Add Rust support

[solatticus]

Rust SDK for the Copilot CLI

I'm sure there's plenty to improve or replace, but just to get the ball rolling ->

• async/await
• typed tool definitions with automatic JSON schema generation via schemars
• streaming support for assistant messages and reasoning
• stdio and TCP transport modes
• documentation and examples
• feature parity with the NodeJS and Python SDKs
• includes custom tool support, session management, and auto-reconnect

Files Added

  rust/
  ├── Cargo.toml          # Package manifest
  ├── README.md        # Documentation
  ├── src/
  │   ├── lib.rs                # Public API exports
  │   ├── client.rs           # CopilotClient implementation
  │   ├── session.rs        # CopilotSession implementation
  │   ├── jsonrpc.rs        # JSON-RPC 2.0 client
  │   ├── error.rs            # Error types
  │   ├── tool.rs             # Custom tool support
  │   ├── types.rs           # Configuration types
  │   └── generated/      # Auto-generated session event types
  ├── examples/
  │   └── basic.rs            # Usage example
  └── e2e/                      # End-to-end test harness

Usage

  use copilot_sdk::{CopilotClient, ClientOptions, SessionConfig, MessageOptions};
  use std::sync::Arc;

  #[tokio::main]
  async fn main() -> Result<(), Box<dyn std::error::Error>> {
      let client = Arc::new(CopilotClient::new(Some(ClientOptions {
          auto_restart: Some(true),
          ..Default::default()
      }))?);

      client.start_arc().await?;

      let session = client.create_session(None).await?;

      session.on(Arc::new(|event| {
          println!("Event: {:?}", event.event_type);
      }));

      session.send(MessageOptions {
          prompt: "Hello!".to_string(),
          ..Default::default()
      }).await?;

      client.stop().await;
      Ok(())
  }

Testing

• cargo build - compiles successfully
• cargo test - all unit tests pass
• cargo clippy -- -D warnings - no warnings
• E2E tests with live CLI server

[SteveSandersonMS]

Thanks for offering to contribute this, @solatticus!

Sorry we didn't previously clarify this, but currently we are not accepting additional language SDKs in this repo. We're evolving both Copilot CLI and its SDK extremely quickly right now, and don't have capacity to let the number of languages we maintain grow beyond the existing four. This might change in the future but we've decided to lock it to the four languages we see most demand for in the short term (JS/TS on Node, Python, Go, and C#).

Instead, would you be interested in maintaining a Rust Copilot SDK as an external project? If so, we'd love to link to it from our docs.

(Sidenote: to clarify this in the future, I've filed #68)

[solatticus]

Fair enough! Thanks for the clarification.

I'll leave it up, but can't make any maintenance promises!

cheers