Limit the data returned in list operations

When running list operations against large instances even the default
limits were causing things like Cursor or Claude Desktop to bail as the
conversation was too large. Using summary types for these calls instead
allow them to return with reasonable limits.

Author: csmarchbanks

src/mcp_grafana/client.py

@@ -8,18 +8,21 @@
 We should separate HTTP types from tool types.
 """
 
+import json
 import math
 from datetime import datetime
-from typing import Any
+from typing import Any, List
 
 import httpx
-from pydantic import UUID4
+from pydantic import UUID4, TypeAdapter
 
 from .settings import grafana_settings
 from .grafana_types import (
     AddActivityToIncidentArguments,
     CreateIncidentArguments,
     CreateSiftInvestigationArguments,
+    Datasource,
+    IncidentPreview,
     QueryIncidentPreviewsRequest,
     Query,
     SearchDashboardsArguments,
@@ -64,8 +67,10 @@ async def post(self, path: str, json: dict[str, Any]) -> bytes:
             raise GrafanaError(r.read().decode())
         return r.read()
 
-    async def list_datasources(self) -> bytes:
-        return await self.get("/api/datasources")
+    async def list_datasources(self) -> List[Datasource]:
+        response = await self.get("/api/datasources")
+        ta = TypeAdapter(List[Datasource])
+        return ta.validate_json(response)
 
     async def get_datasource(
         self, uid: str | None = None, name: str | None = None
@@ -90,11 +95,16 @@ async def get_dashboard(self, dashboard_uid: str) -> bytes:
         return await self.get(f"/api/dashboards/uid/{dashboard_uid}")
 
     # TODO: split incident stuff into a separate client.
-    async def list_incidents(self, body: QueryIncidentPreviewsRequest) -> bytes:
-        return await self.post(
+    async def list_incidents(
+        self, body: QueryIncidentPreviewsRequest
+    ) -> List[IncidentPreview]:
+        response = await self.post(
             "/api/plugins/grafana-incident-app/resources/api/IncidentsService.QueryIncidentPreviews",
             json=body.model_dump(),
         )
+        response = json.loads(response)
+        ta = TypeAdapter(List[IncidentPreview])
+        return ta.validate_python(response["incidentPreviews"])
 
     async def create_incident(self, arguments: CreateIncidentArguments) -> bytes:
         return await self.post(

src/mcp_grafana/tools/datasources.py

@@ -1,13 +1,30 @@
+from typing import List
 from mcp.server import FastMCP
 
+from mcp_grafana.grafana_types import Datasource
+
 from ..client import grafana_client
 
 
-async def list_datasources() -> bytes:
+async def list_datasources() -> List[Datasource]:
     """
     List datasources in the Grafana instance.
     """
-    return await grafana_client.list_datasources()
+    datasources = await grafana_client.list_datasources()
+    resp = []
+    # Only push a subset of fields to save on space.
+    for ds in datasources:
+        resp.append(
+            {
+                "id": ds.id,
+                "uid": ds.uid,
+                "name": ds.name,
+                "type": ds.type,
+                "isDefault": ds.is_default,
+            }
+        )
+
+    return resp
 
 
 async def get_datasource_by_uid(uid: str) -> bytes:

src/mcp_grafana/tools/incident.py

@@ -31,7 +31,9 @@ class ListIncidentsArguments(BaseModel):
     )
 
 
-async def list_incidents(arguments: ListIncidentsArguments) -> bytes:
+async def list_incidents(
+    arguments: ListIncidentsArguments = ListIncidentsArguments(),
+) -> bytes:
     """
     List incidents from the Grafana Incident incident management tool.