fix(purchase): preserve nullable cost with updated library pin

go.mod

@@ -77,10 +77,10 @@ require (
 )
 
 require (
-	github.com/LeanerCloud/cloud-commitments-go/pkg v0.0.0-20260928205306-c5cf5c7fbad8
-	github.com/LeanerCloud/cloud-commitments-go/providers/aws v0.0.0-20260928205306-c5cf5c7fbad8
-	github.com/LeanerCloud/cloud-commitments-go/providers/azure v0.0.0-20260928205306-c5cf5c7fbad8
-	github.com/LeanerCloud/cloud-commitments-go/providers/gcp v0.0.0-20260928205306-c5cf5c7fbad8
+	github.com/LeanerCloud/cloud-commitments-go/pkg v0.0.0-20260928214714-ce9513612901
+	github.com/LeanerCloud/cloud-commitments-go/providers/aws v0.0.0-20260928214714-ce9513612901
+	github.com/LeanerCloud/cloud-commitments-go/providers/azure v0.0.0-20260928214714-ce9513612901
+	github.com/LeanerCloud/cloud-commitments-go/providers/gcp v0.0.0-20260928214714-ce9513612901
 	github.com/google/jsonschema-go v0.4.3
 	github.com/google/uuid v1.6.0
 	github.com/modelcontextprotocol/go-sdk v1.6.1

go.sum

@@ -76,14 +76,14 @@ github.com/GoogleCloudPlatform/opentelemetry-operations-go/internal/cloudmock v0
 github.com/GoogleCloudPlatform/opentelemetry-operations-go/internal/cloudmock v0.54.0/go.mod h1:vB2GH9GAYYJTO3mEn8oYwzEdhlayZIdQz6zdzgUIRvA=
 github.com/GoogleCloudPlatform/opentelemetry-operations-go/internal/resourcemapping v0.54.0 h1:s0WlVbf9qpvkh1c/uDAPElam0WrL7fHRIidgZJ7UqZI=
 github.com/GoogleCloudPlatform/opentelemetry-operations-go/internal/resourcemapping v0.54.0/go.mod h1:Mf6O40IAyB9zR/1J8nGDDPirZQQPbYJni8Yisy7NTMc=
-github.com/LeanerCloud/cloud-commitments-go/pkg v0.0.0-20260928205306-c5cf5c7fbad8 h1:/4MDV2fttTEnjt37Iq49v5SGMvYuBH68q99r9E+juOE=
-github.com/LeanerCloud/cloud-commitments-go/pkg v0.0.0-20260928205306-c5cf5c7fbad8/go.mod h1:ApWBliDXe099f3oDXBz41K/I9v4bHvn1dG/BGoRmHlw=
-github.com/LeanerCloud/cloud-commitments-go/providers/aws v0.0.0-20260928205306-c5cf5c7fbad8 h1:qUmZE0uvsWKU6Gtglo3h61jVEvqoihFjig6e1r/IvDk=
-github.com/LeanerCloud/cloud-commitments-go/providers/aws v0.0.0-20260928205306-c5cf5c7fbad8/go.mod h1:tIUCLVX6utdBPiP6dAjY7GUfwIQngeSMK5A9aRqe6gA=
-github.com/LeanerCloud/cloud-commitments-go/providers/azure v0.0.0-20260928205306-c5cf5c7fbad8 h1:eyAXwyDwIvEI9vdHb2TqkNPRuhbMYWDXN4751LOltKA=
-github.com/LeanerCloud/cloud-commitments-go/providers/azure v0.0.0-20260928205306-c5cf5c7fbad8/go.mod h1:zgCL/ozOkcZUDbEC7a2UwW+6MPcLoBlEU2WUZ0TORUs=
-github.com/LeanerCloud/cloud-commitments-go/providers/gcp v0.0.0-20260928205306-c5cf5c7fbad8 h1:qs2P8PsqKcFl6eGMGvi7EfMXDuni3pqkc8vDRESppKA=
-github.com/LeanerCloud/cloud-commitments-go/providers/gcp v0.0.0-20260928205306-c5cf5c7fbad8/go.mod h1:UnMqDe2mBUHHF6gnKAgJn9/JeXa7WZqQxfWPs4unGrg=
+github.com/LeanerCloud/cloud-commitments-go/pkg v0.0.0-20260928214714-ce9513612901 h1:JWQwkwshjBoEuoIuFK1KHh70yZDYQTrm5GRloD6ojjU=
+github.com/LeanerCloud/cloud-commitments-go/pkg v0.0.0-20260928214714-ce9513612901/go.mod h1:ApWBliDXe099f3oDXBz41K/I9v4bHvn1dG/BGoRmHlw=
+github.com/LeanerCloud/cloud-commitments-go/providers/aws v0.0.0-20260928214714-ce9513612901 h1:18MxQd7+ZQ+Z2uNbZfpIJQ00JWdSdTVSmVWBzg4R0DA=
+github.com/LeanerCloud/cloud-commitments-go/providers/aws v0.0.0-20260928214714-ce9513612901/go.mod h1:tIUCLVX6utdBPiP6dAjY7GUfwIQngeSMK5A9aRqe6gA=
+github.com/LeanerCloud/cloud-commitments-go/providers/azure v0.0.0-20260928214714-ce9513612901 h1:iSdHYdmGUjcjtSmgGZxptBzDuLrJ9KR2mh1/x7FNvSY=
+github.com/LeanerCloud/cloud-commitments-go/providers/azure v0.0.0-20260928214714-ce9513612901/go.mod h1:zgCL/ozOkcZUDbEC7a2UwW+6MPcLoBlEU2WUZ0TORUs=
+github.com/LeanerCloud/cloud-commitments-go/providers/gcp v0.0.0-20260928214714-ce9513612901 h1:i6OwXLUheudN3GfwnYXdKuEq8vPdE9qkNJ+r71LRLKA=
+github.com/LeanerCloud/cloud-commitments-go/providers/gcp v0.0.0-20260928214714-ce9513612901/go.mod h1:UnMqDe2mBUHHF6gnKAgJn9/JeXa7WZqQxfWPs4unGrg=
 github.com/aws/aws-sdk-go-v2 v1.41.5 h1:dj5kopbwUsVUVFgO4Fi5BIT3t4WyqIDjGKCangnV/yY=
 github.com/aws/aws-sdk-go-v2 v1.41.5/go.mod h1:mwsPRE8ceUUpiTgF7QmQIJ7lgsKUPQOUl3o72QBrE1o=
 github.com/aws/aws-sdk-go-v2/config v1.29.12 h1:Y/2a+jLPrPbHpFkpAAYkVEtJmxORlXoo5k2g1fa2sUo=

