Claude in the review

With the Emacs MCP server on (ecc-mcp-enabled), the review works both ways: Claude can open it, comment on its lines and scroll it to the place it is talking about. Ask in plain words, for example “walk me through these changes in the review” or “review the diff and leave comments”. Agentic review goes through one change this way.

Claude’s comments

Claude’s comments appear as ▎ #4 Claude: text, in ecc-review-agent-comment-face. c on a line that has only Claude’s comment replies to it, and the reply is indented under it. a hides Claude’s comments and shows them again. C-c C-c sends only your comments, and the review stays open, so Claude can answer each one there with a reply.

Claude cannot write or change your comments, but it can remove them. Each session works on its own review.

Tool	What Claude does with it
review_open	Opens the session’s changes, a range, or the staged changes, optionally for some files, or reads the review again
review_hunks	Lists the files and the numbered hunks, optionally with their text
review_comment	Puts a comment on a line, on a hunk, or under another comment
review_comment_apply	Puts several comments at once; one that is wrong is reported and the others are added
review_navigate	Scrolls the review to a line, a hunk or a comment
review_list_comments	Reads the comments
review_remove_comment	Removes one comment, including one of yours it has dealt with
review_clear_comments	Removes Claude’s comments, and yours only when asked

review_open takes the same comparisons as the review menu: ask for “the staged changes”, “this whole branch” or “just this commit”. A review Claude opens appears beside the session without taking the keyboard or the window you are in. It follows a display-buffer-alist rule of yours for review buffers, as long as the rule leaves your window and tab alone. If there is no free window, the review waits in its buffer.

The tools write no files, so they are allowed without asking, and the transcript records each call as auto-allowed. To be asked as for any other tool, set ecc-review-agent-auto-allow to nil.

The tools work on an ediff review you have open, where a hunk is one ediff difference. Claude never starts ediff itself: without one open, review_open opens the diff buffer.

Talking to Claude from the review

These keys work in the diff buffer and in an ediff review, and always go to the review’s session:

Key	Action
T	Ask Claude for a tour of the changes, most important first. Claude shows each stop, explains it, comments on the lines that need attention, and waits
t	Ask for the next stop of the tour
M	Type a message in the minibuffer and send it as a prompt. With the region active, the message is about the selected lines

T sends the review’s hunks with their patches, so Claude can plan every stop at once. Past ecc-review-talk-patch-limit (20000 characters) it sends only the list. t and M tell Claude where you are: the file, the line at point and its side, and the hunk.

With the region active, M sends the selected lines instead: for each file and hunk, the line numbers on each side and the lines with their + and - markers. In ediff, select the lines in the left or the right window, and Claude learns which side they are on. Past ecc-review-talk-region-limit (10000 characters), M sends only the line numbers. Sending the message deactivates the region.

While the session is busy, the prompt waits in its queue. T and t need the MCP server. In ediff, Claude’s answer streams into the reply pane; the diff buffer has the session beside it instead.