feat: validate receive files list args

internal/tools/isphere_files_test.go

@@ -88,3 +88,70 @@ func TestISphereReceiveFilesToolReturnsLogBackedFiles(t *testing.T) {
 		t.Fatalf("source queries = %+v, want one unbounded receive query", fake.queries)
 	}
 }
+
+func TestISphereReceiveFilesToolValidatesContractArgs(t *testing.T) {
+	fake := &fakeReceiveMessagesSource{
+		result: isphere.ReceiveMessagesResult{Messages: []isphere.Message{{
+			ID:             "msg-file-1",
+			ConversationID: "alice@imopenfire1-lanzhou|bob@imopenfire1-lanzhou",
+			Text:           "redacted-report.docx",
+			Timestamp:      "1783423807000",
+			Subject:        "FILE_TRANSFER_CANCEL",
+		}}},
+	}
+	session, cleanup := connectToolsTestSession(t, func(server *mcp.Server) {
+		RegisterISphereFileTools(server, fake)
+	})
+	defer cleanup()
+
+	callResult, err := session.CallTool(context.Background(), &mcp.CallToolParams{
+		Name: ToolNameReceiveFiles,
+		Arguments: map[string]any{
+			"mode":              "list",
+			"name_contains":     "report",
+			"source_preference": "local_readonly",
+			"preview":           true,
+			"cursor":            "",
+			"output_dir":        "",
+			"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)
+	}
+
+	bridgeResult, err := session.CallTool(context.Background(), &mcp.CallToolParams{
+		Name:      ToolNameReceiveFiles,
+		Arguments: map[string]any{"mode": "list", "source_preference": "bridge"},
+	})
+	if err == nil && !bridgeResult.IsError {
+		t.Fatalf("bridge source_preference was accepted before connector exists")
+	}
+
+	cursorResult, err := session.CallTool(context.Background(), &mcp.CallToolParams{
+		Name:      ToolNameReceiveFiles,
+		Arguments: map[string]any{"mode": "list", "cursor": "next-page"},
+	})
+	if err == nil && !cursorResult.IsError {
+		t.Fatalf("non-empty cursor was accepted before pagination exists")
+	}
+
+	outputResult, err := session.CallTool(context.Background(), &mcp.CallToolParams{
+		Name:      ToolNameReceiveFiles,
+		Arguments: map[string]any{"mode": "list", "output_dir": "C:\\tmp\\isphere"},
+	})
+	if err == nil && !outputResult.IsError {
+		t.Fatalf("output_dir was accepted in list mode before download exists")
+	}
+
+	downloadResult, err := session.CallTool(context.Background(), &mcp.CallToolParams{
+		Name:      ToolNameReceiveFiles,
+		Arguments: map[string]any{"mode": "download", "file_id": "msg-file-1:redacted-report.docx"},
+	})
+	if err == nil && !downloadResult.IsError {
+		t.Fatalf("download mode was accepted before cache mapping exists")
+	}
+}