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.

equity/read.go

@@ -29,8 +29,18 @@ type PositionsRequest struct {
 	Cursor        string
 }
 
+// Position is one holding from get_equity_positions.
+type Position struct {
+	Symbol  string
+	Qty     decimal.Decimal
+	AvgCost decimal.Decimal
+}
+
 // PositionsResult is the parsed get_equity_positions payload.
-type PositionsResult struct{}
+type PositionsResult struct {
+	Positions  []Position
+	NextCursor string
+}
 
 // TaxLotsRequest is the argument set for get_equity_tax_lots.
 type TaxLotsRequest struct {
@@ -39,8 +49,21 @@ type TaxLotsRequest struct {
 	Cursor        string
 }
 
+// TaxLotRow is one open tax lot from get_equity_tax_lots.
+type TaxLotRow struct {
+	OpenLotID     string
+	Quantity      decimal.Decimal
+	CostBasis     decimal.Decimal
+	AcquiredAt    string
+	Term          string
+	QuantityAvail decimal.Decimal
+}
+
 // TaxLotsResult is the parsed get_equity_tax_lots payload.
-type TaxLotsResult struct{}
+type TaxLotsResult struct {
+	Lots       []TaxLotRow
+	NextCursor string
+}
 
 // QuotesRequest is the argument set for get_equity_quotes.
 type QuotesRequest struct {
@@ -74,7 +97,10 @@ type OrdersRequest struct {
 }
 
 // OrdersResult is the parsed get_equity_orders payload.
-type OrdersResult struct{}
+type OrdersResult struct {
+	Orders     []Order
+	NextCursor string
+}
 
 // TradabilityRequest is the argument set for get_equity_tradability.
 type TradabilityRequest struct {
@@ -82,8 +108,17 @@ type TradabilityRequest struct {
 	Symbols       []string
 }
 
+// SymbolTradability is per-symbol eligibility from get_equity_tradability.
+type SymbolTradability struct {
+	Symbol     string
+	Tradable   bool
+	Fractional bool
+}
+
 // TradabilityResult is the parsed get_equity_tradability payload.
-type TradabilityResult struct{}
+type TradabilityResult struct {
+	Symbols []SymbolTradability
+}
 
 // HistoricalsRequest is the argument set for get_equity_historicals.
 type HistoricalsRequest struct {
@@ -115,16 +150,44 @@ type FundamentalsRequest struct {
 	Bounds  string
 }
 
+// Fundamentals is one symbol's facts from get_equity_fundamentals.
+type Fundamentals struct {
+	Symbol         string
+	AvgVolume      decimal.Decimal
+	InstrumentKind string
+	MarketCap      decimal.Decimal
+	PE             decimal.Decimal
+	High52Week     decimal.Decimal
+	Low52Week      decimal.Decimal
+}
+
 // FundamentalsResult is the parsed get_equity_fundamentals payload.
-type FundamentalsResult struct{}
+type FundamentalsResult struct {
+	Fundamentals []Fundamentals
+}
 
 // PriceBookRequest is the argument set for get_equity_price_book.
 type PriceBookRequest struct {
 	Symbols []string
 }
 
+// BookLevel is one bid or ask rung.
+type BookLevel struct {
+	Price    decimal.Decimal
+	Quantity decimal.Decimal
+}
+
+// PriceBook is a Level-2 snapshot for one symbol.
+type PriceBook struct {
+	Symbol string
+	Bids   []BookLevel
+	Asks   []BookLevel
+}
+
 // PriceBookResult is the parsed get_equity_price_book payload.
-type PriceBookResult struct{}
+type PriceBookResult struct {
+	Books []PriceBook
+}
 
 // TechnicalIndicatorsRequest is the argument set for get_equity_technical_indicators.
 type TechnicalIndicatorsRequest struct {
@@ -145,8 +208,20 @@ type TechnicalIndicatorsRequest struct {
 	Method         string
 }
 
+// IndicatorPoint is one computed indicator bar.
+type IndicatorPoint struct {
+	Time   time.Time
+	Value  decimal.Decimal
+	Upper  decimal.Decimal
+	Lower  decimal.Decimal
+	MACD   decimal.Decimal
+	Signal decimal.Decimal
+}
+
 // TechnicalIndicatorsResult is the parsed get_equity_technical_indicators payload.
-type TechnicalIndicatorsResult struct{}
+type TechnicalIndicatorsResult struct {
+	Points []IndicatorPoint
+}
 
 // NewsRequest is the argument set for get_equity_news.
 type NewsRequest struct {
@@ -155,8 +230,20 @@ type NewsRequest struct {
 	Cursor string
 }
 
+// NewsArticle is one article from get_equity_news.
+type NewsArticle struct {
+	Title       string
+	URL         string
+	PublishedAt string
+	Source      string
+	Summary     string
+}
+
 // NewsResult is the parsed get_equity_news payload.
-type NewsResult struct{}
+type NewsResult struct {
+	Articles   []NewsArticle
+	NextCursor string
+}
 
 // Positions calls get_equity_positions.
 func (c *Client) Positions(ctx context.Context, req PositionsRequest) (PositionsResult, error) {