SACP v2 Migration

Instructions

Apply these transformations when migrating from sacp v1.x to v2.0:

1. Replace JrHandlerChain with role-based connection builder

// Before
JrHandlerChain::new()

// After - choose based on what you're building:
AgentToClient::builder()     // agent serving a client
ClientToAgent::builder()     // client connecting to agent
UntypedRole::builder()       // tests or dynamic scenarios

2. Add connection_cx to all handlers

// Before
.on_receive_request(async move |req: InitializeRequest, request_cx| {

// After
.on_receive_request(async move |req: InitializeRequest, request_cx, _cx| {

3. Update on_receive_message

// Before
.on_receive_message(async move |message: MessageAndCx<UntypedMessage, UntypedMessage>| {
    message.respond_with_error(error)
})

// After
.on_receive_message(async move |message: MessageCx, cx: JrConnectionCx<AgentToClient>| {
    message.respond_with_error(error, cx)
})

4. Parameterize JrConnectionCx

// Before
|cx: sacp::JrConnectionCx|

// After
|cx: sacp::JrConnectionCx<ClientToAgent>|

5. Use cx directly for notifications

// Before
request_cx.connection_cx().send_notification(notification)?;

// After
cx.send_notification(notification)?;

6. Replace successor extension methods

The sacp-proxy crate is deleted. Replace _from_successor and to_successor extension methods with endpoint-targeted sends:

// Before (sacp-proxy)
cx.send_request(request.to_successor())?;
let inner = response.from_successor()?;

// After
cx.send_request_to(sacp::Agent, request)?;

7. Replace message.connection_cx() calls

MessageAndCx no longer has a connection_cx() method. Use the cx parameter passed to your handler:

// Before
.on_receive_message(async move |message: MessageAndCx<...>| {
    let cx = message.connection_cx();
    cx.send_notification(notif)?;
})

// After
.on_receive_message(async move |message: MessageCx, cx: JrConnectionCx<AgentToClient>| {
    cx.send_notification(notif)?;
})

8. Update Cargo.toml

Remove sacp-proxy dependency entirely - it's merged into sacp. MCP server types are now in sacp::mcp_server.

Compiler error quick fixes