fix: parse MCP result payloads and drop place idempotency_key

Typed result structs replace empty envelopes. Equity place sends
ref_id only so live additionalProperties:false schemas accept the call.

crypto/crypto.go

@@ -25,8 +25,17 @@ type PairsRequest struct {
 	Limit  int
 }
 
+// CurrencyPair is one row from get_currency_pairs.
+type CurrencyPair struct {
+	ID     string
+	Symbol string
+}
+
 // PairsResult is the parsed get_currency_pairs payload.
-type PairsResult struct{}
+type PairsResult struct {
+	Pairs      []CurrencyPair
+	NextCursor string
+}
 
 // QuotesRequest is the argument set for get_crypto_quotes.
 type QuotesRequest struct {
@@ -35,8 +44,19 @@ type QuotesRequest struct {
 	RHSAccountNumber string
 }
 
+// CryptoQuote is one pair quote from get_crypto_quotes.
+type CryptoQuote struct {
+	Symbol    string
+	Bid       decimal.Decimal
+	Ask       decimal.Decimal
+	Mark      decimal.Decimal
+	PrevClose decimal.Decimal
+}
+
 // QuotesResult is the parsed get_crypto_quotes payload.
-type QuotesResult struct{}
+type QuotesResult struct {
+	Quotes []CryptoQuote
+}
 
 // PositionsRequest is the argument set for get_crypto_positions.
 type PositionsRequest struct {
@@ -44,8 +64,18 @@ type PositionsRequest struct {
 	Cursor           string
 }
 
+// CryptoPosition is one holding from get_crypto_positions.
+type CryptoPosition struct {
+	Symbol    string
+	Quantity  decimal.Decimal
+	CostBasis decimal.Decimal
+}
+
 // PositionsResult is the parsed get_crypto_positions payload.
-type PositionsResult struct{}
+type PositionsResult struct {
+	Positions  []CryptoPosition
+	NextCursor string
+}
 
 // OrdersRequest is the argument set for get_crypto_orders.
 type OrdersRequest struct {
@@ -61,7 +91,10 @@ type OrdersRequest struct {
 }
 
 // OrdersResult is the parsed get_crypto_orders payload.
-type OrdersResult struct{}
+type OrdersResult struct {
+	Orders     []Order
+	NextCursor string
+}
 
 // PlaceOrderRequest is the argument set for preview_crypto_order and place_crypto_order.
 type PlaceOrderRequest struct {
@@ -78,11 +111,20 @@ type PlaceOrderRequest struct {
 }
 
 // PreviewResult is the pre-trade check from preview_crypto_order.
-type PreviewResult struct{}
+type PreviewResult struct {
+	Errors   []string        `json:"errors"`
+	Warnings []string        `json:"warnings"`
+	Quantity decimal.Decimal `json:"-"`
+	Price    decimal.Decimal `json:"-"`
+}
 
-// Order is a placed crypto order.
+// Order is a placed or listed crypto order.
 type Order struct {
-	ID string `json:"id"`
+	ID     string          `json:"id"`
+	Symbol string          `json:"symbol"`
+	Side   string          `json:"side"`
+	State  string          `json:"state"`
+	Qty    decimal.Decimal `json:"-"`
 }
 
 // CancelOrderRequest is the argument set for cancel_crypto_order.
@@ -190,11 +232,18 @@ func (c *Client) PreviewOrder(ctx context.Context, req PlaceOrderRequest) (Previ
 
 // PlaceOrder calls place_crypto_order. RefID is sent as ref_id.
 func (c *Client) PlaceOrder(ctx context.Context, req PlaceOrderRequest) (Order, error) {
-	var out Order
-	if err := c.parse(ctx, toolPlace, placeArgs(req, true), &out); err != nil {
+	raw, err := c.c.Call(ctx, toolPlace, placeArgs(req, true))
+	if err != nil {
 		return Order{}, err
 	}
-	return out, nil
+	ords, err := parseOrders(raw)
+	if err != nil {
+		return Order{}, client.ToolErrorf(toolPlace, "parse: %w", err)
+	}
+	if len(ords) > 0 {
+		return ords[0], nil
+	}
+	return Order{}, nil
 }
 
 // CancelOrder calls cancel_crypto_order.