import type { AgentMiddleware } from '../create-agent.js';
import type { Workspace } from '../workspace.js';
/** Where `filesystemContext()` reads and writes: a `Workspace` or a `Sandbox`, or anything with the same file methods. */
export type FilesystemContextSource = Pick<Workspace, 'readFile'> & Partial<Pick<Workspace, 'writeFile' | 'listFiles'>>;
/** Where large tool results go instead of the transcript. */
export interface ContextOffloadOptions {
    /** Results longer than this, in characters, are offloaded. Defaults to 20,000. */
    overChars?: number;
    /** The directory they are written to, inside the source. Defaults to `.context`. */
    directory?: string;
    /** How much of a result stays in the transcript as a preview, in characters. Defaults to 1,000. */
    previewChars?: number;
    /** Tools whose results are never offloaded. Defaults to `read_file`, so reading one back cannot loop. */
    exclude?: readonly string[];
}
/** Options for `filesystemContext()`. */
export interface FilesystemContextOptions {
    /** Where files are read from and offloaded to. */
    source: FilesystemContextSource;
    /**
     * Files whose contents the model sees on every call, after the system prompt: project
     * instructions such as `AGENTS.md`, conventions, a glossary. A missing file is skipped.
     */
    include?: readonly string[];
    /** Lists a directory after the files, so the model knows what exists without a tool call. Needs `listFiles`. */
    listing?: {
        directory?: string;
        maxEntries?: number;
    };
    /** The most characters of included files, together. Defaults to 32,000; the rest is cut. */
    maxChars?: number;
    /** Writes large tool results to a file and leaves a preview and the path. Needs `writeFile`. */
    offload?: ContextOffloadOptions | boolean;
}
/**
 * The filesystem as the agent's context: files in, large results out.
 *
 * Instruction files reach the model on every call without a tool call, read once per run and placed
 * right after the system prompt, so the prefix a provider caches stays the same. A tool result too
 * large for the context is written to a file instead, and the model reads a preview and a path it can
 * open with `read_file` when it needs the rest: the transcript stays small however much a tool
 * returns, and nothing is lost.
 */
export declare function filesystemContext(options: FilesystemContextOptions): AgentMiddleware;