diff --git a/equity/client.go b/equity/client.go
index 58e07b3..2f2857b 100644
--- a/equity/client.go
+++ b/equity/client.go
@@ -25,5 +25,8 @@ func Tools() []string {
 		toolPriceBook,
 		toolTechnicalIndicators,
 		toolNews,
+		toolReview,
+		toolPlace,
+		toolCancel,
 	}
 }
diff --git a/equity/read_test.go b/equity/read_test.go
index 8416c1a..4dbf8a4 100644
--- a/equity/read_test.go
+++ b/equity/read_test.go
@@ -225,6 +225,7 @@ func TestEquity_toolNames(t *testing.T) {
 func TestTools(t *testing.T) {
 	t.Parallel()
 	want := []string{
+		"cancel_equity_order",
 		"get_equity_fundamentals",
 		"get_equity_historicals",
 		"get_equity_news",
@@ -235,6 +236,8 @@ func TestTools(t *testing.T) {
 		"get_equity_tax_lots",
 		"get_equity_technical_indicators",
 		"get_equity_tradability",
+		"place_equity_order",
+		"review_equity_order",
 	}
 	got := append([]string(nil), equity.Tools()...)
 	sort.Strings(got)
diff --git a/equity/write.go b/equity/write.go
new file mode 100644
index 0000000..d61876a
--- /dev/null
+++ b/equity/write.go
@@ -0,0 +1,134 @@
+package equity
+
+import (
+	"context"
+
+	decimal "github.com/alpacahq/alpacadecimal"
+	"s1d3sw1ped/robinhood-agentic-mcp/client"
+	"s1d3sw1ped/robinhood-agentic-mcp/internal/wire"
+)
+
+const (
+	toolReview = "review_equity_order"
+	toolPlace  = "place_equity_order"
+	toolCancel = "cancel_equity_order"
+)
+
+// PlaceOrderRequest is the argument set for review_equity_order and place_equity_order.
+type PlaceOrderRequest struct {
+	AccountNumber string
+	Symbol        string
+	Side          client.Side
+	Type          client.OrderType
+	Qty           *decimal.Decimal
+	DollarAmount  *decimal.Decimal
+	LimitPrice    *decimal.Decimal
+	StopPrice     *decimal.Decimal
+	TimeInForce   client.TimeInForce // empty → omit (Robinhood defaults gfd)
+	MarketHours   client.MarketHours
+	TaxLots       []TaxLot
+	RefID         string
+}
+
+// TaxLot is a specified-lot selection for a sell order.
+type TaxLot struct {
+	OpenLotID string
+	Quantity  decimal.Decimal
+}
+
+// ReviewResult is the pre-trade check from review_equity_order.
+type ReviewResult struct {
+	Errors   []string `json:"errors"`
+	Warnings []string `json:"warnings"`
+}
+
+// Order is a placed equity order.
+type Order struct {
+	ID string `json:"id"`
+}
+
+// CancelOrderRequest is the argument set for cancel_equity_order.
+type CancelOrderRequest struct {
+	AccountNumber string
+	OrderID       string
+}
+
+// ReviewOrder calls review_equity_order. RefID is not sent.
+func (c *Client) ReviewOrder(ctx context.Context, req PlaceOrderRequest) (ReviewResult, error) {
+	var out ReviewResult
+	if err := c.parse(ctx, toolReview, placeArgs(req, false), &out); err != nil {
+		return ReviewResult{}, err
+	}
+	return out, nil
+}
+
+// PlaceOrder calls place_equity_order. RefID is sent as both ref_id and idempotency_key.
+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 {
+		return Order{}, err
+	}
+	return out, nil
+}
+
+// CancelOrder calls cancel_equity_order.
