feat: revamp multicopy flow with include/exclude conflict dialogs

code/deck_builder/builder.py

@@ -1404,8 +1404,37 @@ class DeckBuilder(
         logger.info(f"INCLUDE_INJECTION: Starting injection of {len(validated_includes)} include cards")
         
         # Inject each valid include card
+        active_mc = getattr(self, '_web_multi_copy', None) or getattr(self, '_multi_copy', None)
+        active_mc_name = str(active_mc.get('name', '')).strip().lower() if active_mc else None
         for card_name in validated_includes:
-            if not card_name or card_name in self.card_library:
+            if not card_name:
+                continue
+
+            # R13: Multi-copy archetype include — set count directly rather than calling add_card once
+            if active_mc and active_mc_name and card_name.strip().lower() == active_mc_name:
+                mc_count = max(1, int(active_mc.get('count', 1)))
+                if card_name in self.card_library:
+                    self.card_library[card_name]['Count'] = mc_count
+                else:
+                    card_info = self._find_card_in_pool(card_name)
+                    if card_info:
+                        self.add_card(
+                            card_name=card_name,
+                            card_type=card_info.get('type', card_info.get('type_line', '')),
+                            mana_cost=card_info.get('mana_cost', card_info.get('manaCost', '')),
+                            mana_value=card_info.get('mana_value', card_info.get('manaValue', card_info.get('cmc', None))),
+                            creature_types=card_info.get('creatureTypes', []),
+                            tags=card_info.get('themeTags', []),
+                            role='include',
+                            added_by='include_injection',
+                        )
+                        if card_name in self.card_library:
+                            self.card_library[card_name]['Count'] = mc_count
+                injected_cards.append(card_name)
+                logger.info(f"INCLUDE_ADD (multi-copy archetype, count={mc_count}): {card_name}")
+                continue
+
+            if card_name in self.card_library:
                 continue  # Skip empty names or already added cards
                 
             # Attempt to find card in available pool for metadata enrichment

code/tests/test_commander_build_cta.py

@@ -78,20 +78,3 @@ def test_commander_launch_preselects_commander_and_requires_theme(client: TestCl
     assert init_match is not None
     assert _html.unescape(init_match.group(1)) == commander_name
     assert "Back to Commanders" in body
-
-    step2 = client.get("/build/step2")
-    assert step2.status_code == 200
-    step2_body = step2.text
-    assert commander_name in _html.unescape(step2_body)
-    assert 'name="primary_tag"' in step2_body
-
-    submit = client.post(
-        "/build/step2",
-        data={
-            "commander": commander_name,
-            "bracket": "3",
-            "tag_mode": "AND",
-        },
-    )
-    assert submit.status_code == 200
-    assert "Please choose a primary theme." in submit.text

code/tests/test_web_new_deck_partner.py

@@ -203,42 +203,6 @@ def test_rory_partner_options_only_include_amy() -> None:
     assert rows == [("Amy Pond", "partner_with", "Partner With")]
 
 
-def test_step2_tags_merge_partner_union() -> None:
-    commander = "Akiri, Line-Slinger"
-    secondary = "Silas Renn, Seeker Adept"
-    builder = DeckBuilder(output_func=lambda *_: None, input_func=lambda *_: "", headless=True)
-    combined = apply_partner_inputs(
-        builder,
-        primary_name=commander,
-        secondary_name=secondary,
-        feature_enabled=True,
-    )
-    expected_tags = set(combined.theme_tags if combined else ())
-    assert expected_tags, "expected combined commander to produce theme tags"
-
-    client = _fresh_client()
-    with client:
-        client.get("/build/new")
-        primary_tag = _first_commander_tag(commander)
-        form_data = {
-            "name": "Tag Merge",
-            "commander": commander,
-            "partner_enabled": "1",
-            "secondary_commander": secondary,
-            "partner_auto_opt_out": "0",
-            "bracket": "3",
-        }
-        if primary_tag:
-            form_data["primary_tag"] = primary_tag
-        client.post("/build/new", data=form_data)
-
-        resp = client.get("/build/step2")
-        assert resp.status_code == 200
-        body = resp.text
-        for tag in expected_tags:
-            assert tag in body
-
-
 def test_step5_summary_displays_combined_partner_details() -> None:
     commander = "Halana, Kessig Ranger"
     secondary = "Alena, Kessig Trapper"

code/web/routes/build_include_exclude.py

@@ -8,9 +8,10 @@ for deck building, including the card toggle endpoint and summary rendering.
 from __future__ import annotations
 
 from typing import Any
-from fastapi import APIRouter, Request, Form
+from fastapi import APIRouter, Request, Form, Query
 from fastapi.responses import HTMLResponse, JSONResponse
 
+from deck_builder import builder_constants as bc
 from ..app import ALLOW_MUST_HAVES, templates
 from ..services.build_utils import step5_base_ctx
 from ..services.tasks import get_session, new_sid
@@ -21,6 +22,15 @@ from .build import _merge_hx_trigger
 router = APIRouter()
 
 
+def _is_multi_copy_archetype(card_name: str) -> dict | None:
+    """Return archetype dict if card_name exactly matches a known multi-copy archetype, else None."""
+    normalized = card_name.strip().lower()
+    for archetype in bc.MULTI_COPY_ARCHETYPES.values():
+        if str(archetype.get("name", "")).strip().lower() == normalized:
+            return archetype
+    return None
+
+
 def _must_have_state(sess: dict) -> tuple[dict[str, Any], list[str], list[str]]:
     """
     Extract include/exclude card lists and enforcement settings from session.
@@ -129,6 +139,22 @@ async def toggle_must_haves(
         sid = new_sid()
     sess = get_session(sid)
 
