+run_rcon_any_or_detail() {
+    local port="$1"
+    local detail="$2"
+    shift 2
+    local cmd
+    for cmd in "$@"; do
+        if run_rcon "$port" "$cmd"; then
+            return 0
+        fi
+    done
+    FAIL_DETAIL="$detail"
+    return 1
+}
+
+run_rcon_any() {
+    local port="$1"
+    shift
+    local cmd
+    for cmd in "$@"; do
+        if run_rcon "$port" "$cmd"; then
+            return 0
+        fi
+    done
+    return 1
+}
+
+run_rcon_each() {
+    local port="$1"
+    shift
+    local cmd
+    for cmd in "$@"; do
+        run_rcon "$port" "$cmd" || true
+    done
+}
+
+send_mcc_command() {
+    local session="$1"
+    local log_file="$2"
+    local command="$3"
+    local delay="${4:-1}"
+    local block_file="$5"
+    local mark
+    mark="$(wc -c < "$log_file" 2>/dev/null || printf '0')"
+    mcc-cmd --session "$session" "$command" >/dev/null
+    sleep "$delay"
+    LAST_BLOCK="$(tail -c "+$((mark + 1))" "$log_file" 2>/dev/null || true)"
+    {
+        printf '\n>>> %s\n' "$command"
+        printf '%s\n' "$LAST_BLOCK"
+    } >> "$block_file"
+}
+
+assert_contains() {
+    grep -Eq "$2" <<<"$1" || { FAIL_DETAIL="$3"; return 1; }
+}
+
+assert_not_contains() {
+    if grep -Eq "$2" <<<"$1"; then
+        FAIL_DETAIL="$3"
+        return 1
+    fi
+}
+
+assert_no_runtime_crash() {
+    local log_file="$1"
+    if grep -Eq 'Queue empty|Unhandled exception|Object reference not set|Failed to parse packet|Failed to process incoming packet|Connection has been lost' "$log_file"; then
+        FAIL_DETAIL="runtime log contains crash/disconnect marker"
+        return 1
+    fi
+}
+
+clear_dropped_items() {
+    local port="$1"
+    run_rcon_any "$port" "kill @e[type=item]" "kill @e[type=Item]" >/dev/null 2>&1 || true
+}
+
+open_chest() {
+    local session="$1"
+    local log_file="$2"
+    local block_file="$3"
+    send_mcc_command "$session" "$log_file" "useblock 1 80 0" 2 "$block_file"
+    if wait_for_file_pattern_local "$log_file" "Inventory # 1 opened: Chest" 4; then
+        return 0
+    fi
+    send_mcc_command "$session" "$log_file" "useblock 1 80 0" 2 "$block_file"
+    wait_for_file_pattern_local "$log_file" "Inventory # 1 opened: Chest" 12
+}
+
+setup_world() {
+    local port="$1"
+    run_rcon_or_detail "$port" "gamerule sendCommandFeedback true" || return 1
+    run_rcon "$port" "gamerule keepInventory true" || true
+    run_rcon "$port" "time set day" || true
+    run_rcon "$port" "weather clear" || true
+    run_rcon "$port" "difficulty peaceful" || true
+}
+
+setup_area() {
+    local port="$1"
+    run_rcon_each "$port" "fill -2 78 -3 3 82 3 air 0 replace" "fill -2 78 -3 3 82 3 air" "fill -2 78 -3 3 82 3 minecraft:air"
+    run_rcon_each "$port" "fill -2 79 -3 3 79 3 stone 0 replace" "fill -2 79 -3 3 79 3 stone" "fill -2 79 -3 3 79 3 minecraft:stone"
+    run_rcon_each "$port" "setblock 1 80 0 air 0 replace" "setblock 1 80 0 air" "setblock 1 80 0 minecraft:air"
+    run_rcon_each "$port" "setblock 1 80 0 chest 0 replace" "setblock 1 80 0 chest" "setblock 1 80 0 minecraft:chest"
+    run_rcon_each "$port" "blockdata 1 80 0 {Items:[]}" "data merge block 1 80 0 {Items:[]}"
