return Math.max(1, opts?.maxToolResultChars ?? DEFAULT_MAX_LIVE_TOOL_RESULT_CHARS);

}

type UserAgentMessage = Extract<AgentMessage, { role: "user" }>;

function isUserAgentMessage(message: AgentMessage): message is UserAgentMessage {

return message.role === "user";

}

// `details` is runtime/UI metadata, not model-visible tool output. Keep the

// session JSONL useful for debugging without letting metadata blobs dominate

// disk, replay repair, transcript broadcasts, or future tooling that reads raw

event: PluginHookBeforeMessageWriteEvent,

) => PluginHookBeforeMessageWriteResult | undefined;

maxToolResultChars?: number;

suppressNextUserMessagePersistence?: boolean;

onUserMessagePersisted?: (

message: Extract<AgentMessage, { role: "user" }>,

) => void | Promise<void>;

},

): {

flushPendingToolResults: () => void;

const missingToolResultText = opts?.missingToolResultText;

const beforeWrite = opts?.beforeMessageWriteHook;

const maxToolResultChars = resolveMaxToolResultChars(opts);

let suppressNextUserMessagePersistence = opts?.suppressNextUserMessagePersistence === true;

/**

* Run the before_message_write hook. Returns the (possibly modified) message,

if (!finalMessage) {

return undefined;

}

if (isUserAgentMessage(finalMessage) && suppressNextUserMessagePersistence) {

suppressNextUserMessagePersistence = false;

return undefined;

}

const result = originalAppend(finalMessage as never);

const sessionFile = (

if (toolCalls.length > 0) {

pendingState.trackToolCalls(toolCalls);

}

if (isUserAgentMessage(finalMessage)) {

void opts?.onUserMessagePersisted?.(finalMessage);

}

return result;

};