LeanCTX MCP Server: Setup for Claude, Cursor, Codex and Other Apps

• Picks the files that matter for a task

  Given a task description, picks the most relevant files and returns them with their source, sized to fit the context budget.

  Try: “Find the files I need to add rate limiting.”

  Files · ctx_compose

• Reads files with caching and compression

  Reads files in modes such as full, signatures, map, diff or line ranges, and caches them for the session. It can read several files in one call.

  Try: “Read src/server.ts in signatures mode.”

  Files · ctx_read

• Searches code by pattern, meaning or symbol

  One search tool with regex (default), semantic, symbol and find-related actions.

  Try: “Find every place that calls createUser.”

  Files · ctx_search

• Finds files by name pattern

  Matches files by glob, skips what gitignore skips, and works across several roots.

  Try: “List all *.test.ts files.”

  Files · ctx_glob

• Shows a compact folder tree

  Draws the folder structure of a path and shows how many files each folder holds.

  Try: “Show the folder structure of src.”

  Files · ctx_tree

• Finds what calls a function

  Returns the call edges for one symbol, using language servers where available.

  Try: “Who calls parseConfig?”

  Files · ctx_callgraph

• Edits files with anchored changes

  Applies edits tied to anchors from an anchored read, such as replacing a unique string or creating a file. Some editors that have their own editor do not get it by default.

  Try: “Replace the timeout value in config.ts.”

  Write · ctx_patch

• Runs shell commands with shorter output

  Runs a command on your computer and compresses its output. It can run in the background.

  Try: “Run the test suite.”

  Runs code · ctx_shell

• Same as the shell tool, under another name

  An alias for the shell tool for clients whose model prefers a tool called shell.

  Try: “Run npm install.”

  Runs code · shell

• Keeps notes on tasks, findings and decisions

  Notes what you are working on, what was found and what was decided, so the next turn can pick it up.

  Try: “Note that we chose Postgres over MySQL.”

  Write · ctx_session

• Brings back output that was trimmed

  Pulls back a tool result that LeanCTX shortened or stored away, found by its ID, from a list, or by searching.

  Try: “Show the full output that was trimmed.”

  Read · ctx_expand

• Calls any other LeanCTX tool by name

  Lets the assistant call tools that are not shown by default. According to the docs, every registered tool stays callable this way, including code execution and web page reading.

  Try: “Use ctx_call to run the dependency graph tool.”

  Runs code · ctx_call

Watch out for

• It runs shell commands on your machine

  The shell tools run any command you or the assistant ask for, and there is no read-only mode. Review commands before approving them. github.com

• Hidden tools are still callable

  The docs say every registered tool stays callable through the generic call tool, including code execution and web reads. Pin a smaller profile if you want a smaller surface. github.com

• It edits files and rewires your agent setup

  The patch tool changes files, and the wrap command writes MCP config and rules for your editor. Undo with the unwrap or uninstall commands. github.com

• It saves session data locally

  It keeps session memory, caches and metrics on disk. Delete them if the project is sensitive. github.com

Security advisories