CheckFitment MCP server

• Registry namecom.checkfitment/checkfitmentverified in the MCP registry

The registry name sits under checkfitment.com. The registry only lets a publisher use that namespace after proving control of the domain through DNS or HTTP.

• Stateanswerschecked 2026-10-24
• Tools6
• Server calls itselfcheckfitment
• Server version1.1.0
• Protocol version2025-06-18

On 2026-10-24 the server answered initialize and tools/list without a sign-in. First answer in 158 ms.

• Its tools do every use case we checked: check bolt pattern and offset for a wheel; measure tire clearance before fitting larger wheels; recalculate speedometer reading after changing tire size.
• Checked on 5 of the 7 days it takes to judge reliability.

Said by rules from the measurements above. The likely first call is a model's pick from the tool list; read its description before relying on it.

• INITE MCP scoreafter a weeka score needs 7 daily checks: 5 so far
• What an agent can do with it3 of 3 use cases
• Answeredmeasuring5 of the 7 daily checks it takes to print a share
• Median first answer125 ms
• Space in an agent's context≈ 1,632 tokensthe definitions of all its tools (6), which an agent carries on every turn
• Tool definitionsB · 89 of 100
• Typed results6 of 6 toolsdeclared outputSchema: results come typed, read once

• Parameters without a description: in 4 of 6

A program checks the server once a day: initialize and tools/list, no model. Tokens are the definitions' length at about four characters a token. The grade averages six checks of every tool's name, description, schema and annotations; it says how well the tools are described, not whether they work. The score weighs what was measured and nothing else: answering (25%), doing the product's job (25%), definitions (20%), context (10%), use (10%) and how readily a client connects (10%). A part that was not measured is left out, and a hidden instruction caps the score at 40. The state of vendors' MCP servers: method and numbers →

• bolt_pattern_lookup

  Use for "what is the bolt pattern on a 2019 Ford F-150", lug torque, center bore, thread size, OEM wheel size, offset or tire size of a vehicle, or "will these wheels fit my car" when the vehicle is named. Looks the vehicle up in the…

• wheel_fitment_check

  Use to compare a current wheel (and tire) with a new one: how far the outer edge pokes toward the fender and the inner edge toward the suspension, the diameter and ride-height change, speedometer effect, backspacing, and whether the new…

• tire_size_compare

  Use for "what changes if I go from 265/70R17 to 285/75R17", "how far off is my speedometer with 33s", or odometer error after a tire change. Returns diameter, width, sidewall and ride-height change, the true speed when the speedometer…

• wheel_spacer_calculator

  Use for "do I need spacers", "what spacer gets +35 wheels to +20", "is a 10 mm slip-on spacer safe". A spacer lowers the effective offset by its thickness. Returns the spacer needed for a target offset (and the nearest common size), the…

• gear_ratio_calculator

  Use for "what does my 3.73 axle behave like on 35s", "what ratio do I need to regear for 33s", RPM at highway speed after a tire change, or the crawl ratio (with transfer-case low ratio and first gear). Returns the effective ratio, RPM…

• bolt_pattern_facts

  Use for "what is 5x114.3 in inches", "is 5x114.3 the same as 5x115", "will 6x135 wheels fit 6x139.7", or which vehicles use a pattern. Converts mm and inch notation, lists look-alike patterns that do not interchange, the vehicles in the…