Show line range in agent host file-read tool display

[roblourens]

When the Copilot CLI's view tool is called with a view_range argument, the agent host now surfaces the line range in both the invocation message and the past-tense message, instead of just showing the file name.

Before: "Reading file.ts" / "Read file.ts"
After: "Reading file.ts, lines 10 to 20" / "Read file.ts, lines 10 to 20" (or "line 10" for a single line)

All changes are in src/vs/platform/agentHost/node/copilot/copilotToolDisplay.ts:

• Added ICopilotViewToolArgs extending ICopilotFileToolArgs with optional view_range?: number[].
• Added a formatViewRange helper that defensively parses the [start, end] array (handling missing/-1 end-of-file sentinels).
• Updated the View cases in getInvocationMessage and getPastTenseMessage to render the range when present.

The read permission display path is unchanged — the Copilot SDK's read permission request only carries path + intention, not view_range. The line range only flows through the tool.execution_start parsed parameters.

(Written by Copilot)

[Copilot]

Pull request overview

Updates the agent host’s Copilot CLI tool-call display strings so view tool invocations/completions can show a requested line range (when provided via view_range) rather than only the file name.

Changes:

• Add ICopilotViewToolArgs with optional view_range?: number[] for view tool parameters.
• Add formatViewRange helper to parse/normalize view_range.
• Update getInvocationMessage / getPastTenseMessage View cases to render “line …” / “lines … to …” variants.

Show a summary per file

File	Description
src/vs/platform/agentHost/node/copilot/copilotToolDisplay.ts	Parses view_range and includes the formatted line/range in view tool start/complete messages.

Copilot's findings

Comments suppressed due to low confidence (1)

src/vs/platform/agentHost/node/copilot/copilotToolDisplay.ts:95

• formatViewRange currently accepts non-integer and non-positive line numbers (e.g. 0, 1.5) and can also return an endLine that is less than startLine (e.g. [10, 5]), which then renders as “lines 10 to 5”. Since view_range is documented as 1-based inclusive, it should defensively validate Number.isInteger, startLine >= 1, and (when endLine is a number) endLine >= startLine (and treat invalid ranges as absent).

function formatViewRange(view_range: number[] | undefined): { startLine: number; endLine: number | undefined } | undefined {
	if (!Array.isArray(view_range) || view_range.length < 1) {
		return undefined;
	}
	const startLine = view_range[0];
	if (typeof startLine !== 'number' || !isFinite(startLine)) {
		return undefined;
	}
	const rawEnd = view_range.length >= 2 ? view_range[1] : undefined;
	const endLine = typeof rawEnd === 'number' && isFinite(rawEnd) && rawEnd >= 0 ? rawEnd : undefined;
	return { startLine, endLine };
}

• Files reviewed: 1/1 changed files
• Comments generated: 3

[github-actions]

Screenshot Changes

Base: b88dca15 Current: cdbe8cf5

Changed (2)

chat/aiCustomizations/aiCustomizationManagementEditor/McpBrowseMode/Light

Before	After

agentSessionsViewer/CompletedUnread/Dark

Before	After