+}
+
+setup_player() {
+    local port="$1"
+    local username="$2"
+    run_rcon "$port" "op $username" || true
+    run_rcon "$port" "gamemode creative $username" || return 1
+    run_rcon_any "$port" "tp $username 1.5 80 2.5" "tp $username 1 80 2" || true
+}
+
+run_inventory_sequence() {
+    local version="$1"
+    local rcon_port="$2"
+    local session="$3"
+    local username="$4"
+    local log_file="$5"
+    local block_file="$6"
+
+    send_mcc_command "$session" "$log_file" "inventory player drop -1 all" 1 "$block_file" || true
+    for slot in 36 37 38 39 40 41 42 43 44; do
+        send_mcc_command "$session" "$log_file" "inventory creativedelete $slot" 0.2 "$block_file" || true
+    done
+
+    send_mcc_command "$session" "$log_file" "inventory player list" 1 "$block_file"
+    assert_contains "$LAST_BLOCK" 'Inventory #0 - Player Inventory' "player inventory did not list" || return 1
+    send_mcc_command "$session" "$log_file" "inventory inventories" 1 "$block_file"
+    assert_contains "$LAST_BLOCK" '#0[[:space:]]+- Player Inventory' "inventory discovery did not list player inventory" || return 1
+
+    send_mcc_command "$session" "$log_file" "inventory creativegive 36 Diamond 16" 1 "$block_file"
+    send_mcc_command "$session" "$log_file" "inventory player list" 1 "$block_file"
+    assert_contains "$LAST_BLOCK" '#36[[:space:]]*: x16[[:space:]]+Diamond' "creativegive did not populate player slot 36" || return 1
+    send_mcc_command "$session" "$log_file" "inventory search Diamond 16" 1 "$block_file"
+    assert_contains "$LAST_BLOCK" 'Diamond' "inventory search did not find Diamond" || return 1
+    send_mcc_command "$session" "$log_file" "inventory creativedelete 36" 1 "$block_file"
+    send_mcc_command "$session" "$log_file" "inventory player list" 1 "$block_file"
+    assert_not_contains "$LAST_BLOCK" '#36[[:space:]]*: x16[[:space:]]+Diamond' "creativedelete left Diamond in player slot 36" || return 1
+
+    send_mcc_command "$session" "$log_file" "inventory creativegive 36 Dirt 3" 1 "$block_file"
+    run_rcon "$rcon_port" "gamemode survival $username" || return 1
+    sleep 1
+    send_mcc_command "$session" "$log_file" "inventory player click 36 right" 2 "$block_file"
+    send_mcc_command "$session" "$log_file" "inventory player list" 1 "$block_file"
+    assert_contains "$LAST_BLOCK" '#36[[:space:]]*: x1[[:space:]]+Dirt' "player right-click did not halve Dirt stack" || return 1
+    assert_contains "$LAST_BLOCK" '#-1[[:space:]]*: x2[[:space:]]+Dirt' "player right-click did not put Dirt on cursor" || return 1
+    send_mcc_command "$session" "$log_file" "inventory player click 36 left" 2 "$block_file"
+    send_mcc_command "$session" "$log_file" "inventory player list" 1 "$block_file"
+    assert_contains "$LAST_BLOCK" '#36[[:space:]]*: x3[[:space:]]+Dirt' "player left-click did not merge Dirt back into slot 36" || return 1
+    assert_not_contains "$LAST_BLOCK" '#-1[[:space:]]*: x[0-9]+[[:space:]]+Dirt' "player left-click merge left Dirt on cursor" || return 1
+
+    run_rcon_any "$rcon_port" "tp $username 1.5 80 2.5" "tp $username 1 80 2" || true
