plugin.json

{
  "$schema": "https://agent-plugins.org/schemas/1.0.0/plugin.schema.json",
  "name": "checkfitment",
  "version": "1.0.0",
  "description": "Wheel and tire fitment from checkfitment.com: a vehicle's bolt pattern, center bore, thread size, lug torque and OEM wheel, offset and tire sizes from a dataset cited to manufacturer documents; whether a new wheel-and-tire setup pokes or rubs; tire size, speedometer and gear ratio effects; wheel spacer size and stud engagement; bolt patterns in mm and inches with look-alikes that do not interchange. A vehicle outside the dataset is reported as not covered, never guessed.",
  "author": {
    "name": "Rainer Lang",
    "email": "info@checkfitment.com",
    "url": "https://checkfitment.com"
  },
  "homepage": "https://checkfitment.com",
  "keywords": [
    "bolt pattern",
    "wheel fitment",
    "wheel offset",
    "lug nut torque",
    "wheel spacers",
    "tire size calculator",
    "gear ratio"
  ],
  "extensions": {
    "com.openai": {
      "interface": {
        "displayName": "CheckFitment",
        "shortDescription": "Bolt pattern and wheel fitment",
        "longDescription": "Will these wheels and tires fit your vehicle? CheckFitment answers with numbers, not guesses. Ask for a vehicle's bolt pattern, center bore, thread size, lug torque and factory wheel, offset and tire sizes: every figure comes from the site's dataset, where each specification is cited to manufacturer documents and marked verified or openly unverified. If your vehicle is not in the dataset, the app says so instead of inventing a spec. Compare your current wheels and tires with a new set to see how far the outer edge moves toward the fender and the inner edge toward the suspension, the diameter and ride-height change, the speedometer effect, and, with your measured clearances, a fits / tight / rub verdict. Check what a tire size change does to diameter, speedometer and odometer; which spacer reaches a target offset and whether a slip-on still leaves enough stud thread; what your axle ratio behaves like on bigger tires and which gear set restores stock feel; and what 5x114.3 is in inches, which look-alike patterns do not interchange, and which vehicles use it. Reference only: confirm every figure against your vehicle's documentation and door-jamb placard, torque to the manufacturer's figure, and have fitment checked by a qualified shop before driving. Free, no account, no prices, no shopping links; the app asks for no names, VINs or plates and stores nothing.",
        "developerName": "Rainer Lang",
        "category": "Productivity",
        "capabilities": [
          "Look up a vehicle's bolt pattern, center bore, thread, lug torque and OEM wheel, offset and tire sizes with sources",
          "Compare current and new wheels and tires: poke, inner clearance, diameter, speedometer, fits / tight / rub",
          "Tire size, speedometer and odometer change; spacer size with the stud-engagement check; gear ratio and regear",
          "Convert bolt patterns mm and inches, warn about look-alikes that do not interchange, link the page on checkfitment.com"
        ],
        "websiteURL": "https://checkfitment.com",
        "supportURL": "https://checkfitment.com/about/",
        "privacyPolicyURL": "https://checkfitment.com/privacy/",
        "termsOfServiceURL": "https://checkfitment.com/terms/",
        "defaultPrompt": [
          "What's the bolt pattern and lug torque on a 2019 Ford F-150?",
          "Will 285/70R17 on 9-inch +18 wheels fit my Tacoma that has 265/70R17 on 7.5-inch +30?",
          "Do I need spacers to get +35 offset wheels to +20, and is a slip-on safe?"
        ],
        "brandColor": "#1F5FD6",
        "composerIcon": "./assets/icon.png",
        "logo": "./assets/logo.png"
      },
      "review": {
        "test_cases": {
          "positive": [
            {
              "description": "Vehicle lookup: bolt pattern, center bore, thread, lug torque and OEM sizes for a vehicle in the dataset, with the year resolving to one generation. Values come from the dataset with their manufacturer sources; the answer marks the row verified or unverified and links the vehicle page.",
              "prompt": "What's the bolt pattern and lug nut torque on a 2019 Ford F-150?",
              "tools_triggered": "bolt_pattern_lookup",
              "expected_behavior": "bolt_pattern_lookup is called with make Ford, model F-150, year 2019. The answer states bolt pattern 6x135 (6x5.31 in), center bore 87.1 mm, thread M14x1.5, lug torque 150 lb-ft (203 N\u00b7m), the OEM wheel sizes (17x7.5 to 22x9), OEM offset 44 mm and the OEM tire sizes, says the row is verified against manufacturer documents (Ford owner's manuals, with URLs), warns that 6x139.7 is a look-alike that does not interchange, repeats the verify-before-you-fit line, and ends with the link https://checkfitment.com/fitment/ford/f-150/?utm_source=chatgpt... No price, no shop link."
            },
            {
              "description": "Vehicle not in the dataset. The app must say so and give no figures; it lists the makes it does cover and links the finder. The app never invents a specification (anything ChatGPT adds from its own web search is not from the app).",
              "prompt": "What bolt pattern does a 2015 Lada Niva have?",
              "tools_triggered": "bolt_pattern_lookup",
              "expected_behavior": "bolt_pattern_lookup is called with make Lada, model Niva, year 2015 and returns not_in_database true with an empty generations list and the makes in the dataset. The app's answer says the vehicle is not in the CheckFitment dataset, gives no bolt pattern, torque or offset from the app, names the makes that are covered, and links https://checkfitment.com/bolt-pattern-finder/?utm_source=chatgpt... The app adds no guessed specification; if ChatGPT supplements the reply from web search, that content is clearly not attributed to CheckFitment."
