feat: add shell tool wire types

ARCHITECTURE.md

@@ -493,6 +493,11 @@ classification and reshapes those raw calls accordingly:
   synthetic `function_call` events named `tool_search` are projected into that same
   public lifecycle after validation.
 
+Shell functions are restored to `shell_call` for client execution by default.
+When an application explicitly registers a shell executor, the translator instead
+suppresses those internal function frames using the registry's resolved ownership;
+the existing gateway event plan emits the shell call's added/done lifecycle.
+
 It also buffers function-call events that arrive before the call's name is known
 (bounded at 256 KiB) and replays them once the name resolves.
 
@@ -740,13 +745,23 @@ the behavioral layer — routing, handler traits, normalization, and execution.
   reused across requests, specifically for gateway tools that need **lazy, per-request
   connection setup**: MCP servers (connects and caches `McpClient`s keyed by server
   URL, falling back to connecting a fresh request-declared server) and the shared
-  `WebSearchHandler`. As of today it only has slots for `ToolType::Mcp` and
-  `ToolType::WebSearch`; `GatewayExecutorRegistration` has typed variants for those
-  supported slots. Client-owned
+  `WebSearchHandler`. It also has an optional, application-provided `ShellExecutor`
+  slot. `GatewayExecutorRegistration::Shell` is an explicit execution grant; an
+  unregistered shell declaration remains client-executed. `ShellExecutor` accepts
+  a typed call with bounded action limits and cancellation and returns typed command
+  outputs. The adapter binds into the existing gateway scheduler, not a second tool loop.
+  Client-owned
   tools (`function`, `custom`, `namespace`) never touch this file; their registry
   entries are inserted with `ToolOwnership::Client` and no `GatewayExecutors`
   involvement.
 
+Shell item history is preserved publicly in storage. At the inference boundary,
+`ShellHandler::model_input` lowers shell calls and outputs into matching function
+history, just as declarations and explicit shell selectors are normalized. For an
+opt-in gateway executor, storage additionally retains the canonical internal function
+call/output pair; rehydration omits that pair's public shell-call projection to avoid
+replaying the invocation twice. Client-executed shell history is not omitted.
+
 **To add a new tool type:**
 1. Implement `ToolHandler`, including its typed `ToolParams`, for it. If it's client-executed,
    stop there — see `function.rs`/`custom.rs` for the pattern.

crates/agentic-server-core/Cargo.toml

@@ -42,6 +42,7 @@ serde_json.workspace = true
 sse-stream.workspace = true
 thiserror.workspace = true
 tokio = { workspace = true, features = ["time"] }
+tokio-util = { workspace = true, features = ["rt"] }
 tracing.workspace = true
 url.workspace = true
 

crates/agentic-server-core/src/events/normalize.rs

@@ -1,6 +1,7 @@
 use serde_json::Value;
 
-use super::types::{EventFrame, EventPayload, SSEEventType, SSEItemType, WireEvent};
+use super::types::{EventFrame, EventPayload, SSEEventType, SSEItemType, ShellCommandUpdate, WireEvent};
+use crate::types::io::OutputItem;
 use crate::utils::common::{deserialize_from_str_opt, deserialize_from_value_opt};
 
 /// Normalize a raw SSE data line into a typed [`EventFrame`].
@@ -64,6 +65,9 @@ fn extract_payload(event_type: SSEEventType, json: &Value) -> EventPayload {
         SSEEventType::FunctionCallArgumentsDone => extract_fn_call_args_done(json),
         SSEEventType::CustomToolCallInputDelta => extract_custom_tool_call_input_delta(json),
         SSEEventType::CustomToolCallInputDone => extract_custom_tool_call_input_done(json),
+        SSEEventType::ShellCallCommandAdded => extract_shell_call_command_added(json),
+        SSEEventType::ShellCallCommandDelta => extract_shell_call_command_delta(json),
+        SSEEventType::ShellCallCommandDone => extract_shell_call_command_done(json),
 
