export declare const ATRIB_CONTEXT_ID_ENV = "ATRIB_CONTEXT_ID";
export interface BuildSubagentProducerEnvOptions {
    /** Parent session context_id for same-session subagents. */
    contextId?: string | undefined;
    /** Signed parent dispatch record hash, `sha256:<64-hex>`. */
    parentRecordHash?: string | undefined;
    /**
     * Chain tail the child should inherit. Defaults to parentRecordHash when the
     * parent dispatch record is also the latest known tail.
     */
    chainTailRecordHash?: string | undefined;
    /** Existing env to copy before adding atrib handoff values. */
    baseEnv?: Record<string, string | undefined> | undefined;
}
/**
 * Return the per-context chain-tail env var name, or undefined for invalid ids.
 */
export declare function chainTailEnvName(contextId: string): string | undefined;
/**
 * Build the canonical env bundle for spawning a child producer.
 *
 * Invalid context ids or record hashes are omitted rather than throwing. This
 * preserves atrib's degradation contract: a bad attribution hint must not block
 * the subagent from running.
 */
export declare function buildSubagentProducerEnv(opts: BuildSubagentProducerEnvOptions): Record<string, string>;
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