GeezerVison

• Summarize. Summarize the change, even if only briefly; even a short summary is better than no summary.
• Explain. Give reasons for the change (or point where they are given), if you don't think other editors will find it obvious. Why this matters is explained above. Sometimes just a good choice of words for summarizing makes the the text naturally understood as describing an improvement, readily serving as an explanation while being quick to read.

  If you believe a Wikipedia policy or guideline justifies the change then you may include a wikilink to it in your explanation.

• Brevity and abbreviations. Brevity is desired, but its larger purpose is making understanding quicker to the reader. One that only saves the writer from typing is likely achieving the opposite for the reader. In keeping with this, extreme brevity and abbreviations should be used with care. They can be confusing especially for new contributors. For an explanation of some commonly used abbreviations, see this edit summary legend.
• 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, post a comment to the article's talk page to give more information, and include "see talk" or "see discussion page" in the edit summary.
  • If you are copying text within Wikipedia, you must at least put a link to the source page in the edit summary at the destination page.
• Talk pages. When adding talk page comments, consider reflecting the gist of it in the edit summary (expand the Advanced options to do so when using the reply feature); this allows users to check Recent changes, Page history and User contributions (see below) very efficiently.

• Avoid misleading summaries. Mentioning one change but not another one can be misleading to someone who finds the other one more important. If you are sure the unexplained changes are minor, non-contentious ones, you could add something like "and misc." to cover them.
• Avoid vagueness. While edit summaries can be terse, they should still be specific. Providing an edit summary similar to "I made some changes" is functionally equivalent to not providing a summary at all.^[a]
• Avoid long summaries. Edit summaries are not for explaining every detail, writing essays about "the truth", or long-winded arguments with fellow editors. For discussions, you should use the talk page.
• Avoid inappropriate summaries. You should explain your edits, but without being 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.
• Avoid incivility. Snide comments, personal remarks about editors, and other aggressive edit summaries are explicit edit-summary "don'ts" of the Wikipedia Civility policy.

Warning: Be careful of what you write in edit summaries. Inappropriate edit summaries may be used as evidence against you in behavioral complaints. This applies particularly to uncivil and deliberately misleading edit summaries.

Proper use of edit summaries is critical to resolving content disputes. Edit summaries should accurately and succinctly summarize the nature of the edit, especially if it could be controversial. If the edit involves reverting previous changes, it should be marked as a revert ("rv") in the edit summary.

Avoid using edit summaries to carry on debates or negotiations over the content. This creates an atmosphere where the only way to carry on the discussion is to revert other editors! If you notice this happening, start a section on the talk page and place your comments there. This keeps discussions and debates away from the article page itself. For example:

reverted edits by User:Example, see talk for rationale

As with any other Wikipedia space, do not express opinions on other users in edit summaries.

After you publish 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 (a change in the page with no visible effects), and adding further information in the dummy edit's 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.

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^[b] – list of recent changes to watched pages (logged-in users only)
• Diff page – shows the difference between two edits
• Permanent link – shows an old version of a page
• Recent changes – list of all recent edits
• Wikipedia IRC channels – real-time list of all 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.

The source text of the edit summary can be seen at en.wikipedia.org/w/api.php?action=query&prop=revisions&rvprop=comment&revids=id, where id is the revision number. For example, says diff=845523983 in the url so revids=845523983 shows the edit summary source. The link uses mw:API:Revisions, which is mainly intended for programs.

When editing an existing section, the section title is automatically inserted in the edit summary box and enclosed with /* and */ marks; for example /* External links */. When viewing such an edit summary, the section title will appear with a small arrow next to it: →External links. This is a section link that when clicked on will (in most cases) lead you to the section you are editing. If you are editing the lead section, it will instead simply insert "/* */", which will become "→(top)" upon being rendered.^[1][2] Details of the edit should be added after this text (which will add a colon after the section title).

When adding a new section to a discussion page with the "new section" button, the section title is used as the edit summary.

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.^[3]

Note: Tools that track edit summary usage by a user (such as XTools) do not consider the auto-added part as a summary; that's any part within /* and */. You're encouraged to provide a real edit summary, whether the edit box contains such an auto-summary or not.

In certain circumstances, an automatic summary is generated when an edit is published without one. This is slightly different from the summary added when editing a section, as that can be modified by the user before saving.

Except for 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.

When starting a new thread on a talk page by using the "New section" tab, the text you type into the "subject/headline" field becomes both the heading of your discussion topic and the edit summary for that edit.

The limit of 500 characters is an approximation. The actual limit is 500 Unicode codepoints. Most characters occupy one codepoint, but some characters like those with diacritics or emojis may consist of more than one codepoint. The limit of 500 codepoints includes the section title marker (and the associated /*  */) and also any wiki markup that may be present.

For editors who have JavaScript enabled, there is a script included with the page that monitors the codepoint length of the summary and prevents entering summaries longer than 500 codepoints (both in "Edit source" and in Visual editor). A count is displayed at the right-hand end of the text entry field, showing the number of unused codepoints. When JavaScript is disabled, this safeguard can't function and the only protection is the browser's limit of 500 characters, which may overflow the 500-codepoint limit as a result of any characters that are represented by more than one codepoint.

When the edit is done by a bot, through an external tool (such as WP:AWB) or through some user script or gadget, it's the responsibility of the tool or script to safeguard against overflowing this limit. In any situation where more than 500 codepoints are entered for the edit summary, the summary is truncated to 500 codepoints when the revision is published.