MCP guide
Connect LookValid to Claude
Claude can run phone, email, IP, domain and website lookups through the LookValid MCP server. The free tools work with no key. Everything else works with an API key or a browser sign-in.
Server addresses
| Use | Address |
|---|---|
| Free tools, or every tool with a key | https://YOUR_API_HOST/v1/mcp |
| Browser sign-in (OAuth) | https://YOUR_API_HOST/v1/mcp/oauth |
The free tools need no key: 25 lookups per day and 5 per 60 seconds from one address, shared with the free tools on the website. Everything else needs an API key or a sign-in.
Set it up in four steps
1. Choose how Claude signs in
For the free tools you need nothing: connect to https://YOUR_API_HOST/v1/mcp with no header. For every product, either create an API key in the dashboard and keep it in an environment variable named LOOKVALID_API_KEY, or use the sign-in address https://YOUR_API_HOST/v1/mcp/oauth and approve the app in your browser.
Claude Code does not fall back to sign-in when you set an Authorization header, so pick one of the two.
2. Add the server in Claude Code
Run one of these once in a terminal. Claude Code stores the server in its configuration.
With an API key
claude mcp add --transport http lookvalid https://YOUR_API_HOST/v1/mcp --header "Authorization: Bearer $LOOKVALID_API_KEY"
With sign-in (OAuth)
claude mcp add --transport http lookvalid https://YOUR_API_HOST/v1/mcp/oauth
Free tools only
claude mcp add --transport http lookvalid https://YOUR_API_HOST/v1/mcp
3. Check the connection
Run /mcp inside Claude Code. LookValid should appear in the list. A server with bad credentials shows a failure that includes the HTTP status, for example 401. If you used the sign-in address, choose LookValid there and follow the browser steps.
Inside Claude Code
/mcp
4. Or add a custom connector in the Claude apps
The Claude apps take remote servers as custom connectors, added at claude.ai/customize/connectors. Use the sign-in address https://YOUR_API_HOST/v1/mcp/oauth as the server address and approve the app in your browser. On Team and Enterprise plans only an admin can add one. Connectors you add there also appear in Claude Code when you are logged in with a claude.ai account.
Tools the server advertises
| Tool | Product | Needs a key or sign-in |
|---|---|---|
| phone | Phone Numbering-Plan Validation | No, free tool |
| country_code | Country Calling Codes | No, free tool |
| email_domain_check | Email Domain Check | No, free tool |
| ip | IP Intelligence | No, free tool |
| phone_spam | Phone Spam Check | No, free tool |
| link_safety | Link Safety Check | No, free tool |
| carrier_lookup | Carrier Lookup (original carrier) | No, free tool |
| vin_decoder | VIN Decoder | No, free tool |
| link_in_bio_lookup | Link-in-Bio Lookup | No, free tool |
| domain_authority | Domain Authority | No, free tool |
| domain_age | Domain Age | No, free tool |
| website_contacts_scraper | Website Contacts Scraper | No, free tool |
| site_files | Site Files Checker | No, free tool |
| website_scraper | Website Scraper | Yes |
| get_account | Account balance and keys | Yes |
Without a key the server lists only the free tools. Prices are on the pricing page.
Prompts to try
- Where is the IP address 8.8.8.8 located, and does it belong to a hosting provider?
- Check the email setup of example.com: does it have mail servers, SPF and DMARC?
- How old is the domain example.com and who is its registrar?
- Decode this VIN and tell me the make, model and model year: 1HGCM82633A004352.
- Is the number +12025550143 formatted correctly, and what type of number does its numbering plan give it?
- What is my LookValid credit balance?
Troubleshooting
HTTP 401, or the server shows as failed in the client
The key is missing, mistyped or revoked, or you connected to the sign-in address (https://YOUR_API_HOST/v1/mcp/oauth) without signing in. That address always answers 401 until a sign-in finishes. A wrong key is never quietly downgraded to the free tools.
Check that Claude Code sends "Authorization: Bearer <key>" with a live key from the dashboard, or finish the browser sign-in. To use only the free tools, connect to https://YOUR_API_HOST/v1/mcp with no header.
HTTP 429 or a rate_limited tool error
Without a key, the free tools allow 25 lookups per day and 5 per 60 seconds from one address, shared with the free tools on the website. A key has its own per-key limit.
Wait for the number of seconds in the error, which is also sent as a Retry-After header, or add a key. Listing the tools never uses the allowance.
HTTP 503 or a provider_unavailable tool error
The data behind that lookup is not available to the server right now. Nothing was charged.
Retry later, or try another tool. The error body says whether it is retryable.
A tool error says the connection was not given a permission
You signed in but unticked "Run lookups" or "Read your balance and keys" on the approval page.
Disconnect the app under Connected apps in the dashboard (https://lookvalid.com/dashboard/apps), then connect again and approve both permissions.
Every error follows the standard error format.
Questions
Do I need an account to try it in Claude?
No. Connect Claude Code to https://YOUR_API_HOST/v1/mcp with no header and the free tools (phone, country_code, email_domain_check, ip, phone_spam, link_safety, carrier_lookup, vin_decoder, link_in_bio_lookup, domain_authority, domain_age, website_contacts_scraper, site_files) work with no account, limited to 25 lookups per day and 5 per 60 seconds from one address. Creating an account and a key lifts that limit and adds the other products.
Should I use a key or sign in?
Use a key for scripts and shared setups, since it does not depend on a browser. Use the sign-in address when you would rather not store a key: Claude registers itself, opens your browser, and you approve it. Both spend credits the same way.
Does the sign-in token work on the REST API?
No. A token from the sign-in flow opens the MCP server only. Use an API key for the REST API.
How do I stop Claude using my account?
Open Connected apps in the dashboard and disconnect the app. Its access stops on the next request. You can also remove the server from Claude with the claude mcp remove command.
Sources
- Claude Code documentation: Connect Claude Code to tools via MCP https://code.claude.com/docs/en/mcp, read 2026-10-18
- Model Context Protocol specification: Authorization https://modelcontextprotocol.io/specification/2025-06-18/basic/authorization, read 2026-10-18
LookValid is run by Meralume Labs. It is not connected to, endorsed by or a partner of any company or product named on this page, and every product name belongs to its owner.
Related pages
LookValid puts every lookup behind one key and one credit balance, over REST and MCP.
Read the quickstart