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//! Provider- and tool-runner lifecycle events delivered to prompt frontends.
use crate::connection::{notification, SharedClientChannel};
use agent_client_protocol::schema::v1 as acp;
use std::pin::Pin;
/// A semantic event emitted while a prompt is running.
///
/// Output and tool events are emitted in execution order. A proposed tool call
/// precedes its updates, and compaction starts before it finishes or fails.
pub enum PromptLifecycleEvent {
/// Incremental model or transcript-safe tool output.
Output {
/// Text chunk to append to client-visible output.
text: String,
},
/// A provider proposed a tool call that has not yet completed.
ToolCallProposed {
/// Provider-assigned tool call identifier.
call_id: String,
/// Requested tool name.
tool_name: String,
/// Requested JSON arguments.
arguments: serde_json::Value,
},
/// A tool call changed execution state.
ToolCallUpdate {
/// Provider-assigned tool call identifier.
call_id: String,
/// Tool name, or an empty string when unavailable.
tool_name: String,
/// New execution status.
status: ToolUpdateStatus,
/// Optional result or structured error payload.
output: Option<serde_json::Value>,
},
/// An embedded script or one of its child calls changed state.
ScriptActivity {
/// Runtime-assigned script identifier.
script_id: String,
/// Tool call that launched the script.
parent_call_id: String,
/// Machine-readable activity type.
activity_type: String,
/// Machine-readable activity status.
status: String,
/// Optional activity-specific data.
detail: Option<serde_json::Value>,
},
/// Context compaction began.
CompactionStarted {
/// Correlation identifier for the compaction operation.
compaction_id: String,
/// Compaction strategy name.
method: String,
},
/// Context compaction completed successfully.
CompactionFinished {
/// Correlation identifier from the start event.
compaction_id: String,
/// Estimated token count before compaction, when known.
tokens_before: Option<u32>,
/// Estimated token count after compaction, when known.
tokens_after: Option<u32>,
/// Compaction strategy used.
method: String,
},
/// Context compaction failed.
CompactionFailed {
/// Correlation identifier from the start event.
compaction_id: String,
/// Human-readable failure reason.
reason: String,
},
}
/// Client-visible execution state for a tool call.
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub enum ToolUpdateStatus {
/// Execution has started but is not terminal.
InProgress,
/// Execution completed successfully.
Completed,
/// Execution failed, was denied, or was cancelled.
Failed,
}
/// Information presented to a prompt sink for a tool-approval decision.
pub struct ApprovalRequest {
/// Provider-assigned tool call identifier.
pub call_id: String,
/// Requested tool name.
pub tool_name: String,
/// Requested JSON arguments.
pub arguments: serde_json::Value,
}
/// Decision returned by a prompt sink for one permission request.
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub enum ApprovalVerdict {
/// Permit this invocation once.
AllowOnce,
/// Deny this invocation while allowing the prompt loop to continue.
Denied,
/// Cancel the prompt and remaining tool calls.
Cancelled,
}
/// Receives ordered prompt events and resolves tool-approval requests.
pub trait PromptSink {
/// Emits one lifecycle event and resolves after the sink processes it.
fn emit(&self, event: PromptLifecycleEvent) -> Pin<Box<dyn std::future::Future<Output = ()>>>;
/// Requests an approval verdict for a proposed tool call.
fn request_approval(
&self,
request: ApprovalRequest,
) -> Pin<Box<dyn std::future::Future<Output = ApprovalVerdict>>>;
/// Return the underlying client channel if this sink is backed by one.
///
/// Used by delegation to forward child approval requests to the parent UI.
fn parent_client_channel(&self) -> Option<SharedClientChannel> {
None
}
/// Return the parent ACP session id used to route delegation UI events.
fn parent_session_acp_id(&self) -> Option<acp::SessionId> {
None
}
}
/// Adapts prompt lifecycle events to ACP notifications and permission requests.
pub(crate) struct AcpPromptSink {
session_id: acp::SessionId,
client: SharedClientChannel,
}
impl AcpPromptSink {
/// Creates a sink routing events to `client` under `session_id`.
