/**
 * A one-line context header prepended to a HUMAN prompt before it reaches the
 * TUI: the platform it came from, the time, and who sent it (when we know —
 * Telegram tells us, the web usually doesn't). The agent SEES it (useful
 * context — nothing else told it who is talking, or that a message arrived at
 * 3am), but the transcript display STRIPS it, the same way a cron mark is
 * hidden. Difference with the cron/agent marks: those hide the WHOLE message
 * (it is machine-written); here only the header line goes, the message stays.
 *
 * Not added for the terminal view (raw keystrokes bypass the prompt handler)
 * nor for cron/agent prompts (already marked, and not "someone speaking").
 *
 * The header is wrapped in ⟦ ⟧ (U+27E6/U+27E7 — rare in ordinary typing) and
 * always carries a " · " separator, so the strip almost never fires on a line a
 * user actually wrote. Same strict, opens-the-message rule as the other marks.
 */
export declare const META_OPEN = "\u27E6";
export declare const META_CLOSE = "\u27E7";
/** "2026-08-25 14:30" in the given IANA zone (machine zone when omitted). */
export declare function formatWhen(at: Date, timeZone?: string): string;
/** Build the header line: ⟦platform · time [· who]⟧. */
export declare function promptMetaHeader(platform: string, at: Date, who?: string, timeZone?: string): string;
/** Does this text already open with a context header? (idempotence + strip.) */
export declare function hasPromptMeta(text: string): boolean;
/**
 * Parse a leading context header into its fields, or null if there is none.
 * `who` is often empty (the web usually sends no sender name; Telegram does).
 * The name is taken as everything past the time, so a name that itself contains
 * " · " survives. Lets a replayed history restore who spoke — otherwise a
 * Telegram message came back as the generic "pilot", its sender lost with the
 * stripped header.
 */
export declare function parsePromptMeta(text: string): {
    platform: string;
    who: string;
} | null;
/** Prepend the header as its own first line. Idempotent. */
export declare function markPromptMeta(text: string, header: string): string;
/** Remove a leading context header (and only that line); a plain message is
 *  returned untouched. */
export declare function stripPromptMeta(text: string): string;