diff --git a/melody/kit/core.py b/melody/kit/core.py
index 54c6810..2c5fdb1 100644
--- a/melody/kit/core.py
+++ b/melody/kit/core.py
@@ -1,6 +1,7 @@
 from argon2 import PasswordHasher
 from authlib.integrations.starlette_client import OAuth  # type: ignore[import-untyped]
 from fastapi.applications import FastAPI
+from fastapi.exceptions import RequestValidationError
 from fastapi.middleware.cors import CORSMiddleware
 from fastapi.requests import Request
 from fastapi.responses import JSONResponse
@@ -95,6 +96,14 @@ async def http_error_handler(request: Request, error: HTTPError) -> JSONResponse
 
         return await error_handler(request, converted_error)
 
+    @app.exception_handler(RequestValidationError)
+    async def validation_error_handler(
+        request: Request, error: RequestValidationError
+    ) -> JSONResponse:
+        converted_error = Error.from_validation_error(error)
+
+        return await error_handler(request, converted_error)
+
     @app.exception_handler(NormalError)
     async def normal_error_handler(request: Request, error: NormalError) -> JSONResponse:
         internal_error = InternalError()
diff --git a/melody/kit/errors/core.py b/melody/kit/errors/core.py
index 62386db..42696f7 100644
--- a/melody/kit/errors/core.py
+++ b/melody/kit/errors/core.py
@@ -3,6 +3,8 @@
 from enum import Enum
 from typing import ClassVar, Optional, Type
 
+from fastapi import status
+from fastapi.exceptions import RequestValidationError
 from starlette.exceptions import HTTPException as HTTPError
 from typing_aliases import NormalError
 from typing_extensions import Self
@@ -12,6 +14,8 @@
 
 __all__ = ("ErrorCode", "Error", "ErrorData", "ErrorType")
 
+VALIDATION_ERROR = "validation error"
+
 
 class ErrorCode(Enum):
     BASE = 10000
@@ -180,5 +184,15 @@ def from_http_error(cls, error: HTTPError) -> Self:
 
         return cls(message, code, status_code)
 
+    @classmethod
+    def from_validation_error(cls, error: RequestValidationError) -> Self:
+        message = VALIDATION_ERROR
+
+        status_code = status.HTTP_422_UNPROCESSABLE_ENTITY
+
+        code = ErrorCode.from_status_code(status_code)
+
+        return cls(message, code, status_code)
+
 
 ErrorType = Type[Error]
diff --git a/pyproject.toml b/pyproject.toml
index 339fc68..102e781 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -30,7 +30,7 @@ include = "melody"
 [tool.poetry.scripts]
 "melody.bot" = "melody.bot.main:bot"
 "melody.kit" = "melody.kit.main:run"
-"melody.web" = "melody.web.main:web"
+"melody.web" = "melody.web.main:run"
 
 [tool.poetry.dependencies]
 # melody
@@ -146,5 +146,5 @@ wrap_size = 100
 display = ["feature", "change", "fix", "security", "deprecation", "removal", "internal"]
 
 [build-system]
-requires = ["poetry-core >= 1.8.1"]
+requires = ["poetry-core >= 1.9.0"]
 build-backend = "poetry.core.masonry.api"