A syntax graph to find the change. Claude to make it. Your build to prove it.

import Anthropic from "@anthropic-ai/sdk";
import { graphTools, runTool, type CallSite } from "./graph-tools";

const claude = new Anthropic();
const MAX_TURNS = 12;

// One call site at a time: Claude plans with tools that read the syntax graph.
export async function planCallSite(site: CallSite, playbook: string) {
  const messages: Anthropic.MessageParam[] = [
    { role: "user", content: `Plan the edit for ${site.file}:${site.line}` },
  ];

  for (let turn = 0; turn < MAX_TURNS; turn++) {
    const response = await claude.messages.create({
      model: "claude-opus-5-5",
      max_tokens: 16000,
      thinking: { type: "adaptive" },
      output_config: { effort: "high" },
      // Tools render before the system prompt, so this breakpoint caches both:
      // they are identical for every call site in the run.
      system: [{ type: "text", text: playbook, cache_control: { type: "ephemeral" } }],
      tools: graphTools, // find_references, read_node, propose_edit (strict schemas)
      messages,
    });

    if (response.stop_reason !== "tool_use") return response;

    messages.push({ role: "assistant", content: response.content });
    const results = await Promise.all(
      response.content
        .filter((block) => block.type === "tool_use")
        .map(async (call) => ({
          type: "tool_result" as const,
          tool_use_id: call.id,
          content: await runTool(call.name, call.input),
        })),
    );
    messages.push({ role: "user", content: results });
  }
  throw new Error(`No plan for ${site.file}:${site.line} after ${MAX_TURNS} turns`);
}