feat: validate receive message contract args

internal/tools/isphere_read_test.go

@@ -142,6 +142,75 @@ func TestISphereReceiveMessagesToolReturnsSourceMessages(t *testing.T) {
 	}
 }
 
+func TestISphereReceiveMessagesToolValidatesRemainingContractArgs(t *testing.T) {
+	fake := &fakeReceiveMessagesSource{
+		result: isphere.ReceiveMessagesResult{Messages: []isphere.Message{{
+			ID:               "msg-1",
+			ConversationID:   "sender@imopenfire1-lanzhou|receiver@imopenfire1-lanzhou",
+			ConversationType: "chat",
+			SenderID:         "sender@imopenfire1-lanzhou",
+			ReceiverID:       "receiver@imopenfire1-lanzhou",
+			Text:             "redacted-report.docx",
+			Timestamp:        "1783423807000",
+			Subject:          "FILE_TRANSFER_CANCEL",
+		}}},
+	}
+	session, cleanup := connectToolsTestSession(t, func(server *mcp.Server) {
+		RegisterISphereReadTools(server, fake)
+	})
+	defer cleanup()
+
+	callResult, err := session.CallTool(context.Background(), &mcp.CallToolParams{
+		Name: ToolNameReceiveMessages,
+		Arguments: map[string]any{
+			"include_attachment_metadata": false,
+			"source_preference":           "local_readonly",
+			"preview":                     true,
+			"cursor":                      "",
+			"limit":                       5,
+		},
+	})
+	if err != nil {
+		t.Fatalf("call with safe contract args: %v", err)
+	}
+	if callResult.IsError {
+		t.Fatalf("call result is error: %+v", callResult)
+	}
+	var decoded struct {
+		Messages []struct {
+			Attachments []struct {
+				FileID string `json:"file_id"`
+			} `json:"attachments"`
+		} `json:"messages"`
+	}
+	payload, err := json.Marshal(callResult.StructuredContent)
+	if err != nil {
+		t.Fatalf("marshal structured content: %v", err)
+	}
+	if err := json.Unmarshal(payload, &decoded); err != nil {
+		t.Fatalf("decode structured content %s: %v", payload, err)
+	}
+	if len(decoded.Messages) != 1 || len(decoded.Messages[0].Attachments) != 0 {
+		t.Fatalf("attachments = %+v, want suppressed", decoded.Messages)
+	}
+
+	bridgeResult, err := session.CallTool(context.Background(), &mcp.CallToolParams{
+		Name:      ToolNameReceiveMessages,
+		Arguments: map[string]any{"source_preference": "bridge", "limit": 5},
+	})
+	if err == nil && !bridgeResult.IsError {
+		t.Fatalf("bridge source_preference was accepted before connector exists")
+	}
+
+	cursorResult, err := session.CallTool(context.Background(), &mcp.CallToolParams{
+		Name:      ToolNameReceiveMessages,
+		Arguments: map[string]any{"cursor": "next-page", "limit": 5},
+	})
+	if err == nil && !cursorResult.IsError {
+		t.Fatalf("non-empty cursor was accepted before pagination exists")
+	}
+}
+
 type fakeReceiveMessagesSource struct {
 	queries []isphere.ReceiveMessagesQuery
 	result  isphere.ReceiveMessagesResult