Operating on the open buffer rather than on disk is the distinction that matters: the assistant sees the selection, the undo stack is the editor's own, and a bad edit is one keystroke from being reversed. The context-around-match call is the thoughtful bit — it lets an edit be made against the code that surrounds it rather than a blind string replace. Treat the experimental warning as real.
A package for the Pulsar editor that turns the running editor into an MCP server. Instead of an assistant working on files through the filesystem, it operates on the active document in the editor — reading the selection, replacing text in place, and opening other project files into tabs. Pulsar's own chat panel or an external client such as AnythingLLM can drive it.
- Targeted editing: replace a search string with a replacement, replace the whole document, or insert a block of text at a given line number
- Context before you edit: return the lines before and after the Nth match of a query, so an edit is made with the surrounding code in view
- Finding text: search the active editor with a substring or a regular expression and get the position of each occurrence, capped by a maximum match count
- Line operations: insert a blank line at a row, delete a single line, or delete a range
- Reading state: get the selection, the whole document as numbered lines, the line count, the filename and the full path
- Project-level moves: list all project files, open one (or switch to its tab if it is already open), and undo or redo the last change
Pulsar, with the package installed via `ppm install https://github.com/drunnells/pulsar-edit-mcp-server` and the server switched on under Packages → MCP Server → Listen — an "MCP:On" tile appears in the lower left when it is running. Third-party clients connect over streamable HTTP at `http://localhost:3000/mcp`. The author describes it as very experimental and incomplete.
One command — ppm install https://github.com/drunnells/pulsar-edit-mcp-server