Add nearest_nodes tool for coordinate-based node search

lang/agent/graph.py

@@ -100,7 +100,25 @@ def build_tools(mcp: McpInvoker):
             },
         )
 
-    return [search_products, search_offers, match_offers_with_route, order_timeline, search_nodes]
+    @tool
+    def nearest_nodes(
+        lat: float,
+        lon: float,
+        limit: int = 5,
+        user_token: str | None = None,
+    ) -> Any:
+        """Find nearest logistics nodes to given coordinates. Use this when search_nodes by city name returns no results - provide approximate coordinates instead (e.g. Nairobi is roughly -1.29, 36.82)."""
+        return mcp.call(
+            "nearest_nodes",
+            {
+                "lat": lat,
+                "lon": lon,
+                "limit": limit,
+                "userToken": user_token,
+            },
+        )
+
+    return [search_products, search_offers, match_offers_with_route, order_timeline, search_nodes, nearest_nodes]
 
 
 def build_graph():

lang/mcp/src/index.js

@@ -251,6 +251,56 @@ server.registerTool(
   }
 );
 
+// Tool: nearest_nodes (GEO - find nodes by coordinates)
+server.registerTool(
+  "nearest_nodes",
+  {
+    title: "Nearest Nodes",
+    description: "Find nearest logistics nodes to given coordinates. Use this when searching by city name returns no results - provide approximate coordinates instead.",
+    inputSchema: {
+      lat: z.number().describe("Latitude of the location"),
+      lon: z.number().describe("Longitude of the location"),
+      limit: z.number().optional().default(5).describe("Max number of results"),
+      userToken: z.string().optional().describe("Optional Bearer token"),
+    },
+  },
+  async ({ lat, lon, limit = 5, userToken }) => {
+    const geoUrl = process.env.GEO_GRAPHQL_URL;
+    if (!geoUrl) {
+      throw new Error("GEO_GRAPHQL_URL is not set.");
+    }
+
+    const token = resolveToken({
+      userToken,
+      serviceTokenEnv: "GEO_M2M_TOKEN",
+      required: false,
+    });
+
+    const gqlQuery = `
+      query NearestNodes($lat: Float!, $lon: Float!, $limit: Int) {
+        nearestNodes(lat: $lat, lon: $lon, limit: $limit) {
+          uuid
+          name
+          latitude
+          longitude
+          country
+          countryCode
+          transportTypes
+        }
+      }
+    `;
+
+    const data = await gqlRequest(
+      geoUrl,
+      gqlQuery,
+      { lat, lon, limit },
+      token
+    );
+
+    return { content: [{ type: "text", text: JSON.stringify(data.nearestNodes ?? [], null, 2) }] };
+  }
+);
+
 // Tool: order_timeline (orders service)
 server.registerTool(
   "order_timeline",