Registry

Registry for managing GuardrailSpec instances and maintaining a catalog of guardrails.

This module provides the in-memory registry that acts as the authoritative catalog for all available guardrail specifications. The registry supports registration, lookup, removal, and metadata inspection for guardrails, enabling extensibility and dynamic discovery across your application.

default_spec_registry module-attribute

default_spec_registry = GuardrailRegistry()

Global default registry for guardrail specifications.

This instance should be used for registration and lookup unless a custom registry is explicitly required.

Metadata dataclass

Metadata snapshot for a guardrail specification.

This container bundles descriptive and structural details about a guardrail for inspection, discovery, or documentation.

Attributes:

Name	Type	Description
name	str	Unique identifier for the guardrail.
description	str	Explanation of what the guardrail checks.
media_type	str	MIME type (e.g. "text/plain") the guardrail applies to.
config_schema	dict[str, Any] | None	JSON schema for the guardrail's config model.
metadata	dict[str, Any] | None	Additional metadata (e.g., engine type).

Source code in src/guardrails/registry.py

@dataclass(frozen=True, slots=True)
class Metadata:
    """Metadata snapshot for a guardrail specification.

    This container bundles descriptive and structural details about a guardrail
    for inspection, discovery, or documentation.

    Attributes:
        name (str): Unique identifier for the guardrail.
        description (str): Explanation of what the guardrail checks.
        media_type (str): MIME type (e.g. "text/plain") the guardrail applies to.
        config_schema (dict[str, Any] | None): JSON schema for the guardrail's config model.
        metadata (dict[str, Any] | None): Additional metadata (e.g., engine type).
    """

    name: str
    description: str
    media_type: str
    config_schema: dict[str, Any] | None
    metadata: dict[str, Any] | None = None

GuardrailRegistry

Central registry for all registered guardrail specifications.

This class provides methods to register, remove, and look up :class:GuardrailSpec objects by name. It supports dynamic extension of available guardrails and powers discovery and validation throughout the package.

Typical usage

registry = GuardrailRegistry()
registry.register(...)
spec = registry.get("my_guardrail")
all_specs = registry.get_all()

Source code in src/guardrails/registry.py

class GuardrailRegistry:
    """Central registry for all registered guardrail specifications.

    This class provides methods to register, remove, and look up
    :class:`GuardrailSpec` objects by name. It supports dynamic extension
    of available guardrails and powers discovery and validation
    throughout the package.

    Typical usage:
        ```python
        registry = GuardrailRegistry()
        registry.register(...)
        spec = registry.get("my_guardrail")
        all_specs = registry.get_all()
        ```
    """

    def __init__(self) -> None:
        """Initialize an empty registry of guardrail specifications."""
        self._guardrailspecs: dict[str, GuardrailSpec[Any, Any, Any]] = {}
        self._logger = logging.getLogger(__name__ + ".GuardrailSpecRegistry")

    def register(
        self,
        name: str,
        check_fn: CheckFn[TContext, TIn, Any],
        description: str,
        media_type: str,
        *,
        metadata: GuardrailSpecMetadata | None = None,
    ) -> None:
        """Register a new guardrail specification.

        This adds a :class:`GuardrailSpec` to the registry, inferring the required
        context and configuration models from the function signature.

        Args:
            name (str): Unique identifier for the guardrail.
            check_fn (CheckFn): Function that implements the guardrail logic.
            description (str): Human-readable description for docs and discovery.
            media_type (str): MIME type this guardrail operates on.
            metadata (GuardrailSpecMetadata, optional): Additional details for UIs or tooling.

        Raises:
            ValueError: If `media_type` is not a valid MIME type, or if `name`
                is already registered.

        Example:
            ```python
            registry.register(
                name="keyword_filter",
                check_fn=keywords,
                description="Triggers if text contains banned keywords.",
                media_type="text/plain",
            )
            ```
        """
        if name in self._guardrailspecs:
            existing = self._guardrailspecs[name]
            self._logger.error("Duplicate registration attempted for '%s'", name)
            msg = f"Guardrail name '{name}' already bound to {existing.check_fn.__qualname__}. Pick a distinct name or rename the function."
            raise ValueError(msg)

        if isinstance(media_type, str) and not MIME_RE.match(media_type):
            msg = f"Invalid media-type '{media_type}'"
            raise ValueError(msg)

        resolved_ctx = _resolve_ctx_requirements(check_fn)
        resolved_config_schema = _resolve_config_schema(check_fn)

        _name = name or check_fn.__name__
        guardrailspec = GuardrailSpec(
            name=_name,
            description=description,
            media_type=media_type,
            config_schema=resolved_config_schema,
            check_fn=check_fn,
            ctx_requirements=resolved_ctx,
            metadata=metadata or GuardrailSpecMetadata(),
        )

        self._guardrailspecs[guardrailspec.name] = guardrailspec
        self._logger.debug("Registered guardrail spec '%s'", guardrailspec.name)

    def remove(self, name: str) -> None:
        """Remove a registered guardrail specification by name.