+    sleep 1
+    send_mcc_command "$session" "$log_file" "inventory player drop 36" 0.2 "$block_file"
+    clear_dropped_items "$rcon_port"
+    sleep 1
+    send_mcc_command "$session" "$log_file" "inventory player list" 1 "$block_file"
+    assert_contains "$LAST_BLOCK" '#36[[:space:]]*: x2[[:space:]]+Dirt' "single drop did not decrement Dirt stack" || return 1
+
+    run_rcon "$rcon_port" "gamemode creative $username" || return 1
+    sleep 1
+    clear_dropped_items "$rcon_port"
+    send_mcc_command "$session" "$log_file" "inventory creativedelete 36" 1 "$block_file"
+    send_mcc_command "$session" "$log_file" "inventory creativegive 36 Dirt 3" 1 "$block_file"
+    run_rcon "$rcon_port" "gamemode survival $username" || return 1
+    run_rcon_any "$rcon_port" "tp $username 1.5 80 2.5" "tp $username 1 80 2" || true
+    sleep 1
+    send_mcc_command "$session" "$log_file" "inventory player drop 36 all" 0.2 "$block_file"
+    clear_dropped_items "$rcon_port"
+    sleep 1
+    send_mcc_command "$session" "$log_file" "inventory player list" 1 "$block_file"
+    assert_not_contains "$LAST_BLOCK" '#36[[:space:]]*: x[0-9]+[[:space:]]+Dirt' "drop all left Dirt in player slot 36" || return 1
+
+    run_rcon "$rcon_port" "gamemode creative $username" || return 1
+    run_rcon_any "$rcon_port" "tp $username 1.5 80 2.5" "tp $username 1 80 2" || true
+    sleep 2
+    send_mcc_command "$session" "$log_file" "inventory creativegive 36 Diamond 16" 1 "$block_file"
+    send_mcc_command "$session" "$log_file" "inventory creativegive 37 GoldIngot 7" 1 "$block_file"
+    send_mcc_command "$session" "$log_file" "changeslot 9" 1 "$block_file"
+    run_rcon "$rcon_port" "gamemode survival $username" || return 1
+    sleep 1
+    open_chest "$session" "$log_file" "$block_file" || { FAIL_DETAIL="chest did not open"; return 1; }
+
+    send_mcc_command "$session" "$log_file" "inventory container list" 1 "$block_file"
+    assert_contains "$LAST_BLOCK" '#54[[:space:]]*: x16[[:space:]]+Diamond' "container list did not mirror player slot 36 as chest slot 54" || return 1
+    assert_contains "$LAST_BLOCK" '#55[[:space:]]*: x7[[:space:]]+Gold[[:space:]]+Ingot' "container list did not mirror player slot 37 as chest slot 55" || return 1
+
+    send_mcc_command "$session" "$log_file" "inventory container click 54 ShiftClick" 2 "$block_file"
+    send_mcc_command "$session" "$log_file" "inventory container list" 1 "$block_file"
+    assert_contains "$LAST_BLOCK" '#0[[:space:]]*: x16[[:space:]]+Diamond' "container shift-click did not move Diamond to chest slot 0" || return 1
+    send_mcc_command "$session" "$log_file" "inventory player list" 1 "$block_file"
+    assert_not_contains "$LAST_BLOCK" '#36[[:space:]]*: x16[[:space:]]+Diamond' "issue case failed: player slot 36 still showed shifted Diamond" || return 1
+
+    send_mcc_command "$session" "$log_file" "inventory container click 55 ShiftRightClick" 2 "$block_file"
+    send_mcc_command "$session" "$log_file" "inventory container list" 1 "$block_file"
+    assert_contains "$LAST_BLOCK" '#1[[:space:]]*: x7[[:space:]]+Gold[[:space:]]+Ingot' "container shift-right-click did not move GoldIngot to chest slot 1" || return 1
