Skip to content

[v1.x] fix: catch PydanticUserError when generating output schema (pydantic 2.13 compat) #2435

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
maxisbey merged 1 commit into from
Apr 13, 2026
+10 −2
Merged

[v1.x] fix: catch PydanticUserError when generating output schema (pydantic 2.13 compat) #2435

Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
12 changes: 10 additions & 2 deletions src/mcp/server/fastmcp/utilities/func_metadata.py
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -10,6 +10,7 @@
BaseModel,
ConfigDict,
Field,
PydanticUserError,
RootModel,
WithJsonSchema,
create_model,
Expand Down Expand Up @@ -411,9 +412,16 @@ def _try_create_model_and_schema(
# Use StrictJsonSchema to raise exceptions instead of warnings
try:
schema = model.model_json_schema(schema_generator=StrictJsonSchema)
except (TypeError, ValueError, pydantic_core.SchemaError, pydantic_core.ValidationError) as e:
except (
PydanticUserError,
TypeError,
ValueError,
pydantic_core.SchemaError,
pydantic_core.ValidationError,
) as e:
# These are expected errors when a type can't be converted to a Pydantic schema
# TypeError: When Pydantic can't handle the type
# PydanticUserError: When Pydantic can't handle the type (e.g. PydanticInvalidForJsonSchema);
# subclasses TypeError on pydantic <2.13 and RuntimeError on pydantic >=2.13
# ValueError: When there are issues with the type definition (including our custom warnings)
# SchemaError: When Pydantic can't build a schema
# ValidationError: When validation fails
Expand Down
Loading