What
The --tools flag, which restricts which built-in tools Claude Code can use, now parses its entries more carefully and warns about specific common mistakes:
- an entry that doesn't match any recognized built-in tool name (possible typo)
- a rule written with parentheses where a plain tool name was meant
- an exclusion prefix (like
!) separated from the tool name by a stray space - a bare exclusion prefix with nothing after it
Why
These warnings catch malformed --tools entries that would otherwise silently fail to do what was intended, such as a tool being unexpectedly withheld because of a typo, without any explanation.
Names in the bundle--tools
The entry above is what we published on the day. These lines were added later, as Anthropic's own pages caught up, and they sit beside the original rather than replacing it.
Confirmed since
Anthropic's documentation has since written up --tools, on CLI reference.
| `--allowedTools`, `--allowed-tools` | Tools that execute without prompting for permission. See [permission rule syntax](/docs/en/settings-reference#permission-rule-syntax) for pattern matching. To restrict which tools are available, use …cli-reference see the edit
One source agreesOne thing we can check says the same as this entry.
Anthropic's documentation agrees
Anthropic's documentation has since written up --tools, on CLI reference.