/**
 * Context formatter — converts engram observations into an XML context block
 * suitable for injection into agent prompts.
 *
 * Faithfully ported from plugin/engram/hooks/user-prompt.js with TypeScript types.
 */
import type { Observation, RuleRouterPayload } from '../client.js';
interface FormatterOptions {
    /** Token budget (~4 chars per token). Default: 2000. */
    tokenBudget?: number;
}
export interface FormatResult {
    /** Formatted XML context string, or empty string if nothing to inject. */
    context: string;
    /** IDs of observations that made it into the context (after dedup + budget trim). */
    injectedIds: number[];
    /** Number of observations trimmed by token budget. */
    trimmedCount: number;
}
/**
 * Format always_inject observations into a compact behavioral rules block.
 *
 * These are observations marked always_inject=true on the server. They represent
 * standing behavioral rules (e.g., "always use X", "never do Y") that must be
 * injected into every turn regardless of query relevance.
 *
 * Rendered as a lightweight XML block separate from the main engram-context so
 * the agent can distinguish standing rules from query-matched knowledge.
 *
 * @param observations - The always_inject observations from the search response.
 * @returns            A non-empty XML block string, or '' if nothing to render.
 */
export declare function formatAlwaysInject(observations: Observation[]): string;
/**
 * Format bounded rule-router packets. Router-mode packets are already selected
 * by the server and must not be relabeled as legacy always-active rules.
 */
export declare function formatRuleRouter(router?: RuleRouterPayload | null): string;
export declare function isRouterPayloadEnabled(router?: RuleRouterPayload | null): boolean;
/**
 * Format an array of engram observations into an XML context block.
 *
 * Steps:
 *   1. Filter credentials
 *   2. Sort by similarity (descending)
 *   3. Jaccard dedup (>0.8 title word overlap)
 *   4. Group by type (decisions → patterns → changes → general)
 *   5. Apply token budget
 *   6. Re-group and render XML
 */
export declare function formatContext(observations: Observation[], options?: FormatterOptions): FormatResult;
export declare function safePromptScalar(value: unknown): string;
export declare function quotedPromptScalar(value: unknown): string;
export declare function safePromptPayload(value: unknown): string;
export declare function quotedPromptPayload(value: unknown): string;
export {};
//# sourceMappingURL=formatter.d.ts.map