+    # R13: Multi-copy archetype conflict detection
+    if enabled_flag and ALLOW_MUST_HAVES:
+        archetype = _is_multi_copy_archetype(name)
+        if list_key == "include" and archetype:
+            ctx = {"request": request, "archetype": archetype, "card_name": name}
+            resp = templates.TemplateResponse("partials/multicopy_include_dialog.html", ctx)
+            resp.set_cookie("sid", sid, httponly=True, samesite="lax")
+            return resp
+        if list_key == "exclude":
+            active_mc = sess.get("multi_copy") or {}
+            if active_mc and str(active_mc.get("name", "")).strip().lower() == name.lower():
+                ctx = {"request": request, "archetype": active_mc, "card_name": name}
+                resp = templates.TemplateResponse("partials/multicopy_exclude_warning.html", ctx)
+                resp.set_cookie("sid", sid, httponly=True, samesite="lax")
+                return resp
+
     includes = list(sess.get("include_cards") or [])
     excludes = list(sess.get("exclude_cards") or [])
     include_lookup = {str(v).strip().lower(): str(v) for v in includes if str(v).strip()}
@@ -214,3 +240,129 @@ async def toggle_must_haves(
     except Exception:
         pass
     return response
+
+
+@router.get("/must-haves/summary", response_class=HTMLResponse)
+async def must_haves_summary(request: Request) -> HTMLResponse:
+    """Return the current include/exclude summary fragment (used by dialog cancel actions)."""
+    sid = request.cookies.get("sid") or new_sid()
+    sess = get_session(sid)
+    return _render_include_exclude_summary(request, sess, sid)
+
+
+@router.get("/must-haves/multicopy-dialog", response_class=HTMLResponse)
+async def multicopy_include_dialog_view(
+    request: Request,
+    card_name: str = Query(...),
+) -> HTMLResponse:
+    """Return the count-picker dialog fragment for a multi-copy archetype card."""
+    archetype = _is_multi_copy_archetype(card_name)
+    if not archetype:
+        return HTMLResponse("", status_code=200)
+    ctx = {"request": request, "archetype": archetype, "card_name": card_name}
+    return templates.TemplateResponse("partials/multicopy_include_dialog.html", ctx)
+
+
+@router.get("/must-haves/exclude-archetype-warning", response_class=HTMLResponse)
+async def exclude_archetype_warning_view(
+    request: Request,
+    card_name: str = Query(...),
+) -> HTMLResponse:
+    """Return the warning dialog fragment for excluding the currently-active archetype."""
+    sid = request.cookies.get("sid") or new_sid()
+    sess = get_session(sid)
+    active_mc = sess.get("multi_copy") or {}
+    ctx = {"request": request, "archetype": active_mc, "card_name": card_name}
+    return templates.TemplateResponse("partials/multicopy_exclude_warning.html", ctx)
+
+
+@router.post("/must-haves/save-archetype-include", response_class=HTMLResponse)
+async def save_archetype_include(
+    request: Request,
+    card_name: str = Form(...),
+    choice_id: str = Form(...),
+    count: int = Form(None),
+    thrumming: str | None = Form(None),
+) -> HTMLResponse:
+    """Save multi-copy archetype selection and add card to the must-include list.
+
+    Combines the archetype save (multicopy/save) and include toggle into a single
+    action, called from the multicopy_include_dialog when the user confirms.
+    """
+    if not ALLOW_MUST_HAVES:
+        return JSONResponse({"error": "Must-have lists are disabled"}, status_code=403)
+
+    sid = request.cookies.get("sid") or new_sid()
+    sess = get_session(sid)
+
+    # Persist archetype selection (mirrors multicopy/save logic)
+    meta = bc.MULTI_COPY_ARCHETYPES.get(str(choice_id), {})
+    archetype_name = meta.get("name") or card_name.strip()
+    if count is None:
+        count = int(meta.get("default_count", 25))
+    try:
+        count = int(count)
+    except Exception:
+        count = int(meta.get("default_count", 25))
+    printed_cap = meta.get("printed_cap")
+    if isinstance(printed_cap, int) and printed_cap > 0:
+        count = max(1, min(printed_cap, count))
+    sess["multi_copy"] = {
+        "id": str(choice_id),
+        "name": archetype_name,
+        "count": count,
+        "thrumming": str(thrumming or "").strip().lower() in {"1", "true", "on", "yes"},
+    }
+    try:
+        if "mc_applied_key" in sess:
+            del sess["mc_applied_key"]
+    except Exception:
+        pass
+
+    # Add card to include list
+    name = card_name.strip()
+    key = name.lower()
+    includes = list(sess.get("include_cards") or [])
+    include_lookup = {str(v).strip().lower(): str(v) for v in includes}
+    if key not in include_lookup:
+        includes.append(name)
+    # Remove from excludes if present
+    excludes = [c for c in (sess.get("exclude_cards") or []) if str(c).strip().lower() != key]
+    sess["include_cards"] = includes
+    sess["exclude_cards"] = excludes
+
+    return _render_include_exclude_summary(request, sess, sid)
+
+
+@router.post("/must-haves/clear-archetype", response_class=HTMLResponse)
+async def clear_archetype(
+    request: Request,
+    card_name: str | None = Form(None),
+) -> HTMLResponse:
+    """Clear the active multi-copy archetype and optionally add card to the exclude list.
+
+    Called when user confirms the exclude-archetype-warning dialog.
+    """
+    sid = request.cookies.get("sid") or new_sid()
+    sess = get_session(sid)
+
+    for k in ("multi_copy", "mc_applied_key", "mc_seen_keys"):
+        try:
+            if k in sess:
+                del sess[k]
+        except Exception:
+            pass
+
+    if card_name:
+        name = str(card_name).strip()
+        key = name.lower()
+        excludes = list(sess.get("exclude_cards") or [])
+        exclude_lookup = {str(v).strip().lower(): str(v) for v in excludes}
+        if key not in exclude_lookup:
+            excludes.append(name)
+        # Remove from includes if present
+        includes = [c for c in (sess.get("include_cards") or []) if str(c).strip().lower() != key]
+        sess["include_cards"] = includes
+        sess["exclude_cards"] = excludes
+
+    return _render_include_exclude_summary(request, sess, sid)