        Args:
            name (str): The guardrail name to remove.

        Raises:
            KeyError: If `name` is not present in the registry.
        """
        if name in self._guardrailspecs:
            del self._guardrailspecs[name]
            return
        msg = f"Guardrail spec '{name}' not found."
        raise KeyError(msg)

    def get(self, name: str) -> GuardrailSpec[Any, Any, Any]:
        """Retrieve a registered guardrail specification by name.

        Args:
            name (str): The name passed to :meth:`register`.

        Returns:
            GuardrailSpec: The registered guardrail specification.

        Raises:
            KeyError: If nothing is registered under `name`.
        """
        if name in self._guardrailspecs:
            return self._guardrailspecs[name]
        self._logger.warning("Attempted lookup of unknown guardrail '%s'", name)
        msg = f"Guardrail spec '{name}' not found."
        raise KeyError(msg)

    def get_all(self) -> list[GuardrailSpec[Any, Any, Any]]:
        """Return a list of all registered guardrail specifications.

        Returns:
            list[GuardrailSpec]: All registered specs, in registration order.
        """
        return list(self._guardrailspecs.values())

    def get_all_metadata(self) -> list[Metadata]:
        """Return summary metadata for all registered guardrail specifications.

        This provides lightweight, serializable descriptions of all guardrails,
        suitable for documentation, UI display, or catalog listing.

        Returns:
            list[Metadata]: List of metadata entries for each registered spec.
        """
        return [
            Metadata(
                name=d.name,
                description=d.description,
                media_type=d.media_type,
                config_schema=d.schema(),
                metadata=d.metadata.model_dump() if d.metadata else {},
            )
            for d in self._guardrailspecs.values()
        ]

__init__

__init__() -> None

Initialize an empty registry of guardrail specifications.

Source code in src/guardrails/registry.py

def __init__(self) -> None:
    """Initialize an empty registry of guardrail specifications."""
    self._guardrailspecs: dict[str, GuardrailSpec[Any, Any, Any]] = {}
    self._logger = logging.getLogger(__name__ + ".GuardrailSpecRegistry")

register

register(
    name: str,
    check_fn: CheckFn[TContext, TIn, Any],
    description: str,
    media_type: str,
    *,
    metadata: GuardrailSpecMetadata | None = None,
) -> None

Register a new guardrail specification.

This adds a :class:GuardrailSpec to the registry, inferring the required context and configuration models from the function signature.

Parameters:

Name	Type	Description	Default
name	str	Unique identifier for the guardrail.	required
check_fn	CheckFn	Function that implements the guardrail logic.	required
description	str	Human-readable description for docs and discovery.	required
media_type	str	MIME type this guardrail operates on.	required
metadata	GuardrailSpecMetadata	Additional details for UIs or tooling.	None

Raises:

Type	Description
ValueError	If media_type is not a valid MIME type, or if name is already registered.

Example

registry.register(
    name="keyword_filter",
    check_fn=keywords,
    description="Triggers if text contains banned keywords.",
    media_type="text/plain",
)

Source code in src/guardrails/registry.py

def register(
    self,
    name: str,
    check_fn: CheckFn[TContext, TIn, Any],
    description: str,
    media_type: str,
    *,
    metadata: GuardrailSpecMetadata | None = None,
) -> None:
    """Register a new guardrail specification.

    This adds a :class:`GuardrailSpec` to the registry, inferring the required
    context and configuration models from the function signature.

    Args:
        name (str): Unique identifier for the guardrail.
        check_fn (CheckFn): Function that implements the guardrail logic.
        description (str): Human-readable description for docs and discovery.
        media_type (str): MIME type this guardrail operates on.
        metadata (GuardrailSpecMetadata, optional): Additional details for UIs or tooling.

    Raises:
        ValueError: If `media_type` is not a valid MIME type, or if `name`
            is already registered.