         SSEEventType::ReasoningTextDelta => extract_reasoning_text_delta(json),
         SSEEventType::ReasoningTextDone => extract_reasoning_text_done(json),
@@ -133,6 +137,14 @@ fn extract_output_item_added(json: &Value) -> EventPayload {
         name: json_str_opt(item, "name"),
         namespace: json_str_opt(item, "namespace"),
         call_id: json_str_opt(item, "call_id"),
+        shell_call: if item["type"] == "shell_call" {
+            match deserialize_from_value_opt::<OutputItem>(item.clone()) {
+                Some(OutputItem::ShellCall(call)) => Some(Box::new(call)),
+                _ => None,
+            }
+        } else {
+            None
+        },
     }
 }
 
@@ -169,6 +181,27 @@ fn extract_text_done(json: &Value) -> EventPayload {
     }
 }
 
+fn extract_shell_call_command_added(json: &Value) -> EventPayload {
+    extract_shell_command(json, ShellCommandUpdate::Added(json_str(json, "command")))
+}
+
+fn extract_shell_call_command_delta(json: &Value) -> EventPayload {
+    extract_shell_command(json, ShellCommandUpdate::Delta(json_str(json, "delta")))
+}
+
+fn extract_shell_call_command_done(json: &Value) -> EventPayload {
+    extract_shell_command(json, ShellCommandUpdate::Done(json_str(json, "command")))
+}
+
+fn extract_shell_command(json: &Value, update: ShellCommandUpdate) -> EventPayload {
+    EventPayload::ShellCallCommand {
+        item_id: json_str(json, "item_id"),
+        output_index: json_u32(json, "output_index"),
+        command_index: json_u32(json, "command_index"),
+        update,
+    }
+}
+
 fn extract_fn_call_args_delta(json: &Value) -> EventPayload {
     EventPayload::FunctionCallArgsDelta {
         delta: json_str(json, "delta"),

crates/agentic-server-core/src/events/types.rs

@@ -1,7 +1,7 @@
 use serde::{Deserialize, Serialize};
 use serde_json::{Map, Value};
 
-use crate::types::io::{OutputItem, ResponseUsage};
+use crate::types::io::{OutputItem, ResponseUsage, ShellCall};
 
 /// The type of an output item received during streaming.
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
@@ -13,6 +13,7 @@ pub enum SSEItemType {
     WebSearchCall,
     McpCall,
     McpListTools,
+    ShellCall,
     Compaction,
     Message,
 }
@@ -28,6 +29,7 @@ impl SSEItemType {
             Self::WebSearchCall => "web_search_call",
             Self::McpCall => "mcp_call",
             Self::McpListTools => "mcp_list_tools",
+            Self::ShellCall => "shell_call",
             Self::Compaction => "compaction",
             Self::Message => "message",
         }
@@ -52,6 +54,7 @@ impl std::str::FromStr for SSEItemType {
             "web_search_call" => Ok(Self::WebSearchCall),
             "mcp_call" => Ok(Self::McpCall),
             "mcp_list_tools" => Ok(Self::McpListTools),
+            "shell_call" => Ok(Self::ShellCall),
             "compaction" => Ok(Self::Compaction),
             "message" => Ok(Self::Message),
             _ => Err(()),
@@ -71,6 +74,7 @@ impl TryFrom<&OutputItem> for SSEItemType {
             OutputItem::WebSearchCall(_) => Ok(Self::WebSearchCall),
             OutputItem::McpCall(_) => Ok(Self::McpCall),
             OutputItem::McpListTools(_) => Ok(Self::McpListTools),
+            OutputItem::ShellCall(_) => Ok(Self::ShellCall),
             OutputItem::Reasoning(_) => Ok(Self::Reasoning),
             OutputItem::Compaction(_) => Ok(Self::Compaction),
             OutputItem::Unknown => Err(()),
@@ -125,6 +129,9 @@ pub enum SSEEventType {
     FunctionCallArgumentsDone,
     CustomToolCallInputDelta,
     CustomToolCallInputDone,
+    ShellCallCommandAdded,
+    ShellCallCommandDelta,
+    ShellCallCommandDone,
 
