Quarto isn't rendering to GFM from the Positron extension?

[marcdotson]

Description

I can render to GFM using documents like the following using the quarto render from the command line:

---
title: "Validity and Representativeness"
format: gfm
---

During this class we will:
- Start working with real data
- Review exploratory data analysis
- Begin reconciling the data and the model

Start by downloading the soft launch data.

However, when I try to render it using the Cmd + Shift + K or using the Preview button inside of Positron I get the following error:

02_data_5600 % quarto preview /Users/a00714634/Documents/02_data_5600/
topics/06_validity-representativeness/README.qmd --no-browser --no-watch-inputs
pandoc 
  to: >-
    commonmark+autolink_bare_uris+emoji+footnotes+gfm_auto_identifiers+pipe_tables+strikeout+task_lists+tex_math_dollars
  output-file: README.md
  standalone: true
  default-image-extension: png
  
metadata
  title: Validity and Representativeness
  
ERROR: No output created by quarto render README.qmd

Stack trace:
    at handleRenderResult (file:///Applications/quarto/bin/quarto.js:143998:11)
    at renderForPreview (file:///Applications/quarto/bin/quarto.js:144017:23)
    at async render2 (file:///Applications/quarto/bin/quarto.js:143837:23)
    at async preview (file:///Applications/quarto/bin/quarto.js:143854:19)
    at async _Command.actionHandler (file:///Applications/quarto/bin/quarto.js:163655:5)
    at async _Command.execute (file:///Applications/quarto/bin/quarto.js:102189:7)
    at async _Command.parseCommand (file:///Applications/quarto/bin/quarto.js:102066:14)
    at async quarto4 (file:///Applications/quarto/bin/quarto.js:188195:5)
    at async file:///Applications/quarto/bin/quarto.js:188224:5
    at async file:///Applications/quarto/bin/quarto.js:188078:14
    at async mainRunner (file:///Applications/quarto/bin/quarto.js:188080:5)
    at async file:///Applications/quarto/bin/quarto.js:188217:3

I'm running Quarto 1.10.18, Quarto Extension 1.138.0, and Positron 2026.09.1 build 2.

[mcanouil]

I believe that's something in your setup, as you seemed to be in a project, maybe nested.
Could you check your workspace? Ensure it's not nested within another project.
Give more details on your setup.

I cannot reproduce (with 1.11 pre-release) in a small independent workspace with only a file like your.