bug: Errors mentioning 'replace' when using update-task with the --research flag

[cjwdev1]

Description

When I go to use the update-task command, such as

task-master update-task --id=36 --research --prompt="..."

I get the following errors and the operation does not complete:

[INFO] Loading prompt template with variant: research, appendMode: false, useResearch: true
[ERROR] Failed to load prompt update-task: Cannot read properties of undefined (reading 'replace')
[ERROR] Failed to load prompt template: Cannot read properties of undefined (reading 'replace')
[ERROR] Error updating task: Failed to load prompt template: Cannot read properties of undefined (reading 'replace')
Error: Failed to load prompt template: Cannot read properties of undefined (reading 'replace')

However when I execute the same command the only difference being no --research flag, there the task completes without any issues.

Steps to Reproduce

1. Issue an update-task command with the --research flag
2. Observe the resulting errors

Expected Behavior

I expect it to complete the command without errors, and to update the task while using the --research context

Actual Behavior

errors and fails

Screenshots or Logs

Environment

• Task Master version: 0.43.1
• Node.js version: 24.14.1
• Operating system: Windows 11 Business
• IDE (if applicable): Cursor, Powershell terminal

Additional Context

Happy to provide any additional info, I just don't know what info would be relevant! Please reach out.

[daveCode-dot]

The Cannot read properties of undefined (reading 'replace') chain points at the prompt loader looking for a template variant that doesn't exist on disk for the update-task command, then trying to do string interpolation on the undefined it got back.

Two narrowing questions that would localise it quickly:

1. Inside your install, does node_modules/task-master*/prompts/ (or wherever templates live for v0.43.1) contain a file matching update-task*research* or similar? The log shows variant: research, useResearch: true — if there's no update-task.research.{md,txt,json} (or whatever the convention is), the loader returns undefined and the next .replace() blows up.
2. Is --research working for other commands on the same install (e.g. add-task --research)? If yes → the missing variant is update-task-specific. If no → the research provider config (Perplexity / OpenAI / etc.) isn't initialised and every research-flagged command fails the same way.

A couple of repo-side improvements that would have made this self-diagnosing:

• Loader should throw new Error(\prompt variant '${variant}' not found for '${name}' (looked in: ${searchedPaths.join(', ')})`)instead of returningundefinedand letting the consumer crash on.replace`.
• The update-task command is the only one with this surface — quick grep -r "loadPrompt('update-task'" src/ would confirm whether the variant fan-out covers research or only default.

If you can paste the output of task-master --version plus ls $(npm root -g)/task-master*/prompts/ (or local equivalent), happy to point at the missing file path.