Enum AgentEvent 

pub enum AgentEvent {
    AgentMessageChunk {
        session_id: String,
        content: String,
    },
    AgentThoughtChunk {
        session_id: String,
        content: String,
    },
    ToolCall {
        session_id: String,
        tool_call_id: String,
        tool_name: String,
        kind: Option<ToolKind>,
        status: ToolCallStatus,
        raw_input: Value,
        parsing: Option<bool>,
        audit: Option<MutationSessionRecord>,
    },
    ToolCallUpdate {

        session_id: String,
        tool_call_id: String,
        tool_name: String,
        status: ToolCallStatus,
        raw_output: Option<Value>,
        error: Option<String>,
        duration_ms: Option<u64>,
        execution_duration_ms: Option<u64>,
        error_category: Option<ToolCallErrorCategory>,
        executor: Option<ToolExecutor>,
        parsing: Option<bool>,
        raw_input: Option<Value>,
        raw_input_partial: Option<String>,
        audit: Option<MutationSessionRecord>,
    
},
    Plan {
        session_id: String,
        plan: Value,
    },
    TurnStart {
        session_id: String,
        iteration: usize,
    },
    TurnEnd {
        session_id: String,
        iteration: usize,
        turn_info: Value,
    },
    FeedbackInjected {
        session_id: String,
        kind: String,
        content: String,
    },
    BudgetExhausted {
        session_id: String,
        max_iterations: usize,
    },
    LoopStuck {
        session_id: String,
        max_nudges: usize,
        last_iteration: usize,
        tail_excerpt: String,
    },
    DaemonWatchdogTripped {
        session_id: String,
        attempts: usize,
        elapsed_ms: u64,
    },
    SkillActivated {
        session_id: String,
        skill_name: String,
        iteration: usize,
        reason: String,
    },
    SkillDeactivated {
        session_id: String,
        skill_name: String,
        iteration: usize,
    },
    SkillScopeTools {
        session_id: String,
        skill_name: String,
        allowed_tools: Vec<String>,
    },
    ToolSearchQuery {
        session_id: String,
        tool_use_id: String,
        name: String,
        query: Value,
        strategy: String,
        mode: String,
    },
    ToolSearchResult {
        session_id: String,
        tool_use_id: String,
        promoted: Vec<String>,
        strategy: String,
        mode: String,
    },
    TranscriptCompacted {
        session_id: String,
        mode: String,
        strategy: String,
        archived_messages: usize,
        estimated_tokens_before: usize,
        estimated_tokens_after: usize,
        snapshot_asset_id: Option<String>,
    },
    Handoff {
        session_id: String,
        artifact_id: String,
        handoff: Box<HandoffArtifact>,
    },
    FsWatch {
        session_id: String,
        subscription_id: String,
        events: Vec<FsWatchEvent>,
    },
    WorkerUpdate {
        session_id: String,
        worker_id: String,
        worker_name: String,
        worker_task: String,
        worker_mode: String,
        event: WorkerEvent,
        status: String,
        metadata: Value,
        audit: Option<Value>,
    },
}

Events emitted by the agent loop. The first five variants map 1:1 to ACP sessionUpdate variants; the last three are harn-internal.

Variants

AgentMessageChunk

Fields

session_id: String

content: String

AgentThoughtChunk

Fields

session_id: String

content: String

ToolCall

Fields

session_id: String

tool_call_id: String

tool_name: String

kind: Option<ToolKind>

status: ToolCallStatus

raw_input: Value

parsing: Option<bool>

Set to Some(true) by the streaming candidate detector (harn#692) when this event represents a tool-call shape detected in the model’s in-flight assistant text but whose arguments have not finished parsing yet. Clients can render a spinner / placeholder while the model writes the body. The detector follows up with a ToolCallUpdate { parsing: false, .. } carrying either status: pending (promoted) or status: failed with error_category: parse_aborted. None (the default) means “this is a normal post-parse tool call, no candidate phase was active” so the on-disk shape stays compatible with replays recorded before this field existed.

audit: Option<MutationSessionRecord>

Mutation-session audit context active when the tool was dispatched (see harn#699). Hosts use it to group every tool emission belonging to the same write-capable session.

ToolCallUpdate

Fields

session_id: String

tool_call_id: String

tool_name: String

status: ToolCallStatus

raw_output: Option<Value>

error: Option<String>

duration_ms: Option<u64>

Wall-clock milliseconds from the parse-to-execution boundary to the terminal Completed/Failed update. Includes the time spent in any wrapping orchestration logic (loop checks, post-tool hooks, microcompaction). Populated only on the terminal update — None on intermediate Pending / InProgress updates so clients can ignore the field until it shows up.

execution_duration_ms: Option<u64>

Milliseconds spent in the actual host/builtin/MCP dispatch call only (the inner dispatch_tool_execution window). Populated only on the terminal update; None otherwise.

error_category: Option<ToolCallErrorCategory>

Structured classification of the failure (when status is Failed). Paired with error so clients can render each category distinctly without parsing free-form strings. Always None for non-Failed updates and serialized as errorCategory in the ACP wire format.

