Enum UiEvent 

pub enum UiEvent {
    AgentTurnStarted,
    AgentThinking,
    AgentTextDelta(String),
    AgentThinkingDelta(String),
    ThinkingComplete {
        text: String,
    },
    AgentMessageComplete(String),
    ToolCallStarted {
        id: String,
        name: String,
        args: Value,
    },
    ToolCallProgress {
        id: String,
        chunk: ProgressChunk,
    },
    ToolCallCompleted {
        id: String,
        result: UiToolResult,
    },
    AgentTurnComplete,
    TurnStats {
        input_tokens: u64,
        output_tokens: u64,
        cumulative_input: u64,
        cumulative_output: u64,
        model: String,
    },
    PermissionRequested {
        tool: String,
        args: Value,
        resolver: Sender<Decision>,
    },
    PermissionModeChanged {
        mode: PermissionMode,
    },
    InlineBashOutput {
        command: String,
        output: String,
    },
    SessionReplaced {
        session_id: String,
        history: Vec<Message>,
    },
    ModelSwitched(ModelId),
    ForkCandidates(Vec<(String, String)>),
    BranchTree(BranchTree),
    MessagesSnapshot(Vec<Message>),
    StateSnapshot {
        session_id: String,
        model: String,
        active_turn: bool,
    },
    ExtensionList {
        extensions: Vec<ExtensionInfo>,
    },
    SettingsSnapshot {
        settings: Settings,
    },
    Error(String),
    AttachmentError {
        kind: AttachmentErrorKind,
        message: String,
    },
    ExtensionCancelled {
        extension_name: String,
        reason: Option<String>,
    },
    Notice {
        title: String,
        body: String,
    },
}

Variants

AgentTurnStarted

AgentThinking

AgentTextDelta(String)

AgentThinkingDelta(String)

Mid-stream extended-thinking delta from the LLM. Anthropic-only at the wire level (motosan-ai 0.15.4 emits thinking events for the Anthropic provider only). Each delta is a partial chunk; the TUI accumulates them into an InFlight::StreamingThinking block and finalizes on the matching UiEvent::ThinkingComplete. A turn may emit zero or more AgentThinkingDeltas before a single ThinkingComplete; deltas always precede any AgentTextDelta for the same turn.

ThinkingComplete

v0.9 Phase A: emitted by capo-agent after each AssistantContent::Reasoning (thinking/chain-of-thought) ContentPart is observed in a completed assistant Message. Fires BEFORE AgentMessageComplete for the same turn so the TUI’s transcript order is: thinking → text. Multiple thinking phases per turn produce multiple events in stream order. See spec §3.5.

Dual source (since v0.11): this variant has two emitters in capo-agent::app::run_turn:

1. Streaming path — CoreEvent::ThinkingDone maps directly to ThinkingComplete via map_event (Anthropic-only). When live this is preceded by zero or more AgentThinkingDeltas.
2. Post-turn walker path — extract_new_thinking_events walks AssistantContent::Reasoning in the just-finished turn’s messages and emits one ThinkingComplete per part. Used for backends that don’t stream thinking (everything non-Anthropic under motosan-ai 0.15.4 today).

A per-turn streamed_thinking_seen flag ensures only one of the two paths fires for a given turn. The TUI distinguishes the two sources implicitly: if in_flight is StreamingThinking when this event arrives, it’s streamed (collapse default = true); otherwise it’s walker-sourced (collapse default = false, preserving pre-v0.11 UX for non-Anthropic users).

Fields

text: String

AgentMessageComplete(String)

ToolCallStarted

Fields

id: String

name: String

args: Value

ToolCallProgress

Fields

id: String

chunk: ProgressChunk

ToolCallCompleted

Fields

id: String

result: UiToolResult

AgentTurnComplete

TurnStats

Token-count summary emitted after each LLM chat call. Cumulative fields carry the running total for this session. Per-turn deltas (input_tokens / output_tokens) are the increment from THIS turn — 0 if the provider didn’t surface counts (CLI shells may not). See spec §3.1.

Fields

input_tokens: u64

output_tokens: u64

cumulative_input: u64

cumulative_output: u64

model: String

PermissionRequested

Fields

tool: String

args: Value

resolver: Sender<Decision>

PermissionModeChanged

v0.10 Phase A: permission mode changed (Shift+Tab in TUI, –mode CLI flag at startup, or Command::SetPermissionMode RPC). RPC clients with strict UiEvent dispatchers need a new arm.

Fields

mode: PermissionMode

InlineBashOutput

Output of a !!cmd inline-bash run, for transcript display.

Fields

command: String

output: String

SessionReplaced

The session was replaced (/new cleared it, or /resume loaded a stored one). Carries the new session ID + transcript so the TUI can rebuild state.messages and detect same-session rebuilds.

v0.10 Phase B-2: BREAKING wire change from payload [...] to payload { "session_id": "...", "history": [...] }.

Fields

session_id: String

history: Vec<Message>

ModelSwitched(ModelId)

The active model changed successfully.

ForkCandidates(Vec<(String, String)>)

Refreshed /fork candidate list (active-branch user messages, newest first) — (EntryId, preview) pairs. The binary emits this at startup and after every turn so the picker is never stale.

BranchTree(BranchTree)

Refreshed session branch tree — the binary emits this at startup and after every turn so the /tree view is never stale.

MessagesSnapshot(Vec<Message>)

Reply to Command::GetMessages — the session’s persisted message history. RPC clients use this to snapshot transcript state.

StateSnapshot

Reply to Command::GetState — a small status snapshot for RPC clients (the TUI holds these in AppState so does not need it).

Fields

session_id: String

model: String

active_turn: bool

ExtensionList

Reply to Command::ListExtensions — the registered extensions

• per-extension health status.

Fields

extensions: Vec<ExtensionInfo>

SettingsSnapshot

Snapshot of the current settings. Emitted by the binary at startup and after every successful ApplySettings / ReloadSettings so the TUI can update state.settings_snapshot. RPC clients can also consume this to observe live settings changes.

Fields

settings: Settings

Error(String)

AttachmentError

Emitted when an attachment in a UserMessage failed validation (path missing, unsupported extension, oversize, unreadable). No turn is started; the agent stays in Idle. See spec §3 / §4.4.

Fields

kind: AttachmentErrorKind

message: String

ExtensionCancelled

An extension cancelled a before_user_message or session_before_switch hook. The TUI rolls back any optimistic transcript push (via state.pending_turn_submit) and restores the composer buffer. See spec §4.4.

Fields

extension_name: String

reason: Option<String>

Notice

Surface a transcript notice from an extension reply action, /image errors, or other non-fatal informational events.

Fields

title: String

body: String

Trait Implementations

impl Debug for UiEvent

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

Formats the value using the given formatter.

impl Serialize for UiEvent

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

where __S: Serializer,

Serialize this value into the given Serde serializer.