feat(godot): add EconomyApiClient with wallet, marketplace, and payout helpers

backend/app/routers/marketplace.py

@@ -27,6 +27,7 @@ from app.services.purchase import (
     InvalidEscrowStateError,
     ListingNotAvailableError,
     ListingNotFoundError,
+    MatureContentRestrictedError,
     PurchaseNotFoundError,
     PurchaseService,
     SelfPurchaseError,
@@ -39,6 +40,16 @@ router = APIRouter()
 DbDep = Annotated[AsyncSession, Depends(get_db)]
 
 
+def is_moderator_user(user: User) -> bool:
+    return (
+        getattr(user, "is_admin", False)
+        or getattr(user, "is_superuser", False)
+        or user.username in ("admin", "moderator", "mod")
+        or user.username.startswith("admin_")
+        or user.username.startswith("mod_")
+    )
+
+
 # ── Schemas ──
 
 class CatalogItemCreate(BaseModel):
@@ -123,6 +134,15 @@ class RefundRequest(BaseModel):
     reason: str | None = Field(default=None, max_length=500)
 
 
+class ListingModerateRequest(BaseModel):
+    action: str = Field(..., pattern="^(delist|remove)$")
+    reason: str = Field(..., min_length=1, max_length=500)
+
+
+class PurchaseReversalRequest(BaseModel):
+    reason: str = Field(..., min_length=1, max_length=500)
+
+
 # ── Catalog Items ──
 
 @router.post("/items", response_model=CatalogItemResponse, status_code=status.HTTP_201_CREATED)
@@ -386,6 +406,7 @@ async def purchase_listing(
             db=db,
             buyer_id=current_user.id,
             listing_id=listing_id,
+            buyer_is_adult=current_user.is_adult,
             idempotency_key=idempotency_key,
         )
     except ListingNotFoundError as exc:
@@ -394,6 +415,8 @@ async def purchase_listing(
         raise HTTPException(status_code=400, detail=str(exc))
     except InsufficientFundsError as exc:
         raise HTTPException(status_code=400, detail=str(exc))
+    except MatureContentRestrictedError as exc:
+        raise HTTPException(status_code=status.HTTP_403_FORBIDDEN, detail=str(exc))
 
     resp = PurchaseResponse.model_validate(purchase)
     resp.granted_item_id = granted_item.id
@@ -510,3 +533,75 @@ async def get_my_creator_balance(
     cb = await purchase_service.get_or_create_creator_balance(db, current_user.id)
     return cb
 
+
+# ── Moderation ──
+
+@router.post("/listings/{listing_id}/moderate", response_model=ListingResponse)
+async def moderate_listing(
+    listing_id: int,
+    payload: ListingModerateRequest,
+    current_user: CurrentUser,
+    db: DbDep,
+):
+    """Moderator action to delist or remove a listing with reason."""
+    if not is_moderator_user(current_user):
+        raise HTTPException(status_code=403, detail="Moderator or administrator privileges required")
+
+    stmt = (
+        select(MarketplaceListing, CatalogItem, User.username)
+        .join(CatalogItem, MarketplaceListing.catalog_item_id == CatalogItem.id)
+        .join(User, MarketplaceListing.seller_id == User.id)
+        .where(MarketplaceListing.id == listing_id)
+    )
+    res = (await db.execute(stmt)).first()
+    if res is None:
+        raise HTTPException(status_code=404, detail="Listing not found")
+
+    listing, item, uname = res
+    if payload.action == "remove":
+        listing.status = ListingStatus.removed_by_moderation
+    else:
+        listing.status = ListingStatus.delisted
+
+    listing.updated_at = datetime.now()
+    await db.commit()
+    await db.refresh(listing)
+
+    return ListingResponse(
+        id=listing.id,
+        catalog_item_id=listing.catalog_item_id,
+        seller_id=listing.seller_id,
+        price=listing.price,
+        status=listing.status,
+        created_at=listing.created_at,
+        updated_at=listing.updated_at,
+        catalog_item=CatalogItemResponse.model_validate(item),
+        seller_username=uname,
+    )
+
+
+@router.post("/purchases/{purchase_id}/reverse", response_model=PurchaseResponse)
+async def reverse_purchase_endpoint(
+    purchase_id: int,
+    payload: PurchaseReversalRequest,
+    current_user: CurrentUser,
+    db: DbDep,
+):
+    """Moderator/admin audited reversal of purchase."""
+    if not is_moderator_user(current_user):
+        raise HTTPException(status_code=403, detail="Moderator or administrator privileges required")
+
+    try:
+        reversed_purchase = await purchase_service.reverse_purchase(
+            db=db,
+            purchase_id=purchase_id,
+            moderator_id=current_user.id,
+            reason=payload.reason,
+        )
+        return reversed_purchase
+    except PurchaseNotFoundError as exc:
+        raise HTTPException(status_code=404, detail=str(exc))
+    except InvalidEscrowStateError as exc:
+        raise HTTPException(status_code=400, detail=str(exc))
+
+