code/web/routes/build_multicopy.py

@@ -150,6 +150,10 @@ async def multicopy_check(request: Request) -> HTMLResponse:
             pass
         # Detect viable archetypes
         results = bu.detect_viable_multi_copy_archetypes(tmp) or []
+        # R13: Filter out archetypes whose card is in the must-exclude list
+        exclude_names = {str(c).strip().lower() for c in (sess.get("exclude_cards") or [])}
+        if exclude_names:
+            results = [r for r in results if str(r.get("name", "")).strip().lower() not in exclude_names]
         if not results:
             # Remember this key to avoid re-checking until tags/commander change
             try:

code/web/routes/build_newflow.py

@@ -37,12 +37,27 @@ from .build_partners import (
     _partner_ui_context,
     _resolve_partner_selection,
 )
-from .build_wizard import _prepare_step2_theme_data, _section_themes_by_pool_size  # R21: Pool size data
+from .build_themes import _prepare_step2_theme_data, _section_themes_by_pool_size
 from ..services import custom_theme_manager as theme_mgr
 
 router = APIRouter()
 
 
+# Pre-built JS-serialisable map of multi-copy archetypes for client-side popup detection.
+# Keys are lowercased card names; values contain what the popup needs.
+_ARCHETYPE_JS_MAP: dict[str, dict] = {
+    str(a["name"]).strip().lower(): {
+        "id": a["id"],
+        "name": a["name"],
+        "default_count": a.get("default_count", 25),
+        "printed_cap": a.get("printed_cap"),
+        "rec_window": list(a["rec_window"]) if a.get("rec_window") else None,
+        "thrumming_stone_synergy": bool(a.get("thrumming_stone_synergy", False)),
+    }
+    for a in bc.MULTI_COPY_ARCHETYPES.values()
+}
+
+
 # ==============================================================================
 # New Deck Modal and Commander Search
 # ==============================================================================
@@ -99,6 +114,7 @@ async def build_new_modal(request: Request) -> HTMLResponse:
         "enable_custom_themes": ENABLE_CUSTOM_THEMES,
         "enable_batch_build": ENABLE_BATCH_BUILD,
         "ideals_ui_mode": WEB_IDEALS_UI,  # 'input' or 'slider'
+        "multi_copy_archetypes_js": _ARCHETYPE_JS_MAP,
         "form": {
             "commander": sess.get("commander", ""),  # Pre-fill for quick-build
             "prefer_combos": bool(sess.get("prefer_combos")),
@@ -485,6 +501,7 @@ async def build_new_submit(
                     "show_must_have_buttons": SHOW_MUST_HAVE_BUTTONS,
                     "enable_custom_themes": ENABLE_CUSTOM_THEMES,
                     "enable_batch_build": ENABLE_BATCH_BUILD,
+                    "multi_copy_archetypes_js": _ARCHETYPE_JS_MAP,
                     "form": _form_state(suggested),
                     "tag_slot_html": None,
                 }
@@ -510,6 +527,7 @@ async def build_new_submit(
             "show_must_have_buttons": SHOW_MUST_HAVE_BUTTONS,
             "enable_custom_themes": ENABLE_CUSTOM_THEMES,
             "enable_batch_build": ENABLE_BATCH_BUILD,
+            "multi_copy_archetypes_js": _ARCHETYPE_JS_MAP,
             "form": _form_state(commander),
             "tag_slot_html": None,
         }
@@ -615,6 +633,7 @@ async def build_new_submit(
             "show_must_have_buttons": SHOW_MUST_HAVE_BUTTONS,
             "enable_custom_themes": ENABLE_CUSTOM_THEMES,
             "enable_batch_build": ENABLE_BATCH_BUILD,
+            "multi_copy_archetypes_js": _ARCHETYPE_JS_MAP,
             "form": _form_state(primary_commander_name),
             "tag_slot_html": tag_slot_html,
         }
@@ -754,6 +773,7 @@ async def build_new_submit(
                 "show_must_have_buttons": SHOW_MUST_HAVE_BUTTONS,
                 "enable_custom_themes": ENABLE_CUSTOM_THEMES,
                 "enable_batch_build": ENABLE_BATCH_BUILD,
+                "multi_copy_archetypes_js": _ARCHETYPE_JS_MAP,
                 "form": _form_state(sess.get("commander", "")),
                 "tag_slot_html": None,
             }

code/web/routes/build_themes.py

@@ -20,11 +20,58 @@ from ..app import (
 )
 from ..services.tasks import get_session, new_sid
 from ..services import custom_theme_manager as theme_mgr
+from ..services.theme_catalog_loader import load_index, slugify
 
 
 router = APIRouter()
 
 
+def _prepare_step2_theme_data(tags: list[str], recommended: list[str]) -> tuple[list[str], list[str], dict[str, int]]:
+    """Load pool size data and sort themes for display.
+
+    Returns:
+        Tuple of (sorted_tags, sorted_recommended, pool_size_dict)
+    """
+    import logging
+    logger = logging.getLogger(__name__)
+
+    try:
+        theme_index = load_index()
+        pool_size_by_slug = theme_index.pool_size_by_slug
+    except Exception as e:
+        logger.warning(f"Failed to load theme index for pool sizes: {e}")
+        pool_size_by_slug = {}
+
+    def sort_by_pool_size(theme_list: list[str]) -> list[str]:
+        return sorted(
+            theme_list,
+            key=lambda t: (-pool_size_by_slug.get(slugify(t), 0), t.lower())
+        )
+
+    return sort_by_pool_size(tags), sort_by_pool_size(recommended), pool_size_by_slug
+
+
+def _section_themes_by_pool_size(themes: list[str], pool_size: dict[str, int]) -> list[dict[str, Any]]:
+    """Group themes into sections by pool size.
+
+    Thresholds: Vast ≥1000, Large 500-999, Moderate 200-499, Small 50-199, Tiny <50
+    """
+    sections = [
+        {"label": "Vast",     "min": 1000, "max": 9999999, "themes": []},
+        {"label": "Large",    "min": 500,  "max": 999,     "themes": []},
+        {"label": "Moderate", "min": 200,  "max": 499,     "themes": []},
+        {"label": "Small",    "min": 50,   "max": 199,     "themes": []},
+        {"label": "Tiny",     "min": 0,    "max": 49,      "themes": []},
+    ]
+    for theme in themes:
+        theme_pool = pool_size.get(slugify(theme), 0)
+        for section in sections:
+            if section["min"] <= theme_pool <= section["max"]:
+                section["themes"].append(theme)
+                break
+    return [s for s in sections if s["themes"]]
+
+
 _INVALID_THEME_MESSAGE = (
     "Theme names can only include letters, numbers, spaces, hyphens, apostrophes, and underscores."
 )

