diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
index 85269eb37..9dd5e8e00 100644
--- a/.pre-commit-config.yaml
+++ b/.pre-commit-config.yaml
@@ -9,7 +9,7 @@ repos:
       - id: black
 
   - repo: https://github.com/asottile/pyupgrade
-    rev: v2.31.1
+    rev: v2.32.1
     hooks:
       - id: pyupgrade
         args: [--py3-plus, --keep-percent-format]
@@ -37,7 +37,7 @@ repos:
         language_version: python3.10  # needed for match
 
   - repo: https://github.com/pre-commit/pre-commit-hooks
-    rev: v4.1.0
+    rev: v4.2.0
     hooks:
       - id: trailing-whitespace
       - id: end-of-file-fixer
diff --git a/changelog.d/951.change.rst b/changelog.d/951.change.rst
new file mode 100644
index 000000000..6ded5fe7b
--- /dev/null
+++ b/changelog.d/951.change.rst
@@ -0,0 +1 @@
+``attrs.validators._in()``'s ``ValueError`` is not missing the attribute, expected options, and the value it got anymore.
diff --git a/docs/api.rst b/docs/api.rst
index 47fce5c16..ecaee7e68 100644
--- a/docs/api.rst
+++ b/docs/api.rst
@@ -9,7 +9,7 @@ If you're confused by the many names, please check out `names` for clarification
 
 What follows is the API explanation, if you'd like a more hands-on introduction, have a look at `examples`.
 
-As of version 21.3.0, ``attrs`` consists of **two** to-level package names:
+As of version 21.3.0, ``attrs`` consists of **two** top-level package names:
 
 - The classic ``attr`` that powered the venerable `attr.s` and `attr.ib`
 - The modern ``attrs`` that only contains most modern APIs and relies on `attrs.define` and `attrs.field` to define your classes.
@@ -566,24 +566,24 @@ All objects from ``attrs.validators`` are also available from ``attr.validators`
 
    .. doctest::
 
-       >>> import enum
-       >>> class State(enum.Enum):
-       ...     ON = "on"
-       ...     OFF = "off"
-       >>> @attrs.define
-       ... class C:
-       ...     state = attrs.field(validator=attrs.validators.in_(State))
-       ...     val = attrs.field(validator=attrs.validators.in_([1, 2, 3]))
-       >>> C(State.ON, 1)
-       C(state=<State.ON: 'on'>, val=1)
-       >>> C("on", 1)
-       Traceback (most recent call last):
-          ...
-       ValueError: 'state' must be in <enum 'State'> (got 'on')
-       >>> C(State.ON, 4)
-       Traceback (most recent call last):
-          ...
-       ValueError: 'val' must be in [1, 2, 3] (got 4)
+      >>> import enum
+      >>> class State(enum.Enum):
+      ...     ON = "on"
+      ...     OFF = "off"
+      >>> @attrs.define
+      ... class C:
+      ...     state = attrs.field(validator=attrs.validators.in_(State))
+      ...     val = attrs.field(validator=attrs.validators.in_([1, 2, 3]))
+      >>> C(State.ON, 1)
+      C(state=<State.ON: 'on'>, val=1)
+      >>> C("on", 1)
+      Traceback (most recent call last):
+         ...
+      ValueError: 'state' must be in <enum 'State'> (got 'on'), Attribute(name='state', default=NOTHING, validator=<in_ validator with options <enum 'State'>>, repr=True, eq=True, eq_key=None, order=True, order_key=None, hash=None, init=True, metadata=mappingproxy({}), type=None, converter=None, kw_only=False, inherited=False, on_setattr=None), <enum 'State'>, 'on')
+      >>> C(State.ON, 4)
+      Traceback (most recent call last):
+      ...
+      ValueError: 'val' must be in [1, 2, 3] (got 4), Attribute(name='val', default=NOTHING, validator=<in_ validator with options [1, 2, 3]>, repr=True, eq=True, eq_key=None, order=True, order_key=None, hash=None, init=True, metadata=mappingproxy({}), type=None, converter=None, kw_only=False, inherited=False, on_setattr=None), [1, 2, 3], 4)
 
