DERATE — truck fault codes

Heavy-duty truck SPN/FMI and OBD fault codes: meaning, safe-to-drive verdict, parts and recalls.

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What it can do

    What data it sees

    Do you need an account

    No: the server works without sign-in

    Heavy-duty truck SPN/FMI and OBD fault codes: meaning, safe-to-drive verdict, parts and recalls.

    How to connect

    How to connect DERATE — truck fault codes to Claude

    The server address to paste into Claude settings:

    https://derate.app/mcp

    1. Open Claude (claude.ai or the desktop app).
    2. Go to Settings → Connectors.
    3. Click Add custom connector.
    4. Paste the server address copied below into Remote MCP server URL and click Add.
    5. In a chat, click + → Connectors and switch the new connector on.

    Custom connectors are available on Free, Pro, Max, Team and Enterprise plans (Free is limited to one). On Team and Enterprise an organization Owner adds the connector first under Organization settings → Connectors.

    Authorization

    After you click Add, a sign-in window for the service opens. Sign in with your own account and approve access. Claude never sees your password.

    How to connect DERATE — truck fault codes to ChatGPT

    The server address to paste into ChatGPT settings:

    https://derate.app/mcp

    1. Open ChatGPT in a browser (chatgpt.com). A Plus, Pro, Business, Enterprise or Edu plan is required.
    2. Turn on developer mode once: Settings → Apps → Advanced settings → Developer mode.
    3. Open Settings → Connectors and click Create.
    4. Fill in the form: Name (anything), Description (one line about what the service does), MCP server URL (copy it below).
    5. Under Authentication choose OAuth if the service requires sign-in, otherwise None. Click Create.
    6. In a new chat open + → Apps/Connectors and enable the connector.

    OpenAI has renamed this section before (Connectors → Apps/Plugins). If the label differs, search settings for "developer mode". On Business/Enterprise workspaces an admin must allow custom connectors first.

    Authorization

    On first use ChatGPT opens the service's sign-in window. Sign in and approve access.

    How to connect DERATE — truck fault codes to Cursor

    The server address to paste into Cursor settings:

    https://derate.app/mcp

    Fastest: click Open in Cursor below and confirm the prompt.

    Manually:

    1. In Cursor open Settings → Cursor Settings → MCP and click Add new global MCP server.
    2. Paste the JSON copied below into ~/.cursor/mcp.json (per project: .cursor/mcp.json in the repo root).
    3. Save the file. The server appears in the MCP list; authorize it there if asked.

    Authorization

    If the service needs sign-in, an authorize button appears next to the server in the MCP list.

    Server tool list (13)

    Raw names from tools/list. Only developers need these.

    buscar_codigoSearch DERATE's 56-code heavy-truck library by SPN/FMI, P-code or free text. Returns severity, derates yes/no, meaning, part and estimated part-price range, and the page URL. / Busca en la biblioteca de códigos de DERATE.
    es_seguro_manejarSafe-to-drive verdict (stop / service_soon / info) for a truck fault code, from DERATE's library only. Unknown codes return 'unknown'. / Veredicto de si es seguro seguir manejando.
    retiros_de_camionHow to check heavy-truck safety recalls (NHTSA-based), with per-make source links for Freightliner, Volvo, Kenworth, Peterbilt, International, Mack and Western Star. / Cómo revisar retiros de seguridad.
    get_data_notesDERATE dataset notes: code count, sources, known gaps, license (CC BY 4.0), how to cite and download URLs. / Notas de calidad, licencia y cómo citar.
    get_truck_fault_codeLook up a diesel truck fault code (J1939 SPN/FMI such as 'SPN 3251 FMI 0', or an OBD-II code such as 'P2002') in DERATE's public fault-code library. Returns what the code means, its severity, whether it is safe to keep driving, probable causes, the recommended tests, and the canonical URL of the public page for that code. Works without any account.
    interpret_derateExplain a diesel truck engine derate or power-loss symptom described in plain language (for example 'DEF light on and truck limited to 55 mph'). Returns the most likely cause, how urgent it is, the immediate action to take, and matching public fault-code pages. This is the free public interpretation; the full guided diagnosis with tests and a work order runs in the DERATE app.
    search_fault_code_libraryFull-text search over DERATE's public diesel truck fault-code library by code, system, dashboard light or symptom words. Returns a list of matching entries with code, title, severity, system and the canonical public URL.
    list_supported_engine_familiesList the diesel truck engine families and code protocols DERATE interprets (J1939 SPN/FMI and OBD-II), so an agent knows whether a given truck is covered before looking up a code.
    get_pricingList DERATE's plans and prices in USD. The app is a free download; plans are purchased inside the iOS/Android app (App Store / Google Play). Monthly Driver and Shop plans include a 7-day free trial for new subscribers.
    get_download_linksReturn the official App Store and Google Play links for the DERATE native app (iOS and Android). DERATE runs only as a mobile app.
    get_diagnosisReturn the full DERATE demo diagnosis for a truck: verdict (STOP/CAUTION/CLEAR), derate countdown, every fault code and the work order summary.
    list_fault_codesList the fault codes (SPN/FMI) in the current DERATE diagnosis with severity, system, fault type and whether they are a root cause.
    explain_fault_codeExplain a truck fault code or symptom in DERATE terms: plain-language meaning, severity, probable causes, recommended tests with expected values, repair steps and cost estimate.