update fd instructions

Author: noahp

ai/AGENTS.md

@@ -7,6 +7,11 @@
 ## Tools
 
 - Always use `rg` (ripgrep) instead of `grep` for searching file contents.
-- Always use `fd` instead of `find` for searching files and directories.
+- Always use `fd` instead of `find` for searching files and directories. Key differences from `find`:
+  - Pattern comes first, path second (opposite of `find`): `fd PATTERN [PATH]`
+  - Patterns are regex by default; use `--glob` for glob patterns: `fd --glob '*.c'`
+  - No `-name`, `-type`, `-path` flags needed — just: `fd foo`, `fd --type f`, `fd --type d`
+  - Includes hidden files with `-H`; follows symlinks with `-L`
+  - Use `--exec` instead of `-exec`: `fd --glob '*.log' --exec rm {}`
 - Always use the `gh` CLI when accessing or operating on GitHub resources (PRs, issues, releases, etc.).
 - When accessing serial ports, ALWAYS use named ports via `/dev/serial/by-id` (Linux — not macOS-style `/dev/tty.usbserial-*` paths).