Enum AgentEvent 

pub enum AgentEvent {
    ToolStart {
        tool_name: String,
        tool_call_id: String,
        input: Value,
        display_name: Option<String>,
        summary: Option<String>,
        activity_description: Option<String>,
    },
    ToolComplete {
        tool_name: String,
        tool_call_id: String,
        result: ToolResult,
        display_name: Option<String>,
        rendered_result: Option<String>,
    },
    ToolError {
        tool_name: String,
        tool_call_id: String,
        error: String,
    },
    Thinking {
        turn: u32,
    },
    Done {
        result: QueryResult,
    },
    MessageStart {
        message_id: String,
    },
    ContentBlockStart {
        index: u32,
        block_type: String,
    },
    ContentBlockDelta {
        index: u32,
        delta: ContentDelta,
    },
    ContentBlockStop {
        index: u32,
    },
    MessageStop,
    RequestStart,
    StreamRequestEnd,
    RateLimitStatus {
        is_rate_limited: bool,
        retry_after_secs: Option<f64>,
    },
    MaxTurnsReached {
        max_turns: u32,
        turn_count: u32,
    },
    Tombstone {
        message: String,
    },
    Compact {
        event: CompactProgressEvent,
    },
    TokenUsage {
        usage: TokenUsage,
        cost: f64,
    },
    ApiRetry {
        attempt: u32,
        max_retries: u32,
        retry_delay_ms: u64,
        error_status: Option<u16>,
        error: String,
    },
}

Agent event types for streaming updates (matches TypeScript behavior)

Variants

ToolStart

Tool is about to be executed

Fields

tool_name: String

tool_call_id: String

input: Value

display_name: Option<String>

Human-readable display name (e.g., “Update” for edits, “Create” for new files). Overrides tool_name for display in the TUI.

summary: Option<String>

Short summary for compact views (e.g., file path for FileEdit).

activity_description: Option<String>

Activity description for spinner display (e.g., “Updating file.rs”).

ToolComplete

Tool execution completed

Fields

tool_name: String

tool_call_id: String

result: ToolResult

display_name: Option<String>

Human-readable display name (e.g., “Update(file.rs) (1 +, 1 -)”).

rendered_result: Option<String>

Rendered result message from Tool::render_tool_result_message.

ToolError

Tool execution failed

Fields

tool_name: String

tool_call_id: String

error: String

Thinking

LLM is thinking (started a new turn)

Fields

turn: u32

Done

Final response ready

Fields

result: QueryResult

MessageStart

Message started (streaming begins)

Fields

message_id: String

ContentBlockStart

Content block started (matches TypeScript StreamEvent content_block_start)

Fields

index: u32

block_type: String

ContentBlockDelta

Content block delta (matches TypeScript StreamEvent content_block_delta)

Fields

index: u32

delta: ContentDelta

ContentBlockStop

Content block stopped (matches TypeScript StreamEvent content_block_stop)

Fields

index: u32

MessageStop

Message stopped (streaming ends)

RequestStart

Request started (before API call) - matches TypeScript ‘stream_request_start’

StreamRequestEnd

Request completed (API response received, streaming finished) Matches TypeScript ‘stream_request_end’ — useful for TUI spinner management.

RateLimitStatus

Rate limit status change — notifies TUI/CLI when a rate limit is hit or cleared

Fields

is_rate_limited: bool

true if currently rate-limited, false if rate limit has cleared

retry_after_secs: Option<f64>

Optional retry-after seconds (if the server provided it)

MaxTurnsReached

Max turns reached - matches TypeScript ‘max_turns_reached’ attachment

Fields

max_turns: u32

turn_count: u32

Tombstone

Tombstone event for orphaned messages on streaming fallback (matches TypeScript ‘tombstone’ event)

Fields

message: String

Compact

Compact progress event (hooks_start, compact_start, compact_end) Matches TypeScript ToolUseContext.onCompactProgress

Fields

event: CompactProgressEvent

TokenUsage

Actual API token usage from message_delta event Emitted after all content_block_stop events, before message_stop

Fields

usage: TokenUsage

cost: f64

ApiRetry

API retry progress — emitted during 429/529 retry backoff Matches TypeScript’s ‘api_retry’ subtype yielded by QueryEngine from createSystemAPIErrorMessage in withRetry.ts

Fields

attempt: u32

Current retry attempt (1-based)

max_retries: u32

Maximum retries configured

retry_delay_ms: u64

Delay in milliseconds before next retry

error_status: Option<u16>

HTTP error status code that triggered the retry

error: String

Categorized error type (e.g., “rate_limit”, “server_error”)

Trait Implementations

impl Clone for AgentEvent

fn clone(&self) -> AgentEvent

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for AgentEvent

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

Formats the value using the given formatter.