use rmcp::model::Tool;
use rmcp::ErrorData;
use serde_json::{json, Map, Value};
use crate::server::tool_trait::{McpTool, ToolContext, ToolOutput};
use crate::tool_defs::tool_def;
pub struct CtxSmartReadTool;
impl McpTool for CtxSmartReadTool {
fn name(&self) -> &'static str {
"ctx_smart_read"
}
fn tool_def(&self) -> Tool {
tool_def(
"ctx_smart_read",
"Auto-select optimal read mode for a file.",
json!({
"type": "object",
"properties": {
"path": { "type": "string", "description": "Absolute file path to read" }
},
"required": ["path"]
}),
)
}
fn handle(
&self,
_args: &Map<String, Value>,
ctx: &ToolContext,
) -> Result<ToolOutput, ErrorData> {
let path = ctx
.resolved_path("path")
.ok_or_else(|| ErrorData::invalid_params("path is required", None))?
.to_string();
if crate::core::binary_detect::is_binary_file(&path) {
let msg = crate::core::binary_detect::binary_file_message(&path);
return Err(ErrorData::invalid_params(msg, None));
}
{
let cap = crate::core::limits::max_read_bytes() as u64;
if let Ok(meta) = std::fs::metadata(&path) {
if meta.len() > cap {
let msg = format!(
"File too large ({} bytes, limit {} bytes via LCTX_MAX_READ_BYTES). \
Use mode=\"lines:1-100\" for partial reads or increase the limit.",
meta.len(),
cap
);
return Err(ErrorData::invalid_params(msg, None));
}
}
}
tokio::task::block_in_place(|| {
let cache_lock = ctx
.cache
.as_ref()
.ok_or_else(|| ErrorData::internal_error("cache not available", None))?;
let mut cache = cache_lock.blocking_write();
let output = crate::tools::ctx_smart_read::handle(&mut cache, &path, ctx.crp_mode);
let original = cache.get(&path).map_or(0, |e| e.original_tokens);
let tokens = crate::core::tokens::count_tokens(&output);
drop(cache);
let saved = original.saturating_sub(tokens);
Ok(ToolOutput {
text: output,
original_tokens: original,
saved_tokens: saved,
mode: Some("auto".to_string()),
path: Some(path),
changed: false,
})
})
}
}