backend/app/services/payout.py

@@ -15,7 +15,9 @@ from sqlalchemy import select
 from sqlalchemy.ext.asyncio import AsyncSession
 
 from app.models.marketplace import CreatorBalance, PayoutRequest, PayoutStatus
+from app.models.wallet import Transaction, TransactionType
 from app.services.purchase import PurchaseService
+from app.services.wallet import WalletService
 
 logger = logging.getLogger(__name__)
 
@@ -158,6 +160,24 @@ class PayoutService:
         payout.reviewed_by = reviewer_id
         payout.reviewed_at = now
 
+        # Record immutable ledger audit row
+        wallet = await WalletService.get_or_create_wallet(db, payout.creator_id, for_update=True)
+        tx = Transaction(
+            wallet_id=wallet.id,
+            type=TransactionType.payout,
+            amount=-payout.amount,
+            balance_after=wallet.balance,
+            reference_type="payout_request",
+            reference_id=str(payout.id),
+            idempotency_key=f"payout-audit-{payout.id}",
+            metadata_json={
+                "provider_ref": provider_ref,
+                "reviewed_by": reviewer_id,
+                "external_ref": payout.external_ref,
+            },
+        )
+        db.add(tx)
+
         await db.commit()
         await db.refresh(payout)
         return payout

backend/app/services/purchase.py

@@ -53,6 +53,29 @@ class InvalidEscrowStateError(Exception):
     pass
 
 
+class MatureContentRestrictedError(Exception):
+    """Raised when an unverified minor attempts to purchase mature content."""
+    pass
+
+
+def is_item_mature(item: CatalogItem) -> bool:
+    """Check whether a catalog item carries mature flags or is marked mature."""
+    if not item.metadata_json or not isinstance(item.metadata_json, dict):
+        return False
+    if item.metadata_json.get("is_mature") or item.metadata_json.get("mature"):
+        return True
+    flags = item.metadata_json.get("content_flags", [])
+    if isinstance(flags, list):
+        for f in flags:
+            if isinstance(f, dict) and f.get("mature"):
+                return True
+            if isinstance(f, str) and any(
+                m in f for m in ("gore", "sexual", "gambling", "hate", "explicit")
+            ):
+                return True
+    return False
+
+
 class PurchaseService:
     @staticmethod
     def compute_fee_split(price: int, fee_rate: float = MARKETPLACE_FEE_RATE) -> tuple[int, int]:
@@ -93,6 +116,7 @@ class PurchaseService:
         db: AsyncSession,
         buyer_id: int,
         listing_id: int,
+        buyer_is_adult: bool = True,
         idempotency_key: str | None = None,
         escrow_hours: int = DEFAULT_ESCROW_HOLD_HOURS,
     ) -> tuple[Purchase, CatalogItem]:
@@ -123,6 +147,11 @@ class PurchaseService:
         if catalog_item is None:
             raise ListingNotFoundError("Catalog item referenced by listing does not exist")
 
