semantic-edit-mcp: Instructions file for Claude Code

CLAUDE.md

This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.

What this is

An MCP (Model Context Protocol) server for AST-aware code editing. Instead of line/character edits, edits target tree-sitter AST nodes located by a short text anchor; the content is laid out in-process, and the result is re-parsed and checked to guarantee it is still syntactically valid before anything touches disk. Running a language-native formatter is optional and off unless configured; when it runs, by default only its changes to the edit and the lines next to it are kept, plus any that move the edit's own text elsewhere (sorting an inserted import).

Commands

cargo build                          # build
cargo test                           # run all tests (the snapshot suite + unit tests)
cargo fmt --all -- --check           # formatting check (CI gate)
cargo clippy                         # lint (CI gate)
cargo run -- serve                   # run the MCP stdio server locally
cargo run -- serve --format built-in # ...with every built-in formatter on

Snapshot tests (the main test surface)

Most behavior is covered by data-driven snapshot tests under tests/snapshots/, discovered and run by src/tests/snapshot_runner.rs via the single run_snapshot_tests Rust test. Each test is a directory containing args.json (one tool call or an array of them), an optional input.<ext>, and the expected response.txt / output.<ext>.

TEST_FILTER=rust cargo test                    # run a category (prefix match)
TEST_FILTER=rust::attributes cargo test        # run one test (its full "::"-joined path)
TEST_FILTER=rust::repair cargo test            # run every test beneath a "::" path
TEST_FILTER=json,rust cargo test               # multiple, comma-separated
UPDATE_SNAPSHOTS=1 cargo test                  # regenerate all expected files
UPDATE_SNAPSHOTS=1 TEST_FILTER=rust::attributes cargo test   # regenerate one