PlateQuery MCP — US License Plate & Vehicle Information

PlateQuery MCP — US License Plate & Vehicle Information

License plate lookup for AI agents, built on PlateQuery — the license plate lookup site people use to notify vehicle owners, report bad driving, or flag illegal parking. This Model Context Protocol server lets an agent read those same messages for any U.S. license plate, plus public ALPR (automated license plate reader) sighting history from the Flock Safety camera network, by state or region.

• Website: https://platequery.com/
• API docs / pricing: https://api.platequery.com/
• MCP endpoint: https://api.platequery.com/mcp (Streamable HTTP)
• Registry listing: com.platequery/plate-api on the official MCP registry

This repository holds public documentation for the server. The implementation lives in PlateQuery's main application repository, which is closed-source.

Tools

Tool	Cost	Description
check_credits	Free	Check your account's remaining credit balance. Doesn't count against the rate limit.
lookup_plate	1 credit	Quick summary for one plate: privacy status, the latest 3 messages (plus a total count), and a count of ALPR mentions, if any are public.
list_plate_messages	1 credit	Full, paginated list of messages posted about a plate.
list_plate_alpr_mentions	1 credit	Full, paginated ALPR search history for a plate, including the searching agency and source.
post_plate_message	Free	Post a new message about a plate -- e.g. "reported for speeding" -- optionally with vehicle make/model/year/color and an approximate location. Requires the write scope. See Posting messages below.

A plate marked private by its owner returns zeroed messages/mentions to everyone except that owner. Free plan grants a starting credit balance on signup; additional credits are purchased in bulk packages — see api-settings for current pricing. Paid tools are rate-limited per account; call check_credits as often as you like to check balance without spending a credit.

Posting messages

post_plate_message is free but deliberately conservative, since it's the only tool that writes anything:

• Requires a PlateQuery account with a confirmed email.
• Rate-limited: 2 posts/minute, 10 posts/day, 3 posts/day about the same plate.
• Not published immediately. Every post goes into the same moderation queue a website submission does -- it's invisible (and the plate's followers aren't notified) until a human moderator approves it.
• vehicle_make/vehicle_model/vehicle_year/vehicle_color and location are all optional free text -- location should be an approximate description (e.g. "Hwy 37 near Los Altos, CA" or a cross-street), never precise GPS coordinates.

Authentication

The server is OAuth 2.1 only — no manual API keys. It supports PKCE and dynamic client registration (DCR), so a compliant MCP client (Claude, or any client following the MCP authorization spec) can connect by:

1. Pointing at https://api.platequery.com/mcp.
2. Following the WWW-Authenticate challenge to discover https://platequery.com as the authorization server (RFC 9728 protected resource metadata).
3. Registering itself dynamically (RFC 7591) and running the standard Authorization Code + PKCE flow.
4. Signing in with (or creating) a PlateQuery account when prompted.

No client secret or pre-issued API key is needed — sign-in happens in the browser the first time an agent connects.

Two scopes exist: read (the default -- covers every tool except post_plate_message) and write (required for post_plate_message, opt-in only). A client must explicitly request write at connect time to be able to post; an existing read-only connection can't post without reconnecting.

Adding it to an MCP client

Most MCP clients (including Claude) let you add a remote server by URL. Add https://api.platequery.com/mcp as a Streamable HTTP connector and follow the sign-in prompt on first use.

Support

Questions or issues: https://platequery.com/contact/