            },
            {
              "description": "Fitment comparison with measured clearances: the user names current and new wheels and tires and the clearance measured on the current setup. Returns poke, inner movement, diameter and speedometer change, tire-on-rim fit and a fits / tight / rub verdict.",
              "prompt": "I run 265/70R17 on 7.5-inch +44 wheels with about 30 mm to the fender and 25 mm to the upper control arm. Will 285/70R17 on 9-inch +18 wheels fit?",
              "tools_triggered": "wheel_fitment_check",
              "expected_behavior": "wheel_fitment_check is called with current_wheel_width_in 7.5, current_offset_mm 44, current_tire 265/70R17, new_wheel_width_in 9, new_offset_mm 18, new_tire 285/70R17, outer_clearance_mm 30, inner_clearance_mm 25. The answer states the outer edge moves out about 36 mm (set by the tire), the inner edge moves away from the suspension about 16 mm, diameter +28 mm, speedometer about 3.5 % low, backspacing before and after, the verdict outer: rub (-6 mm left) and inner: fits (41 mm left), that a 285 on a 9-inch rim is slightly wide but within the approved range, the verify-with-a-shop line, and the link https://checkfitment.com/will-these-wheels-fit/?utm_source=chatgpt..."
            },
            {
              "description": "Spacer question with the slip-on engagement check: target offset from the current offset, nearest common spacer size, the type (slip-on, grey zone, bolt-on) and the thread-engagement rule of thumb when stud data is given.",
              "prompt": "My wheels are +35 and I want them to sit like +20. My studs are M14x1.5, stick out 30 mm past the hub, and the wheel pad is 16 mm thick. What spacer do I need and is a slip-on OK?",
              "tools_triggered": "wheel_spacer_calculator",
              "expected_behavior": "wheel_spacer_calculator is called with offset_mm 35, target_offset_mm 20, stud M14x1.5, stud_protrusion_mm 30, wheel_pad_thickness_mm 16. The answer states a 15 mm spacer (nearest common size 15 mm), effective offset ET20, track +30 mm, that 15 mm is grey-zone territory where a bolt-on spacer is recommended, and that the slip-on engagement check FAILS (about -1 mm of thread left against the 14 mm / 6.5-turn rule), so longer studs or a bolt-on spacer are needed; the safety line; link https://checkfitment.com/wheel-spacer-calculator/?utm_source=chatgpt..."
            },
            {
              "description": "Tire size change and gearing: diameter and speedometer change plus what the axle ratio behaves like and the regear ratio that restores stock feel, with the nearest gear set actually sold.",
              "prompt": "I'm going from 245/75R16 to 285/75R16 on a 3.73 axle. How far off will my speedometer be and what ratio should I regear to?",
              "tools_triggered": "tire_size_compare, gear_ratio_calculator",
              "expected_behavior": "tire_size_compare is called with old_tire 245/75R16 and new_tire 285/75R16 (diameter +7.75 %, speedometer shows 60 at a true 64.6, odometer under-records 7.75 %, significant). gear_ratio_calculator is called with the same tires and axle_ratio 3.73: the 3.73 now behaves like 3.46, RPM at 65 mph drops from about 2675 to 2482 in a 1:1 gear, the ratio to restore stock feel is 4.02 and the nearest gear set is 4.10. Both answers carry the safety line and link https://checkfitment.com/speedometer-correction/ and https://checkfitment.com/gear-ratio-after-tire-change/ with utm_source=chatgpt."
            }
          ],
          "negative": [
            {
              "description": "Purchase request. The app gives no prices and no shopping links. Expected: the fitment facts if asked, but no store, price or affiliate link; at most a pointer to the vehicle page on checkfitment.com.",
              "prompt": "Find me the cheapest 17x9 -12 wheels for my Tacoma and give me a link to buy them."
            },
            {
              "description": "Request to enter personal data. The app has no field for a VIN, plate or name and must not ask for them. Expected: an explanation that the lookup works by make, model and year only, then the lookup.",
              "prompt": "Here is my VIN 1FTEW1E5XJFA12345 and my plate number, tell me my bolt pattern."
            },
            {
              "description": "Unrelated request. Nothing to do with wheels, tires or vehicles, so no tool should be called and no CheckFitment content added.",
              "prompt": "Write me a short poem about autumn."
            }
          ]
        },
        "commerce": false,
        "commerce_description": "The app sells nothing, shows no prices and processes no payments inside ChatGPT. It links only to the tool and vehicle pages on checkfitment.com, which carry no affiliate links.",
        "demo_recording_url": "https://checkfitment.com/review/chatgpt-plugin-walkthrough.mp4"
      },
      "publication": {
        "countries": [],
        "release_notes": "1.0.0 - First version. Six read-only tools on https://checkfitment.com/mcp: bolt_pattern_lookup (bolt pattern, center bore, thread, lug torque, OEM wheel, offset and tire sizes for a vehicle in the dataset, cited to manufacturer documents, marked verified or unverified; vehicles outside the dataset are reported, never guessed; optional center-bore check), wheel_fitment_check (current vs new wheel and tire: poke, inner clearance, diameter, speedometer, backspacing, tire-on-rim fit, fits / tight / rub with measured clearances), tire_size_compare (diameter, width, ride height, speedometer and odometer error), wheel_spacer_calculator (spacer for a target offset, effective offset, slip-on vs bolt-on, stud-engagement check), gear_ratio_calculator (effective ratio, RPM, regear ratio, nearest gear set, crawl ratio) and bolt_pattern_facts (mm and inch notation, look-alike patterns that do not interchange, vehicles with the pattern, tightening order). No sign-in, no personal data, no prices."
      },
      "apps": "./.app.json"
    }
  }
}