Enum KernelEvent 

#[non_exhaustive]
pub enum KernelEvent {
    SchemaVersion {
        version: u32,
    },
    TurnStarted {
        turn_id: TurnId,
        mode: TurnLoopMode,
        input_text: String,
        max_steps: u32,
    },
    TurnEnded {
        turn_id: TurnId,
        outcome: TurnOutcome,
        total_steps: u32,
    },
    ModelRequestIssued {
        turn_id: TurnId,
        step_idx: u32,
        request_fp: RequestFingerprint,
        token_budget: u32,
    },
    ModelDelta {
        turn_id: TurnId,
        step_idx: u32,
        kind: DeltaKind,
        call_id: Option<CallId>,
        text: String,
    },
    ModelMessage {
        turn_id: TurnId,
        step_idx: u32,
        usage: Usage,
        block_count: u32,
        text_preview: String,
        assistant_text: String,
    },
    ToolCallPlanned {
        turn_id: TurnId,
        step_idx: u32,
        call_id: CallId,
        tool_name: String,
        input_json: String,
        decision: PolicyDecision,
    },
    ToolCallStarted {
        turn_id: TurnId,
        call_id: CallId,
        wave_idx: u32,
    },
    ToolCallFinished {
        turn_id: TurnId,
        call_id: CallId,
        tool_name: String,
        outcome: ToolOutcome,
        duration_ms: u32,
        wrote_state: bool,
        result_preview: String,
        session_content: String,
    },
    ApprovalResolved {
        turn_id: TurnId,
        call_id: CallId,
        verdict: ApprovalVerdict,
    },
    CompactionArtifactCreated {
        turn_id: TurnId,
        artifact_id: ArtifactId,
        replaced_range: MessageRange,
        summary_token_count: u32,
    },
    ContextOverflowRecovered {
        turn_id: TurnId,
        step_idx: u32,
        strategy: OverflowStrategy,
        source_budget_cap: Option<u32>,
    },
    SteerInjected {
        turn_id: TurnId,
        step_idx: u32,
        text: String,
    },
    ScratchpadReminderInjected {
        turn_id: TurnId,
        step_idx: u32,
        area_path: String,
    },
    ScratchpadSummaryInjected {
        turn_id: TurnId,
        at_step: u32,
    },
    CycleBriefingInjected {
        turn_id: TurnId,
        cycle: u32,
        step_idx: u32,
    },
    TopicMemoryInjected {
        turn_id: TurnId,
        step_idx: u32,
        block_token_est: u32,
    },
    MemoryPlaneQueried {
        turn_id: TurnId,
        step_idx: u32,
        layer: String,
        query_key: String,
        compiler_source: String,
    },
    LayeredContextSeamInjected {
        turn_id: TurnId,
        step_idx: u32,
        level: u32,
        messages_covered: u32,
        text_preview: String,
    },
    LoopGuardTriggered {
        turn_id: TurnId,
        call_id: CallId,
        reason: String,
    },
    CapacityCheckpoint {
        turn_id: TurnId,
        step_idx: u32,
        kind: CapacityCheckpointKind,
        tokens_used: u32,
        token_budget: u32,
        action: CapacityAction,
        cooldown_blocked: bool,
    },
    CycleAdvanced {
        turn_id: TurnId,
        from_cycle: u32,
        to_cycle: u32,
        reason: String,
    },
    StepLimitContinuation {
        turn_id: TurnId,
        step_idx: u32,
        lht_objective_injected: bool,
    },
    LoopGuardContinuation {
        turn_id: TurnId,
        step_idx: u32,
    },
    DeferredToolActivated {
        turn_id: TurnId,
        step_idx: u32,
        tool_name: String,
    },
}

Append-only, strongly-typed, monotonically-sequenced log of all observable state transitions in a single turn.

Replaces: core::Event free-string table, RuntimeEventRecord, EventFrame, and SSE-compat surface — four representations become one.

Schema evolution

• Adding a variant: add #[serde(default)] fields; increment nothing.
• Adding a field to existing variant: add #[serde(default)]; no bump.
• Removing or renaming: provide upcast_v{N}_to_v{N+1}() and bump SchemaVersion.

Variants (Non-exhaustive)

Non-exhaustive enums could have additional variants added in future. Therefore, when matching against variants of non-exhaustive enums, an extra wildcard arm must be added to account for any future variants.

SchemaVersion

First record in every kernel_events table partition. Currently always version: 1.

Fields

version: u32

TurnStarted

Fields

turn_id: TurnId

mode: TurnLoopMode

input_text: String

Serialised user message text. Attachments / large blobs: None with a separate EmitArtifact event carrying the blob reference.

max_steps: u32

TurnEnded

Fields

turn_id: TurnId

outcome: TurnOutcome

total_steps: u32

ModelRequestIssued

Fields

turn_id: TurnId

step_idx: u32

request_fp: RequestFingerprint

token_budget: u32

Resolved token budget for this request.

