The problem
Coding agents write plans and specs in Markdown before they build. Reviewing one in a terminal or a pull request works for engineers, but a product manager or a client will not open a diff. Pasting it into a chat loses where each comment was meant to go.
How it works with Onlay
onlay push plans/onboarding-spec.md
Onlay renders the Markdown on the server with a clean stylesheet that follows the reader's light or dark setting, and gives you a link. Reviewers select a sentence and comment, or pin a comment on a heading, a list item or a table row. With editing on, they rewrite a line themselves.
onlay pull plans/onboarding-spec.md
Each comment comes back with the words it quotes and the lines of your Markdown file it sits on, so the agent edits the right line in the source. The next push publishes the revised plan to the same link and answers the threads.
Why not a pull request
A pull request is the right place when the reviewers are engineers and the plan lives in the repo. You can do both: keep the Markdown in the repo and publish it with Onlay for the people who will not read a diff. The label line Onlay writes at the top of the file is an HTML comment, so it does not show in the rendered Markdown.
When to make it HTML instead
If the plan would be clearer with a flow diagram, a screen mockup or a table that sorts, ask your agent for HTML. Everything above works the same way. The homepage has a live plan with a flow diagram and mockups.