+func (c *Client) CancelOrder(ctx context.Context, req CancelOrderRequest) error {
+	args := map[string]any{}
+	if req.AccountNumber != "" {
+		args["account_number"] = req.AccountNumber
+	}
+	if req.OrderID != "" {
+		args["order_id"] = req.OrderID
+	}
+	_, err := c.c.Call(ctx, toolCancel, args)
+	return err
+}
+
+func placeArgs(req PlaceOrderRequest, withRef bool) map[string]any {
+	args := map[string]any{}
+	if req.AccountNumber != "" {
+		args["account_number"] = req.AccountNumber
+	}
+	if req.Symbol != "" {
+		args["symbol"] = req.Symbol
+	}
+	if req.Side != "" {
+		args["side"] = string(req.Side)
+	}
+	if req.Type != "" {
+		args["type"] = string(req.Type)
+	}
+	if req.Qty != nil {
+		args["quantity"] = wire.Encode(*req.Qty)
+	}
+	if req.DollarAmount != nil {
+		args["dollar_amount"] = wire.Encode(*req.DollarAmount)
+	}
+	if req.LimitPrice != nil {
+		args["limit_price"] = wire.Encode(*req.LimitPrice)
+	}
+	if req.StopPrice != nil {
+		args["stop_price"] = wire.Encode(*req.StopPrice)
+	}
+	if req.TimeInForce != "" {
+		args["time_in_force"] = string(req.TimeInForce)
+	}
+	if req.MarketHours != "" {
+		args["market_hours"] = string(req.MarketHours)
+	}
+	if len(req.TaxLots) > 0 {
+		lots := make([]map[string]any, len(req.TaxLots))
+		for i, lot := range req.TaxLots {
+			lots[i] = map[string]any{
+				"open_lot_id": lot.OpenLotID,
+				"quantity":    wire.Encode(lot.Quantity),
+			}
+		}
+		args["tax_lots"] = lots
+	}
+	if withRef && req.RefID != "" {
+		args["ref_id"] = req.RefID
+		args["idempotency_key"] = req.RefID
+	}
+	return args
+}
diff --git a/equity/write_test.go b/equity/write_test.go
new file mode 100644
index 0000000..f888367
--- /dev/null
+++ b/equity/write_test.go
@@ -0,0 +1,252 @@
+package equity_test
+
+import (
+	"context"
+	"encoding/json"
+	"testing"
+
+	decimal "github.com/alpacahq/alpacadecimal"
+	"github.com/google/go-cmp/cmp"
+	"s1d3sw1ped/robinhood-agentic-mcp/client"
+	"s1d3sw1ped/robinhood-agentic-mcp/equity"
+	"s1d3sw1ped/robinhood-agentic-mcp/internal/rhntest"
+)
+
+func TestPlaceOrder_decimalStrings(t *testing.T) {
+	t.Parallel()
+	var got map[string]any
+	c := equity.New(client.Func(func(ctx context.Context, name string, args map[string]any) (json.RawMessage, error) {
+		if name != "place_equity_order" {
+			t.Fatalf("%s", name)
+		}
+		got = args
+		return json.RawMessage(`{"id":"o1"}`), nil
+	}))
+	qty := decimal.NewFromInt(3)
+	px := decimal.RequireFromString("99.6")
+	_, err := c.PlaceOrder(context.Background(), equity.PlaceOrderRequest{
+		AccountNumber: "acct", Symbol: "MU", Side: client.Buy, Type: client.Limit,
+		Qty: &qty, LimitPrice: &px, TimeInForce: client.GFD, RefID: "buy:2026-08-18:MU",
+	})
+	if err != nil {
+		t.Fatal(err)
+	}
+	if got["type"] != "limit" || got["time_in_force"] != "gfd" || got["quantity"] != "3" {
+		t.Fatalf("%+v", got)
+	}
+	if got["limit_price"] != "99.6" && got["limit_price"] != "99.60" {
+		t.Fatalf("limit %v", got["limit_price"])
+	}
+	if got["ref_id"] != "buy:2026-08-18:MU" {
+		t.Fatalf("ref %v", got["ref_id"])
+	}
+}
+
