Struct SystemEvent 

pub struct SystemEvent {

    pub uuid: Option<String>,
    pub parent_uuid: Option<String>,
    pub logical_parent_uuid: Option<String>,
    pub session_id: String,
    pub timestamp: DateTime<Utc>,
    pub is_sidechain: bool,
    pub user_type: Option<String>,
    pub cwd: Option<String>,
    pub version: Option<String>,
    pub git_branch: Option<String>,
    pub slug: Option<String>,
    pub subtype: Option<String>,
    pub content: Option<String>,
    pub is_meta: Option<bool>,
    pub level: Option<String>,
    pub compact_metadata: Option<CompactMetadata>,
    pub error: Option<ErrorDetails>,
}

System event

Represents system-level events:

• Compact boundaries (conversation compaction)
• API errors (overload, rate limits)
• System reminders

Special Fields

System events don’t use flattened EventMetadata because:

• uuid can be None for some system events
• Need special handling for compact boundaries

Frequency

~6 occurrences per large session (rare but important!)

Fields

uuid: Option<String>

Event UUID (can be None for some system events)

parent_uuid: Option<String>

Parent UUID

logical_parent_uuid: Option<String>

Logical parent UUID (for compact boundaries)

Compact boundaries have both:

• parent_uuid - points to compact boundary system message
• logical_parent_uuid - points to last real message before compaction

This preserves conversation flow across compaction.

session_id: String

Session ID

timestamp: DateTime<Utc>

Timestamp

is_sidechain: bool

Is this part of a sidechain

user_type: Option<String>

User type (typically None for system events)

cwd: Option<String>

Current working directory

version: Option<String>

Claude Code version

git_branch: Option<String>

Git branch

slug: Option<String>

Agent slug

subtype: Option<String>

System event subtype

Common values:

• "compact_boundary" - Conversation compaction point
• "microcompact_boundary" - Smaller compaction
• "error" - System error

content: Option<String>

Content/message

is_meta: Option<bool>

Is this a meta event

level: Option<String>

Severity level: “info”, “warning”, “error”

compact_metadata: Option<CompactMetadata>

Compact boundary metadata (only for compact_boundary subtype)

error: Option<ErrorDetails>

Error details (only for error subtype)

Implementations

impl SystemEvent

pub fn is_compact_boundary(&self) -> bool

Check if this is a compact boundary

pub fn is_microcompact_boundary(&self) -> bool

Check if this is a microcompact boundary

pub fn is_error(&self) -> bool

Check if this is an error event

pub fn compact_metadata(&self) -> Option<&CompactMetadata>

Get compact metadata if this is a compact boundary

pub fn metadata(&self) -> EventMetadata

Convert to EventMetadata (for consistent interface)

Trait Implementations

impl Clone for SystemEvent

fn clone(&self) -> Self

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for SystemEvent

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

Formats the value using the given formatter.

impl<'de> Deserialize<'de> for SystemEvent

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

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl Serialize for SystemEvent

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

where __S: Serializer,

Serialize this value into the given Serde serializer.