Claude Tool Use

Intercept Anthropic Claude tool_use blocks and route sensitive actions through Cheqpoint before executing them.

Install

npm install @cheqpoint/sdk @anthropic-ai/sdk

npm install @cheqpoint/sdk @anthropic-ai/sdk

Full agentic loop with Cheqpoint approval

TypeScript

import Anthropic from "@anthropic-ai/sdk";
import { CheqpointClient } from "@cheqpoint/sdk";

const client = new Anthropic();
const cheqpoint = new CheqpointClient({ apiKey: process.env.CHEQPOINT_API_KEY! });

const SENSITIVE_TOOLS = ["process_refund", "transfer_funds", "delete_record"];

async function runAgent(userMessage: string) {
  const messages: Anthropic.MessageParam[] = [{ role: "user", content: userMessage }];

  while (true) {
    const response = await client.messages.create({
      model: "claude-opus-4-6",
      max_tokens: 4096,
      tools: yourTools,
      messages,
    });

    if (response.stop_reason === "end_turn") {
      return response.content;
    }

    const toolUseBlocks = response.content.filter(b => b.type === "tool_use");
    const toolResults: Anthropic.ToolResultBlockParam[] = [];

    for (const block of toolUseBlocks) {
      if (block.type !== "tool_use") continue;

      let result: unknown;

      if (SENSITIVE_TOOLS.includes(block.name)) {
        const approval = await cheqpoint.checkpoint({
          action: block.name,
          summary: `Claude wants to call ${block.name}`,
          details: block.input as Record<string, unknown>,
          riskLevel: "high",
        });

        if (approval.status !== "APPROVED") {
          result = { error: `Action not approved: ${approval.decisionNote ?? "rejected"}` };
        } else {
          result = await executeTool(block.name, block.input);
        }
      } else {
        result = await executeTool(block.name, block.input);
      }

      toolResults.push({ type: "tool_result", tool_use_id: block.id, content: JSON.stringify(result) });
    }

    messages.push({ role: "assistant", content: response.content });
    messages.push({ role: "user", content: toolResults });
  }
}

import Anthropic from "@anthropic-ai/sdk";
import { CheqpointClient } from "@cheqpoint/sdk";

const client = new Anthropic();
const cheqpoint = new CheqpointClient({ apiKey: process.env.CHEQPOINT_API_KEY! });

const SENSITIVE_TOOLS = ["process_refund", "transfer_funds", "delete_record"];

async function runAgent(userMessage: string) {
  const messages: Anthropic.MessageParam[] = [{ role: "user", content: userMessage }];

  while (true) {
    const response = await client.messages.create({
      model: "claude-opus-4-6",
      max_tokens: 4096,
      tools: yourTools,
      messages,
    });

    if (response.stop_reason === "end_turn") {
      return response.content;
    }

    const toolUseBlocks = response.content.filter(b => b.type === "tool_use");
    const toolResults: Anthropic.ToolResultBlockParam[] = [];

    for (const block of toolUseBlocks) {
      if (block.type !== "tool_use") continue;

      let result: unknown;

      if (SENSITIVE_TOOLS.includes(block.name)) {
        const approval = await cheqpoint.checkpoint({
          action: block.name,
          summary: `Claude wants to call ${block.name}`,
          details: block.input as Record<string, unknown>,
          riskLevel: "high",
        });

        if (approval.status !== "APPROVED") {
          result = { error: `Action not approved: ${approval.decisionNote ?? "rejected"}` };
        } else {
          result = await executeTool(block.name, block.input);
        }
      } else {
        result = await executeTool(block.name, block.input);
      }

      toolResults.push({ type: "tool_result", tool_use_id: block.id, content: JSON.stringify(result) });
    }

    messages.push({ role: "assistant", content: response.content });
    messages.push({ role: "user", content: toolResults });
  }
}