 .. autofunction:: attrs.validators.provides
 
diff --git a/docs/examples.rst b/docs/examples.rst
index 1cf98ac86..ae5ffa78e 100644
--- a/docs/examples.rst
+++ b/docs/examples.rst
@@ -329,6 +329,8 @@ The method receives the partially initialized instance which enables you to base
    >>> C()
    C(x=1, y=2, z=[])
 
+Please keep in mind that the decorator approach *only* works if the attribute in question has a ``field`` assigned to it.
+As a result, annotating an attribute with a type is *not* enough if you use ``@default``.
 
 .. _examples_validators:
 
@@ -401,7 +403,7 @@ You can use a decorator:
    ValueError: value out of bounds
 
 Please note that the decorator approach only works if -- and only if! -- the attribute in question has a ``field`` assigned.
-Therefore if you use ``@default``, it is *not* enough to annotate said attribute with a type.
+Therefore if you use ``@validator``, it is *not* enough to annotate said attribute with a type.
 
 ``attrs`` ships with a bunch of validators, make sure to `check them out <api_validators>` before writing your own:
 
diff --git a/docs/init.rst b/docs/init.rst
index cbe2a1557..330642dab 100644
--- a/docs/init.rst
+++ b/docs/init.rst
@@ -147,6 +147,8 @@ The method has to accept three arguments:
 #. the *attribute* that it's validating, and finally
 #. the *value* that is passed for it.
 
+These values are passed as *positional arguments*, therefore their names don't matter.
+
 If the value does not pass the validator's standards, it just raises an appropriate exception.
 
    >>> @define
@@ -172,6 +174,7 @@ Callables
 If you want to re-use your validators, you should have a look at the ``validator`` argument to `attrs.field`.
 
 It takes either a callable or a list of callables (usually functions) and treats them as validators that receive the same arguments as with the decorator approach.
+Also as with the decorator approach, they are passed as *positional arguments* so you can name them however you want.
 
 Since the validators run *after* the instance is initialized, you can refer to other attributes while validating:
 
diff --git a/src/attr/validators.py b/src/attr/validators.py
index 6a1e198f8..eece517da 100644
--- a/src/attr/validators.py
+++ b/src/attr/validators.py
@@ -299,7 +299,10 @@ def __call__(self, inst, attr, value):
             raise ValueError(
                 "'{name}' must be in {options!r} (got {value!r})".format(
                     name=attr.name, options=self.options, value=value
-                )
+                ),
+                attr,
+                self.options,
+                value,
             )
 
     def __repr__(self):
@@ -322,6 +325,10 @@ def in_(options):
        got.
 
     .. versionadded:: 17.1.0
+    .. versionchanged:: 22.1.0
+       The ValueError was incomplete until now and only contained the human
+       readable error message. Now it contains all the information that has
+       been promised since 17.1.0.
     """
     return _InValidator(options)
 
diff --git a/tests/test_validators.py b/tests/test_validators.py
index f3fe69cc1..51fe2f41e 100644
--- a/tests/test_validators.py
+++ b/tests/test_validators.py
@@ -469,9 +469,16 @@ def test_fail(self):
         """
         v = in_([1, 2, 3])
         a = simple_attr("test")
+
         with pytest.raises(ValueError) as e:
             v(None, a, None)
-        assert ("'test' must be in [1, 2, 3] (got None)",) == e.value.args
+
+        assert (
+            "'test' must be in [1, 2, 3] (got None)",
+            a,
+            [1, 2, 3],
+            None,
+        ) == e.value.args
 
     def test_fail_with_string(self):
         """
@@ -482,7 +489,12 @@ def test_fail_with_string(self):
         a = simple_attr("test")
         with pytest.raises(ValueError) as e:
             v(None, a, None)
-        assert ("'test' must be in 'abc' (got None)",) == e.value.args
+        assert (
+            "'test' must be in 'abc' (got None)",
+            a,
+            "abc",
+            None,
+        ) == e.value.args
 
     def test_repr(self):
         """