import type { ContextBlock, InputAssemblyLayout, Message, ProviderRequest, Skill, TokenEstimate, ToolDefinition } from "./contracts.js";
import { type LoadedSkillSet, type SkillRenderContext, type SkillsDisclosure } from "./skill-disclosure.js";
/**
 * Host-supplied token estimator. Budget-only: it never reaches billing, provider
 * usage, or the wire — it decides what the assembler evicts and nothing else.
 */
export type TokenEstimator = (text: string) => number;
/** Assembler-time input budget. At least one max required when present. */
export interface ContextBudget {
    readonly maxInputTokens?: number;
    readonly maxInputBytes?: number;
    readonly reportOmissions?: boolean;
    /**
     * Overrides the built-in UTF-16/4 heuristic for eviction accounting. Must return a
     * non-negative finite token count (a NaN/negative/absent return fails the assembly
     * closed with a `TypeError`). Byte caps are estimator-independent and always enforced.
     */
    readonly tokenEstimator?: TokenEstimator;
}
export type ContextBudgetOmissionKind = "skills" | "skill_body" | "context" | "history" | "tool_results" | "summaries" | "attachments" | "tools";
export interface ContextBudgetOmission {
    readonly kind: ContextBudgetOmissionKind;
    readonly id?: string;
    readonly tokenEstimate: number;
    readonly byteLength: number;
}
export interface ContextBudgetReport {
    readonly omitted: readonly ContextBudgetOmission[];
    readonly keptTokens: number;
    readonly keptBytes: number;
    readonly maxInputTokens?: number;
    readonly maxInputBytes?: number;
    readonly truncated: boolean;
}
export interface ContextBudgetMessageGroups {
    readonly instructions: readonly Message[];
    readonly summaries: readonly Message[];
    readonly history: readonly Message[];
    readonly input: readonly Message[];
    readonly attachments: readonly Message[];
    readonly toolResults: readonly Message[];
}
export declare const CONTEXT_BUDGET_REPORT_METADATA_KEY: "contextBudgetReport";
export declare const HARD_MAX_CONTEXT_BUDGET_TOKENS = 2000000;
export declare const HARD_MAX_CONTEXT_BUDGET_BYTES: number;
export declare const DEFAULT_MAX_CONTEXT_BUDGET_OMISSIONS = 256;
export declare const HARD_MAX_CONTEXT_BUDGET_OMISSIONS = 1024;
export declare const CONTEXT_BUDGET_ERROR_CODE: "context_budget_exceeded";
export declare class ContextBudgetError extends Error {
    readonly code: "context_budget_exceeded";
    constructor(message?: string);
}
export declare function isContextBudgetError(error: unknown): error is ContextBudgetError;
/** UTF-16 code units / 4. Estimate only — not billing. */
export declare function estimateTextTokens(text: string): number;
export declare function estimateTextBytes(text: string): number;
export declare function estimateMessageTokens(message: Message, estimateTokens?: TokenEstimator): number;
export declare function estimateMessageTokens(messages: readonly Message[], modelFamily?: string): TokenEstimate;
export declare function estimateMessageBytes(message: Message): number;
export declare function estimateAssemblyTokens(messages: readonly Message[]): number;
export declare function resolveContextBudget(budget: ContextBudget): Required<Pick<ContextBudget, "reportOmissions">> & ContextBudget;
export declare function getContextBudgetReport(request: ProviderRequest): ContextBudgetReport | undefined;
export declare function applyContextBudget(options: {
    readonly groups: ContextBudgetMessageGroups;
    readonly context?: readonly ContextBlock[];
    readonly skills?: readonly Skill[];
    readonly tools?: readonly ToolDefinition[];
    readonly budget: ContextBudget;
    readonly layout?: InputAssemblyLayout;
    readonly skillsDisclosure?: SkillsDisclosure;
    readonly loadedSkills?: LoadedSkillSet;
}): {
    readonly groups: ContextBudgetMessageGroups;
    readonly context: readonly ContextBlock[];
    readonly skills: readonly Skill[];
    readonly tools: readonly ToolDefinition[] | undefined;
    readonly demotedSkillBodies: readonly string[];
    readonly report: ContextBudgetReport;
};
/** Everything the assembler will send, in the order it will send it. */
export interface MeasureInputCostOptions {
    readonly groups: ContextBudgetMessageGroups;
    readonly context?: readonly ContextBlock[];
    readonly skills?: readonly Skill[];
    readonly tools?: readonly ToolDefinition[];
    readonly skillContext?: SkillRenderContext;
    readonly demotedBodies?: ReadonlySet<string>;
    readonly estimateTokens?: TokenEstimator;
}
/**
 * One O(n) cost measurement of the whole request (groups, context, skills, tool declarations).
 * Shared with the attention-compiler gate, which measures once per turn and then subtracts a
 * per-mutation delta instead of re-measuring — the same trick `applyContextBudget` uses.
 */
export declare function measureInputCost(options: MeasureInputCostOptions): {
    tokens: number;
    bytes: number;
};
/** Plan 103 T6: the host's `contextBudget.tokenEstimator`, validated exactly like the budget pass
 * validates it (a non-function, or a non-finite/negative count, fails closed with `TypeError`).
 * `undefined` when no host estimator is configured, so callers can fall through to the built-in
 * heuristic. Exported for the usage seam (`provider-round.ts`) — deliberately not re-exported by
 * `src/index.ts`, so the public surface is unchanged. */
export declare function resolveHostTokenEstimator(budget: ContextBudget | undefined): TokenEstimator | undefined;
/** Plan 103 T6: tool declarations and context blocks projected with the assembler's own
 * `measureAll` text shapes, so the usage-fallback estimate and the budget pass cannot drift
 * (never `JSON.stringify` of the raw schemas). Exported for the usage seam — deliberately not
 * re-exported by `src/index.ts`. */
export declare function estimateRequestExtrasTokens(tools: readonly ToolDefinition[] | undefined, context: readonly ContextBlock[] | undefined, estimateTokens: TokenEstimator): number;