feat(cli): add subcommand completion to generate various shell completions (#6313)

Signed-off-by: Sai Karthik <kskarthik@disroot.org>

Cargo.lock

@@ -1430,6 +1430,15 @@ dependencies = [
  "terminal_size",
 ]
 
+[[package]]
+name = "clap_complete"
+version = "4.5.62"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "004eef6b14ce34759aa7de4aea3217e368f463f46a3ed3764ca4b5a4404003b4"
+dependencies = [
+ "clap",
+]
+
 [[package]]
 name = "clap_derive"
 version = "4.5.49"
@@ -3078,6 +3087,7 @@ dependencies = [
  "bat",
  "chrono",
  "clap",
+ "clap_complete",
  "cliclack",
  "console 0.16.2",
  "dotenvy",

crates/goose-cli/Cargo.toml

@@ -61,6 +61,7 @@ anstream = "0.6.18"
 url = "2.5.7"
 open = "5.3.2"
 urlencoding = "2.1"
+clap_complete = "4.5.62"
 
 [target.'cfg(target_os = "windows")'.dependencies]
 winapi = { version = "0.3", features = ["wincred"] }

crates/goose-cli/src/cli.rs

@@ -1,6 +1,6 @@
 use anyhow::Result;
-use clap::{Args, Parser, Subcommand};
-
+use clap::{Args, CommandFactory, Parser, Subcommand};
+use clap_complete::{generate, Shell as ClapShell};
 use goose::config::{Config, ExtensionConfig};
 use goose_mcp::mcp_server_runner::{serve, McpCommand};
 use goose_mcp::{
@@ -855,6 +855,12 @@ enum Command {
         #[command(subcommand)]
         command: TermCommand,
     },
+    /// Generate completions for various shells
+    #[command(about = "Generate the autocompletion script for the specified shell")]
+    Completion {
+        #[arg(value_enum)]
+        shell: ClapShell,
+    },
 }
 
 #[derive(Subcommand)]
@@ -962,6 +968,7 @@ pub async fn cli() -> anyhow::Result<()> {
         Some(Command::Recipe { .. }) => "recipe",
         Some(Command::Web { .. }) => "web",
         Some(Command::Term { .. }) => "term",
+        Some(Command::Completion { .. }) => "completion",
         None => "default_session",
     };
 
@@ -972,6 +979,11 @@ pub async fn cli() -> anyhow::Result<()> {
     );
 
     match cli.command {
+        Some(Command::Completion { shell }) => {
+            let mut cmd = Cli::command();
+            let bin_name = cmd.get_name().to_string();
+            generate(shell, &mut cmd, bin_name, &mut std::io::stdout());
+        }
         Some(Command::Configure {}) => handle_configure().await?,
         Some(Command::Info { verbose }) => handle_info(verbose)?,
         Some(Command::Mcp { server }) => {