ModelDelta

Fields

turn_id: TurnId

step_idx: u32

kind: DeltaKind

call_id: Option<CallId>

For ToolCallArg deltas: the call_id of the in-progress tool block.

text: String

ModelMessage

Fields

turn_id: TurnId

step_idx: u32

usage: Usage

block_count: u32

Number of content blocks in the final message (avoids embedding full message text which belongs in the session store).

text_preview: String

Truncated assistant text for log-driven transcript rebuild (Phase 3b 5c).

assistant_text: String

Full assistant text written to session JSON (Phase 3b 5c closure).

ToolCallPlanned

Fields

turn_id: TurnId

step_idx: u32

call_id: CallId

tool_name: String

input_json: String

JSON-serialised tool input. Large inputs (>16 KB) are stored as an artifact reference; this field holds the truncated preview or {} with a large_input_artifact_id field added.

decision: PolicyDecision

ToolCallStarted

Fields

turn_id: TurnId

call_id: CallId

wave_idx: u32

DAG wave index (0 in legacy sequential mode).

ToolCallFinished

Fields

turn_id: TurnId

call_id: CallId

tool_name: String

outcome: ToolOutcome

duration_ms: u32

wrote_state: bool

Whether the tool performed any filesystem/state writes. Mirrors tool_writes_state() at call time; used to rebuild deferred-tool activation projection in Phase 3b.

result_preview: String

Truncated tool result / error text for log-driven transcript rebuild (Phase 3b 5c).

session_content: String

Exact tool-result body written to session JSON (Phase 3b 5c closure).

ApprovalResolved

Fields

turn_id: TurnId

call_id: CallId

verdict: ApprovalVerdict

CompactionArtifactCreated

Fields

turn_id: TurnId

artifact_id: ArtifactId

replaced_range: MessageRange

Message indices [from, to] replaced by this compaction artifact.

summary_token_count: u32

ContextOverflowRecovered

Fields

turn_id: TurnId

step_idx: u32

strategy: OverflowStrategy

source_budget_cap: Option<u32>

Token budget cap applied during budget-recompile (None for other strategies).

SteerInjected

Fields

turn_id: TurnId

step_idx: u32

text: String

ScratchpadReminderInjected

Fields

turn_id: TurnId

step_idx: u32

area_path: String

ScratchpadSummaryInjected

Fields

turn_id: TurnId

at_step: u32

Step at which the summary was first injected. Subsequent steps read the flag from the projection without a new event.

CycleBriefingInjected

Fields

turn_id: TurnId

cycle: u32

step_idx: u32

TopicMemoryInjected

Episodic topic-memory block injected into the system prompt (B2 double-write).

Fields

turn_id: TurnId

step_idx: u32

block_token_est: u32

Estimated tokens in the injected <topic_memory> block.

MemoryPlaneQueried

Read-side memory plane query executed (v3 Effect::QueryMemory double-write).

Fields

turn_id: TurnId

step_idx: u32

layer: String

working | episodic | archival

query_key: String

compiler_source: String

ContextCompiler source id resolved for this query (empty when unknown).

LayeredContextSeamInjected

Flash layered-context seam appended as assistant message (v3 #159 double-write).

Fields

turn_id: TurnId

step_idx: u32

level: u32

messages_covered: u32

text_preview: String

Truncated seam text for observability (full body remains in session store until 5c).

LoopGuardTriggered

Fields

turn_id: TurnId

call_id: CallId

reason: String

“identical_call” | “deferred_set_area_batch” | “failure_halt” …

CapacityCheckpoint

Fields

turn_id: TurnId

step_idx: u32

kind: CapacityCheckpointKind

tokens_used: u32

token_budget: u32

action: CapacityAction

cooldown_blocked: bool

When true, a proposed guardrail was suppressed by cooldown (replay → Effect::Sleep).

CycleAdvanced

Fields

turn_id: TurnId

from_cycle: u32

to_cycle: u32

reason: String

Human-readable reason emitted by the LHT cycle-advance hook.

StepLimitContinuation

Fields

turn_id: TurnId

step_idx: u32

lht_objective_injected: bool

LoopGuardContinuation

Fields

turn_id: TurnId

step_idx: u32

DeferredToolActivated

A previously-deferred tool was promoted into the active tool set.

This event is emitted by maybe_activate_deferred_tool whenever the model requests a tool that was not yet active. It is necessary for Phase 3b: active_tool_names (host state) must be rebuildable from the log so that TurnMachine::step can be a pure function.

Fields

turn_id: TurnId

step_idx: u32

tool_name: String

Implementations

impl KernelEvent

pub fn turn_id(&self) -> Option<&str>

Extract the turn_id field present in every variant except KernelEvent::SchemaVersion.

pub fn kind_str(&self) -> &'static str

Variant name string for logging and schema drift CI.

Trait Implementations

impl Clone for KernelEvent

fn clone(&self) -> KernelEvent

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for KernelEvent

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

Formats the value using the given formatter.

impl<'de> Deserialize<'de> for KernelEvent

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

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl Serialize for KernelEvent

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

where __S: Serializer,

Serialize this value into the given Serde serializer.