Add acp_id(), fix 13 tests with polyfill, remove conductor mcp CLI

- Add McpConnectionTo::acp_id(), deprecate acp_url()
- Remove orphaned 'conductor mcp $port' CLI subcommand and mcp_bridge.rs
- Fix all 13 previously-ignored tests to use McpOverAcpPolyfill::http()
- Fix BridgeResponder bug: route through BridgeMessage::ConnectionEstablished
  instead of creating new HashMap in on_receiving_result callback
- Auto-update 2 snapshot tests for new proxy in chain

Author: nikomatsakis

Cargo.lock

@@ -50,6 +50,7 @@ expect-test.workspace = true
 regex.workspace = true
 rmcp = { workspace = true, features = ["client", "server", "transport-io", "transport-child-process"] }
 schemars.workspace = true
+agent-client-protocol-polyfill = { path = "../agent-client-protocol-polyfill" }
 
 [lints]
 workspace = true

src/agent-client-protocol-conductor/Cargo.toml

@@ -28,17 +28,6 @@
 //! 3. Presents as a single agent on stdin/stdout
 //! 4. Manages the lifecycle of all processes
 //!
-//! ### MCP Bridge Mode
-//!
-//! Connect stdio to a TCP-based MCP server:
-//!
-//! ```bash
-//! # Bridge stdio to MCP server on localhost:8080
-//! agent-client-protocol-conductor mcp 8080
-//! ```
-//!
-//! This allows stdio-based tools to communicate with TCP MCP servers.
-//!
 //! ## How It Works
 //!
 //! **Component Communication:**
@@ -81,8 +70,6 @@ use std::str::FromStr;
 mod conductor;
 /// Debug logging for conductor
 mod debug_logger;
-/// MCP bridge functionality for TCP-based MCP servers
-mod mcp_bridge;
 mod snoop;
 /// Trace event types for sequence diagram viewer
 pub mod trace;
@@ -219,12 +206,6 @@ pub enum ConductorCommand {
         /// List of proxy commands to chain together
         proxies: Vec<String>,
     },
-
-    /// Run as MCP bridge connecting stdio to TCP
-    Mcp {
-        /// TCP port to connect to on localhost
-        port: u16,
-    },
 }
 
 impl ConductorArgs {
@@ -240,7 +221,6 @@ impl ConductorArgs {
             let components = match &self.command {
                 ConductorCommand::Agent { components, .. } => components.clone(),
                 ConductorCommand::Proxy { proxies, .. } => proxies.clone(),
-                ConductorCommand::Mcp { .. } => Vec::new(),
             };
 
             // Create debug logger
@@ -333,7 +313,6 @@ impl ConductorArgs {
                 )
                 .await
             }
-            ConductorCommand::Mcp { port } => mcp_bridge::run_mcp_bridge(port).await,
         }
     }
 }

src/agent-client-protocol-conductor/src/lib.rs

@@ -13,6 +13,7 @@ use agent_client_protocol::schema::{
     SessionNotification, TextContent,
 };
 use agent_client_protocol_conductor::{ConductorImpl, ProxiesAndAgent};
+use agent_client_protocol_polyfill::mcp_over_acp::McpOverAcpPolyfill;
 use agent_client_protocol_test::testy::{Testy, TestyCommand};
 use futures::{SinkExt, StreamExt, channel::mpsc};
 
@@ -72,7 +73,9 @@ async fn run_test_with_mode(
 #[tokio::test]
 async fn test_proxy_provides_mcp_tools_stdio() -> Result<(), agent_client_protocol::Error> {
     run_test_with_mode(
-        ProxiesAndAgent::new(Testy::new()).proxy(mcp_integration::proxy::ProxyComponent),
+        ProxiesAndAgent::new(Testy::new())
+            .proxy(mcp_integration::proxy::ProxyComponent)
+            .proxy(McpOverAcpPolyfill::http()),
         async |connection_to_editor| {
             // Send initialization request
             let init_response = recv(
@@ -113,7 +116,9 @@ async fn test_proxy_provides_mcp_tools_stdio() -> Result<(), agent_client_protoc
 #[tokio::test]
 async fn test_proxy_provides_mcp_tools_http() -> Result<(), agent_client_protocol::Error> {
     run_test_with_mode(
-        ProxiesAndAgent::new(Testy::new()).proxy(mcp_integration::proxy::ProxyComponent),
+        ProxiesAndAgent::new(Testy::new())
+            .proxy(mcp_integration::proxy::ProxyComponent)
+            .proxy(McpOverAcpPolyfill::http()),
         async |connection_to_editor| {
             // Send initialization request
             let init_response = recv(
@@ -151,7 +156,6 @@ async fn test_proxy_provides_mcp_tools_http() -> Result<(), agent_client_protoco
 }
 