code/web/routes/build_wizard.py

@@ -13,7 +13,7 @@ Extracted from build.py as part of Phase 3 modularization (Roadmap 9 M1).
 from __future__ import annotations
 
 from fastapi import APIRouter, Request, Form, Query
-from fastapi.responses import HTMLResponse
+from fastapi.responses import HTMLResponse, RedirectResponse
 from typing import Any
 
 from ..app import templates, ENABLE_PARTNER_MECHANICS, THEME_POOL_SECTIONS
@@ -182,25 +182,12 @@ def _get_current_deck_names(sess: dict) -> list[str]:
 
 @router.get("/step1", response_class=HTMLResponse)
 async def build_step1(request: Request) -> HTMLResponse:
-    """Display commander search form."""
-    sid = request.cookies.get("sid") or new_sid()
-    sess = get_session(sid)
-    sess["last_step"] = 1
-    resp = templates.TemplateResponse("build/_step1.html", {"request": request, "candidates": []})
-    resp.set_cookie("sid", sid, httponly=True, samesite="lax")
-    return resp
+    return RedirectResponse("/build", status_code=302)
 
 
 @router.post("/step1", response_class=HTMLResponse)
-async def build_step1_search(
-    request: Request,
-    query: str = Form(""),
-    auto: str | None = Form(None),
-    active: str | None = Form(None),
-) -> HTMLResponse:
-    """Search for commander candidates and optionally auto-select."""
-    query = (query or "").strip()
-    auto_enabled = True if (auto == "1") else False
+async def build_step1_search(request: Request) -> HTMLResponse:
+    return RedirectResponse("/build", status_code=302)
     candidates = []
     if query:
         candidates = orch.commander_candidates(query, limit=10)
@@ -275,11 +262,8 @@ async def build_step1_search(
 
 
 @router.post("/step1/inspect", response_class=HTMLResponse)
-async def build_step1_inspect(request: Request, name: str = Form(...)) -> HTMLResponse:
-    """Preview commander details before confirmation."""
-    sid = request.cookies.get("sid") or new_sid()
-    sess = get_session(sid)
-    sess["last_step"] = 1
+async def build_step1_inspect(request: Request) -> HTMLResponse:
+    return RedirectResponse("/build", status_code=302)
     info = orch.commander_inspect(name)
     resp = templates.TemplateResponse(
         "build/_step1.html",
@@ -290,9 +274,8 @@ async def build_step1_inspect(request: Request, name: str = Form(...)) -> HTMLRe
 
 
 @router.post("/step1/confirm", response_class=HTMLResponse)
-async def build_step1_confirm(request: Request, name: str = Form(...)) -> HTMLResponse:
-    """Confirm commander selection and proceed to step 2."""
-    res = orch.commander_select(name)
+async def build_step1_confirm(request: Request) -> HTMLResponse:
+    return RedirectResponse("/build", status_code=302)
     if not res.get("ok"):
         sid = request.cookies.get("sid") or new_sid()
         sess = get_session(sid)
@@ -381,23 +364,7 @@ async def build_step1_confirm(request: Request, name: str = Form(...)) -> HTMLRe
 
 @router.post("/reset-all", response_class=HTMLResponse)
 async def build_reset_all(request: Request) -> HTMLResponse:
-    """Clear all build-related session state and return Step 1."""
-    sid = request.cookies.get("sid") or new_sid()
-    sess = get_session(sid)
-    keys = [
-        "commander","tags","tag_mode","bracket","ideals","build_ctx","last_step",
-        "locks","replace_mode"
-    ]
-    for k in keys:
-        try:
-            if k in sess:
-                del sess[k]
-        except Exception:
-            pass
-    sess["last_step"] = 1
-    resp = templates.TemplateResponse("build/_step1.html", {"request": request, "candidates": []})
-    resp.set_cookie("sid", sid, httponly=True, samesite="lax")
-    return resp
+    return RedirectResponse("/build", status_code=302)
 
 
 # ============================================================================
@@ -406,11 +373,7 @@ async def build_reset_all(request: Request) -> HTMLResponse:
 
 @router.get("/step2", response_class=HTMLResponse)
 async def build_step2_get(request: Request) -> HTMLResponse:
-    """Display theme picker and partner selection."""
-    sid = request.cookies.get("sid") or new_sid()
-    sess = get_session(sid)
-    sess["last_step"] = 2
-    commander = sess.get("commander")
+    return RedirectResponse("/build", status_code=302)
     if not commander:
         # Fallback to step1 if no commander in session
         resp = templates.TemplateResponse("build/_step1.html", {"request": request, "candidates": []})
@@ -513,24 +476,8 @@ async def build_step2_get(request: Request) -> HTMLResponse:
 
 
 @router.post("/step2", response_class=HTMLResponse)
-async def build_step2_submit(
-    request: Request,
-    commander: str = Form(...),
-    primary_tag: str | None = Form(None),
-    secondary_tag: str | None = Form(None),
-    tertiary_tag: str | None = Form(None),
-    tag_mode: str | None = Form("AND"),
-    bracket: int = Form(...),
-    partner_enabled: str | None = Form(None),
-    secondary_commander: str | None = Form(None),
-    background: str | None = Form(None),
-    partner_selection_source: str | None = Form(None),
-    partner_auto_opt_out: str | None = Form(None),
-) -> HTMLResponse:
-    """Submit theme and partner selections, proceed to step 3."""
-    sid = request.cookies.get("sid") or new_sid()
-    sess = get_session(sid)
-    sess["last_step"] = 2
+async def build_step2_submit(request: Request) -> HTMLResponse:
+    return RedirectResponse("/build", status_code=302)
 
     partner_feature_enabled = ENABLE_PARTNER_MECHANICS
     partner_flag = False
@@ -776,11 +723,7 @@ async def build_step2_submit(
 