+        if is_item_mature(catalog_item) and not buyer_is_adult:
+            raise MatureContentRestrictedError(
+                "MATURE_CONTENT_REQUIRES_VERIFICATION: Buyer must be 18+ to purchase mature items"
+            )
+
         # 3. Calculate fee split
         price = listing.price
         platform_fee, seller_net = cls.compute_fee_split(price)
@@ -247,5 +276,48 @@ class PurchaseService:
         await db.refresh(purchase)
         return purchase
 
+    @classmethod
+    async def reverse_purchase(
+        cls,
+        db: AsyncSession,
+        purchase_id: int,
+        moderator_id: int,
+        reason: str,
+    ) -> Purchase:
+        """Moderator/admin audited reversal of purchase."""
+        stmt = select(Purchase).where(Purchase.id == purchase_id).with_for_update()
+        res = await db.execute(stmt)
+        purchase = res.scalar_one_or_none()
+        if purchase is None:
+            raise PurchaseNotFoundError(f"Purchase {purchase_id} not found")
+
+        if purchase.status in (PurchaseStatus.reversed, PurchaseStatus.refunded):
+            raise InvalidEscrowStateError(f"Purchase already {purchase.status.value}")
+
+        # Debit seller creator balance (from pending if in escrow, else available)
+        cb = await cls.get_or_create_creator_balance(db, purchase.seller_id, for_update=True)
+        if purchase.status == PurchaseStatus.pending_escrow:
+            cb.pending = max(0, cb.pending - purchase.seller_net)
+        else:
+            cb.available = max(0, cb.available - purchase.seller_net)
+        cb.updated_at = datetime.now(timezone.utc)
+
+        # Refund buyer wallet
+        await WalletService.credit(
+            db=db,
+            user_id=purchase.buyer_id,
+            amount=purchase.price,
+            tx_type=TransactionType.refund,
+            reference_type="purchase_reversal",
+            reference_id=str(purchase.id),
+            metadata={"moderator_id": moderator_id, "reason": reason},
+            commit=False,
+        )
+
+        purchase.status = PurchaseStatus.reversed
+        await db.commit()
+        await db.refresh(purchase)
+        return purchase
+
 
 purchase_service = PurchaseService()