tools/aws_ec2_ri_test.go

@@ -2,8 +2,11 @@ package tools
 
 import (
 	"context"
+	"encoding/json"
 	"testing"
+	"time"
 
+	"github.com/modelcontextprotocol/go-sdk/mcp"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 
@@ -208,6 +211,68 @@ func TestAWSEC2RIPurchaseHandleRealPurchaseResolvesEC2Client(t *testing.T) {
 	assert.Equal(t, common.PurchaseSourceMCP, fake.lastOpts.Source)
 }
 
+func TestAWSEC2RIPurchaseCostJSON(t *testing.T) {
+	t.Parallel()
+	zero, positive := 0.0, 600.0
+	cases := []struct {
+		name string
+		cost *float64
+	}{
+		{"unknown", nil},
+		{"zero", &zero},
+		{"positive", &positive},
+	}
+	for _, tc := range cases {
+		t.Run(tc.name, func(t *testing.T) {
+			t.Parallel()
+			fake := &fakeServiceClient{purchaseResult: common.PurchaseResult{Success: true, Cost: tc.cost}}
+			var gotService common.ServiceType
+			var gotRegion string
+			tool := &awsEC2RIPurchaseTool{
+				createProvider: func(_ string, _ *provider.ProviderConfig) (provider.Provider, error) {
+					return &recordingProvider{
+						fakeProvider: &fakeProvider{name: "aws"}, client: fake,
+						gotService: &gotService, gotRegion: &gotRegion,
+					}, nil
+				},
+			}
+			ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
+			defer cancel()
+			server := mcp.NewServer(&mcp.Implementation{Name: "test-server"}, nil)
+			require.NoError(t, tool.Register(server))
+			clientTransport, serverTransport := mcp.NewInMemoryTransports()
+			serverSession, err := server.Connect(ctx, serverTransport, nil)
+			require.NoError(t, err)
+			defer serverSession.Close()
+			client := mcp.NewClient(&mcp.Implementation{Name: "test-client"}, nil)
+			session, err := client.Connect(ctx, clientTransport, nil)
+			require.NoError(t, err)
+			defer session.Close()
+			args := validEC2Args()
+			args.DryRun, args.Confirm = boolPtr(false), boolPtr(true)
+			result, err := session.CallTool(ctx, &mcp.CallToolParams{Name: awsEC2RIPurchaseName, Arguments: args})
+			require.NoError(t, err)
+			require.False(t, result.IsError)
+			structured, err := json.Marshal(result.StructuredContent)
+			require.NoError(t, err)
+			var fields map[string]any
+			require.NoError(t, json.Unmarshal(structured, &fields))
+			assert.Equal(t, true, fields["success"])
+			assert.Equal(t, false, fields["dry_run"])
+			assert.Equal(t, 1, fake.purchaseCalls)
+			if tc.cost == nil {
+				assert.NotContains(t, fields, "cost")
+			} else {
+				require.Contains(t, fields, "cost")
+				assert.Equal(t, *tc.cost, fields["cost"])
+			}
+			assert.NotContains(t, fields, "on_demand_cost")
+			assert.NotContains(t, fields, "estimated_savings")
+			assert.NotContains(t, fields, "savings_percentage")
+		})
+	}
+}
+
 // recordingProvider wraps fakeProvider to capture the service/region passed
 // to GetServiceClient and always return a fixed ServiceClient.
 type recordingProvider struct {