pub(crate) fn new(session_id: acp::SessionId, client: SharedClientChannel) -> Self {
Self { session_id, client }
}
}
impl PromptSink for AcpPromptSink {
fn emit(&self, event: PromptLifecycleEvent) -> Pin<Box<dyn std::future::Future<Output = ()>>> {
match event {
PromptLifecycleEvent::Output { text } => {
let notif = notification(
&self.session_id,
acp::SessionUpdate::AgentMessageChunk(acp::ContentChunk::new(
acp::ContentBlock::Text(acp::TextContent::new(&text)),
)),
);
let client = self.client.clone();
Box::pin(async move {
let _ = client.send_notification(notif).await;
})
}
PromptLifecycleEvent::ToolCallProposed {
call_id,
tool_name,
arguments,
} => {
let notif = notification(
&self.session_id,
acp::SessionUpdate::ToolCall(
acp::ToolCall::new(acp::ToolCallId::new(call_id), &tool_name)
.raw_input(arguments)
.status(acp::ToolCallStatus::Pending),
),
);
let client = self.client.clone();
Box::pin(async move {
let _ = client.send_notification(notif).await;
})
}
PromptLifecycleEvent::ToolCallUpdate {
call_id,
tool_name,
status,
output,
} => {
let acp_status = match status {
ToolUpdateStatus::InProgress => acp::ToolCallStatus::InProgress,
ToolUpdateStatus::Completed => acp::ToolCallStatus::Completed,
ToolUpdateStatus::Failed => acp::ToolCallStatus::Failed,
};
let mut fields = acp::ToolCallUpdateFields::new().status(acp_status);
if !tool_name.is_empty() {
fields = fields.title(&tool_name);
}
if let Some(out) = output {
fields = fields.raw_output(out);
}
let notif = notification(
&self.session_id,
acp::SessionUpdate::ToolCallUpdate(acp::ToolCallUpdate::new(
acp::ToolCallId::new(call_id),
fields,
)),
);
let client = self.client.clone();
Box::pin(async move {
let _ = client.send_notification(notif).await;
})
}
PromptLifecycleEvent::ScriptActivity {
script_id,
parent_call_id,
activity_type,
status,
detail,
} => {
let client = self.client.clone();
Box::pin(async move {
let _ = client
.emit_script_activity(
&script_id,
&parent_call_id,
&activity_type,
&status,
detail,
)
.await;
})
}
PromptLifecycleEvent::CompactionStarted {
compaction_id,
method,
} => {
let client = self.client.clone();
Box::pin(async move {
let _ = client
.emit_compaction_event("started", None, None, &method, None, &compaction_id)
.await;
})
}
PromptLifecycleEvent::CompactionFinished {
compaction_id,
tokens_before,
tokens_after,
method,
} => {
let client = self.client.clone();
Box::pin(async move {
let _ = client
.emit_compaction_event(
"finished",
tokens_before,
tokens_after,
&method,
None,
&compaction_id,
)
.await;
})
}
PromptLifecycleEvent::CompactionFailed {
compaction_id,
reason,
} => {
let client = self.client.clone();
Box::pin(async move {
let _ = client
.emit_compaction_event(
"failed",
None,
None,
"",
Some(&reason),
&compaction_id,
)
.await;
})
}
}
}
fn request_approval(
&self,
request: ApprovalRequest,
) -> Pin<Box<dyn std::future::Future<Output = ApprovalVerdict>>> {
let tool_call_update = acp::ToolCallUpdate::new(
acp::ToolCallId::new(request.call_id.clone()),
acp::ToolCallUpdateFields::new()
.title(&request.tool_name)
.raw_input(request.arguments)
.status(acp::ToolCallStatus::InProgress),
);
let perm_request = acp::RequestPermissionRequest::new(
self.session_id.clone(),
tool_call_update,
vec![
acp::PermissionOption::new(
acp::PermissionOptionId::new("allow_once"),
"Allow once",
acp::PermissionOptionKind::AllowOnce,
),
acp::PermissionOption::new(
acp::PermissionOptionId::new("reject_once"),
"Deny",
acp::PermissionOptionKind::RejectOnce,
),
],
);
let client = self.client.clone();
Box::pin(async move {
match client.request_permission(perm_request).await {
Ok(response) => match response.outcome {
acp::RequestPermissionOutcome::Cancelled => ApprovalVerdict::Cancelled,
acp::RequestPermissionOutcome::Selected(sel) => {
let option_id = sel.option_id.to_string();
if option_id.contains("allow") {
ApprovalVerdict::AllowOnce
} else {
ApprovalVerdict::Denied
}
}
_ => ApprovalVerdict::Denied,
},
Err(_) => ApprovalVerdict::Denied,
}
})
}
fn parent_client_channel(&self) -> Option<SharedClientChannel> {
Some(self.client.clone())
}
fn parent_session_acp_id(&self) -> Option<acp::SessionId> {
Some(self.session_id.clone())
}
}