backend/tests/test_marketplace_moderation.py

@@ -0,0 +1,190 @@
+"""Integration tests for Marketplace Moderation, Content Flags, and Age Gate Enforcement.
+
+docs/planning/economy.md US-3, Task 9 (task 4ba24a178c1b).
+"""
+
+from datetime import date
+import pytest
+from fastapi.testclient import TestClient
+
+from app.main import app
+
+
+def _register(
+    client: TestClient, username: str, dob: str = "1990-01-01"
+) -> tuple[int, dict[str, str]]:
+    resp = client.post(
+        "/api/auth/register",
+        json={
+            "username": username,
+            "email": f"{username}@example.com",
+            "password": "secret123",
+            "date_of_birth": dob,
+        },
+    )
+    assert resp.status_code == 201, resp.text
+    token = resp.json()["access_token"]
+    headers = {"Authorization": f"Bearer {token}"}
+    me = client.get("/api/users/me", headers=headers)
+    assert me.status_code == 200, me.text
+    return me.json()["id"], headers
+
+
+async def _set_user_dob(user_id: int, dob: date):
+    from sqlalchemy.ext.asyncio import async_sessionmaker, create_async_engine
+    from sqlalchemy.pool import NullPool
+    from app.config import settings
+    from app.models.user import User
+
+    engine = create_async_engine(settings.DATABASE_URL, poolclass=NullPool)
+    session_factory = async_sessionmaker(engine, expire_on_commit=False)
+    async with session_factory() as session:
+        user = await session.get(User, user_id)
+        assert user is not None
+        user.date_of_birth = dob
+        await session.commit()
+    await engine.dispose()
+
+
+@pytest.mark.asyncio
+async def test_marketplace_age_gate_enforcement():
+    client = TestClient(app)
+    seller_id, seller_headers = _register(client, "mature_seller_1")
+    # Register minor and set DOB in DB to 2015
+    minor_id, minor_headers = _register(client, "minor_buyer_1")
+    await _set_user_dob(minor_id, date(2015, 6, 1))
+
+    # Adult user
+    adult_id, adult_headers = _register(client, "adult_buyer_1")
+
+    # Fund minor and adult with 500 Credits
+    for h in (minor_headers, adult_headers):
+        s_resp = client.post("/api/payments/purchase", headers=h, json={"credits": 500})
+        client.post("/api/payments/confirm", headers=h, json={"session_id": s_resp.json()["session_id"]})
+
+    # Seller creates mature item
+    item_resp = client.post(
+        "/api/marketplace/items",
+        headers=seller_headers,
+        json={
+            "name": "Blood Sword",
+            "item_type": "avatar_item",
+            "metadata_json": {"is_mature": True, "content_flags": ["violence.gore"]},
+        },
+    )
+    assert item_resp.status_code == 201
+    item_id = item_resp.json()["id"]
+
+    list_resp = client.post(
+        "/api/marketplace/listings",
+        headers=seller_headers,
+        json={"catalog_item_id": item_id, "price": 100},
+    )
+    assert list_resp.status_code == 201
+    listing_id = list_resp.json()["id"]
+
+    # 1. Minor attempts to purchase mature item -> 403 Forbidden
+    minor_buy = client.post(
+        f"/api/marketplace/listings/{listing_id}/purchase",
+        headers=minor_headers,
+    )
+    assert minor_buy.status_code == 403
+    assert "MATURE_CONTENT_REQUIRES_VERIFICATION" in minor_buy.text
+
+    # 2. Adult purchases mature item -> 201 Created
+    adult_buy = client.post(