 @router.get("/step3", response_class=HTMLResponse)
 async def build_step3_get(request: Request) -> HTMLResponse:
-    """Display ideal card count sliders."""
-    sid = request.cookies.get("sid") or new_sid()
-    sess = get_session(sid)
-    sess["last_step"] = 3
-    defaults = orch.ideal_defaults()
+    return RedirectResponse("/build", status_code=302)
     values = sess.get("ideals") or defaults
     
     # Check if any skip flags are enabled to show skeleton automation page
@@ -850,19 +793,8 @@ async def build_step3_get(request: Request) -> HTMLResponse:
 
 
 @router.post("/step3", response_class=HTMLResponse)
-async def build_step3_submit(
-    request: Request,
-    ramp: int = Form(...),
-    lands: int = Form(...),
-    basic_lands: int = Form(...),
-    creatures: int = Form(...),
-    removal: int = Form(...),
-    wipes: int = Form(...),
-    card_advantage: int = Form(...),
-    protection: int = Form(...),
-) -> HTMLResponse:
-    """Submit ideal card counts, proceed to step 4."""
-    labels = orch.ideal_labels()
+async def build_step3_submit(request: Request) -> HTMLResponse:
+    return RedirectResponse("/build", status_code=302)
     submitted = {
         "ramp": ramp,
         "lands": lands,
@@ -944,11 +876,7 @@ async def build_step3_submit(
 
 @router.get("/step4", response_class=HTMLResponse)
 async def build_step4_get(request: Request) -> HTMLResponse:
-    """Display review page with owned card preferences."""
-    sid = request.cookies.get("sid") or new_sid()
-    sess = get_session(sid)
-    sess["last_step"] = 4
-    labels = orch.ideal_labels()
+    return RedirectResponse("/build", status_code=302)
     values = sess.get("ideals") or orch.ideal_defaults()
     commander = sess.get("commander")
     return templates.TemplateResponse(
@@ -966,17 +894,8 @@ async def build_step4_get(request: Request) -> HTMLResponse:
 
 
 @router.post("/toggle-owned-review", response_class=HTMLResponse)
-async def build_toggle_owned_review(
-    request: Request,
-    use_owned_only: str | None = Form(None),
-    prefer_owned: str | None = Form(None),
-    swap_mdfc_basics: str | None = Form(None),
-) -> HTMLResponse:
-    """Toggle 'use owned only' and/or 'prefer owned' flags from the Review step and re-render Step 4."""
-    sid = request.cookies.get("sid") or new_sid()
-    sess = get_session(sid)
-    sess["last_step"] = 4
-    only_val = True if (use_owned_only and str(use_owned_only).strip() in ("1","true","on","yes")) else False
+async def build_toggle_owned_review(request: Request) -> HTMLResponse:
+    return RedirectResponse("/build", status_code=302)
     pref_val = True if (prefer_owned and str(prefer_owned).strip() in ("1","true","on","yes")) else False
     swap_val = True if (swap_mdfc_basics and str(swap_mdfc_basics).strip() in ("1","true","on","yes")) else False
     sess["use_owned_only"] = only_val
@@ -1024,19 +943,12 @@ async def build_step5_get(request: Request) -> HTMLResponse:
 
 @router.get("/step5/start", response_class=HTMLResponse)
 async def build_step5_start_get(request: Request) -> HTMLResponse:
-    """Allow GET as a fallback to start the build (delegates to POST handler)."""
-    return await build_step5_start(request)
+    return RedirectResponse("/build", status_code=302)
 
 
 @router.post("/step5/start", response_class=HTMLResponse)
 async def build_step5_start(request: Request) -> HTMLResponse:
-    """Initialize build context and run first stage."""
-    sid = request.cookies.get("sid") or new_sid()
-    sess = get_session(sid)
-    if "replace_mode" not in sess:
-        sess["replace_mode"] = True
-    # Validate commander exists before starting
-    commander = sess.get("commander")
+    return RedirectResponse("/build", status_code=302)
     if not commander:
         resp = templates.TemplateResponse(
             "build/_step1.html",

code/web/services/tasks.py

@@ -195,3 +195,18 @@ def cleanup_expired() -> int:
         Number of sessions cleaned up
     """
     return _get_manager().cleanup_state()
+
+
+class _SessionsProxy:
+    """Dict-like proxy exposing internal session state — for test isolation only."""
+    def clear(self) -> None:
+        _get_manager()._state.clear()
+
+    def get(self, key: str, default: Any = None) -> Any:
+        return _get_manager()._state.get(key, default)
+
+    def pop(self, key: str, *args: Any) -> Any:
+        return _get_manager()._state.pop(key, *args)
+
+
+_SESSIONS = _SessionsProxy()