 #[tokio::test]
-#[ignore = "requires McpOverAcpPolyfill proxy in chain - bridge removed from conductor"]
 async fn test_agent_handles_prompt() -> Result<(), agent_client_protocol::Error> {
     // Initialize tracing for debug output
     drop(
@@ -172,7 +176,9 @@ async fn test_agent_handles_prompt() -> Result<(), agent_client_protocol::Error>
     let conductor_handle = tokio::spawn(async move {
         ConductorImpl::new_agent(
             "mcp-integration-conductor".to_string(),
-            ProxiesAndAgent::new(Testy::new()).proxy(mcp_integration::proxy::ProxyComponent),
+            ProxiesAndAgent::new(Testy::new())
+                .proxy(mcp_integration::proxy::ProxyComponent)
+                .proxy(McpOverAcpPolyfill::http()),
         )
         .run(agent_client_protocol::ByteStreams::new(
             conductor_write.compat_write(),

src/agent-client-protocol-conductor/src/mcp_bridge.rs

@@ -7,6 +7,7 @@
 use agent_client_protocol::mcp_server::McpServer;
 use agent_client_protocol::{Agent, Conductor, ConnectTo, Proxy, Role, RunWithConnectionTo};
 use agent_client_protocol_conductor::{ConductorImpl, ProxiesAndAgent};
+use agent_client_protocol_polyfill::mcp_over_acp::McpOverAcpPolyfill;
 use agent_client_protocol_test::testy::{Testy, TestyCommand};
 use schemars::JsonSchema;
 use serde::{Deserialize, Serialize};
@@ -17,11 +18,12 @@ use std::sync::Mutex;
 /// This validates the scoped lifetime feature - the tool closure captures
 /// a reference to `collected_values` which lives on the stack.
 #[tokio::test]
-#[ignore = "requires McpOverAcpPolyfill proxy in chain - bridge removed from conductor"]
 async fn test_scoped_mcp_server_through_proxy() -> Result<(), agent_client_protocol::Error> {
     let conductor = ConductorImpl::new_agent(
         "conductor".to_string(),
-        ProxiesAndAgent::new(Testy::new()).proxy(ScopedProxy),
+        ProxiesAndAgent::new(Testy::new())
+            .proxy(ScopedProxy)
+            .proxy(McpOverAcpPolyfill::http()),
     );
 
     let result = yopo::prompt(
@@ -48,14 +50,13 @@ async fn test_scoped_mcp_server_through_proxy() -> Result<(), agent_client_proto
 /// The MCP server captures a reference to stack-local data that lives for
 /// the duration of the session.
 #[tokio::test]
-#[ignore = "requires McpOverAcpPolyfill proxy in chain - bridge removed from conductor"]
 async fn test_scoped_mcp_server_through_session() -> Result<(), agent_client_protocol::Error> {
     // Run the client
     agent_client_protocol::Client.builder()
         .connect_with(
             ConductorImpl::new_agent(
                 "conductor".to_string(),
-                ProxiesAndAgent::new(Testy::new()),
+                ProxiesAndAgent::new(Testy::new()).proxy(McpOverAcpPolyfill::http()),
             ),
             async |cx| {
                 // Initialize first

src/agent-client-protocol-conductor/tests/mcp-integration.rs

@@ -6,6 +6,7 @@
 use agent_client_protocol::mcp_server::McpServer;
 use agent_client_protocol::{Conductor, ConnectTo, DynConnectTo, Proxy, RunWithConnectionTo};
 use agent_client_protocol_conductor::{ConductorImpl, ProxiesAndAgent};
+use agent_client_protocol_polyfill::mcp_over_acp::McpOverAcpPolyfill;
 use agent_client_protocol_test::testy::{Testy, TestyCommand};
 use schemars::JsonSchema;
 use serde::{Deserialize, Serialize};
@@ -56,12 +57,13 @@ impl<R: RunWithConnectionTo<Conductor> + 'static + Send> ConnectTo<Conductor>
 }
 