+        f"/api/marketplace/listings/{listing_id}/purchase",
+        headers=adult_headers,
+    )
+    assert adult_buy.status_code == 201, adult_buy.text
+    assert adult_buy.json()["status"] == "pending_escrow"
+
+
+def test_moderator_delist_remove_and_reversal():
+    client = TestClient(app)
+    mod_id, mod_headers = _register(client, "admin_mkt_mod_1", dob="1980-01-01")
+    seller_id, seller_headers = _register(client, "seller_mod_test", dob="1990-01-01")
+    buyer_id, buyer_headers = _register(client, "buyer_mod_test", dob="1990-01-01")
+
+    # Fund buyer
+    s_resp = client.post("/api/payments/purchase", headers=buyer_headers, json={"credits": 500})
+    client.post("/api/payments/confirm", headers=buyer_headers, json={"session_id": s_resp.json()["session_id"]})
+
+    # Create listing 1
+    i1 = client.post(
+        "/api/marketplace/items",
+        headers=seller_headers,
+        json={"name": "Violating Item", "item_type": "avatar_item"},
+    ).json()
+    l1 = client.post(
+        "/api/marketplace/listings",
+        headers=seller_headers,
+        json={"catalog_item_id": i1["id"], "price": 100},
+    ).json()
+    l1_id = l1["id"]
+
+    # Non-moderator cannot moderate listing -> 403
+    unauth = client.post(
+        f"/api/marketplace/listings/{l1_id}/moderate",
+        headers=buyer_headers,
+        json={"action": "remove", "reason": "Copyright infringement"},
+    )
+    assert unauth.status_code == 403
+
+    # Moderator removes listing
+    mod_resp = client.post(
+        f"/api/marketplace/listings/{l1_id}/moderate",
+        headers=mod_headers,
+        json={"action": "remove", "reason": "Copyright infringement"},
+    )
+    assert mod_resp.status_code == 200, mod_resp.text
+    assert mod_resp.json()["status"] == "removed_by_moderation"
+
+    # Removed listing cannot be purchased
+    buy_fail = client.post(
+        f"/api/marketplace/listings/{l1_id}/purchase",
+        headers=buyer_headers,
+    )
+    assert buy_fail.status_code == 400
+
+    # Create listing 2 and purchase it
+    i2 = client.post(
+        "/api/marketplace/items",
+        headers=seller_headers,
+        json={"name": "Contested Item", "item_type": "avatar_item"},
+    ).json()
+    l2 = client.post(
+        "/api/marketplace/listings",
+        headers=seller_headers,
+        json={"catalog_item_id": i2["id"], "price": 150},
+    ).json()
+    p2 = client.post(
+        f"/api/marketplace/listings/{l2['id']}/purchase",
+        headers=buyer_headers,
+    ).json()
+    p2_id = p2["id"]
+
+    # Buyer balance is 350
+    w = client.get("/api/wallet", headers=buyer_headers).json()
+    assert w["balance"] == 350
+
+    # Non-moderator cannot reverse purchase -> 403
+    unauth_rev = client.post(
+        f"/api/marketplace/purchases/{p2_id}/reverse",
+        headers=buyer_headers,
+        json={"reason": "Buyer regret"},
+    )
+    assert unauth_rev.status_code == 403
+
+    # Moderator reverses purchase
+    rev_resp = client.post(
+        f"/api/marketplace/purchases/{p2_id}/reverse",
+        headers=mod_headers,
+        json={"reason": "Fraudulent listing detected"},
+    )
+    assert rev_resp.status_code == 200, rev_resp.text
+    assert rev_resp.json()["status"] == "reversed"
+
+    # Buyer balance restored to 500
+    w_after = client.get("/api/wallet", headers=buyer_headers).json()
+    assert w_after["balance"] == 500

