view tool rejects a normal 8.6 KB file as too large to read at once

Describe the bug

The built-in view tool (shown as Read in the VS Code UI) reports File too large to read at once (8.6 KB) when asked to read a small, ordinary multiline Markdown file. This appears to be a false-positive size warning and makes normal full-file inspection unnecessarily cumbersome.

This is not the large single-line JSON or custom-tool-output case. The file is a regular Markdown document and is approximately 8.6 KB.

Affected version

Unknown - encountered in the Copilot CLI runtime integrated with VS Code.

Steps to reproduce the behavior

1. Use the Copilot CLI runtime in VS Code on Windows.
2. Ask the agent to read a normal multiline Markdown file of approximately 8.6 KB.
3. Allow the built-in view/Read tool to read the file without specifying a range.
4. Observe the File too large to read at once (8.6 KB) warning instead of the file contents.

Expected behavior

A normal file of this size should be read successfully in full. If a size threshold is required, the threshold should be consistent, documented, and should not report ordinary small files as too large without a clear reason.

Additional context

• OS: Windows 11
• Host: Visual Studio Code
• Tool: built-in view/Read
• File type: regular Markdown, approximately 8.6 KB
• The warning recommends using view_range, even though the file is small enough that a full read would normally be expected.
• This report is about the view tool's full-file size handling, not Azure DevOps or the repository being inspected.

Repérez l'implémentation intégrée de view/Read et la vérification de la taille du fichier complet, puis reproduisez le problème avec un fichier Markdown multiligne d'environ 8.6 KB dans la configuration Windows et VS Code décrite. Déterminez pourquoi ce fichier normal est rejeté ; le travail est terminé lorsque le fichier est lu intégralement sans l'avertissement de faux positif, tandis que les entrées réellement trop volumineuses ou sur une seule ligne conservent un traitement approprié.