{
  "id": "markup.too_long",
  "category": "request_validation",
  "summary": "Telegram rejected the size of the reply markup.",
  "match_any": [
    {
      "error_code": 400,
      "description_exact": "Bad Request: reply markup is too long"
    }
  ],
  "scope": {
    "method_examples": [
      "sendMessage",
      "editMessageReplyMarkup"
    ],
    "exhaustive": false
  },
  "possible_causes": [
    "The reply markup exceeds a size constraint enforced by Telegram."
  ],
  "diagnostic_limits": "The mapping does not specify a size limit or identify which keyboard field exceeds it.",
  "evidence": [
    {
      "source": "server-10.3",
      "path": "telegram-bot-api/Client.cpp",
      "lines": [
        121,
        123
      ],
      "note": "REPLY_MARKUP_TOO_LONG becomes this description in the code-400 branch."
    },
    {
      "source": "server-10.3",
      "path": "telegram-bot-api/Client.cpp",
      "lines": [
        85,
        106
      ],
      "note": "Normalizes lower codes, 404, and uppercase machine-style 403 errors to 400 before rewriting."
    },
    {
      "source": "server-10.3",
      "path": "telegram-bot-api/Client.cpp",
      "lines": [
        165,
        205
      ],
      "note": "Adds the code-specific prefix and lowercases only the initial character of ordinary messages."
    }
  ],
  "example": {
    "method": "sendMessage",
    "response": {
      "ok": false,
      "error_code": 400,
      "description": "Bad Request: reply markup is too long"
    }
  },
  "evidence_level": "source_derived",
  "guidance": {
    "action": "reduce_reply_markup",
    "repeat_request": "after_relevant_change",
    "preconditions": [
      "Reduce the keyboard or button payload and check the current limits for the chosen button types."
    ]
  }
}