+    send_mcc_command "$session" "$log_file" "inventory player list" 1 "$block_file"
+    assert_not_contains "$LAST_BLOCK" '#37[[:space:]]*: x7[[:space:]]+Gold[[:space:]]+Ingot' "player slot 37 still showed shifted GoldIngot" || return 1
+
+    send_mcc_command "$session" "$log_file" "inventory search GoldIngot 7" 1 "$block_file"
+    assert_contains "$LAST_BLOCK" 'Gold[[:space:]]+Ingot' "inventory search did not find GoldIngot after moving to container" || return 1
+
+    send_mcc_command "$session" "$log_file" "inventory container click 0 right" 2 "$block_file"
+    send_mcc_command "$session" "$log_file" "inventory container list" 1 "$block_file"
+    assert_contains "$LAST_BLOCK" '#0[[:space:]]*: x8[[:space:]]+Diamond' "container right-click did not halve chest stack" || return 1
+    send_mcc_command "$session" "$log_file" "inventory player list" 1 "$block_file"
+    assert_contains "$LAST_BLOCK" '#-1[[:space:]]*: x8[[:space:]]+Diamond' "container right-click did not put half stack on cursor" || return 1
+
+    send_mcc_command "$session" "$log_file" "inventory container click 2 right" 2 "$block_file"
+    send_mcc_command "$session" "$log_file" "inventory container list" 1 "$block_file"
+    assert_contains "$LAST_BLOCK" '#2[[:space:]]*: x1[[:space:]]+Diamond' "container right-click did not place one item into empty slot 2" || return 1
+    send_mcc_command "$session" "$log_file" "inventory container click 2 left" 2 "$block_file"
+    send_mcc_command "$session" "$log_file" "inventory container list" 1 "$block_file"
+    assert_contains "$LAST_BLOCK" '#2[[:space:]]*: x8[[:space:]]+Diamond' "container left-click did not merge cursor into slot 2" || return 1
+    send_mcc_command "$session" "$log_file" "inventory player list" 1 "$block_file"
+    assert_not_contains "$LAST_BLOCK" '#-1[[:space:]]*: x[0-9]+[[:space:]]+Diamond' "container left-click merge left Diamond on cursor" || return 1
+
+    send_mcc_command "$session" "$log_file" "inventory container drop 2" 0.2 "$block_file"
+    clear_dropped_items "$rcon_port"
+    sleep 1
+    send_mcc_command "$session" "$log_file" "inventory container list" 1 "$block_file"
+    assert_contains "$LAST_BLOCK" '#2[[:space:]]*: x7[[:space:]]+Diamond' "container single drop did not decrement chest slot 2" || return 1
+    send_mcc_command "$session" "$log_file" "inventory container drop 2 all" 0.2 "$block_file"
+    clear_dropped_items "$rcon_port"
+    sleep 1
+    send_mcc_command "$session" "$log_file" "inventory container list" 1 "$block_file"
+    assert_not_contains "$LAST_BLOCK" '#2[[:space:]]*: x[0-9]+[[:space:]]+Diamond' "container drop all left Diamond in chest slot 2" || return 1
+
+    send_mcc_command "$session" "$log_file" "inventory container close" 1 "$block_file"
+    send_mcc_command "$session" "$log_file" "inventory inventories" 1 "$block_file"
+    assert_not_contains "$LAST_BLOCK" '#1[[:space:]]*-' "container close left inventory #1 visible" || return 1
+
+    run_rcon "$rcon_port" "gamemode creative $username" || return 1
+    sleep 1