     // Reasoning
     ReasoningTextDelta,
@@ -171,6 +178,9 @@ impl From<&str> for SSEEventType {
             "response.function_call_arguments.done" => Self::FunctionCallArgumentsDone,
             "response.custom_tool_call_input.delta" => Self::CustomToolCallInputDelta,
             "response.custom_tool_call_input.done" => Self::CustomToolCallInputDone,
+            "response.shell_call_command.added" => Self::ShellCallCommandAdded,
+            "response.shell_call_command.delta" => Self::ShellCallCommandDelta,
+            "response.shell_call_command.done" => Self::ShellCallCommandDone,
             "response.reasoning_text.delta" => Self::ReasoningTextDelta,
             "response.reasoning_text.done" => Self::ReasoningTextDone,
             "response.reasoning_part.added" => Self::ReasoningPartAdded,
@@ -215,6 +225,9 @@ impl TryFrom<SSEEventType> for &'static str {
             SSEEventType::FunctionCallArgumentsDone => Ok("response.function_call_arguments.done"),
             SSEEventType::CustomToolCallInputDelta => Ok("response.custom_tool_call_input.delta"),
             SSEEventType::CustomToolCallInputDone => Ok("response.custom_tool_call_input.done"),
+            SSEEventType::ShellCallCommandAdded => Ok("response.shell_call_command.added"),
+            SSEEventType::ShellCallCommandDelta => Ok("response.shell_call_command.delta"),
+            SSEEventType::ShellCallCommandDone => Ok("response.shell_call_command.done"),
             SSEEventType::ReasoningTextDelta => Ok("response.reasoning_text.delta"),
             SSEEventType::ReasoningTextDone => Ok("response.reasoning_text.done"),
             SSEEventType::ReasoningPartAdded => Ok("response.reasoning_part.added"),
@@ -276,6 +289,14 @@ impl WireEvent {
     }
 }
 
+/// One command's incremental lifecycle within a shell output item.
+#[derive(Debug, Clone)]
+pub enum ShellCommandUpdate {
+    Added(String),
+    Delta(String),
+    Done(String),
+}
+
 /// Typed payload extracted from an SSE event's JSON data.
 #[derive(Debug, Clone)]
 #[non_exhaustive]
@@ -296,6 +317,8 @@ pub enum EventPayload {
         name: Option<String>,
         namespace: Option<String>,
         call_id: Option<String>,
+        /// Preserve the typed initial shell item before command events arrive.
+        shell_call: Option<Box<ShellCall>>,
     },
 
     /// `response.output_item.done`
@@ -339,6 +362,12 @@ pub enum EventPayload {
     },
 
     /// `response.custom_tool_call_input.delta`
+    ShellCallCommand {
+        item_id: String,
+        output_index: u32,
+        command_index: u32,
+        update: ShellCommandUpdate,
+    },
     CustomToolCallInputDelta {
         delta: String,
         item_id: String,
@@ -468,6 +497,9 @@ mod tests {
             SSEEventType::FunctionCallArgumentsDone,
             SSEEventType::CustomToolCallInputDelta,
             SSEEventType::CustomToolCallInputDone,
+            SSEEventType::ShellCallCommandAdded,
+            SSEEventType::ShellCallCommandDelta,
+            SSEEventType::ShellCallCommandDone,
             SSEEventType::ReasoningTextDelta,
             SSEEventType::ReasoningTextDone,
             SSEEventType::ReasoningPartAdded,

crates/agentic-server-core/src/events/validate.rs

@@ -49,7 +49,7 @@ pub(crate) fn validate_frame(frame: &EventFrame) -> Result<ValidatedFrame<'_>, E
         SSEEventType::Other => Ok(ValidatedFrame { item: None }),
         event_type => {
             let output_index = required_output_index(frame, event_name)?;
-            let item_id = required_str(&frame.wire.rest, "item_id", event_name)?;
+            let item_id = validate_event_item_id(frame, event_name)?;
             validate_event_fields(&frame.wire.rest, event_type, event_name)?;
             let item_type = expected_item_type(event_type).ok_or_else(|| {
                 invalid(format!(
@@ -80,6 +80,9 @@ fn expected_item_type(event_type: SSEEventType) -> Option<SSEItemType> {
         SSEEventType::CustomToolCallInputDelta | SSEEventType::CustomToolCallInputDone => {
             Some(SSEItemType::CustomToolCall)
         }
+        SSEEventType::ShellCallCommandAdded
+        | SSEEventType::ShellCallCommandDelta
+        | SSEEventType::ShellCallCommandDone => Some(SSEItemType::ShellCall),
         SSEEventType::ReasoningTextDelta
         | SSEEventType::ReasoningTextDone
         | SSEEventType::ReasoningPartAdded
@@ -192,12 +195,30 @@ fn validate_output_item<'a>(
     })
 }
 
