Struct AcpSession 

pub struct AcpSession {
    pub runtime: AgentRuntime,
    pub cwd: PathBuf,
    pub turn: u64,
    pub session_id: SessionId,
    pub transcript: Vec<Message>,
    pub cancel_token: Arc<CancellationToken>,
    pub system_prompt: Option<String>,
    pub mcp_servers: Option<Value>,
    pub client_capabilities: Option<ClientCapabilities>,
    pub acp_state: Arc<Mutex<AcpClientFsState>>,
    pub mcp_child_pids: Vec<u32>,
}

State for one active ACP session.

Fields

runtime: AgentRuntime

The agent runtime that processes session/prompt requests.

cwd: PathBuf

The sandbox root for filesystem tools.

turn: u64

Monotonically-increasing turn counter.

session_id: SessionId

Session identifier (copied from the manager’s key for convenience).

transcript: Vec<Message>

Accumulated transcript of messages exchanged so far.

cancel_token: Arc<CancellationToken>

Cancellation token for the current (or next) agent turn. Fired by session/cancel; observed by the LLM stream loop (tokio::select!) and agent→client RPC calls.

This is an Arc<CancellationToken> to guarantee shared ownership across concurrent tasks (e.g. SSE parse loop and in-flight RPCs). Dropping the AcpSession does NOT cancel the token if other Arc clones exist.

system_prompt: Option<String>

The original system prompt for this session (used for session/resume).

mcp_servers: Option<Value>

MCP server configurations (used for session/resume).

client_capabilities: Option<ClientCapabilities>

Client capabilities declared during initialize (S2-E1/E3). Controls conditional registration of ClientReadFile/ClientWriteFile.

acp_state: Arc<Mutex<AcpClientFsState>>

Shared ACP client FS state for conditional tool visibility and routing.

mcp_child_pids: Vec<u32>

MCP child processes managed by this session (for cleanup on close/load/resume).

Implementations

impl AcpSession

pub fn refresh_cancel_token(&mut self) -> Arc<CancellationToken>

Create a fresh CancellationToken for the next turn and wire it to the agent runtime via set_interrupt_token. Returns an Arc clone of the new token for the caller to hold.

Must be called exactly once per turn, before runtime.run().

pub async fn kill_mcp_children(&mut self)

Kill all tracked MCP child processes using the graceful shutdown protocol (SIGTERM → timeout → SIGKILL). Called during session/close, session/load, session/resume, and client disconnect cleanup.