import type { CallToolResult } from "@modelcontextprotocol/sdk/types.js";
/**
 * Lightweight read-only mode (issue #154) — an interim, additive gate that
 * blocks all mutation without the structural read/write/destroy refactor
 * (#106, deferred to 0.5.0).
 *
 * Strategy: fail-closed allowlist. Only a small, stable set of read actions
 * is permitted; everything else is denied by default, so a new/renamed/
 * unknown action can never "escape" the gate.
 */
/** The only actions allowed to execute in read-only mode. */
export declare const READ_ACTIONS: ReadonlySet<string>;
export declare function isReadOnlyMode(raw?: string | undefined): boolean;
export declare function manageHasMutatingFields(params: Record<string, unknown>): boolean;
/**
 * Structured rejection returned instead of executing a blocked action.
 * Not an error — a controlled refusal, in the pass-through/structured style
 * of the rest of the server (no prose message).
 */
export declare function readOnlyRejection(action: string): CallToolResult;
/**
 * Best-effort extraction of an `action` enum's options from a tool's Zod
 * schema, tolerant of ZodDefault/ZodOptional wrappers and zod-version shape
 * differences. Returns null when there is no `action` param or introspection
 * fails — callers treat null conservatively.
 */
export declare function getActionOptions(schema: unknown): string[] | null;
export type ReadOnlyClass = "read" | "gated" | "mutation";
/**
 * Classifies a tool for read-only mode:
 *  - "read"     — declares readOnlyHint, always exposed.
 *  - "gated"    — multi-action tool with at least one read action (or
 *                 `manage`); stays registered, gated per-action at dispatch.
 *  - "mutation" — single-purpose write/destroy tool; skipped in read-only.
 */
export declare function classifyTool(readOnlyHint: boolean | undefined, actionOptions: string[] | null): ReadOnlyClass;
/** Duck-typed access to a tool's read-only classification. */
export declare function toolReadOnlyClass(tool: unknown): ReadOnlyClass;
/**
 * Drops single-purpose mutation tools in read-only mode, keeping read and
 * gated tools. Returns the kept tools plus per-class counts for logging.
 */
export declare function applyReadOnlyFilter(tools: Tool[]): {
    tools: Tool[];
    read: number;
    gated: number;
    skipped: number;
};
export declare function readOnlySummary(read: number, gated: number, skipped: number): string;
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