+fn validate_event_item_id<'a>(frame: &'a EventFrame, event_name: &str) -> Result<&'a str, EventError> {
+    if matches!(
+        frame.event_type,
+        SSEEventType::ShellCallCommandAdded | SSEEventType::ShellCallCommandDelta | SSEEventType::ShellCallCommandDone
+    ) && !frame.wire.rest.contains_key("item_id")
+    {
+        // Only native shell command events may omit the ID and resolve by output_index.
+        return Ok("");
+    }
+    let item_id = required_str(&frame.wire.rest, "item_id", event_name)?;
+    Ok(item_id)
+}
+
 fn validate_event_fields(
     event: &Map<String, Value>,
     event_type: SSEEventType,
     event_name: &str,
 ) -> Result<(), EventError> {
     match event_type {
+        SSEEventType::ShellCallCommandAdded
+        | SSEEventType::ShellCallCommandDelta
+        | SSEEventType::ShellCallCommandDone => {
+            required_u32(event, "command_index", event_name)?;
+        }
         SSEEventType::OutputTextDelta
         | SSEEventType::OutputTextDone
         | SSEEventType::ContentPartAdded
@@ -218,6 +239,7 @@ fn validate_event_fields(
         SSEEventType::OutputTextDelta
         | SSEEventType::FunctionCallArgumentsDelta
         | SSEEventType::CustomToolCallInputDelta
+        | SSEEventType::ShellCallCommandDelta
         | SSEEventType::ReasoningTextDelta
         | SSEEventType::ReasoningSummaryTextDelta
         | SSEEventType::McpCallArgumentsDelta => Some("delta"),
@@ -226,6 +248,7 @@ fn validate_event_fields(
         }
         SSEEventType::FunctionCallArgumentsDone | SSEEventType::McpCallArgumentsDone => Some("arguments"),
         SSEEventType::CustomToolCallInputDone => Some("input"),
+        SSEEventType::ShellCallCommandAdded | SSEEventType::ShellCallCommandDone => Some("command"),
         SSEEventType::ContentPartAdded
         | SSEEventType::ContentPartDone
         | SSEEventType::ReasoningPartAdded
@@ -308,3 +331,48 @@ fn missing_field(owner: &str, field: &str) -> EventError {
 fn invalid(message: impl Into<String>) -> EventError {
     EventError(message.into())
 }
+
+#[cfg(test)]
+mod tests {
+    use serde_json::json;
+
+    use super::validate_frame;
+    use crate::events::normalize_sse_line;
+
+    #[test]
+    fn only_native_shell_command_events_allow_omitted_item_id() {
+        for (event_type, allows_omitted_id) in [
+            ("response.shell_call_command.added", true),
+            ("response.shell_call_command.delta", true),
+            ("response.shell_call_command.done", true),
+            ("response.function_call_arguments.delta", false),
+            ("response.function_call_arguments.done", false),
+            ("response.custom_tool_call_input.delta", false),
+            ("response.custom_tool_call_input.done", false),
+            ("response.mcp_call_arguments.delta", false),
+        ] {
+            let event = json!({
+                "type": event_type,
+                "output_index": 0,
+                "command_index": 0,
+                "command": "pwd",
+                "delta": "",
+                "arguments": "{}",
+                "input": "pwd"
+            });
+            let frame = normalize_sse_line(&format!("data: {event}")).unwrap();
+            assert_eq!(validate_frame(&frame).is_ok(), allows_omitted_id, "{event_type}");
+
+            for item_id in [json!(""), json!(null), json!(42), json!("sh_1")] {
+                let mut event = event.clone();
+                event["item_id"] = item_id.clone();
+                let frame = normalize_sse_line(&format!("data: {event}")).unwrap();
+                assert_eq!(
+                    validate_frame(&frame).is_ok(),
+                    item_id == json!("sh_1"),
+                    "{event_type} with item_id={item_id}"
+                );
+            }
+        }
+    }
+}