executor: Option<ToolExecutor>

Where the tool actually ran. None only for events emitted from sites that pre-date the dispatch decision (e.g. the pending → in-progress transition the loop emits before the dispatcher picks a backend).

parsing: Option<bool>

Companion to ToolCall.parsing (harn#692). The streaming candidate detector emits the terminal candidate event as a ToolCallUpdate with parsing: Some(false) to retract the in-flight parsing: true chip — either by promoting the candidate (status: pending, populated raw_output: None, error: None) or aborting it (status: failed, error_category: parse_aborted). None means this update is not part of a candidate-phase transition.

raw_input: Option<Value>

Best-effort partial parse of the streamed tool-call arguments. Populated by the SSE transport on Pending updates as the model streams input_json_delta (Anthropic) or tool_calls[].function.arguments deltas (OpenAI). None on terminal updates and on emissions from non-streaming paths (#693). When the partial bytes are not yet parseable as JSON the transport falls back to raw_input_partial.

raw_input_partial: Option<String>

Raw concatenated bytes of the streamed tool-call arguments when a permissive parse failed (#693). Mutually exclusive with raw_input: clients render whichever is present.

audit: Option<MutationSessionRecord>

Mutation-session audit context for the tool call. Carries the same payload as on the paired ToolCall event so a host processing a single update doesn’t have to correlate against the prior pending event.

Plan

Fields

session_id: String

plan: Value

TurnStart

Fields

session_id: String

iteration: usize

TurnEnd

Fields

session_id: String

iteration: usize

turn_info: Value

FeedbackInjected

Fields

session_id: String

kind: String

content: String

BudgetExhausted

Emitted when the agent loop exhausts max_iterations without any explicit break condition firing. Distinct from a natural “done” or a “stuck” nudge-exhaustion: this is strictly a budget cap.

Fields

session_id: String

max_iterations: usize

LoopStuck

Emitted when the loop breaks because consecutive text-only turns hit max_nudges. Parity with BudgetExhausted / TurnEnd for hosts that key off agent-terminal events.

Fields

session_id: String

max_nudges: usize

last_iteration: usize

tail_excerpt: String

DaemonWatchdogTripped

Emitted when the daemon idle-wait loop trips its watchdog because every configured wake source returned None for N consecutive attempts. Exists so a broken daemon doesn’t hang the session silently.

Fields

session_id: String

attempts: usize

elapsed_ms: u64

SkillActivated

Emitted when a skill is activated. Carries the match reason so replayers can reconstruct why a given skill took effect at this iteration.

Fields

session_id: String

skill_name: String

iteration: usize

reason: String

SkillDeactivated

Emitted when a previously-active skill is deactivated because the reassess phase no longer matches it.

Fields

session_id: String

skill_name: String

iteration: usize

SkillScopeTools

Emitted once per activation when the skill’s allowed_tools filter narrows the effective tool surface exposed to the model.

Fields

session_id: String

skill_name: String

allowed_tools: Vec<String>

ToolSearchQuery

Emitted when a tool_search query is issued by the model. Carries the raw query args, the configured strategy, and a mode tag distinguishing the client-executed fallback ("client") from provider-native paths ("anthropic" / "openai"). Mirrors the transcript event shape so hosts can render a search-in-progress chip in real time — the replay path walks the transcript after the turn, which is too late for live UX.

Fields

session_id: String

tool_use_id: String

name: String

query: Value

strategy: String

mode: String

ToolSearchResult

Emitted when tool_search resolves — carries the list of tool names newly promoted into the model’s effective surface for the next turn. Pair-emitted with ToolSearchQuery on every search.

Fields

session_id: String

tool_use_id: String

promoted: Vec<String>

strategy: String

mode: String

TranscriptCompacted

Fields

session_id: String

mode: String

strategy: String

archived_messages: usize

estimated_tokens_before: usize

estimated_tokens_after: usize

snapshot_asset_id: Option<String>

Handoff

Fields

session_id: String

artifact_id: String

handoff: Box<HandoffArtifact>

FsWatch

Fields

session_id: String

subscription_id: String

events: Vec<FsWatchEvent>

WorkerUpdate

Lifecycle update for a delegated/background worker. Carries the canonical typed event variant alongside the worker’s current status string and the structured metadata payload that worker_bridge_metadata builds (task, mode, timing, child run/snapshot paths, audit-session, etc.). The audit field is the same MutationSessionRecord JSON serialization carried on the bridge wire so ACP/A2A consumers don’t need to re-derive it.

One-to-one with the bridge-side worker_update session-update notification: ACP and A2A adapters subscribe to this variant and translate it into their respective wire formats. The session_id is the parent agent session that owns the worker (i.e. the session whose VM spawned the worker), so a single host stays subscribed to the same sink for both message and worker traffic.

Fields

session_id: String

worker_id: String

worker_name: String

worker_task: String

worker_mode: String

event: WorkerEvent

status: String

metadata: Value

audit: Option<Value>

Implementations

impl AgentEvent

pub fn session_id(&self) -> &str

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.

impl<'de> Deserialize<'de> for AgentEvent

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

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl Serialize for AgentEvent

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

where __S: Serializer,

Serialize this value into the given Serde serializer.