/**
 * Zoe Middleware Pipeline
 *
 * Composable middleware chain that wraps `runAgentLoop`.
 * Follows the `(ctx, next) => Promise<void>` pattern for cross-cutting
 * concerns like logging, rate limiting, and auth.
 */
import type { Message, Usage, StepResult, ToolCall } from "./types.js";
import type { LLMProvider } from "../providers/types.js";
import type { ToolDefinition } from "../tools/interface.js";
export interface PipelineContext {
    /** Unique ID for this request */
    requestId: string;
    /** Input messages (mutable — middleware can inspect or modify) */
    messages: Message[];
    /** Resolved provider */
    provider: LLMProvider;
    /** Model identifier */
    model: string;
    /** Tool definitions available for this request */
    toolDefs: ToolDefinition[];
    /** Adapter-specific metadata (e.g., userId, source) */
    metadata: Record<string, unknown>;
    /** Result populated after the loop runs */
    result?: {
        messages: Message[];
        steps: StepResult[];
        toolCalls: ToolCall[];
        usage: Usage;
        finishReason: string;
    };
    /** Abort signal */
    signal?: AbortSignal;
    /** Timestamp when the pipeline started */
    startedAt: number;
}
export type Middleware = (ctx: PipelineContext, next: () => Promise<void>) => Promise<void>;
/**
 * Compose an array of middleware into a single function.
 *
 * Each middleware receives `(ctx, next)`. Calling `next()` invokes the
 * next middleware in the chain (or the final handler if last). Errors
 * propagate upward so callers can handle them (e.g., auth rejection).
 *
 * @param middlewares - Ordered list of middleware functions
 * @returns A function that runs the full chain
 */
export declare function compose(middlewares: Middleware[]): (ctx: PipelineContext, finalHandler: () => Promise<void>) => Promise<void>;