rusty-hooks 0.1.0

PostToolUse validation hook for Claude Code — blocks Edit/Write when on-disk content diverges from expected
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# rusty-hooks

A `PostToolUse` validation hook for [Claude Code](https://claude.ai/code) that blocks `Edit` and `Write`
operations when the on-disk file content diverges from what the tool reported writing.

## What it does

Claude Code supports hooks — shell commands that run before or after tool calls. `rusty-hooks` installs as
a `PostToolUse` hook and validates every `Edit` and `Write` by reading the file back from disk and comparing
it to the content the tool claimed to write. If they differ, the hook emits a `block` decision with a reason,
preventing the divergence from being silently accepted.

## Installation

```bash
cargo install rusty-hooks
```

Then add to your Claude Code settings (`~/.claude/settings.json`):

```json
{
  "hooks": {
    "PostToolUse": [
      {
        "matcher": { "tool_name": "Edit|Write" },
        "hooks": [{ "type": "command", "command": "validate-hook" }]
      }
    ]
  }
}
```

## How it works

The hook reads a JSON payload from stdin (the Claude Code hook protocol), extracts the `tool_name` and
`tool_input`, and for `Edit`/`Write` calls reads the target file from disk. If the on-disk content does not
match `tool_input.content`, it exits with code 2 and emits:

```json
{ "decision": "block", "reason": "Write validation failed: on-disk content does not match expected for path/to/file" }
```

A successful validation exits with code 0 and no output.

## License

MIT