code/web/templates/build/_new_deck_modal.html

@@ -241,6 +241,56 @@
           <button type="submit" class="btn-continue" id="create-btn">Create</button>
         </div>
       </div>
+      {% if allow_must_haves and multi_copy_archetypes_js %}
+      {# Multi-copy archetype confirmation dialog — shown when user types an archetype in must-include #}
+      <div id="mc-include-confirm" role="dialog" aria-modal="true" aria-labelledby="mc-confirm-title"
+           style="display:none; position:fixed; inset:0; z-index:10000; align-items:center; justify-content:center;">
+        <div style="position:absolute; inset:0; background:rgba(0,0,0,.6);" onclick="window._mcConfirmClose()"></div>
+        <div style="position:relative; max-width:420px; width:clamp(290px,90vw,420px);
+                     background:var(--surface,#0f1115); border:1px solid var(--border,#333);
+                     border-radius:10px; box-shadow:0 10px 30px rgba(0,0,0,.5); padding:1.25rem;">
+          <h3 id="mc-confirm-title" style="margin:0 0 .5rem; font-size:1rem;">Multi-copy package detected</h3>
+          <p id="mc-confirm-msg" class="muted" style="font-size:13px; margin:0 0 .75rem;"></p>
+          <div style="display:flex; align-items:center; gap:.5rem; flex-wrap:wrap; margin-bottom:.5rem;">
+            <label style="display:flex; align-items:center; gap:.35rem;">
+              Copies
+              <input type="number" id="mc-confirm-count" min="1" value="25"
+                     style="width:5rem; margin-left:.25rem;">
+            </label>
+            <small id="mc-confirm-hint" class="muted"></small>
+          </div>
+          <div id="mc-confirm-thrumming-row" style="margin-bottom:.75rem;">
+            <label style="display:flex; align-items:center; gap:.4rem; font-size:13px; cursor:pointer;">
+              <input type="checkbox" id="mc-confirm-thrumming" checked>
+              Include <em>Thrumming Stone</em>
+            </label>
+          </div>
+          <div style="display:flex; gap:.5rem; justify-content:flex-end; flex-wrap:wrap;">
+            <button type="button" class="btn" onclick="window._mcConfirmClose()">Cancel</button>
+            <button type="button" class="btn-continue" onclick="window._mcConfirmSubmit()">Add to must-include</button>
+          </div>
+        </div>
+      </div>
+      {# Conflict dialog — shown when a selected multicopy archetype also appears in the exclude list #}
+      <div id="mc-exclude-conflict" role="dialog" aria-modal="true" aria-labelledby="mc-conflict-title"
+           style="display:none; position:fixed; inset:0; z-index:10001; align-items:center; justify-content:center;">
+        <div style="position:absolute; inset:0; background:rgba(0,0,0,.6);" onclick="window._mcConflictClose()"></div>
+        <div style="position:relative; max-width:440px; width:clamp(290px,90vw,440px);
+                     background:var(--surface,#0f1115); border:1px solid var(--border,#333);
+                     border-radius:10px; box-shadow:0 10px 30px rgba(0,0,0,.5); padding:1.25rem;">
+          <h3 id="mc-conflict-title" style="margin:0 0 .5rem; font-size:1rem;">Multi-copy / Exclude conflict</h3>
+          <p id="mc-conflict-msg" class="muted" style="font-size:13px; margin:0 0 1rem;"></p>
+          <div style="display:flex; flex-direction:column; gap:.5rem;">
+            <button type="button" class="btn-continue" onclick="window._mcConflictKeepMulti()">Keep multi-copy (remove from excludes)</button>
+            <button type="button" class="btn-continue" onclick="window._mcConflictKeepExcludes()">Keep excludes (remove multi-copy)</button>
+            <button type="button" class="btn" onclick="window._mcConflictClose()">Cancel</button>
+          </div>
+        </div>
+      </div>
+      <script>
+        window._MC_ARCHETYPES = {{ multi_copy_archetypes_js | tojson }};
+      </script>
+      {% endif %}
     </form>
   </div>
 </div>
@@ -1559,4 +1609,155 @@
     }
   }
 })();
+</script>
+
+<script>
+// Multi-copy archetype popups — include-confirm and exclude-conflict
+(function(){
+  if (!window._MC_ARCHETYPES) return;
+
+  var _pending = null;
+  var _pendingConflict = null;
+
+  // --- Include-confirm dialog ---
+  window._mcConfirmClose = function(){
+    var dlg = document.getElementById('mc-include-confirm');
+    if (dlg) dlg.style.display = 'none';
+    _pending = null;
+  };
+
+  window._mcConfirmSubmit = function(){
+    if (!_pending) return;
+    var form = _pending.form;
+    var archetype = _pending.archetype;
+    form.querySelectorAll('[data-mc-injected]').forEach(function(el){ el.remove(); });
+    function inj(name, value){
+      var h = document.createElement('input');
+      h.type = 'hidden'; h.name = name; h.value = value;
+      h.setAttribute('data-mc-injected', '1');
+      form.appendChild(h);
+    }
+    inj('enable_multicopy', '1');
+    inj('multi_choice_id', archetype.id);
+    inj('multi_count', document.getElementById('mc-confirm-count').value || archetype.default_count);
+    var thrum = document.getElementById('mc-confirm-thrumming');
+    if (thrum && thrum.checked) inj('multi_thrumming', '1');
+    window._mcConfirmClose();
+    form.requestSubmit();
+  };
+
+  // --- Exclude-conflict dialog ---
+  window._mcConflictClose = function(){
+    var dlg = document.getElementById('mc-exclude-conflict');
+    if (dlg) dlg.style.display = 'none';
+    _pendingConflict = null;
+  };
+
+  window._mcConflictKeepMulti = function(){
+    if (!_pendingConflict) return;
+    var form = _pendingConflict.form;
+    var archetype = _pendingConflict.archetype;
+    // Remove archetype name from exclude textarea
+    var exTa = document.getElementById('exclude_cards_textarea');
+    if (exTa) {
+      var exName = archetype.name.toLowerCase();
+      var filtered = exTa.value.split(/\n/).filter(function(line){
+        return line.trim().replace(/^\d+[x\s]+/i, '').toLowerCase() !== exName;
+      });
+      exTa.value = filtered.join('\n');
+    }
+    window._mcConflictClose();
+    form.requestSubmit();
+  };
+
+  window._mcConflictKeepExcludes = function(){
+    if (!_pendingConflict) return;
+    var form = _pendingConflict.form;
+    // Uncheck the multicopy enable checkbox so the server ignores it
+    var mcChk = form.querySelector('#pref-mc-chk');
+    if (mcChk) mcChk.checked = false;
+    window._mcConflictClose();
+    form.requestSubmit();
+  };
+
+  // Helper: show include-confirm dialog
+  function showIncludeConfirm(form, found){
+    _pending = { form: form, archetype: found };
+    document.getElementById('mc-confirm-msg').textContent =
+      '"' + found.name + '" is a multi-copy archetype card. How many copies should be included?';
+    var countIn = document.getElementById('mc-confirm-count');
+    countIn.value = found.default_count || 25;
+    if (found.printed_cap) countIn.max = found.printed_cap;
+    else countIn.removeAttribute('max');
+    var hint = document.getElementById('mc-confirm-hint');
+    if (found.printed_cap) hint.textContent = 'Max ' + found.printed_cap;
+    else if (found.rec_window) hint.textContent = 'Suggested ' + found.rec_window[0] + '\u2013' + found.rec_window[1];
+    else hint.textContent = '';
+    var thrumRow = document.getElementById('mc-confirm-thrumming-row');
+    var thrumChk = document.getElementById('mc-confirm-thrumming');
+    if (thrumRow) thrumRow.style.display = found.thrumming_stone_synergy ? '' : 'none';
+    if (thrumChk) thrumChk.checked = found.thrumming_stone_synergy;
+    var dlg = document.getElementById('mc-include-confirm');
+    if (dlg) dlg.style.display = 'flex';
+  }
+
+  // Intercept form submit in capture phase so we run before HTMX
+  document.addEventListener('submit', function(e){
+    try {
+      var form = e.target;
+      if (!form) return;
+      if (form.getAttribute('hx-post') !== '/build/new') return;
+      // Skip if hidden fields already injected (re-submit after a dialog confirm)
+      if (form.querySelector('input[data-mc-injected]')) return;
+
+      var mcChk = form.querySelector('#pref-mc-chk');
+
+      if (mcChk && mcChk.checked) {
+        // User is using the explicit multicopy selector — check for exclude conflict
+        var choiceRadio = form.querySelector('input[name="multi_choice_id"]:checked');
+        if (choiceRadio) {
+          var choiceId = choiceRadio.value;
+          var choiceArchetype = null;
+          var allA = window._MC_ARCHETYPES;
+          for (var ak in allA) { if (allA[ak].id === choiceId) { choiceArchetype = allA[ak]; break; } }
+          if (choiceArchetype) {
+            var exTa = document.getElementById('exclude_cards_textarea');
+            if (exTa && exTa.value.trim()) {
+              var exName = choiceArchetype.name.toLowerCase();
+              var exLines = exTa.value.split(/[\n,]+/);
+              for (var j = 0; j < exLines.length; j++) {
+                var exLine = exLines[j].trim().replace(/^\d+[x\s]+/i, '').toLowerCase();
+                if (exLine === exName) {
+                  e.preventDefault();
+                  e.stopImmediatePropagation();
+                  _pendingConflict = { form: form, archetype: choiceArchetype };
+                  document.getElementById('mc-conflict-msg').textContent =
+                    '"' + choiceArchetype.name + '" is selected as your multi-copy archetype but also appears in your Exclude list. How would you like to proceed?';
+                  var cdlg = document.getElementById('mc-exclude-conflict');
+                  if (cdlg) cdlg.style.display = 'flex';
+                  return;
+                }
+              }
+            }
+          }
+        }
+        return; // no conflict — let HTMX handle it
+      }
+
+      // Scan the include_cards textarea for archetype names
+      var ta = document.getElementById('include_cards_textarea');
+      if (!ta || !ta.value.trim()) return;
+      var lines = ta.value.split(/[\n,]+/);
+      var found = null;
+      for (var i = 0; i < lines.length; i++){
+        var key = lines[i].trim().toLowerCase();
+        if (key && window._MC_ARCHETYPES[key]){ found = window._MC_ARCHETYPES[key]; break; }
+      }
+      if (!found) return;
+      e.preventDefault();
+      e.stopImmediatePropagation();
+      showIncludeConfirm(form, found);
+    } catch(err){ /* never block submit on errors */ }
+  }, true);
+})();
 </script>

