diff --git a/lib/galaxy/dependencies/pinned-requirements.txt b/lib/galaxy/dependencies/pinned-requirements.txt
index 471c31e7b27..a7e3fce6afa 100644
--- a/lib/galaxy/dependencies/pinned-requirements.txt
+++ b/lib/galaxy/dependencies/pinned-requirements.txt
@@ -207,6 +207,7 @@ pydantic-ai==1.99.0
 pydantic-ai-slim==1.99.0
 pydantic-core==2.46.4
 pydantic-evals==1.99.0
+pydantic-extra-types==2.11.1
 pydantic-graph==1.99.0
 pydantic-handlebars==0.1.0
 pydantic-settings==2.14.1
diff --git a/lib/galaxy/tool_util_models/parameters.py b/lib/galaxy/tool_util_models/parameters.py
index 4aa956fc41d..3922cf39b70 100644
--- a/lib/galaxy/tool_util_models/parameters.py
+++ b/lib/galaxy/tool_util_models/parameters.py
@@ -41,6 +41,7 @@ from pydantic import (
     TypeAdapter,
 )
 from pydantic.json_schema import SkipJsonSchema
+from pydantic_extra_types.color import Color
 from typing_extensions import (
     Annotated,
     Literal,
@@ -1540,15 +1541,10 @@ def ensure_color_valid(value: Optional[Any]):
         return
     if not isinstance(value, str):
         raise ValueError(f"Invalid color value type {value.__class__} encountered.")
-    value_str: str = value
-    message = f"Invalid color value string format {value_str} encountered."
-    if len(value_str) != 7:
-        raise ValueError(message + "0")
-    if value_str[0] != "#":
-        raise ValueError(message + "1")
-    for byte_str in value_str[1:]:
-        if byte_str not in "0123456789abcdef":
-            raise ValueError(message + "2")
+    try:
+        Color(value)
+    except Exception as e:
+        raise ValueError(f"Invalid color value {value!r}: {e}")
 
 
 class ColorParameterModel(BaseGalaxyToolParameterModelDefinition):
@@ -1558,7 +1554,7 @@ class ColorParameterModel(BaseGalaxyToolParameterModelDefinition):
 
     def field_kwargs(self) -> Dict[str, Any]:
         kwargs = super().field_kwargs()
-        kwargs["json_schema_extra"]["pattern"] = "^#[0-9a-f]{6}$"
+        kwargs["json_schema_extra"]["format"] = "color"
         return kwargs
 
     @property
diff --git a/packages/tool_util_models/setup.cfg b/packages/tool_util_models/setup.cfg
index 7b39184dd28..ad7ded316f0 100644
--- a/packages/tool_util_models/setup.cfg
+++ b/packages/tool_util_models/setup.cfg
@@ -15,6 +15,7 @@ version = 26.1.dev0
 include_package_data = True
 install_requires =
     pydantic>=2.7.4
+    pydantic-extra-types
     typing-extensions
 package_dir =
     =src
diff --git a/pyproject.toml b/pyproject.toml
index 58136807761..c1c16e97891 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -76,6 +76,7 @@ dependencies = [
     "pycryptodome",
     "pydantic[email]>=2.7.4",  # https://github.com/pydantic/pydantic/pull/9639
     "pydantic-ai>=1.56.0",  # https://github.com/pydantic/pydantic-ai/security/advisories/GHSA-2jrp-274c-jhv3
+    "pydantic-extra-types",
     "pydicom; python_version >= '3.10'",
     "PyJWT",
     "pykwalify",
diff --git a/test/unit/tool_util/parameter_specification.yml b/test/unit/tool_util/parameter_specification.yml
index dc34e7061ce..ca475a8c3e7 100644
--- a/test/unit/tool_util/parameter_specification.yml
+++ b/test/unit/tool_util/parameter_specification.yml
@@ -1233,10 +1233,10 @@ gx_color:
   request_valid:
    - parameter: '#aabbcc'
    - parameter: '#000000'
+   - parameter: '#abcd'
   request_invalid:
    - parameter: null
    - parameter: {}
-   - parameter: '#abcd'
   workflow_step_valid:
    - parameter: '#aabbcc'
    - parameter: '#000000'
@@ -1253,6 +1253,9 @@ gx_color:
     - parameter: 'foobar'
     - parameter: 5
     - parameter: {__class__: 'ConnectedValue2'}
+  _json_schema_skip:
+    workflow_step_invalid: "color validator uses AfterValidator"
+    workflow_step_linked_invalid: "color validator uses AfterValidator"
 
 gx_data:
   request_valid: