AI Agent Development Guide
Email Verification Agent Skills
Agent skills are reusable capabilities AI agents invoke. BillionVerify gives Claude Code, OpenCode, Gemini CLI the ability to verify emails via natural language commands.
Get the BillionVerify Skill
Install the official skill from ClawHub or review the source on GitHub.
What an Email Verification Skill Must Do
A useful agent must distinguish a valid mailbox from an address that only looks correct.
BillionVerify handles mailbox checks and returns a clear status your agent can use without sending an email.
Syntax Checking Alone Fails
A valid format does not prove that the mailbox exists.
DNS/MX Checks Are Insufficient
MX records describe the domain, not the individual mailbox.
Most APIs Skip Real Verification
The agent needs a clear status it can branch on, not a guessed score.
Choose How Your Agent Connects
Use the official skill, the hosted MCP server, or the API behind your own tool.
Claude Code Agent Skills
Install the official skill or connect Claude Code to the hosted MCP server.
Gemini CLI Tool Use
Connect through MCP when supported, or expose the API as a tool.
Custom Agents
Wrap the REST API or MCP tools for any agent framework.
Design the Workflow, Not Just the Tool
Four rules keep automated verification predictable.
Handle All Result Types
Branch on valid, invalid, and unknown. Retry unknown only when the workflow can wait.
Batch When Possible
Send lists as batches instead of looping over single-email calls.
Respect Cache
Reuse recent results instead of verifying the same address repeatedly.
Monitor Credits
Check the balance before large jobs so the agent can stop cleanly.
Frequently Asked Questions
1. How do I add email verification to Claude Code?
For Claude Code, add the hosted MCP server with: claude mcp add --transport http billionverify https://mcp.billionverify.com/mcp. Then run /mcp and complete OAuth. If you need API-key automation, use the CLI or REST API.
2. How do I use this with Cursor or Windsurf?
Go to Settings > MCP in Cursor or Windsurf, add the billionverify config. Both editors natively support MCP for AI agent skills.
3. Which AI frameworks support email verification skills?
All major frameworks: Claude Agent SDK, LangChain, CrewAI, AutoGPT. MCP works with Claude Desktop, ChatGPT, DeepSeek, Kimi, plus coding tools like Cursor, Windsurf, Cline.
4. What are AI agent skills?
Agent skills are reusable capabilities AI agents invoke. BillionVerify gives Claude Code, OpenCode, Gemini CLI the ability to verify emails via natural language commands.
5. How does verification pricing work?
Valid and invalid results cost 1 credit. Only unknown results cost 0 credits. Start free with 100 credits, no credit card required.
Give Your Agent a Reliable Verification Step
Install the skill or connect through MCP and start with a real email workflow.
Real SMTP Verification · Native MCP Support · Fair Pricing