Struct ToolExecutionStartData 

pub struct ToolExecutionStartData {
    pub arguments: Option<Value>,
    pub display_verbatim: Option<bool>,
    pub mcp_server_name: Option<String>,
    pub mcp_tool_name: Option<String>,
    pub model: Option<String>,
    pub shell_tool_info: Option<ToolExecutionStartShellToolInfo>,
    pub tool_call_id: String,
    pub tool_description: Option<ToolExecutionStartToolDescription>,
    pub tool_name: String,
    pub turn_id: Option<String>,
    /* private fields */
}

Session event “tool.execution_start”. Tool execution startup details including MCP server information when applicable

Fields

arguments: Option<Value>

Arguments passed to the tool

display_verbatim: Option<bool>

When true, the tool output should be displayed expanded (verbatim) in the CLI timeline

mcp_server_name: Option<String>

Name of the MCP server hosting this tool, when the tool is an MCP tool

mcp_tool_name: Option<String>

Original tool name on the MCP server, when the tool is an MCP tool

model: Option<String>

Model identifier that generated this tool call

shell_tool_info: Option<ToolExecutionStartShellToolInfo>

Shell-tool path hints derived from the command at start time for shell tools (bash/powershell/local_shell). Produced by the same shell-aware extractor as PermissionRequestShell.possiblePaths, so it is present even when the command is auto-approved and no permission request fires. Absent for non-shell tools.

tool_call_id: String

Unique identifier for this tool call

tool_description: Option<ToolExecutionStartToolDescription>

Tool definition metadata, present for MCP tools with MCP Apps support

tool_name: String

Name of the tool being executed

turn_id: Option<String>

Identifier for the agent loop turn this tool was invoked in, matching the corresponding assistant.turn_start event

Trait Implementations

impl Clone for ToolExecutionStartData

fn clone(&self) -> ToolExecutionStartData

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for ToolExecutionStartData

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for ToolExecutionStartData

fn default() -> ToolExecutionStartData

Returns the “default value” for a type.

impl<'de> Deserialize<'de> for ToolExecutionStartData

fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error>

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl Serialize for ToolExecutionStartData

fn serialize<__S>(&self, __serializer: __S) -> Result<__S::Ok, __S::Error>

where __S: Serializer,

Serialize this value into the given Serde serializer.