+    send_mcc_command "$session" "$log_file" "inventory creativegive 37 Emerald 1" 1 "$block_file"
+    send_mcc_command "$session" "$log_file" "inventory player click 37 middle" 1 "$block_file"
+    assert_contains "$LAST_BLOCK" 'middle' "middle-click command path did not execute" || return 1
+
+    assert_no_runtime_crash "$log_file" || return 1
+}
+
+run_one_version() {
+    local version="$1"
+    local target
+    target="$(server_target_for "$version")"
+    local safe session username version_dir cfg log_file block_file mcc_root rcon_port
+    safe="$(sanitize_version "$version")"
+    session="inventory-full-$safe"
+    username="InvF${safe//_/}"
+    username="${username:0:16}"
+    version_dir="$RUN_ROOT/$version"
+    cfg="$version_dir/MinecraftClient.ini"
+    log_file="/tmp/mcc-debug/$session/mcc-debug.log"
+    block_file="$version_dir/command-blocks.log"
+    mkdir -p "$version_dir" "/tmp/mcc-debug/$session"
+    : > "$log_file"
+    : > "$block_file"
+
+    echo "== inventory $version =="
+    bash "$SCRIPT_DIR/ensure_offline_server.sh" "$target" >/dev/null || { printf '%s\tFAIL\t%s\t%s\n' "$version" "server setup failed" "$log_file" >> "$SUMMARY"; return 1; }
+    mc-start "$target" >/dev/null || { printf '%s\tFAIL\t%s\t%s\n' "$version" "server start failed" "$log_file" >> "$SUMMARY"; return 1; }
+    wait_for_server_ready "$target" >/dev/null || true
+    rcon_port="$(rcon_port_for "$target")"
+
+    bash "$SCRIPT_DIR/prepare_offline_mcc_config.sh" "$cfg" "$version" "$username" >/dev/null || { printf '%s\tFAIL\t%s\t%s\n' "$version" "config setup failed" "$log_file" >> "$SUMMARY"; mc-stop "$target" --confirm >/dev/null 2>&1 || true; return 1; }
+    sed -i 's#^Server = .*#Server = { Host = "localhost", Port = 25565 }#' "$cfg"
+    FAIL_DETAIL=""
+    setup_world "$rcon_port" || { printf '%s\tFAIL\t%s\t%s\n' "$version" "${FAIL_DETAIL:-world setup failed}" "$log_file" >> "$SUMMARY"; mc-stop "$target" --confirm >/dev/null 2>&1 || true; return 1; }
+
+    mcc_root="$(dirname "$cfg")"
+    mkdir -p "/tmp/mcc-debug/$session"
+    local input_file="/tmp/mcc-debug/$session/mcc_input.txt"
+    local pid_file="/tmp/mcc-debug/$session/mcc.pid"
+    : > "$input_file"
+    (
+        cd "$mcc_root" || exit 1
+        printf '%s\n' "$$" > "$pid_file"
+        exec env MCC_FILE_INPUT=1 MCC_INPUT_FILE="$input_file" dotnet run --project "$REPO_ROOT/MinecraftClient" -c Release --no-build > "$log_file" 2>&1
+    ) &
+    local mcc_pid=$!
+    printf '%s\n' "$mcc_pid" > "$pid_file"
+
+    local ok=0
+    if ! wait_for_file_pattern_local "$log_file" "Server was successfully joined" 40; then
+        FAIL_DETAIL="MCC did not join server"
+        ok=1
+    else
+        setup_player "$rcon_port" "$username" || { FAIL_DETAIL="player setup failed after join"; ok=1; }
+        setup_area "$rcon_port" || { ok=1; }
+        setup_player "$rcon_port" "$username" || { FAIL_DETAIL="player setup failed after area setup"; ok=1; }
+        sleep 2
+        if [[ -z "${FAIL_DETAIL:-}" ]]; then
+            FAIL_DETAIL=""
+            run_inventory_sequence "$version" "$rcon_port" "$session" "$username" "$log_file" "$block_file"
+            ok=$?