tools/purchase.go

@@ -287,16 +287,8 @@ func ResolveDryRunConfirm(dryRun, confirm *bool) (effectiveDryRun, effectiveConf
 // protocol-level error -- ExecutePurchase itself still returns a Go error
 // for gate refusals and provider-call failures.
 //
-// Cost/OnDemandCost/EstimatedSavings/SavingsPercentage are pointers with
-// omitempty: none of the *FromArgs constructors in this package populate
-// Recommendation's cost fields (they build a fresh Recommendation from the
-// caller's typed args, not from a priced search result), and some provider
-// clients (e.g. AWS EC2 RIs, Savings Plans) never populate
-// PurchaseResult.Cost either. A plain float64 could not distinguish "not
-// known" from "genuinely $0", so every response reported 0 for money fields
-// it never actually priced. A pointer that's nil (and omitted from the JSON
-// payload entirely) when no real value exists lets a caller tell "unknown"
-// apart from "confirmed zero" (feedback_nullable_not_zero).
+// Executed Cost is the provider-reported total upfront cost: nil is omitted,
+// while a known zero is retained. Unpriced recommendation fields are omitted.
 //
 // EffectiveDate is a pointer for the same reason, and it is not a
 // hypothetical concern: `omitempty` on a string only drops "", so a
@@ -380,12 +372,7 @@ func termYearsFromRecommendationTerm(term string) int {
 	return years
 }
 
-// nonZeroCostPtr returns a pointer to v, or nil when v is exactly zero. Cost
-// and savings fields on common.Recommendation and common.PurchaseResult are
-// plain (unpointered) float64s that upstream code sometimes never populates
-// (see the PurchaseResponse doc comment above); this treats an unpopulated
-// zero as "unknown" rather than fabricating a real $0 figure the caller
-// never priced.
+// Recommendation's scalar cost and savings fields use zero for unpriced values.
 func nonZeroCostPtr(v float64) *float64 {
 	if v == 0 {
 		return nil
@@ -670,7 +657,7 @@ func ExecutePurchase(ctx context.Context, req PurchaseRequest) (*PurchaseRespons
 		Success:           purchaseSucceeded(result),
 		DryRun:            result.DryRun,
 		CommitmentID:      result.CommitmentID,
-		Cost:              nonZeroCostPtr(result.Cost),
+		Cost:              result.Cost,
 		OnDemandCost:      nonZeroCostPtr(rec.OnDemandCost),
 		EstimatedSavings:  nonZeroCostPtr(rec.EstimatedSavings),
 		SavingsPercentage: nonZeroCostPtr(rec.SavingsPercentage),

tools/purchase_test.go

@@ -425,11 +425,12 @@ func TestExecutePurchaseRealPurchaseGate(t *testing.T) {
 // token -- never a caller-suppliable source string.
 func TestExecutePurchaseRealPurchaseCallsProviderWithMCPSource(t *testing.T) {
 	t.Parallel()
+	cost := 600.0
 	fake := &fakeServiceClient{
 		purchaseResult: common.PurchaseResult{
 			Success:      true,
 			CommitmentID: "ri-12345",
-			Cost:         600,
+			Cost:         &cost,
 		},
 	}
 	resolve := func(_ context.Context) (provider.ServiceClient, error) {