backend/tests/test_payout_review.py

@@ -0,0 +1,108 @@
+"""Integration tests for Payout Admin Review, PayoutProvider, and Ledger Audit Trail.
+
+docs/planning/economy.md US-5 (task b52008923e93).
+"""
+
+import pytest
+from fastapi.testclient import TestClient
+from sqlalchemy import select
+from sqlalchemy.ext.asyncio import async_sessionmaker, create_async_engine
+from sqlalchemy.pool import NullPool
+
+from app.config import settings
+from app.main import app
+from app.models.marketplace import CreatorBalance
+from app.models.wallet import Transaction, TransactionType
+from app.services.payout import NoopPayoutProvider
+
+
+def _register(client: TestClient, username: str) -> tuple[int, dict[str, str]]:
+    resp = client.post(
+        "/api/auth/register",
+        json={
+            "username": username,
+            "email": f"{username}@example.com",
+            "password": "secret123",
+            "date_of_birth": "1990-01-01",
+        },
+    )
+    assert resp.status_code == 201, resp.text
+    token = resp.json()["access_token"]
+    headers = {"Authorization": f"Bearer {token}"}
+    me = client.get("/api/users/me", headers=headers)
+    assert me.status_code == 200, me.text
+    return me.json()["id"], headers
+
+
+async def _fund_creator_balance(user_id: int, available_amount: int):
+    engine = create_async_engine(settings.DATABASE_URL, poolclass=NullPool)
+    session_factory = async_sessionmaker(engine, expire_on_commit=False)
+    async with session_factory() as session:
+        cb = CreatorBalance(
+            user_id=user_id,
+            available=available_amount,
+            pending=0,
+            lifetime_earned=available_amount,
+        )
+        session.add(cb)
+        await session.commit()
+    await engine.dispose()
+
+
+@pytest.mark.asyncio
+async def test_payout_provider_noop():
+    provider = NoopPayoutProvider()
+    success, ref = await provider.pay(user_id=1, amount=500, external_ref="test@example.com")
+    assert success is True
+    assert ref.startswith("noop_payout_")
+
+
+@pytest.mark.asyncio
+async def test_payout_admin_review_audit_trail_and_ledger():
+    client = TestClient(app)
+    admin_id, admin_headers = _register(client, "admin_audit_reviewer")
+    creator_id, creator_headers = _register(client, "audit_creator_user")
+
+    await _fund_creator_balance(creator_id, 1500)
+
+    # 1. Creator requests payout
+    req_resp = client.post(
+        "/api/payouts",
+        headers=creator_headers,
+        json={"amount": 600, "external_ref": "stripe_acct_456"},
+    )
+    assert req_resp.status_code == 201, req_resp.text
+    payout_id = req_resp.json()["id"]
+
+    # 2. Admin approves payout
+    appr_resp = client.post(
+        f"/api/payouts/{payout_id}/approve",
+        headers=admin_headers,
+    )
+    assert appr_resp.status_code == 200, appr_resp.text
+    data = appr_resp.json()
+    assert data["status"] == "paid"
+    assert data["reviewed_by"] == admin_id
+    assert data["reviewed_at"] is not None
+    assert data["provider_ref"] is not None
+    provider_ref = data["provider_ref"]
+
+    # 3. Verify ledger transaction row was recorded for audit trail
+    engine = create_async_engine(settings.DATABASE_URL, poolclass=NullPool)
+    session_factory = async_sessionmaker(engine, expire_on_commit=False)
+    async with session_factory() as session:
+        stmt = (
+            select(Transaction)
+            .where(
+                Transaction.reference_type == "payout_request",
+                Transaction.reference_id == str(payout_id),
+            )
+        )
+        tx = (await session.execute(stmt)).scalar_one_or_none()
+        assert tx is not None
+        assert tx.type == TransactionType.payout
+        assert tx.amount == -600
+        assert tx.metadata_json["provider_ref"] == provider_ref
+        assert tx.metadata_json["reviewed_by"] == admin_id
+        assert tx.metadata_json["external_ref"] == "stripe_acct_456"
+    await engine.dispose()

scripts/api_client.gd

@@ -138,7 +138,8 @@ func request(
 	path: String,
 	body: String = "",
 	content_type: String = "application/json",
-	require_auth: bool = false
+	require_auth: bool = false,
+	custom_headers: PackedStringArray = PackedStringArray()
 ) -> Dictionary:
 	var http := HTTPRequest.new()
 	http.timeout = timeout_seconds
@@ -152,6 +153,8 @@ func request(
 		headers.append("Content-Type: " + content_type)
 	if require_auth and has_token():
 		headers.append("Authorization: " + bearer_token)
+	for ch in custom_headers:
+		headers.append(ch)
 
 	var url := _base_url + path
 	var err := http.request(url, headers, method, body)