+        fi
+    fi
+
+    kill "$mcc_pid" >/dev/null 2>&1 || true
+    wait "$mcc_pid" >/dev/null 2>&1 || true
+    mc-stop "$target" --confirm >/dev/null 2>&1 || true
+    wait_for_server_stop "$target" >/dev/null 2>&1 || true
+
+    if [[ "$ok" -eq 0 ]]; then
+        printf '%s\tPASS\tfull inventory command/API sweep\t%s\n' "$version" "$log_file" >> "$SUMMARY"
+        echo "PASS $version"
+        return 0
+    fi
+
+    printf '%s\tFAIL\t%s\t%s\n' "$version" "${FAIL_DETAIL:-unknown failure}" "$log_file" >> "$SUMMARY"
+    echo "${FAIL_DETAIL:-unknown failure}" >&2
+    echo "FAIL $version"
+    return 1
+}
+
+write_issue3112_script() {
+    local script_path="$1"
+    cat > "$script_path" <<'CS'
+//MCCScript 1.0
+
+MCC.LoadBot(new Issue3112InventoryReproBot());
+
+//MCCScript Extensions
+
+public class Issue3112InventoryReproBot : ChatBot
+{
+    private int ticks;
+    private int phase;
+    private bool finished;
+
+    public override void AfterGameJoined()
+    {
+        ticks = 0;
+        phase = 0;
+        finished = false;
+        LogToConsole("ISSUE3112_REPRO_START");
+    }
+
+    public override void Update()
+    {
+        if (finished)
+            return;
+
+        ticks++;
+
+        if (phase == 0 && ticks >= 20)
+        {
+            PerformInternalCommand("inventory creativedelete 36");
+            PerformInternalCommand("inventory creativegive 36 DiamondOre 1");
+            PerformInternalCommand("changeslot 9");
+            phase = 1;
+            ticks = 0;
+            return;
+        }
+
+        if (phase == 1 && ticks >= 20)
+        {
+            if (!PlayerHasOre())
+            {
+                Fail("missing ore before container click");
+                return;
+            }
+
+            PerformInternalCommand("useblock 1 80 0");
+            phase = 2;
+            ticks = 0;
+            return;
+        }
+
+        if (phase == 2 && ticks >= 40)
+        {
+            if (!GetInventories().ContainsKey(1))
+            {
+                Fail("container did not open");
+                return;
+            }
+
+            PerformInternalCommand("inventory container click 54 ShiftClick");
+            phase = 3;
+            ticks = 0;
+            return;
+        }
+
+        if (phase == 3 && ticks >= 40)
+        {
+            if (PlayerHasOre())
+                Fail("ISSUE3112_REPRO_STALE_FAIL");
+            else
+                Pass();
+        }
+    }
+
+    private bool PlayerHasOre()
+    {
+        foreach (var item in GetPlayerInventory().Items.Values)
+        {
+            if (item.Type == ItemType.DiamondOre && item.Count > 0)
+                return true;
+        }
+
+        return false;
+    }
+
+    private void Pass()
+    {
+        finished = true;
+        LogToConsole("ISSUE3112_REPRO_PASS");
+        PerformInternalCommand("inventory container close");
+    }
+
+    private void Fail(string reason)
+    {
+        finished = true;
+        LogToConsole(reason);
+    }
+}
+CS
+}
+
+run_issue3112_repro() {
+    local version="$1"
+    local target
+    target="$(server_target_for "$version")"
+    local safe session username version_dir cfg log_file script_file mcc_root rcon_port
+    safe="$(sanitize_version "$version")"
+    session="issue3112-$safe"
+    username="Iss3112${safe//_/}"
+    username="${username:0:16}"
+    version_dir="$RUN_ROOT/issue3112-$version"
+    cfg="$version_dir/MinecraftClient.ini"
+    log_file="/tmp/mcc-debug/$session/mcc-debug.log"
+    script_file="$version_dir/issue3112_repro.cs"
