Plugin hooks can't invoke relative bundled scripts

[ao-Barbosa]

• Copilot Chat Extension Version: 0.42.3
• VS Code Version: 1.114.0
• OS Version: Windows 11 23H2 22631.6199
• Feature (e.g. agent/edit/ask mode): Agent via Copilot Plugin
• Selected model (e.g. GPT 4.1, Claude 3.7 Sonnet): Any

Steps to Reproduce:

1. Create a basic plugin following the official documentation.
   This plugin must include:
   1.1. Any custom agent, just to trigger the hooks.
   1.2. /hooks/*.ts scripts. Can also be any language, even powershell.
   1.3. /hooks.json

{
  "version": 1,
  "hooks": {
    "HOOK NAME HERE, USE ALL FOR MORE DEBUG INFO": [
      {
        "type": "command",
        "bash": "bun ./.github/hooks/scripts/session-start.ts",
        "powershell": "bun ./.github/hooks/scripts/session-start.ts",
        // OR
        "windows": "powershell.exe -NoLogo -NoProfile -Command \"bun ./.github/hooks/scripts/session-start.ts\"",
        "cwd": ".",
        "timeoutSec": 10
      }
    ],
  }
}

2. Publish plugin via marketplace.
3. Install plugin in VSCode (works differently if installed using Copilot CLI.
4. Any hook invocation (sessionStart, preToolUse, userPromptSubmitted...) will now generate an warning | execution error.

Warning output:

. : O arquivo %USERPROFILE%\Documents\WindowsPowerShell\Microsoft.PowerShell_profile.ps1 não pode ser 
carregado porque a execução de scripts foi desabilitada neste sistema. Para obter mais informações, consulte 
about_Execution_Policies em https://go.microsoft.com/fwlink/?LinkID=135170.
No linha:1 caractere:3
+ . '%USERPROFILE%\Documents\WindowsPowerShell\Microsoft.Powe ...
+   ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : ErrodeSegurança: (:) [], PSSecurityException
    + FullyQualifiedErrorId : UnauthorizedAccess
error: Module not found "./.github/hooks/scripts/pre-tool-guard.ts"

this include another unrelated issue with powershell execution policies in my company, can be circumvented by using "windows": "powershell.exe -NoLogo -NoProfile

I have also tried:

• Utilizing the cwd property but that is also relative to current VSCode directory
• An absolute path but it gets inconsistent with the plugin installation path

[tspascoal]

I've create a repro repo. The repro also works as a workspace hooks. cloning the repo and watch the hooks work correctly as workspace hooks

To repro the install the plugin from source directly from the repo and see hooks execution failure as a warning in the chat window:

The hooks are correctly discovered

But when they are executed the cwd is the workspace (from the logs) which works fine for workspace hooks, but not plugins.

2026-05-14 12:57:34.958 [info] [#3] [UserPromptSubmit] Input: {"timestamp":"2026-05-14T11:57:34.949Z","hook_event_name":"UserPromptSubmit","session_id":"69ca5628-0d08-4d8c-b9be-f3d08242b31a","transcript_path":"/home/tspascoal/.vscode-server-insiders/data/User/workspaceStorage/69e455d2be94d33a9623ea8e95491ac6/GitHub.copilot-chat/transcripts/69ca5628-0d08-4d8c-b9be-f3d08242b31a.jsonl","prompt":"let's see if you run the hook from the installed plugin","cwd":"/home/tspascoal/tests/test-hook"}
2026-05-14 12:57:34.960 [info] [#3] [UserPromptSubmit] Completed (NonBlockingError) in 10ms
2026-05-14 12:57:34.960 [info] [#3] [UserPromptSubmit] Output: /bin/sh: 1: scripts/on-user-prompt.sh: not found

Note: the plugin works correctly in CLI

[samcarrington]

Encountering similar issues here - hooks declared in a Copilot format plugin via the hooks.json file don't receive an expanded ${PLUGIN_ROOT} at execution time so script resolution fails. Configuring the hooks in the plugin.json manifest does allow VS Code to find the hooks. There's a different execution path in each case:

Hooks in plugin.json
https://github.com/microsoft/vscode/blob/b85394774d09f3ff383404c08343ce116cc23ba7/src/vs/platform/agentPlugins/common/pluginParsers.ts#L1296

vs

Hooks in a file
https://github.com/microsoft/vscode/blob/b85394774d09f3ff383404c08343ce116cc23ba7/src/vs/platform/agentPlugins/common/pluginParsers.ts#L152-L161

Connor Peet (@connor4312)