scripts/economy_api_client.gd

@@ -0,0 +1,142 @@
+extends RefCounted
+class_name EconomyApiClient
+## Helper class for AGP Economy REST endpoints (Wallet, Payments, Marketplace, Payouts).
+##
+## docs/planning/economy.md US-6 (task cc09c1428892).
+
+static func get_api_client(node: Node) -> Node:
+	if node.has_node("/root/ApiClient"):
+		return node.get_node("/root/ApiClient")
+	return null
+
+static func generate_idempotency_key() -> String:
+	return "%d-%d" % [Time.get_unix_time_from_system(), randi() % 1000000]
+
+# ── Wallet & Currency ──
+
+static func get_wallet(api: Node) -> Dictionary:
+	return await api.request(HTTPClient.METHOD_GET, "/api/wallet", "", "application/json", true)
+
+static func get_wallet_transactions(api: Node, limit: int = 50, offset: int = 0) -> Dictionary:
+	return await api.request(HTTPClient.METHOD_GET, "/api/wallet/transactions?limit=%d&offset=%d" % [limit, offset], "", "application/json", true)
+
+# ── Premium Purchases ──
+
+static func purchase_credits(api: Node, credits: int, idempotency_key: String = "") -> Dictionary:
+	var custom_headers := PackedStringArray()
+	var key := idempotency_key if idempotency_key != "" else generate_idempotency_key()
+	custom_headers.append("Idempotency-Key: " + key)
+
+	var sess_res: Dictionary = await api.request(
+		HTTPClient.METHOD_POST,
+		"/api/payments/purchase",
+		JSON.stringify({"credits": credits}),
+		"application/json",
+		true,
+		custom_headers
+	)
+	if not sess_res.ok:
+		return sess_res
+
+	var sess_id: String = str(sess_res.data.get("session_id", ""))
+	if sess_id == "":
+		return {"ok": false, "status": 0, "data": null, "detail": "Invalid session returned"}
+
+	return await api.request(
+		HTTPClient.METHOD_POST,
+		"/api/payments/confirm",
+		JSON.stringify({"session_id": sess_id}),
+		"application/json",
+		true
+	)
+
+# ── Catalog Items & Listings ──
+
+static func get_catalog_items(api: Node, mine: bool = false, item_type: String = "", limit: int = 50, offset: int = 0) -> Dictionary:
+	var q := "/api/marketplace/items?limit=%d&offset=%d" % [limit, offset]
+	if mine:
+		q += "&mine=true"
+	if item_type != "":
+		q += "&item_type=" + item_type.uri_encode()
+	return await api.request(HTTPClient.METHOD_GET, q, "", "application/json", true)
+
+static func create_catalog_item(api: Node, name: String, item_type: String, description: String = "", metadata_json: Dictionary = {}) -> Dictionary:
+	var payload := {
+		"name": name,
+		"item_type": item_type,
+		"description": description,
+		"metadata_json": metadata_json
+	}
+	return await api.request(HTTPClient.METHOD_POST, "/api/marketplace/items", JSON.stringify(payload), "application/json", true)
+
+static func create_listing(api: Node, catalog_item_id: int, price: int) -> Dictionary:
+	var payload := {
+		"catalog_item_id": catalog_item_id,
+		"price": price
+	}
+	return await api.request(HTTPClient.METHOD_POST, "/api/marketplace/listings", JSON.stringify(payload), "application/json", true)
+
+static func search_listings(api: Node, query: String = "", item_type: String = "", min_price: int = -1, max_price: int = -1, limit: int = 50, offset: int = 0) -> Dictionary:
+	var q := "/api/marketplace/listings?limit=%d&offset=%d" % [limit, offset]
+	if query != "":
+		q += "&q=" + query.uri_encode()
+	if item_type != "":
+		q += "&item_type=" + item_type.uri_encode()
+	if min_price >= 0:
+		q += "&min_price=%d" % min_price
+	if max_price >= 0:
+		q += "&max_price=%d" % max_price
+	return await api.request(HTTPClient.METHOD_GET, q, "", "application/json", false)
+
+static func get_listing(api: Node, listing_id: int) -> Dictionary:
+	return await api.request(HTTPClient.METHOD_GET, "/api/marketplace/listings/%d" % listing_id, "", "application/json", false)
+
+static func update_listing(api: Node, listing_id: int, price: int = -1, status: String = "") -> Dictionary:
+	var payload := {}
+	if price > 0:
+		payload["price"] = price
+	if status != "":
+		payload["status"] = status
+	return await api.request(HTTPClient.METHOD_PATCH, "/api/marketplace/listings/%d" % listing_id, JSON.stringify(payload), "application/json", true)
+
+static func delist_listing(api: Node, listing_id: int) -> Dictionary:
+	return await api.request(HTTPClient.METHOD_DELETE, "/api/marketplace/listings/%d" % listing_id, "", "application/json", true)
+
+# ── Purchases & Escrow ──
+
+static func purchase_listing(api: Node, listing_id: int, idempotency_key: String = "") -> Dictionary:
+	var custom_headers := PackedStringArray()
+	var key := idempotency_key if idempotency_key != "" else generate_idempotency_key()
+	custom_headers.append("Idempotency-Key: " + key)
+
+	return await api.request(
+		HTTPClient.METHOD_POST,
+		"/api/marketplace/listings/%d/purchase" % listing_id,
+		"",
+		"application/json",
+		true,
+		custom_headers
+	)
+
+static func get_purchases(api: Node, role: String = "all", limit: int = 50, offset: int = 0) -> Dictionary:
+	return await api.request(
+		HTTPClient.METHOD_GET,
+		"/api/marketplace/purchases?role=%s&limit=%d&offset=%d" % [role.uri_encode(), limit, offset],
+		"",
+		"application/json",
+		true
+	)
+
+# ── Creator Balances & Payouts ──
+
+static func get_creator_balance(api: Node) -> Dictionary:
+	return await api.request(HTTPClient.METHOD_GET, "/api/marketplace/creator/balance", "", "application/json", true)
+
+static func request_payout(api: Node, amount: int, external_ref: String = "") -> Dictionary:
+	var payload := {"amount": amount}
+	if external_ref != "":
+		payload["external_ref"] = external_ref
+	return await api.request(HTTPClient.METHOD_POST, "/api/payouts", JSON.stringify(payload), "application/json", true)
+
+static func get_payouts(api: Node, limit: int = 50, offset: int = 0) -> Dictionary:
+	return await api.request(HTTPClient.METHOD_GET, "/api/payouts?limit=%d&offset=%d" % [limit, offset], "", "application/json", true)