    Example:
        ```python
        registry.register(
            name="keyword_filter",
            check_fn=keywords,
            description="Triggers if text contains banned keywords.",
            media_type="text/plain",
        )
        ```
    """
    if name in self._guardrailspecs:
        existing = self._guardrailspecs[name]
        self._logger.error("Duplicate registration attempted for '%s'", name)
        msg = f"Guardrail name '{name}' already bound to {existing.check_fn.__qualname__}. Pick a distinct name or rename the function."
        raise ValueError(msg)

    if isinstance(media_type, str) and not MIME_RE.match(media_type):
        msg = f"Invalid media-type '{media_type}'"
        raise ValueError(msg)

    resolved_ctx = _resolve_ctx_requirements(check_fn)
    resolved_config_schema = _resolve_config_schema(check_fn)

    _name = name or check_fn.__name__
    guardrailspec = GuardrailSpec(
        name=_name,
        description=description,
        media_type=media_type,
        config_schema=resolved_config_schema,
        check_fn=check_fn,
        ctx_requirements=resolved_ctx,
        metadata=metadata or GuardrailSpecMetadata(),
    )

    self._guardrailspecs[guardrailspec.name] = guardrailspec
    self._logger.debug("Registered guardrail spec '%s'", guardrailspec.name)

remove

remove(name: str) -> None

Remove a registered guardrail specification by name.

Parameters:

Name	Type	Description	Default
name	str	The guardrail name to remove.	required

Raises:

Type	Description
KeyError	If name is not present in the registry.

Source code in src/guardrails/registry.py

def remove(self, name: str) -> None:
    """Remove a registered guardrail specification by name.

    Args:
        name (str): The guardrail name to remove.

    Raises:
        KeyError: If `name` is not present in the registry.
    """
    if name in self._guardrailspecs:
        del self._guardrailspecs[name]
        return
    msg = f"Guardrail spec '{name}' not found."
    raise KeyError(msg)

get

get(name: str) -> GuardrailSpec[Any, Any, Any]

Retrieve a registered guardrail specification by name.

Parameters:

Name	Type	Description	Default
name	str	The name passed to :meth:register.	required

Returns:

Name	Type	Description
GuardrailSpec	GuardrailSpec[Any, Any, Any]	The registered guardrail specification.

Raises:

Type	Description
KeyError	If nothing is registered under name.

Source code in src/guardrails/registry.py

def get(self, name: str) -> GuardrailSpec[Any, Any, Any]:
    """Retrieve a registered guardrail specification by name.

    Args:
        name (str): The name passed to :meth:`register`.

    Returns:
        GuardrailSpec: The registered guardrail specification.

    Raises:
        KeyError: If nothing is registered under `name`.
    """
    if name in self._guardrailspecs:
        return self._guardrailspecs[name]
    self._logger.warning("Attempted lookup of unknown guardrail '%s'", name)
    msg = f"Guardrail spec '{name}' not found."
    raise KeyError(msg)

get_all

get_all() -> list[GuardrailSpec[Any, Any, Any]]

Return a list of all registered guardrail specifications.

Returns:

Type	Description
list[GuardrailSpec[Any, Any, Any]]	list[GuardrailSpec]: All registered specs, in registration order.

Source code in src/guardrails/registry.py

def get_all(self) -> list[GuardrailSpec[Any, Any, Any]]:
    """Return a list of all registered guardrail specifications.

    Returns:
        list[GuardrailSpec]: All registered specs, in registration order.
    """
    return list(self._guardrailspecs.values())

get_all_metadata

get_all_metadata() -> list[Metadata]

Return summary metadata for all registered guardrail specifications.

This provides lightweight, serializable descriptions of all guardrails, suitable for documentation, UI display, or catalog listing.

Returns:

Type	Description
list[Metadata]	list[Metadata]: List of metadata entries for each registered spec.

Source code in src/guardrails/registry.py

def get_all_metadata(self) -> list[Metadata]:
    """Return summary metadata for all registered guardrail specifications.

    This provides lightweight, serializable descriptions of all guardrails,
    suitable for documentation, UI display, or catalog listing.

    Returns:
        list[Metadata]: List of metadata entries for each registered spec.
    """
    return [
        Metadata(
            name=d.name,
            description=d.description,
            media_type=d.media_type,
            config_schema=d.schema(),
            metadata=d.metadata.model_dump() if d.metadata else {},
        )
        for d in self._guardrailspecs.values()
    ]