use claude_rust_errors::{AppError, AppResult};
use claude_rust_types::{PermissionLevel, SearchReadInfo, Tool};
use serde_json::{Value, json};
pub struct ReadTool;
#[async_trait::async_trait]
impl Tool for ReadTool {
fn name(&self) -> &str {
"read"
}
fn description(&self) -> &str {
"Read the contents of a file. Returns numbered lines."
}
fn input_schema(&self) -> Value {
json!({
"type": "object",
"properties": {
"file_path": {
"type": "string",
"description": "Absolute path to the file to read"
},
"offset": {
"type": "integer",
"description": "Line number to start reading from (1-based)"
},
"limit": {
"type": "integer",
"description": "Maximum number of lines to read"
}
},
"required": ["file_path"]
})
}
fn permission_level(&self) -> PermissionLevel {
PermissionLevel::ReadOnly
}
fn is_read_only(&self, _input: &Value) -> bool { true }
fn is_concurrent_safe(&self, _input: &Value) -> bool { true }
fn is_search_or_read_command(&self, _input: &Value) -> SearchReadInfo {
SearchReadInfo { is_search: false, is_read: true, is_list: false }
}
fn get_path(&self, input: &Value) -> Option<String> {
input.get("file_path").and_then(|v| v.as_str()).map(|s| s.to_string())
}
async fn execute(&self, input: Value) -> AppResult<String> {
let path = input
.get("file_path")
.and_then(|v| v.as_str())
.ok_or_else(|| AppError::Tool("missing 'file_path' field".into()))?;
let offset = input
.get("offset")
.and_then(|v| v.as_u64())
.unwrap_or(1)
.max(1) as usize;
let limit = input
.get("limit")
.and_then(|v| v.as_u64())
.unwrap_or(2000) as usize;
tracing::info!(path, offset, limit, "reading file");
let content = tokio::fs::read_to_string(path)
.await
.map_err(|e| AppError::Tool(format!("cannot read '{path}': {e}")))?;
let lines: Vec<&str> = content.lines().collect();
let start = (offset - 1).min(lines.len());
let end = (start + limit).min(lines.len());
let mut result = String::new();
for (i, line) in lines[start..end].iter().enumerate() {
let line_num = start + i + 1;
result.push_str(&format!("{line_num:>6}\t{line}\n"));
}
if result.is_empty() {
result.push_str("(empty file)");
}
Ok(result)
}
}