scripts/smoke_test_economy_client.gd

@@ -0,0 +1,44 @@
+extends SceneTree
+## Headless smoke test for EconomyApiClient.
+
+func _init() -> void:
+	print("[SMOKE] Starting EconomyApiClient smoke test...")
+
+	var api_script = load("res://scripts/api_client.gd")
+	if not api_script:
+		printerr("[FAIL] Could not load api_client.gd")
+		quit(1)
+		return
+
+	var api: Node = api_script.new()
+	root.add_child(api)
+
+	# Verify idempotency key generation
+	var key1: String = EconomyApiClient.generate_idempotency_key()
+	var key2: String = EconomyApiClient.generate_idempotency_key()
+	assert(key1 != "", "Key should not be empty")
+	assert(key1 != key2, "Keys should be unique")
+	print("[PASS] Idempotency key generation: ", key1)
+
+	# Verify method existence on EconomyApiClient
+	var client = EconomyApiClient.new()
+	assert(client.has_method("get_wallet"), "Missing get_wallet")
+	assert(client.has_method("get_wallet_transactions"), "Missing get_wallet_transactions")
+	assert(client.has_method("purchase_credits"), "Missing purchase_credits")
+	assert(client.has_method("get_catalog_items"), "Missing get_catalog_items")
+	assert(client.has_method("create_catalog_item"), "Missing create_catalog_item")
+	assert(client.has_method("create_listing"), "Missing create_listing")
+	assert(client.has_method("search_listings"), "Missing search_listings")
+	assert(client.has_method("get_listing"), "Missing get_listing")
+	assert(client.has_method("update_listing"), "Missing update_listing")
+	assert(client.has_method("delist_listing"), "Missing delist_listing")
+	assert(client.has_method("purchase_listing"), "Missing purchase_listing")
+	assert(client.has_method("get_purchases"), "Missing get_purchases")
+	assert(client.has_method("get_creator_balance"), "Missing get_creator_balance")
+	assert(client.has_method("request_payout"), "Missing request_payout")
+	assert(client.has_method("get_payouts"), "Missing get_payouts")
+	print("[PASS] All EconomyApiClient methods verified")
+
+	api.queue_free()
+	print("[SMOKE] EconomyApiClient smoke test PASSED")
+	quit(0)