docs: enhance data fetching instructions for clarity and efficiency

Author: NoOne7135

custom/skills/analyze_data/SKILL.md

@@ -10,7 +10,7 @@ Then you need to select between two main tools for fetching data:
 
 - Load and call `aggregate` tool to fetch data for analytics. This is the main tool for fast server-side aggregations, including filtered data, grouped metrics, and date buckets such as day, week, or month. Always prioritize this way of fetching data for analytics, as it is optimized for performance and reduces the amount of data transferred and processed in-memory.
 
-- Load and call `get_resource_data` tool only when the requested analysis cannot be answered with `aggregate`. This is heavier because it returns original rows with all fields, but it allows complex calculations, comparisons, and custom groupings in-memory.
+- Load and call `get_resource_data` tool only when the requested analysis cannot be answered with `aggregate`. When using it, pass `columns` with only the fields required for the calculation so large result sets do not include unrelated row data.
 
 # Instructions
 
@@ -19,6 +19,7 @@ When the user asks for analytics, reports, trends, comparisons, or distributions
 - Fetch the requested data using `aggregate` whenever possible.
 - If it is not possible to get the required aggregates using `aggregate`, fetch the underlying rows with `get_resource_data`.
 - Prefer narrow requests: use filters, sorting, pagination, and date ranges whenever possible.
+- Prefer narrow row payloads: include `columns` when only one or a few fields are needed.
 - If the request is ambiguous, clarify the resource, metric, grouping, or date range before fetching data.
 - Return a short written summary with the key finding and most important numbers.
 - If the user asks for a chart, or if a chart would help and you decide to produce one, invoke the `charts` skill for chart formatting and Vega-Lite requirements.

custom/skills/fetch_data/SKILL.md

@@ -6,6 +6,8 @@ description: Fetch one or more records. Use to find records entities. To use thi
 
 You can use tool `get_resource_data` it returns one or more records and is capable of using filters
 
+When you only need specific fields, pass `columns` with the exact resource column names you need. This keeps large result sets small. For record links or user-facing record choices, include the primary key and enough display fields, or omit `columns` when you need the full row context.
+
 # Instructions
 
 To find specific data record you should use filters. ILIKE filters are preferred when we are unsure the input is clear.You can combine filters with OR if you want to search multiple fields.If user queries one record you should try to fetch up to 5 records and if more then one returned return output them all to user and ask to select one. When you communicate about record with user, show its several most important fields.