diff --git a/server/src/mcp/tools/transports.ts b/server/src/mcp/tools/transports.ts
index c6e44812..535ab7bc 100644
--- a/server/src/mcp/tools/transports.ts
+++ b/server/src/mcp/tools/transports.ts
@@ -44,7 +44,7 @@ export function registerTransportTools(server: McpServer, userId: number, scopes
         reservation_end_time: z.string().optional().describe('ISO 8601 datetime or time string for arrival'),
         confirmation_number: z.string().max(100).optional(),
         notes: z.string().max(1000).optional(),
-        metadata: z.record(z.string()).optional().describe('Type-specific metadata: flights → { airline, flight_number, departure_airport, arrival_airport }; trains → { train_number, platform, seat }'),
+        metadata: z.record(z.string(), z.string()).optional().describe('Type-specific metadata: flights → { airline, flight_number, departure_airport, arrival_airport }; trains → { train_number, platform, seat }'),
         endpoints: endpointSchema,
         needs_review: z.boolean().optional(),
       },
@@ -95,7 +95,7 @@ export function registerTransportTools(server: McpServer, userId: number, scopes
         reservation_end_time: z.string().optional().describe('ISO 8601 datetime or time string for arrival'),
         confirmation_number: z.string().max(100).optional(),
         notes: z.string().max(1000).optional(),
-        metadata: z.record(z.string()).optional().describe('Type-specific metadata: flights → { airline, flight_number, departure_airport, arrival_airport }; trains → { train_number, platform, seat }'),
+        metadata: z.record(z.string(), z.string()).optional().describe('Type-specific metadata: flights → { airline, flight_number, departure_airport, arrival_airport }; trains → { train_number, platform, seat }'),
         endpoints: endpointSchema,
         needs_review: z.boolean().optional(),
       },