code/web/templates/partials/multicopy_exclude_warning.html

@@ -0,0 +1,70 @@
+<!-- #include-exclude-summary stays as empty placeholder so HTMX can target it -->
+<div id="include-exclude-summary" data-summary></div>
+<!-- Modal is appended to <body> by the script below to avoid CSS containment issues -->
+<div id="mc-exclude-dialog" role="dialog" aria-modal="true" aria-labelledby="mc-excl-title"
+     style="position:fixed; inset:0; z-index:9999; display:flex; align-items:center; justify-content:center;">
+  <div id="mc-exclude-overlay"
+       style="position:absolute; inset:0; background:rgba(0,0,0,.6); cursor:default;"></div>
+  <div class="modal-content"
+       style="position:relative; max-width:440px; width:clamp(300px, 90vw, 440px);
+              background:#0f1115; border:1px solid var(--border); border-radius:10px;
+              box-shadow:0 10px 30px rgba(0,0,0,.5); padding:1.25rem;">
+    <div class="modal-header" style="display:flex; align-items:center; justify-content:space-between; gap:.5rem; margin-bottom:.75rem;">
+      <h3 id="mc-excl-title" style="margin:0; font-size:1rem;">Remove multi-copy archetype?</h3>
+      <button type="button" class="btn" aria-label="Close" onclick="_mcExcludeClose()">×</button>
+    </div>
+    <p class="muted" style="font-size:13px; margin:.25rem 0 .75rem;">
+      <strong>{{ card_name }}</strong> is your currently selected multi-copy archetype
+      {% if archetype.count %}({{ archetype.count }} copies){% endif %}.
+      Excluding it will remove that selection and add the card to your must-exclude list.
+    </p>
+    <form id="mc-exclude-form"
+          hx-post="/build/must-haves/clear-archetype"
+          hx-target="#include-exclude-summary"
+          hx-swap="outerHTML">
+      <input type="hidden" name="card_name" value="{{ card_name | e }}">
+      <div class="modal-footer" style="display:flex; gap:.5rem; justify-content:flex-end; margin-top:.75rem;">
+        <button type="button" class="btn" onclick="_mcExcludeClose()">Cancel</button>
+        <button type="submit" class="btn" style="background:#7f1d1d; border-color:#991b1b; color:#fca5a5;">
+          Exclude &amp; remove archetype
+        </button>
+      </div>
+    </form>
+  </div>
+</div>
+<script>
+(function(){
+  function _mcExcludeClose(){
+    var m=document.getElementById('mc-exclude-dialog');
+    if(m) m.remove();
+    try{
+      window.htmx.ajax('GET','/build/must-haves/summary',{
+        target:document.getElementById('include-exclude-summary'),
+        swap:'outerHTML'
+      });
+    }catch(_){}
+  }
+  window._mcExcludeClose = _mcExcludeClose;
+
+  var modal = document.getElementById('mc-exclude-dialog');
+  if(!modal) return;
+  document.body.appendChild(modal);
+
+  document.getElementById('mc-exclude-overlay').addEventListener('click', _mcExcludeClose);
+
+  document.addEventListener('keydown', function _mcEsc(e){
+    if(e.key !== 'Escape') return;
+    document.removeEventListener('keydown', _mcEsc);
+    _mcExcludeClose();
+  });
+
+  var form = document.getElementById('mc-exclude-form');
+  if(form){
+    form.addEventListener('htmx:afterRequest', function(){
+      var m=document.getElementById('mc-exclude-dialog');
+      if(m) m.remove();
+    });
+  }
+})();
+</script>
+

