An edit summary is a brief explanation of an edit to a MozillaWiki page. When you edit a page, there is a small text entry field labeled Edit summary located under the main edit box and above the Save page button. Edit summaries are displayed in lists of changes (such as page histories and watchlists), and at the top of diff pages.
It is good practice to fill in the Edit summary field, or add to it in the case of section editing, as this helps others to understand the intention of your edit. To avoid accidentally leaving edit summaries blank, all users have enabled the preference "Prompt me when entering a blank edit summary." You can disable this reminder on the Editing tab of your user preferences.
Always provide an edit summary
It is considered good practice to provide a summary for every edit, especially when reverting (undoing) the actions of other editors or deleting existing text; otherwise, people may question your motives for the edit. Edits that do not have an edit summary are more likely to be reverted, because it may not be obvious what the purpose of the edit was.
Accurate summaries help other contributors decide whether it is worthwhile for them to review an edit, and to understand the change should they choose to review it. When a major edit (e.g. deletion of a substantial amount of text, a significant addition, or a substantial rewrite) doesn't have an edit summary, there are fewer reasons to assume good faith and busy editors may be more inclined to revert the change without checking it in detail. Summaries are less important for minor changes (which means generally unchallengeable changes such as spelling or grammar corrections), but a brief note like "fixed spelling" is helpful even then.
How to summarize
- Summarize. Summarize the change, even if only briefly; even a short summary is better than no summary.
- Explain. Give reasons for the change, if there is a reasonable chance that other editors may be unclear as to why it was made.
- Abbreviations. Abbreviations should be used with care. They can be confusing for new contributors.
- Talk pages. When editing talk pages, consider copying your comment to the edit summary, if it is brief; this allows users to check Recent changes, Page history and User contributions (see below) very efficiently. It also reduces the load on the servers.
- Expand on important information. Readers who see only the summary might not get the entire picture. Prevent misunderstanding: If an edit requires more explanation than will fit in the summary box, use the Talk page to give more information, adding "See Talk" or "See Discussion Page" to the summary.
- Avoid misleading summaries. Mentioning one change but not another one can be misleading to someone who finds the other one more important; add "and misc." to cover the other changes.
- Avoid vagueness. While edit summaries can be terse, they should still be specific as to what was done. For example, "I made some changes" is functionally equivalent to no edit summary being provided.
- Avoid inappropriate summaries. Editors should explain their edits, but not be overly critical or harsh when editing or reverting others' work. This may be perceived as uncivil, and cause resentment or conflict. Explain what you changed, citing the relevant policies, guidelines or principles of good writing, but do not target others in a way that may come across as a personal attack.
After you save the page, you cannot change the edit summary, so be careful with it, particularly if you are in a heated content dispute – do not write things you will regret.
If you make an important omission or error in an edit summary, you can correct this by making a dummy edit (an edit with no changes), and adding further information in its own edit summary.
In the extreme case of an edit summary containing certain kinds of harmful content, the summary can be deleted on request. They may be removed from public view by administrators using Revision Deletion; such edit summaries remain visible to administrators. In even more limited circumstances the entire edit may be oversighted, leaving it and its edit summary visible only to the handful of users with the Oversight permission.
Edit summary properties and features
- Limited to 250 characters. The edit summary box can hold one line of 250 characters. If you attempt to type or paste more, only the first 250 characters will be displayed – the rest will be discarded. For example attempting to add 10 new characters (at the end or in between) to a summary already containing 245 characters will result in the first 5 new characters being inserted and the second 5 being disregarded.
- Show Preview. The "Show preview" button also provides a preview of the edit summary to facilitate checking links.
- Can't be changed after saving. After you save the page, you cannot change the edit summary.
- Doesn't appear in searches. The search function cannot search edit summaries, and they are not indexed by external search engines.
- Wikilinks always rendered; other wikitext coding ignored. Text in edit summaries renders internal links, including piped links, and interwiki links, even when enclosed within <nowiki> and </nowiki>. Therefore, copying wikitext in the edit summary box may be preferable to copying text from the preview, except when one wants to save space. Other wikitext coding is not interpreted.
~~~~has no effect, so do not sign edit summaries.
- URLs. When copying an external link from the preview into the edit summary box then, depending on the operating system, the "printable version" is copied, i.e. how it is normally rendered, and in addition, between parentheses, the URL; hence the same information as in the wikitext, but in a different format, as well as a possible sequential number.
Places where the edit summary appears
The edit summary appears in black italics in the following places:
- Page history – list of changes to the page you edited
- User contributions – list of all your edits
- Watchlist<ref group="note">Use the enhanced watchlist to see all recent changes in the watched pages, not just the last change in each page.</ref> – list of recent changes to watched pages (logged-in users only)
- diff page – shows the difference between two edits
- Recent changes – list of all recent edits
- Related changes – list of recent changes to pages linked to the page you edited
- List of new pages – shows the edit summary of the creation.
When adding a new section to a discussion page with the "new section" button, the section title is used as the edit summary. When editing an existing section, the section title is inserted at the beginning of the edit summary, enclosed with /* and / marks, for example / External links */. Details of the edit should be added after this text. In the case that you provide a long summary yourself, you can delete the section title in order to stay within the limit of 250 characters.
When viewing such an edit summary, the section name will appear in grey, with a small link next to it: → External links. Click the link to view the section (if the section no longer exists, the link will just take you to the page).
If you create a new section before or after an existing section by clicking a section "edit" link, delete the text between /* and / marks (or change it to the new section title) to avoid confusion.<ref>It used to be possible to manually include links to multiple sections using the / */ syntax – this may be useful when editing several sections at once.
In certain circumstances, an automatic summary is generated when an edit is saved without one. This is slightly different from the summary added when editing a section, as that can be modified by the user before saving.
With the exception of the automatic summary when creating a redirect, which usually says all that needs to be said, these are not a substitute for a proper edit summary – you should always leave a meaningful summary, even in the above cases. They are, however, useful in providing some context for edits made by inexperienced users who are not aware of the importance of edit summaries, and for spotting vandalism.