+func TestEquity_writeArgs(t *testing.T) {
+	t.Parallel()
+	qty := decimal.NewFromInt(3)
+	px := decimal.RequireFromString("99.6")
+	dollars := decimal.RequireFromString("100")
+	lotQty := decimal.RequireFromString("1.5")
+	tests := []struct {
+		name     string
+		call     func(*equity.Client) error
+		wantName string
+		wantArgs map[string]any
+	}{
+		{
+			name: "ReviewOrder",
+			call: func(c *equity.Client) error {
+				_, err := c.ReviewOrder(context.Background(), equity.PlaceOrderRequest{
+					AccountNumber: "acct",
+					Symbol:        "MU",
+					Side:          client.Buy,
+					Type:          client.Limit,
+					Qty:           &qty,
+					LimitPrice:    &px,
+					TimeInForce:   client.GFD,
+					MarketHours:   client.ExtendedHours,
+					RefID:         "buy:2026-08-18:MU",
+				})
+				return err
+			},
+			wantName: "review_equity_order",
+			wantArgs: map[string]any{
+				"account_number": "acct",
+				"symbol":         "MU",
+				"side":           "buy",
+				"type":           "limit",
+				"quantity":       "3",
+				"limit_price":    "99.6",
+				"time_in_force":  "gfd",
+				"market_hours":   "extended_hours",
+			},
+		},
+		{
+			name: "PlaceOrderStop",
+			call: func(c *equity.Client) error {
+				_, err := c.PlaceOrder(context.Background(), equity.PlaceOrderRequest{
+					AccountNumber: "acct",
+					Symbol:        "MU",
+					Side:          client.Sell,
+					Type:          client.Stop,
+					Qty:           &qty,
+					StopPrice:     &px,
+					RefID:         "sell:2026-08-18:MU",
+				})
+				return err
+			},
+			wantName: "place_equity_order",
+			wantArgs: map[string]any{
+				"account_number":  "acct",
+				"symbol":          "MU",
+				"side":            "sell",
+				"type":            "stop_market",
+				"quantity":        "3",
+				"stop_price":      "99.6",
+				"ref_id":          "sell:2026-08-18:MU",
+				"idempotency_key": "sell:2026-08-18:MU",
+			},
+		},
+		{
+			name: "PlaceOrderDollarAndLots",
+			call: func(c *equity.Client) error {
+				_, err := c.PlaceOrder(context.Background(), equity.PlaceOrderRequest{
+					AccountNumber: "acct",
+					Symbol:        "MU",
+					Side:          client.Sell,
+					Type:          client.Market,
+					DollarAmount:  &dollars,
+					TaxLots: []equity.TaxLot{{
+						OpenLotID: "lot-1",
+						Quantity:  lotQty,
+					}},
+					RefID: "sell:lots",
+				})
+				return err
+			},
+			wantName: "place_equity_order",
+			wantArgs: map[string]any{
+				"account_number": "acct",
+				"symbol":         "MU",
+				"side":           "sell",
+				"type":           "market",
+				"dollar_amount":  "100",
+				"tax_lots": []map[string]any{
+					{"open_lot_id": "lot-1", "quantity": "1.5"},
+				},
+				"ref_id":          "sell:lots",
+				"idempotency_key": "sell:lots",
+			},
+		},
+		{
+			name: "CancelOrder",
+			call: func(c *equity.Client) error {
+				return c.CancelOrder(context.Background(), equity.CancelOrderRequest{
+					AccountNumber: "acct",
+					OrderID:       "o1",
+				})
+			},
+			wantName: "cancel_equity_order",
+			wantArgs: map[string]any{"account_number": "acct", "order_id": "o1"},
