excessive sequential tool calls instead of batching

### Describe the bug

When analyzing a 1.8MB JSON file with over 150 records, Copilot made 7+ separate tool calls across multiple rounds to extract data that could have been gathered in a single Python script

### Affected version

_No response_

### Steps to reproduce the behavior

Repro Steps:
1. Open Copilot CLI and point it at a JSON file
2. Ask: "Read and parse this file, extract fields a b c d e, and create categories from the data."
3. Count the number of separate tool calls Copilot makes before it has all the data it needs.

### Expected behavior

Copilot should generate a single Python script that parses the JSON, extracts all relevant fields, and outputs a consolidated summary. This should require 1-2 tool calls at most

### Additional context

_No response_

Start by reproducing the behavior in Copilot CLI with a 1.8MB JSON file containing over 150 records and the stated extraction request, then trace where its tool calls are coordinated. Done means the request gathers the needed fields and categories in one generated Python script with no more than 1-2 tool calls.

Written by the indexing model from the issue text.