/**
 * Immutable graph query and mutation utilities for investigation taskflow graphs.
 * All mutation functions return new objects — input graphs are never mutated.
 */
import type { Edge, Node, TaskFlowGraph, ValidationResult } from './types.js';
export declare function findNodeById(graph: TaskFlowGraph, nodeId: string): Node | undefined;
export declare function findEdgeById(graph: TaskFlowGraph, edgeId: string): Edge | undefined;
export declare function findEdgeByEndpoints(graph: TaskFlowGraph, source: string, target: string, sourceOutputIndex?: number): Edge | undefined;
export declare function getIncomingEdges(graph: TaskFlowGraph, nodeId: string): Edge[];
export declare function getOutgoingEdges(graph: TaskFlowGraph, nodeId: string): Edge[];
export declare function getPredecessors(graph: TaskFlowGraph, nodeId: string): Node[];
export declare function getSuccessors(graph: TaskFlowGraph, nodeId: string): Node[];
export declare function addNode(graph: TaskFlowGraph, node: Node): TaskFlowGraph;
export declare function removeNode(graph: TaskFlowGraph, nodeId: string, options?: {
    reconnect?: boolean;
}): {
    edges: Edge[];
    graph: TaskFlowGraph;
};
export declare function updateNode(graph: TaskFlowGraph, nodeId: string, updates: Partial<Node>): TaskFlowGraph;
export declare function addEdge(graph: TaskFlowGraph, edge: Edge): TaskFlowGraph;
export declare function removeEdge(graph: TaskFlowGraph, edgeId: string): TaskFlowGraph;
export declare function validateGraph(graph: TaskFlowGraph): ValidationResult;