+		},
+	}
+	for _, tc := range tests {
+		t.Run(tc.name, func(t *testing.T) {
+			t.Parallel()
+			var gotName string
+			var gotArgs map[string]any
+			c := equity.New(client.Func(func(ctx context.Context, name string, args map[string]any) (json.RawMessage, error) {
+				gotName, gotArgs = name, args
+				return json.RawMessage(`{"id":"o1"}`), nil
+			}))
+			if err := tc.call(c); err != nil {
+				t.Fatal(err)
+			}
+			if gotName != tc.wantName {
+				t.Fatalf("%s %+v", gotName, gotArgs)
+			}
+			if diff := cmp.Diff(tc.wantArgs, gotArgs); diff != "" {
+				t.Fatal(diff)
+			}
+			if tc.name == "ReviewOrder" {
+				if _, ok := gotArgs["ref_id"]; ok {
+					t.Fatalf("ref_id on review: %+v", gotArgs)
+				}
+				if _, ok := gotArgs["idempotency_key"]; ok {
+					t.Fatalf("idempotency_key on review: %+v", gotArgs)
+				}
+			}
+			if tc.name == "PlaceOrderStop" {
+				if _, ok := gotArgs["time_in_force"]; ok {
+					t.Fatalf("time_in_force injected: %+v", gotArgs)
+				}
+			}
+		})
+	}
+}
+
+func TestPlaceOrder_rhntest(t *testing.T) {
+	t.Parallel()
+	s := rhntest.New(t)
+	s.Set("place_equity_order", json.RawMessage(`{"id":"o1"}`))
+	c := equity.New(&client.Client{URL: s.URL})
+	qty := decimal.NewFromInt(3)
+	px := decimal.RequireFromString("99.6")
+	got, err := c.PlaceOrder(context.Background(), equity.PlaceOrderRequest{
+		AccountNumber: "acct", Symbol: "MU", Side: client.Buy, Type: client.Limit,
+		Qty: &qty, LimitPrice: &px, TimeInForce: client.GFD, RefID: "buy:2026-08-18:MU",
+	})
+	if err != nil {
+		t.Fatal(err)
+	}
+	if got.ID != "o1" {
+		t.Fatalf("%+v", got)
+	}
+	if s.LastName() != "place_equity_order" {
+		t.Fatalf("%s", s.LastName())
+	}
+}
+
+func TestReviewOrder_rhntest(t *testing.T) {
+	t.Parallel()
+	s := rhntest.New(t)
+	s.Set("review_equity_order", json.RawMessage(`{"data":{"errors":["insufficient buying power"],"warnings":["PDT"]}}`))
+	c := equity.New(&client.Client{URL: s.URL})
+	qty := decimal.NewFromInt(3)
+	got, err := c.ReviewOrder(context.Background(), equity.PlaceOrderRequest{
+		AccountNumber: "acct", Symbol: "MU", Side: client.Buy, Type: client.Market, Qty: &qty,
+	})
+	if err != nil {
+		t.Fatal(err)
+	}
+	if diff := cmp.Diff([]string{"insufficient buying power"}, got.Errors); diff != "" {
+		t.Fatal(diff)
+	}
+	if diff := cmp.Diff([]string{"PDT"}, got.Warnings); diff != "" {
+		t.Fatal(diff)
+	}
+	if s.LastName() != "review_equity_order" {
+		t.Fatalf("%s", s.LastName())
+	}
+}
+
+func TestCancelOrder_rhntest(t *testing.T) {
+	t.Parallel()
+	s := rhntest.New(t)
+	s.Set("cancel_equity_order", json.RawMessage(`{}`))
+	c := equity.New(&client.Client{URL: s.URL})
+	if err := c.CancelOrder(context.Background(), equity.CancelOrderRequest{
+		AccountNumber: "acct",
+		OrderID:       "o1",
+	}); err != nil {
+		t.Fatal(err)
+	}
+	if s.LastName() != "cancel_equity_order" {
+		t.Fatalf("%s", s.LastName())
+	}
+	want := map[string]any{"account_number": "acct", "order_id": "o1"}
+	if diff := cmp.Diff(want, s.LastArgs()); diff != "" {
+		t.Fatal(diff)
+	}
+}