Bug: Copilot custom chat modes cannot access #runTasks tool

[Donnerstagnacht]

Does this issue occur when all extensions are disabled?: Yes/No

• VS Code Version: 1.101.1
• OS Version: windows 11

Steps to Reproduce:

1. Create a custom chat mode in the settings and select the 'runTasks' as tool.

---
description: 'Description of the custom chat mode.'
tools: ['runTasks']
---

3. Add some tasks in tasks.json

{
  "version": "2.0.0",
  "tasks": [
    {
      "label": "Start TanStack App",
      "type": "shell",
      "command": "npm run dev",
      "group": "none",
      "isBackground": true,
      "problemMatcher": []
    },
    {
      "label": "Push current Git branch",
      "type": "shell",
      "command": "git push origin $(git rev-parse --abbrev-ref HEAD)",
      "problemMatcher": [],
      "group": {
        "kind": "build",
        "isDefault": true
      }
    }
  ]
}

5. Start a chat session using the new custom mode.
6. Attempt to access or invoke the added tasks.

Expected Behavior:

Invoking the #runTasks tool should work for custom chat modes as for the default in build agent mode.

Actual Behavior:

Invoking the #runTasks tool works in the default agent mode but does not work in custom chat modes. Instead in claimes that in cannot access tasks or the terminal.

Impact:

• Limits the extensibility and usefulness of custom chat modes.
• Blocks workflows that depend on accessing tasks from chat.

Additional Information:

• Issue is reproducible with different task types and custom chat modes.
• No relevant errors in logs.
• See attached screenshot for error message.

[Donnerstagnacht]

Used the inbuild tool for reporting

microsoft/vscode-copilot-release#13437