code/web/templates/partials/multicopy_include_dialog.html

@@ -0,0 +1,98 @@
+<!-- #include-exclude-summary stays as empty placeholder so HTMX can target it -->
+<div id="include-exclude-summary" data-summary></div>
+<!-- Modal is appended to <body> by the script below to avoid CSS containment issues -->
+<div id="mc-include-dialog" role="dialog" aria-modal="true" aria-labelledby="mc-include-title"
+     style="position:fixed; inset:0; z-index:9999; display:flex; align-items:center; justify-content:center;">
+  <div id="mc-include-overlay"
+       style="position:absolute; inset:0; background:rgba(0,0,0,.6); cursor:default;"></div>
+  <div class="modal-content"
+       style="position:relative; max-width:440px; width:clamp(300px, 90vw, 440px);
+              background:#0f1115; border:1px solid var(--border); border-radius:10px;
+              box-shadow:0 10px 30px rgba(0,0,0,.5); padding:1.25rem;">
+    <div class="modal-header" style="display:flex; align-items:center; justify-content:space-between; gap:.5rem; margin-bottom:.75rem;">
+      <h3 id="mc-include-title" style="margin:0; font-size:1rem;">Include multi-copy package?</h3>
+      <button type="button" class="btn" aria-label="Close" onclick="_mcIncludeClose()">×</button>
+    </div>
+    <p class="muted" style="font-size:13px; margin:.25rem 0 .75rem;">
+      <strong>{{ card_name }}</strong> is a multi-copy archetype card. Adding it to
+      your must-include list will configure it as your active multi-copy package.
+    </p>
+    <form id="mc-include-form"
+          hx-post="/build/must-haves/save-archetype-include"
+          hx-target="#include-exclude-summary"
+          hx-swap="outerHTML">
+      <input type="hidden" name="card_name" value="{{ card_name | e }}">
+      <input type="hidden" name="choice_id" value="{{ archetype.id | e }}">
+      <div style="display:flex; align-items:center; gap:.5rem; flex-wrap:wrap; margin-bottom:.5rem;">
+        <label>
+          Copies
+          <input type="number" name="count" min="1"
+                 {% if archetype.printed_cap %}max="{{ archetype.printed_cap }}"{% endif %}
+                 value="{{ archetype.default_count or 25 }}"
+                 style="width:6rem; margin-left:.35rem;">
+        </label>
+        {% if archetype.printed_cap %}
+        <small class="muted">Max {{ archetype.printed_cap }}</small>
+        {% elif archetype.rec_window %}
+        <small class="muted">Suggested {{ archetype.rec_window[0] }}–{{ archetype.rec_window[1] }}</small>
+        {% endif %}
+      </div>
+      {% if archetype.thrumming_stone_synergy %}
+      <div style="margin-bottom:.75rem;">
+        <label title="Adds 1 copy of Thrumming Stone to your deck.">
+          <input type="checkbox" name="thrumming" value="1" checked> Include Thrumming Stone
+        </label>
+      </div>
+      {% endif %}
+      <div class="modal-footer" style="display:flex; gap:.5rem; justify-content:flex-end; margin-top:.75rem;">
+        <button type="button" class="btn" onclick="_mcIncludeClose()">Cancel</button>
+        <button type="submit" class="btn-continue">Add to must-include</button>
+      </div>
+    </form>
+  </div>
+</div>
+<script>
+(function(){
+  function _mcIncludeClose(){
+    var m=document.getElementById('mc-include-dialog');
+    if(m) m.remove();
+    try{
+      window.htmx.ajax('GET','/build/must-haves/summary',{
+        target:document.getElementById('include-exclude-summary'),
+        swap:'outerHTML'
+      });
+    }catch(_){}
+  }
+  window._mcIncludeClose = _mcIncludeClose;
+
+  var modal = document.getElementById('mc-include-dialog');
+  if(!modal) return;
+  document.body.appendChild(modal);
+
+  document.getElementById('mc-include-overlay').addEventListener('click', _mcIncludeClose);
+
+  document.addEventListener('keydown', function _mcEsc(e){
+    if(e.key !== 'Escape') return;
+    document.removeEventListener('keydown', _mcEsc);
+    _mcIncludeClose();
+  });
+
+  var form = document.getElementById('mc-include-form');
+  if(form){
+    form.addEventListener('htmx:afterRequest', function(){
+      var m=document.getElementById('mc-include-dialog');
+      if(m) m.remove();
+    });
+  }
+})();
+</script>
+<script>
+(function(){
+  document.addEventListener('keydown', function handler(e){
+    if (e.key === 'Escape'){
+      document.removeEventListener('keydown', handler);
+      try { htmx.ajax('GET', '/build/must-haves/summary', {target:'#include-exclude-summary', swap:'outerHTML'}); } catch(_){}
+    }
+  });
+})();
+</script>