banthis

Persist "banned behaviors" into CLAUDE.md / AGENTS.md so AI coding agents remember never to repeat annoying patterns across sessions.

When an agent does something frustrating repeatedly (hedging language, over-explaining, editing migration files directly, etc.), banthis turns it into a standing rule that later sessions read. The agent proposes the title, the rule and its scope, and writes it after you confirm the wording.

Installation

npm install -g github:agent-sh/banthis

Or use via npx:

npx --yes github:agent-sh/banthis add "No hedging" "Do not start responses with 'To be honest' or 'I think': it undermines confidence."

Core Commands

• banthis <title> <rule>: Quick add (shortcut for add)
• banthis add <title> <rule>: Add or update a banned behavior
• banthis list: List current bans
• banthis remove <title>: Remove a ban
• banthis init: Install the meta-rule so agents know to propose a rule and save it with banthis once you confirm
• banthis install-command: Drop the /banthis slash command into .claude/commands/

Flags

• -g, --global: Target ~/.claude/CLAUDE.md (user-wide)
• --file <NAME>: Target specific filename
• --dir <PATH>: Target specific directory

How It Works

banthis maintains a managed section in CLAUDE.md or AGENTS.md (between <!-- banthis:start --> and <!-- banthis:end -->).

The section opens with a short preamble: these are standing rules from past sessions, and the user's own words in the current conversation come first. When a rule conflicts with what you ask now, the agent does what you asked and mentions the conflict. Sections written by older versions get the new preamble on the next add, remove or init.

If the end marker goes missing (a hand edit or a bad merge), the next add, remove or init restores it after the last rule of the existing block instead of writing a second block.

banthis has no dependencies on other plugins. A config linter such as agnix can validate the result if you use one.

Philosophy

A short rule with its reason is one of the cheapest instructions you can give an agent, and it survives long context windows well. banthis makes it quick to capture one at the moment of frustration, in your own wording, scoped to the project unless it applies everywhere.

Related Projects

Optional, not required by banthis:

• agnix: linter and validator for agent configurations
• skill-curator, system-prompt-curator: help writing SKILL.md files and system prompts

License

MIT