Support Agent: Answer From Docs, Escalate via Email

import { agent, tool, Sandbox } from "@21st-sdk/agent"
import { z } from "zod"

export default agent({
  runtime: "claude-code",
  model: "claude-sonnet-4-6",
  permissionMode: "bypassPermissions",
  maxTurns: 25,

  systemPrompt: `You are a support agent. Answer questions using the product
documentation. When you cannot find an answer, offer to forward via email.

ESCALATION - when to use send_email:
- You searched thoroughly and could not find a relevant answer.
- The user explicitly asks to contact the team.
- The question involves account-specific issues or billing.

WORKFLOW:
1. Grep /workspace/llms.txt to find relevant pages.
2. Grep /workspace/llms-full.txt for detailed content.
3. Use fetch_doc_page if you need full page content.
4. If no answer found, ask to forward the question - then use send_email.`,

  sandbox: Sandbox({
    setup: [
      `mkdir -p /home/user/workspace && cd /home/user/workspace && \
if [ -n "$DOCS_URL" ]; then \
  BASE=$(echo "$DOCS_URL" | sed 's|/$||'); \
  curl -fsSL "$BASE/llms.txt" -o llms.txt 2>/dev/null || echo "# Could not fetch" > llms.txt; \
  curl -fsSL "$BASE/llms-full.txt" -o llms-full.txt 2>/dev/null || true; \
else \
  echo "# No DOCS_URL configured." > llms.txt; \
fi`,
    ],
  }),

  tools: {
    fetch_doc_page: tool({
      description: "Fetch a specific documentation page by URL.",
      inputSchema: z.object({ url: z.string().url() }),
      execute: async ({ url }) => {
        const res = await fetch(url, { signal: AbortSignal.timeout(15_000) })
        const text = await res.text()
        return { content: [{ type: "text", text: text.slice(0, 30_000) }] }
      },
    }),

    search_docs: tool({
      description: "Search local documentation files for a keyword.",
      inputSchema: z.object({
        query: z.string().min(1),
        file: z.enum(["llms.txt", "llms-full.txt"]).optional().default("llms-full.txt"),
      }),
      execute: async ({ query, file }) => {
        const { execSync } = await import("child_process")
        const result = execSync(
          `grep -i -n -C 5 ${JSON.stringify(query)} /home/user/workspace/${file} | head -200`,
          { encoding: "utf-8", timeout: 10_000 },
        )
        return { content: [{ type: "text", text: result || "No matches found." }] }
      },
    }),

    send_email: tool({
      description: "Escalate to support team via Resend. Use after confirming with the user.",
      inputSchema: z.object({
        subject: z.string().min(1),
        message: z.string().min(1),
        user_email: z.string().email().optional(),
      }),
      execute: async ({ subject, message, user_email }) => {
        const apiKey = process.env.RESEND_API_KEY
        const to = process.env.SUPPORT_EMAIL
        if (!apiKey || !to) {
          return { content: [{ type: "text", text: "RESEND_API_KEY or SUPPORT_EMAIL not configured." }], isError: true }
        }
        const res = await fetch("https://api.resend.com/emails", {
          method: "POST",
          headers: { Authorization: `Bearer ${apiKey}`, "Content-Type": "application/json" },
          body: JSON.stringify({
            from: process.env.RESEND_FROM_EMAIL || "onboarding@resend.dev",
            to: [to],
            subject: `[Support Agent] ${subject}`,
            text: user_email ? `${message}\n\n---\nUser: ${user_email}` : message,
            ...(user_email && { reply_to: user_email }),
          }),
          signal: AbortSignal.timeout(15_000),
        })
        const data = await res.json()
        return { content: [{ type: "text", text: res.ok ? `Email sent (id: ${data.id})` : "Failed to send." }] }
      },
    }),
  },
})