agent-toolbelt

Instructions

Implementation Reference

• mcp-server/src/index.ts:233-285 (handler)

  Registration and handler implementation for the 'build_regex' tool. It calls the 'regex-builder' endpoint of the Agent Toolbelt API.

  server.registerTool(
    "build_regex",
    {
      title: "Regex Builder & Tester",
      description:
        "Build and test regular expressions from natural language descriptions. " +
        "Supports emails, URLs, phones, dates, IPs, colors, UUIDs, and 15+ more patterns. " +
        "Returns the pattern, code snippets in JS/Python/TS, and optional test results.",
      inputSchema: {
        description: z
          .string()
          .describe("What to match (e.g., 'email addresses', 'hex color codes', 'semantic versions')"),
        testStrings: z
          .array(z.string())
          .optional()
          .describe("Optional strings to test the regex against"),
        flags: z
          .string()
          .default("g")
          .describe("Regex flags (default: 'g')"),
      },
    },
    async ({ description, testStrings, flags }) => {
      const result = await callToolApi("regex-builder", { description, testStrings, flags });
      const data = result as any;
      const r = data.result;
  
      const lines = [
        `**Pattern:** \`${r.regexLiteral}\``,
        `**Description:** ${r.description}`,
        "",
        "**Code snippets:**",
        "```javascript",
        r.codeSnippets.javascript,
        "```",
        "```python",
        r.codeSnippets.python,
        "```",
      ];
  
      if (r.testResults) {
        lines.push("", "**Test results:**");
        for (const t of r.testResults) {
          const status = t.matched ? "✓" : "✗";
          lines.push(`  ${status} "${t.input}" → ${t.matched ? t.matches.join(", ") : "no match"}`);
        }
      }
  
      return {
        content: [{ type: "text" as const, text: lines.join("\n") }],
      };
    }
  );