Method handleImpact

src/mcp/tools.ts:1680–1739

* Handle codegraph_impact

(args: Record<string, unknown>)

   * Handle codegraph_impact
   */
  private async handleImpact(args: Record<string, unknown>): Promise<ToolResult> {
    const symbol = this.validateString(args.symbol, 'symbol');
    if (typeof symbol !== 'string') return symbol;

    const cg = this.getCodeGraph(args.projectPath as string | undefined);
    const depth = clamp((args.depth as number) || 2, 1, 10);
    const fileFilter = typeof args.file === 'string' ? args.file : undefined;

    const allMatches = this.findAllSymbols(cg, symbol);
    if (allMatches.nodes.length === 0) {
      return this.textResult(`Symbol "${symbol}" not found in the codebase`);
    }

    const { groups, filteredOut } = this.groupDefinitions(allMatches.nodes, fileFilter);
    const filterNote = filteredOut
      ? `\n\n> **Note:** no definition of "${symbol}" matches file "${fileFilter}" — showing all definitions instead.`
      : '';

    const impactOf = (defNodes: Node[]) => {
      const mergedNodes = new Map<string, Node>();
      const mergedEdges: Edge[] = [];
      const seenEdges = new Set<string>();
      for (const node of defNodes) {
        const impact = cg.getImpactRadius(node.id, depth);
        for (const [id, n] of impact.nodes) {
          mergedNodes.set(id, n);
        }
        for (const e of impact.edges) {
          const key = `${e.source}->${e.target}:${e.kind}`;
          if (!seenEdges.has(key)) {
            seenEdges.add(key);
            mergedEdges.push(e);
          }
        }
      }
      return { nodes: mergedNodes, edges: mergedEdges, roots: defNodes.map((n) => n.id) };
    };

    // Single definition (or same-file overloads): the familiar merged report.
    if (groups.length === 1) {
      const formatted = this.formatImpact(symbol, impactOf(groups[0]!)) + (fileFilter && !filteredOut ? "" : allMatches.note) + filterNote;
      return this.textResult(this.truncateOutput(formatted));
    }

    // Multiple DISTINCT definitions (#764): a blast radius PER definition —
    // merging unrelated same-named classes (one UserService per monorepo app)
    // overstated impact and confused agents. Narrow with `file`.
    const sections: string[] = [
      `**Impact of ${symbol} — ${groups.length} distinct definitions (each with its own blast radius; narrow with \`file\`)**`,
    ];
    for (const group of groups) {
      const head = group[0]!;
      const line = head.startLine ? `:${head.startLine}` : '';
      sections.push(
        '',
        this.formatImpact(`${head.qualifiedName} (${head.filePath}${line})`, impactOf(group))
      );
    }