+    mkdir -p "$version_dir" "/tmp/mcc-debug/$session"
+    : > "$log_file"
+    write_issue3112_script "$script_file"
+
+    echo "== issue3112 $version =="
+    bash "$SCRIPT_DIR/ensure_offline_server.sh" "$target" >/dev/null || { printf '%s\tFAIL\t%s\t%s\n' "issue3112-$version" "server setup failed" "$log_file" >> "$SUMMARY"; return 1; }
+    mc-start "$target" >/dev/null || { printf '%s\tFAIL\t%s\t%s\n' "issue3112-$version" "server start failed" "$log_file" >> "$SUMMARY"; return 1; }
+    wait_for_server_ready "$target" >/dev/null || true
+    rcon_port="$(rcon_port_for "$target")"
+
+    bash "$SCRIPT_DIR/prepare_offline_mcc_config.sh" "$cfg" "$version" "$username" >/dev/null || { printf '%s\tFAIL\t%s\t%s\n' "issue3112-$version" "config setup failed" "$log_file" >> "$SUMMARY"; mc-stop "$target" --confirm >/dev/null 2>&1 || true; return 1; }
+    sed -i 's#^Server = .*#Server = { Host = "localhost", Port = 25565 }#' "$cfg"
+    FAIL_DETAIL=""
+    setup_world "$rcon_port" || { printf '%s\tFAIL\t%s\t%s\n' "issue3112-$version" "${FAIL_DETAIL:-world setup failed}" "$log_file" >> "$SUMMARY"; mc-stop "$target" --confirm >/dev/null 2>&1 || true; return 1; }
+
+    mcc_root="$(dirname "$cfg")"
+    local input_file="/tmp/mcc-debug/$session/mcc_input.txt"
+    local pid_file="/tmp/mcc-debug/$session/mcc.pid"
+    : > "$input_file"
+    (
+        cd "$mcc_root" || exit 1
+        printf '%s\n' "$$" > "$pid_file"
+        exec env MCC_FILE_INPUT=1 MCC_INPUT_FILE="$input_file" dotnet run --project "$REPO_ROOT/MinecraftClient" -c Release --no-build > "$log_file" 2>&1
+    ) &
+    local mcc_pid=$!
+    printf '%s\n' "$mcc_pid" > "$pid_file"
+
+    local ok=0
+    if ! wait_for_file_pattern_local "$log_file" "Server was successfully joined" 40; then
+        FAIL_DETAIL="MCC did not join server"
+        ok=1
+    else
+        setup_player "$rcon_port" "$username" || { FAIL_DETAIL="player setup failed after join"; ok=1; }
+        setup_area "$rcon_port" || { ok=1; }
+        setup_player "$rcon_port" "$username" || { FAIL_DETAIL="player setup failed after area setup"; ok=1; }
+        sleep 2
+        if [[ -z "${FAIL_DETAIL:-}" ]]; then
+            mcc-cmd --session "$session" "script $script_file" >/dev/null
+            if wait_for_file_pattern_local "$log_file" "ISSUE3112_REPRO_PASS" 30; then
+                ok=0
+            else
+                FAIL_DETAIL="Issue #3112 repro did not pass"
+                ok=1
+            fi
+        fi
+    fi
+
+    kill "$mcc_pid" >/dev/null 2>&1 || true
+    wait "$mcc_pid" >/dev/null 2>&1 || true
+    mc-stop "$target" --confirm >/dev/null 2>&1 || true
+    wait_for_server_stop "$target" >/dev/null 2>&1 || true
+
+    if [[ "$ok" -eq 0 ]]; then
+        printf '%s\tPASS\tIssue #3112 mirrored inventory script\t%s\n' "issue3112-$version" "$log_file" >> "$SUMMARY"
+        echo "PASS issue3112 $version"
+        return 0
+    fi
+
+    printf '%s\tFAIL\t%s\t%s\n' "issue3112-$version" "${FAIL_DETAIL:-unknown failure}" "$log_file" >> "$SUMMARY"
+    echo "${FAIL_DETAIL:-unknown failure}" >&2
+    echo "FAIL issue3112 $version"
+    return 1
+}
+
+overall=0
+for version in $VERSIONS; do
+    if ! run_one_version "$version"; then
+        overall=1
+        [[ "$STOP_ON_FAIL" == "1" ]] && break
+    fi
+done
+
+echo "SUMMARY=$SUMMARY"
+
+if [[ "$RUN_ISSUE_SCRIPT" == "1" && "$overall" -eq 0 ]]; then
+    if ! run_issue3112_repro "$ISSUE_VERSION"; then
+        overall=1
+    fi
+    echo "SUMMARY=$SUMMARY"
+fi
+
+exit "$overall"