feat: add mixtape-acp crate for ACP support

Cargo.toml

@@ -1,5 +1,5 @@
 [workspace]
-members = ["mixtape-core", "mixtape-anthropic-sdk", "mixtape-tools", "mixtape-cli", "mixtape-server"]
+members = ["mixtape-core", "mixtape-anthropic-sdk", "mixtape-tools", "mixtape-cli", "mixtape-server", "mixtape-acp"]
 resolver = "2"
 
 [workspace.package]
@@ -16,6 +16,7 @@ mixtape-anthropic-sdk = { version = "0.3.1", path = "./mixtape-anthropic-sdk" }
 mixtape-tools = { path = "./mixtape-tools" }
 mixtape-cli = { path = "./mixtape-cli" }
 mixtape-server = { path = "./mixtape-server" }
+mixtape-acp = { path = "./mixtape-acp" }
 
 # Async runtime
 tokio = { version = "1.41", features = ["full"] }
@@ -24,6 +25,8 @@ tokio-stream = "0.1"
 async-trait = "0.1"
 async-stream = "0.3"
 futures = "0.3"
+agent-client-protocol = "0.9"
+tokio-util = { version = "0.7", features = ["compat"] }
 
 # HTTP Server
 axum = { version = "0.7", features = ["macros"] }
@@ -73,6 +76,7 @@ regex = "1.10"
 url = "2.5"
 http = "1.1"
 shellexpand = "3.1"
+log = "0.4"
 
 # MCP
 rmcp = { version = "0.11", features = ["client", "transport-child-process", "transport-streamable-http-client-reqwest"] }

mixtape-acp/Cargo.toml

@@ -0,0 +1,38 @@
+[package]
+name = "mixtape-acp"
+version.workspace = true
+edition.workspace = true
+license.workspace = true
+repository.workspace = true
+homepage.workspace = true
+description = "ACP (Agent Client Protocol) adapter for the mixtape agent framework"
+documentation = "https://docs.rs/mixtape-acp"
+readme = "../README.md"
+keywords = ["ai", "agents", "acp", "editor", "coding"]
+categories = ["development-tools", "api-bindings", "asynchronous"]
+exclude = [".cargo-husky/", ".claude/", ".github/", ".idea/"]
+
+[dependencies]
+mixtape-core.workspace = true
+agent-client-protocol.workspace = true
+tokio.workspace = true
+tokio-util.workspace = true
+futures.workspace = true
+serde.workspace = true
+serde_json.workspace = true
+thiserror.workspace = true
+uuid.workspace = true
+parking_lot.workspace = true
+async-trait.workspace = true
+log.workspace = true
+
+[dev-dependencies]
+mixtape-core = { workspace = true, features = ["test-utils", "bedrock"] }
+tokio-test.workspace = true
+cargo-husky.workspace = true
+
+[[example]]
+name = "echo_agent"
+
+[[example]]
+name = "echo_agent_bedrock"

mixtape-acp/examples/echo_agent.rs

@@ -0,0 +1,25 @@
+// ACP echo agent using MockProvider — no credentials required.
+//
+// This example starts an ACP server over stdio that responds to every prompt
+// with a fixed text reply. Useful for verifying that the ACP protocol wiring
+// works end-to-end without needing real LLM credentials.
+//
+// Run with:
+//   cargo run -p mixtape-acp --example echo_agent
+
+use mixtape_acp::{serve_stdio, MixtapeAcpBuilder};
+use mixtape_core::test_utils::MockProvider;
+use mixtape_core::Agent;
+
+#[tokio::main]
+async fn main() -> Result<(), Box<dyn std::error::Error>> {
+    let server = MixtapeAcpBuilder::new("echo-agent", env!("CARGO_PKG_VERSION"))
+        .with_agent_factory(|| async {
+            let provider = MockProvider::new().with_text("Hello from the echo agent!");
+            Agent::builder().provider(provider).build().await
+        })
+        .build()?;
+
+    serve_stdio(server).await?;
+    Ok(())
+}

mixtape-acp/examples/echo_agent_bedrock.rs

@@ -0,0 +1,27 @@
+// ACP agent backed by Claude Haiku 4.5 on Bedrock.
+//
+// This example starts an ACP server over stdio that creates a real
+// mixtape Agent for each session, using Claude Haiku 4.5 via AWS Bedrock.
+// Requires valid AWS credentials in the environment.
+//
+// Run with:
+//   cargo run -p mixtape-acp --example echo_agent_bedrock
+
+use mixtape_acp::{serve_stdio, MixtapeAcpBuilder};
+use mixtape_core::{Agent, ClaudeHaiku4_5};
+
+#[tokio::main]
+async fn main() -> Result<(), Box<dyn std::error::Error>> {
+    let server = MixtapeAcpBuilder::new("bedrock-agent", env!("CARGO_PKG_VERSION"))
+        .with_agent_factory(|| async {
+            Agent::builder()
+                .bedrock(ClaudeHaiku4_5)
+                .with_system_prompt("You are a helpful coding assistant.")
+                .build()
+                .await
+        })
+        .build()?;
+
+    serve_stdio(server).await?;
+    Ok(())
+}