/**
 * Largest attachment body copied into SQL `resources` for `read-attachment`.
 * Only text with no storage URL is copied; an upload keeps a reference and is
 * re-read from storage, so large file bodies stay out of SQL.
 */
export declare const MAX_ATTACHMENT_RESOURCE_BODY_CHARS = 1000000;
/** Total body copies one request may write into SQL. */
export declare const MAX_ATTACHMENT_RESOURCE_BODY_TOTAL_CHARS = 2000000;
export declare const ATTACHMENT_REFERENCE_MIME_TYPE = "application/vnd.agent-native.attachment-reference+json";
/** Most characters of one text attachment the prompt shows inline. */
export declare const MAX_INLINE_TEXT_ATTACHMENT_CHARS = 60000;
/** Most characters of all text attachments in one prompt. */
export declare const MAX_INLINE_TEXT_ATTACHMENTS_TOTAL_CHARS = 80000;
/**
 * Largest text or SVG file read on any path: browser reads, owned-URL
 * hydration and data URLs a caller sends directly all stop here.
 */
export declare const MAX_TEXT_ATTACHMENT_BYTES: number;
export declare function isTextLikeMimeType(contentType: string | undefined): boolean;
export declare function isTextLikeFilename(name: string | undefined): boolean;
export declare function isSvgTextAttachment(att: {
    name?: string;
    contentType?: string;
}): boolean;
/**
 * Unwraps the composer's envelope only when it names this very file, so a
 * stored or legacy upload that kept its wrapper reads as its body, while a
 * real document that merely looks like one is left as written. Every path
 * that reads attachment text uses this one function, so the prompt, the
 * stored copy and read-attachment offsets agree.
 */
export declare function unwrapOwnAttachmentEnvelope(text: string, name: string | undefined): string;
export type DecodedAttachmentText = {
    kind: "text";
    text: string;
} | {
    kind: "not-text";
} | {
    kind: "undecodable";
    mediaType: string;
    reason: "invalid-base64" | "not-utf8" | "too-large";
};
export declare function decodeTextAttachmentData(att: {
    name?: string | undefined;
    contentType?: string | undefined;
    data?: string | undefined;
}): DecodedAttachmentText;
/** Cuts at `end` without leaving half of a surrogate pair at the edge. */
export declare function sliceTextHead(text: string, end: number): string;
/**
 * The one size check for text attachments, whether the bytes arrive as a data
 * URL or as composer text. Pre-upload runs it before encoding or uploading,
 * and the prompt and persistence run it so all three agree the file is too
 * large.
 */
export declare function isOverTextAttachmentLimit(att: {
    name?: string | undefined;
    contentType?: string | undefined;
    data?: string | undefined;
    text?: string | undefined;
}): boolean;
export type TextAttachmentStorage = {
    kind: "stored";
    resourceId: string;
    path: string;
    totalChars: number;
} | {
    kind: "failed";
    reason: "too-large" | "write-failed";
    error?: string;
};