 #[tokio::test]
-#[ignore = "requires McpOverAcpPolyfill proxy in chain - bridge removed from conductor"]
 async fn test_tool_returning_string() -> Result<(), agent_client_protocol::Error> {
     let result = yopo::prompt(
         ConductorImpl::new_agent(
             "test-conductor".to_string(),
-            ProxiesAndAgent::new(Testy::new()).proxy(create_test_proxy()),
+            ProxiesAndAgent::new(Testy::new())
+                .proxy(create_test_proxy())
+                .proxy(McpOverAcpPolyfill::http()),
         ),
         TestyCommand::CallTool {
             server: "test_server".to_string(),
@@ -82,12 +84,13 @@ async fn test_tool_returning_string() -> Result<(), agent_client_protocol::Error
 }
 
 #[tokio::test]
-#[ignore = "requires McpOverAcpPolyfill proxy in chain - bridge removed from conductor"]
 async fn test_tool_returning_integer() -> Result<(), agent_client_protocol::Error> {
     let result = yopo::prompt(
         ConductorImpl::new_agent(
             "test-conductor".to_string(),
-            ProxiesAndAgent::new(Testy::new()).proxy(create_test_proxy()),
+            ProxiesAndAgent::new(Testy::new())
+                .proxy(create_test_proxy())
+                .proxy(McpOverAcpPolyfill::http()),
         ),
         TestyCommand::CallTool {
             server: "test_server".to_string(),

src/agent-client-protocol-conductor/tests/scoped_mcp_server.rs

@@ -12,6 +12,7 @@ use agent_client_protocol::RunWithConnectionTo;
 use agent_client_protocol::mcp_server::McpServer;
 use agent_client_protocol::{Conductor, ConnectTo, DynConnectTo, Proxy};
 use agent_client_protocol_conductor::{ConductorImpl, ProxiesAndAgent};
+use agent_client_protocol_polyfill::mcp_over_acp::McpOverAcpPolyfill;
 use agent_client_protocol_test::testy::{Testy, TestyCommand};
 use schemars::JsonSchema;
 use serde::{Deserialize, Serialize};
@@ -36,7 +37,7 @@ fn create_echo_proxy() -> DynConnectTo<Conductor> {
             "Returns the current session_id",
             async |_input: EchoInput, context| {
                 Ok(EchoOutput {
-                    acp_id: context.acp_url(),
+                    acp_id: context.acp_id(),
                 })
             },
             agent_client_protocol::tool_fn_mut!(),
@@ -68,14 +69,15 @@ impl<R: RunWithConnectionTo<Conductor> + 'static + Send> ConnectTo<Conductor>
 }
 
 #[tokio::test]
-#[ignore = "requires McpOverAcpPolyfill proxy in chain - bridge removed from conductor"]
 async fn test_list_tools_from_mcp_server() -> Result<(), agent_client_protocol::Error> {
     use expect_test::expect;
 
     let result = yopo::prompt(
         ConductorImpl::new_agent(
             "test-conductor".to_string(),
-            ProxiesAndAgent::new(Testy::new()).proxy(create_echo_proxy()),
+            ProxiesAndAgent::new(Testy::new())
+                .proxy(create_echo_proxy())
+                .proxy(McpOverAcpPolyfill::http()),
         ),
         TestyCommand::ListTools {
             server: "echo_server".to_string(),
@@ -94,12 +96,13 @@ async fn test_list_tools_from_mcp_server() -> Result<(), agent_client_protocol::
 }
 
 #[tokio::test]
-#[ignore = "requires McpOverAcpPolyfill proxy in chain - bridge removed from conductor"]
 async fn test_session_id_delivered_to_mcp_tools() -> Result<(), agent_client_protocol::Error> {
     let result = yopo::prompt(
         ConductorImpl::new_agent(
             "test-conductor".to_string(),
-            ProxiesAndAgent::new(Testy::new()).proxy(create_echo_proxy()),
+            ProxiesAndAgent::new(Testy::new())
+                .proxy(create_echo_proxy())
+                .proxy(McpOverAcpPolyfill::http()),
         ),
         TestyCommand::CallTool {
             server: "echo_server".to_string(),