# lean-ctx — Context Engineering Layer

PREFER lean-ctx MCP tools over native equivalents for token savings:

| PREFER | OVER | Why |
|--------|------|-----|
| `ctx_read(path)` | `Read` | Cached, 10 compression modes |
| `ctx_shell(command)` | `Shell` | Pattern compression |
| `ctx_search(pattern, path)` | `Grep` | Compact results |
| `ctx_tree(path, depth)` | `ls` / `find` | Directory maps |
| `ctx_edit(path, old_string, new_string)` | `Edit` (when Read unavailable) | Search-and-replace without native Read |

Edit files: use native Edit/StrReplace if available. If Edit requires Read and Read is unavailable, use ctx_edit.
Write, Delete, Glob — use normally. NEVER loop on Edit failures — switch to ctx_edit immediately.
