llmignore 0.1.0

# llmignore

Parse and match `.llmignore` files — the `.gitignore` for AI.

Prevent AI coding tools from ingesting secrets, credentials, large binaries, and sensitive data into LLM context windows. Works with all 13 known AI ignore formats.

**Spec:** [rival.tips/llmignore](https://rival.tips/llmignore)

## Installation

Add to your `Cargo.toml`:

```toml
[dependencies]
llmignore = "0.1"
```

## Usage

### Parse and match

```rust
use llmignore::{parse, matches};

let content = r#"
# Secrets
.env
.env.*
**/*.pem
**/*.key

# Large binaries
**/*.wasm
**/node_modules/**

# But keep the example
!.env.example
"#;

let patterns = parse(content);

assert!(matches(&patterns, ".env"));           // ignored
assert!(matches(&patterns, ".env.local"));     // ignored
assert!(!matches(&patterns, ".env.example"));  // negation re-includes it
assert!(matches(&patterns, "certs/server.pem")); // ignored
assert!(!matches(&patterns, "src/main.rs"));   // not matched
```

### Debug which patterns match

```rust
use llmignore::{parse, match_all};

let content = ".env.*\n!.env.example";
let patterns = parse(content);
let matching = match_all(&patterns, ".env.example");

for pat in &matching {
    let prefix = if pat.is_negation { "!" } else { " " };
    println!("  line {}: {}{}", pat.line_number, prefix, pat.pattern);
}
// Output:
//   line 1:  .env.*
//   line 2: !.env.example
```

### Read from file

```rust
use llmignore::{parse, matches};
use std::fs;

if let Ok(content) = fs::read_to_string(".llmignore") {
    let patterns = parse(&content);

    if matches(&patterns, "secrets/api-key.pem") {
        println!("This file should be excluded from AI context");
    }
}
```

### Explore supported formats

```rust
use llmignore::FORMATS;

for fmt in FORMATS {
    let negation = if fmt.supports_negation { "yes" } else { "no" };
    let official = if fmt.official { "official" } else { "community" };
    println!("  {:<20} {:<16} negation={}  ({})", fmt.filename, fmt.tool, negation, official);
}
```

## Supported Formats

| File | Tool | Official | Negation | Cascading |
|------|------|----------|----------|-----------|
| `.llmignore` | Universal | Yes | Yes | Yes |
| `.cursorignore` | Cursor | Yes | Yes | No |
| `.aiignore` | JetBrains | Yes | Yes | No |
| `.aiexclude` | Google Gemini | Yes | No | Yes |
| `.claudeignore` | Claude Code | No | Yes | Yes |
| `.codeiumignore` | Windsurf | Yes | Yes | No |
| `.geminiignore` | Gemini CLI | Yes | Yes | No |
| `.aiderignore` | Aider | Yes | Yes | No |
| `.clineignore` | Cline | Yes | Yes | No |
| `.rooignore` | Roo Code | Yes | Yes | No |
| `.augmentignore` | Augment | Yes | Yes | No |
| `.copilotignore` | GitHub Copilot | No | No | No |
| `.repomixignore` | Repomix | Yes | Yes | No |

## Glob Syntax

The syntax is identical to `.gitignore`:

| Pattern | Matches |
|---------|---------|
| `*.log` | Any `.log` file at any depth |
| `**/*.pem` | Any `.pem` file in any subdirectory |
| `**/node_modules/**` | Everything inside any `node_modules` directory |
| `build/` | The `build` directory and all its contents |
| `!important.log` | Re-includes `important.log` even if `*.log` excludes it |
| `src/secrets/**` | Everything inside `src/secrets/` (anchored) |
| `??.txt` | Any two-character `.txt` filename |
| `[abc].txt` | `a.txt`, `b.txt`, or `c.txt` |

## API Reference

### `parse(content: &str) -> Vec<Pattern>`

Parse ignore file content into a list of `Pattern` structs. Handles comments, blank lines, negation, and escaped characters.

### `matches(patterns: &[Pattern], path: &str) -> bool`

Check whether a path should be ignored. Evaluates patterns in order with last-match-wins semantics. Negation patterns (`!`) re-include previously excluded files.

### `match_all(patterns: &[Pattern], path: &str) -> Vec<&Pattern>`

Return all patterns that match a path (both inclusions and negations). Useful for debugging ignore rules.

### `FORMATS: &[Format]`

All 13 known AI ignore file format definitions with metadata about tool support, negation, and cascading behavior.

### `Pattern`

```rust
pub struct Pattern {
    pub pattern: String,
    pub is_negation: bool,
    pub line_number: usize,
}
```

### `Format`

```rust
pub struct Format {
    pub id: &'static str,
    pub filename: &'static str,
    pub tool: &'static str,
    pub tool_url: &'static str,
    pub description: &'static str,
    pub official: bool,
    pub supports_negation: bool,
    pub supports_cascading: bool,
    pub docs_url: Option<&'static str>,
    pub notes: Option<&'static str>,
}
```

## Zero Dependencies

This crate uses only the Rust standard library. No external crates required.

## Links

- [.llmignore spec](https://rival.tips/llmignore)
- [Template builder](https://rival.tips/llmignore)
- [RIVAL -- AI model comparison](https://rival.tips)

## License

MIT