rtk: Skill for Claude Code

RTK Code Simplifier

Review and simplify Rust code in RTK while respecting the project's constraints.

Constraints (never simplify away)

• LazyLock regex — cannot be moved inside functions even if "simpler"
• .context() on every ? — verbose but mandatory
• Fallback to raw command — never remove even if it looks like dead code
• Exit code propagation — never simplify to Ok(())
• #[cfg(test)] mod tests — never remove test modules

Simplification Patterns

1. Iterator chains over manual loops

// ❌ Verbose
let mut result = Vec::new();
for line in input.lines() {
    let trimmed = line.trim();
    if !trimmed.is_empty() && trimmed.starts_with("error") {
        result.push(trimmed.to_string());
    }
}

// ✅ Idiomatic
let result: Vec<String> = input.lines()
    .map(|l| l.trim())
    .filter(|l| !l.is_empty() && l.starts_with("error"))
    .map(str::to_string)
    .collect();

2. String building

// ❌ Verbose push loop
let mut out = String::new();
for (i, line) in lines.iter().enumerate() {
    out.push_str(line);
    if i < lines.len() - 1 {
        out.push('\n');
    }
}

// ✅ join
let out = lines.join("\n");

3. Option/Result chaining

// ❌ Nested match
let result = match maybe_value {
    Some(v) => match transform(v) {
        Ok(r) => r,
        Err(_) => default,
    },
    None => default,
};

// ✅ Chained
let result = maybe_value
    .and_then(|v| transform(v).ok())
    .unwrap_or(default);

4. Struct destructuring

// ❌ Repeated field access
fn process(args: &MyArgs) -> String {
    format!("{} {}", args.command, args.subcommand)
}

// ✅ Destructure
fn process(&MyArgs { ref command, ref subcommand, .. }: &MyArgs) -> String {
    format!("{} {}", command, subcommand)
}

5. Early returns over nesting

// ❌ Deeply nested
fn filter(input: &str) -> Option<String> {
    if !input.is_empty() {
        if let Some(line) = input.lines().next() {
            if line.starts_with("error") {
                return Some(line.to_string());
            }
        }
    }
    None
}

// ✅ Early return
fn filter(input: &str) -> Option<String> {
    if input.is_empty() { return None; }
    let line = input.lines().next()?;
    if !line.starts_with("error") { return None; }
    Some(line.to_string())
}