use anyhow::{Context, Result};
use appam::prelude::*;
use rustyline::DefaultEditor;
use std::io::Write;
use std::process::Command;
#[derive(Deserialize, Schema)]
struct ReadFileInput {
#[description = "Path to the file to read"]
file_path: String,
}
#[derive(Serialize)]
struct ReadFileOutput {
success: bool,
contents: Option<String>,
file_path: String,
size_bytes: Option<usize>,
error: Option<String>,
}
#[tool(description = "Read the contents of a file from the filesystem")]
fn read_file(input: ReadFileInput) -> Result<ReadFileOutput> {
match std::fs::read_to_string(&input.file_path) {
Ok(contents) => Ok(ReadFileOutput {
success: true,
contents: Some(contents.clone()),
file_path: input.file_path,
size_bytes: Some(contents.len()),
error: None,
}),
Err(e) => Ok(ReadFileOutput {
success: false,
contents: None,
file_path: input.file_path,
size_bytes: None,
error: Some(format!("Failed to read file: {}", e)),
}),
}
}
#[derive(Deserialize, Schema)]
struct WriteFileInput {
#[description = "Path where the file should be written"]
file_path: String,
#[description = "Content to write to the file"]
content: String,
}
#[derive(Serialize)]
struct WriteFileOutput {
success: bool,
message: Option<String>,
file_path: String,
bytes_written: Option<usize>,
error: Option<String>,
}
#[tool(description = "Write content to a file, creating it if it doesn't exist")]
fn write_file(input: WriteFileInput) -> Result<WriteFileOutput> {
match std::fs::write(&input.file_path, &input.content) {
Ok(_) => Ok(WriteFileOutput {
success: true,
message: Some(format!(
"Successfully wrote {} bytes to {}",
input.content.len(),
input.file_path
)),
file_path: input.file_path,
bytes_written: Some(input.content.len()),
error: None,
}),
Err(e) => Ok(WriteFileOutput {
success: false,
message: None,
file_path: input.file_path,
bytes_written: None,
error: Some(format!("Failed to write file: {}", e)),
}),
}
}
#[derive(Serialize)]
struct BashOutput {
success: bool,
exit_code: i32,
stdout: String,
stderr: String,
command: String,
}
#[tool(description = "Execute a bash command and return its output")]
fn bash(#[arg(description = "The bash command to execute")] command: String) -> Result<BashOutput> {
let output = Command::new("bash")
.arg("-c")
.arg(&command)
.output()
.context("Failed to execute bash command")?;
let stdout = String::from_utf8_lossy(&output.stdout).to_string();
let stderr = String::from_utf8_lossy(&output.stderr).to_string();
Ok(BashOutput {
success: output.status.success(),
exit_code: output.status.code().unwrap_or(-1),
stdout,
stderr,
command,
})
}
#[derive(Deserialize, Schema)]
struct ListFilesInput {
#[description = "Directory path to list"]
directory: String,
#[description = "Whether to list recursively"]
#[serde(default)]
recursive: bool,
}
#[derive(Serialize)]
struct ListFilesOutput {
success: bool,
directory: String,
entries: Vec<serde_json::Value>,
count: usize,
error: Option<String>,
}
#[tool(description = "List files and subdirectories in a directory")]
fn list_files(input: ListFilesInput) -> Result<ListFilesOutput> {
let mut entries = Vec::new();
if input.recursive {
for entry in walkdir::WalkDir::new(&input.directory)
.max_depth(5)
.into_iter()
.filter_map(|e| e.ok())
{
entries.push(json!({
"path": entry.path().display().to_string(),
"is_dir": entry.file_type().is_dir(),
"depth": entry.depth()
}));
}
Ok(ListFilesOutput {
success: true,
directory: input.directory,
count: entries.len(),
entries,
error: None,
})
} else {
match std::fs::read_dir(&input.directory) {
Ok(dir_entries) => {
for entry in dir_entries.filter_map(|e| e.ok()) {
entries.push(json!({
"path": entry.path().display().to_string(),
"is_dir": entry.path().is_dir()
}));
}
Ok(ListFilesOutput {
success: true,
directory: input.directory,
count: entries.len(),
entries,
error: None,
})
}
Err(e) => Ok(ListFilesOutput {
success: false,
directory: input.directory,
entries: vec![],
count: 0,
error: Some(format!("Failed to read directory: {}", e)),
}),
}
}
}
#[tokio::main]
async fn main() -> Result<()> {
let model = std::env::var("GOOGLE_VERTEX_MODEL")
.unwrap_or_else(|_| "gemini-3.1-pro-preview".to_string());
println!("🚀 Coding Agent - Gemini (Google Vertex)\n");
let agent = AgentBuilder::new("vertex-coding-assistant")
.provider(LlmProvider::Vertex)
.model(model)
.system_prompt(
"You are an expert coding assistant powered by Gemini via Google Vertex AI. \
You have access to file operations, bash commands, and directory listing. \
Help users analyze code, refactor projects, debug issues, and manage files. \
Always think through problems step-by-step and use tools when appropriate.",
)
.with_tool(Arc::new(read_file()))
.with_tool(Arc::new(write_file()))
.with_tool(Arc::new(bash()))
.with_tool(Arc::new(list_files()))
.max_tokens(8192)
.temperature(0.2)
.build()?;
println!("✓ Model: Gemini via Vertex");
println!("✓ Tools: read_file, write_file, bash, list_files");
println!("✓ Type 'exit', 'quit', or 'bye' to end conversation\n");
let mut rl = DefaultEditor::new()?;
loop {
let readline = rl.readline("You> ");
match readline {
Ok(line) => {
let input = line.trim();
if input.eq_ignore_ascii_case("exit")
|| input.eq_ignore_ascii_case("quit")
|| input.eq_ignore_ascii_case("bye")
{
println!("\n👋 Goodbye!");
break;
}
if input.is_empty() {
continue;
}
let _ = rl.add_history_entry(input);
println!("\nAssistant:\n");
let reasoning_shown = Arc::new(std::sync::atomic::AtomicBool::new(false));
let reasoning_shown_clone = Arc::clone(&reasoning_shown);
match agent
.stream(input)
.on_content(|content| {
print!("{}", content);
std::io::stdout().flush().ok();
})
.on_reasoning(move |content| {
if !reasoning_shown_clone.load(std::sync::atomic::Ordering::Relaxed) {
println!("\n\n💭 Reasoning:\n");
reasoning_shown_clone.store(true, std::sync::atomic::Ordering::Relaxed);
}
print!("{}", content);
std::io::stdout().flush().ok();
})
.on_tool_call(|tool_name, arguments| {
println!("\n\n🔧 {}", tool_name);
let args_str = arguments.to_string();
if args_str.len() > 200 {
println!(" Args: {}...", &args_str[..200]);
} else {
println!(" Args: {}", args_str);
}
})
.on_tool_result(|tool_name, result| {
println!(" ✓ {} completed", tool_name);
let result_str = serde_json::to_string_pretty(&result).unwrap_or_default();
if result_str.len() > 300 {
println!(" Result: {}...", &result_str[..300]);
} else {
println!(" Result: {}", result_str);
}
})
.run()
.await
{
Ok(_) => {
println!("\n");
}
Err(e) => {
eprintln!("\n❌ Error: {}\n", e);
}
}
}
Err(rustyline::error::ReadlineError::Interrupted) => {
println!("\n👋 Goodbye!");
break;
}
Err(rustyline::error::ReadlineError::Eof) => {
println!("\n👋 Goodbye!");
break;
}
Err(err) => {
eprintln!("Error: {:?}", err);
break;
}
}
}
Ok(())
}