RegTail

Measured conclusion: Deep-tested. L2 outcome: tools_ok.

UK used-car checks: MOT history, mileage and an advert's claims tested against the records

Add to your agent

Copy this into your MCP client config:

{
  "mcpServers": {
    "RegTail": {
      "url": "https://regtail.com/mcp",
      "transport": "streamable-http"
    }
  }
}

Measured tools (10)

• decode_plate read-only

  When a UK plate of this format could have been issued, from the plate alone (format, age identifier, and the window as first and last month). Offline: it does not look the car up; use free_check for that. No account needed.

  Parameters:

  • plate (required) — string — UK registration plate, any spacing or case

  Hints: read-only yes · destructive no · idempotent yes · open-world no

• free_check read-only

  The site's free check: identity, tax and MOT status, latest MOT test, its defects and recorded mileage, the existing since-previous-test summary and mileage-unverified flag. Includes presentation, up to three questions from these free facts, a verdict image, locked teasers and a report link. No account or credit needed. Show the returned markdown field as-is to the user. Next-MOT estimates, repair prices, mileage analysis and older MOT details require the detailed report.

  Parameters:

  • plate (required) — string — UK registration plate, any spacing or case

  Hints: read-only yes · destructive no · idempotent yes · open-world yes

• resolve_vehicle read-only

  Resolve a typed plate, car photo data URL or supported advert URL to a plate only. No account or spend. If uncertain, ask the user to confirm; if unavailable, ask for the typed plate. Then use free_check.

  Parameters:

  • input (required)

  Hints: read-only yes · destructive no · idempotent yes · open-world yes

• compare_vehicles read-only

  Compare the site's free projections for exactly two plates: identity, status and latest MOT test. Duplicate plates use one lookup. Includes questions from free facts, comparison image and report links. No prediction-based ranking; next-MOT estimates and likely repairs stay in the detailed report. No account or credit needed.

  Parameters:

  • plates (required) — array

  Hints: read-only yes · destructive no · idempotent yes · open-world yes

• sample_report read-only

  The detailed report and viewing advice for one public sample car (CX52HHM, a 2002 Land Rover Defender), to show what a detailed report contains. Use when the user asks what RegTail's detailed report looks like. No account needed. It is always the same sample car, never the user's car.

  Hints: read-only yes · destructive no · idempotent yes · open-world no

• full_report read-only

  The detailed report of a car the user has unlocked on their RegTail account: verdict and top risks, every MOT test with defects and advisories, mileage analysis, recurring advisories, other sections, the viewing checklist, what was not checked, and guidance for explaining it. Use to discuss a car in depth. Needs the user's RegTail account linked. Never spends: for a plate that is not unlocked it returns unlocked=false and a message; then ask the user before calling unlock_report.

  Parameters:

  • plate (required) — string — UK registration plate, any spacing or case

  Hints: read-only yes · destructive no · idempotent yes · open-world yes

• unlock_report

  Spends one of the user's RegTail credits to unlock the detailed report for this plate for 30 days, then returns the detailed report (as full_report does). Ask the user first, every time, and call this only after they agree; never unlock on your own initiative or to answer a general question. A plate already unlocked costs nothing again. Needs the user's RegTail account linked. With no credits left it unlocks nothing and spends nothing.

  Parameters:

  • plate (required) — string — UK registration plate, any spacing or case
  • confirmed (required) — boolean — True only when the user has just said yes to spending one credit on this plate

  Hints: read-only no · destructive no · idempotent yes · open-world yes

• viewing_advice read-only

  Advice for viewing an unlocked car in person: a summary, priorities to check (each with why and the report records behind it) and known weak spots of the model. Needs the user's RegTail account linked and the plate unlocked; never spends.

  Parameters:

  • plate (required) — string — UK registration plate, any spacing or case

  Hints: read-only yes · destructive no · idempotent yes · open-world yes

• credits_balance read-only

  How many credits the user's RegTail account holds, and pricing_url, a page explaining how credits work. Needs the user's RegTail account linked.

  Hints: read-only yes · destructive no · idempotent yes · open-world no

• my_reports read-only

  The cars the user has unlocked (with when each unlock ends) and their recent checks, so a conversation can pick up a car checked earlier. Needs the user's RegTail account linked.

  Hints: read-only yes · destructive no · idempotent yes · open-world no

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Measured by MCPYP probing. Untested fields are omitted, never estimated. Listing is always free; MCPYP never proxies calls or stores user tokens.