LCORE-1831: Implement Redaction Safety Capability in Pydantic AI

src/models/config.py

@@ -2176,6 +2176,118 @@ class SkillsConfiguration(ConfigurationBase):
     )
 
 
+class RedactionRule(ConfigurationBase):
+    """A single regex-based redaction rule.
+
+    Attributes:
+        pattern: Raw regex pattern string to match sensitive data.
+        replacement: Text to substitute for each match.
+        case_sensitive: Per-rule override for case sensitivity.
+            When None, the global ``RedactionConfig.case_sensitive``
+            flag applies.
+    """
+
+    pattern: str = Field(
+        ...,
+        title="Pattern",
+        description="Regex pattern to match sensitive data",
+    )
+    replacement: str = Field(
+        ...,
+        title="Replacement",
+        description="Replacement string for matched text",
+    )
+    case_sensitive: bool | None = Field(
+        None,
+        title="Case sensitive",
+        description=(
+            "Per-rule case sensitivity override. "
+            "When None, the global config flag applies."
+        ),
+    )
+
+
+class RedactionConfig(ConfigurationBase):
+    """Configuration for PII redaction with regex-based rules.
+
+    Rules are validated and compiled at construction time. Invalid
+    regex patterns raise a ``ValueError`` immediately.
+
+    Attributes:
+        rules: Ordered list of redaction rules applied sequentially.
+        case_sensitive: When False, patterns are compiled with
+            ``re.IGNORECASE``. Defaults to False.
+    """
+
+    rules: list[RedactionRule] = Field(
+        default_factory=list,
+        title="Redaction rules",
+        description="Ordered list of PII redaction rules",
+    )
+    case_sensitive: bool = Field(
+        False,
+        title="Case sensitive",
+        description=("When False, patterns are compiled with re.IGNORECASE"),
+    )
+
+    _compiled_patterns: list[tuple[Pattern[str], str]] = PrivateAttr(
+        default_factory=list,
+    )
+
+    @model_validator(mode="after")
+    def compile_patterns(self) -> Self:
+        """Compile regex patterns and reject invalid ones.
+
+        Per-rule ``case_sensitive`` overrides the global flag when set.
+
+        Raises:
+            ValueError: If any rule contains an invalid regex pattern.
+
+        Returns:
+            The validated configuration instance.
+        """
+        global_case_sensitive = self.case_sensitive
+        compiled: list[tuple[Pattern[str], str]] = []
+        for rule in self.rules:
+            effective = (
+                rule.case_sensitive
+                if rule.case_sensitive is not None
+                else global_case_sensitive
+            )
+            flags = 0 if effective else re.IGNORECASE
+            try:
+                pattern = re.compile(rule.pattern, flags)
+            except re.error as e:
+                raise ValueError(f"Invalid regex pattern: {rule.pattern}: {e}") from e
+            compiled.append((pattern, rule.replacement))
+        self._compiled_patterns = compiled
+        return self
+
+    @property
+    def compiled_patterns(self) -> list[tuple[Pattern[str], str]]:
+        """Pre-compiled (regex, replacement) pairs.
+
+        Returns a shallow copy to prevent mutation of internal state.
+        """
+        return list(self._compiled_patterns)
+
+
+class RedactionResult(BaseModel):
+    """Result of applying PII redaction rules to text.
+
+    Attributes:
+        content: The text after all redaction rules have been applied.
+        redacted: True if at least one rule matched and changed the text.
+        redaction_count: Total number of substitutions made across all rules.
+    """
+
+    model_config = ConfigDict(frozen=True)
+
+    content: str
+    redacted: bool
+    redaction_count: int
+
+
 class Configuration(ConfigurationBase):
     """Global service configuration."""
 

src/pydantic_ai_lightspeed/capabilities/__init__.py

@@ -0,0 +1 @@
+"""Pydantic AI capabilities for Lightspeed Core Stack."""

src/pydantic_ai_lightspeed/capabilities/redaction/__init__.py

@@ -0,0 +1,21 @@
+"""PII redaction capability for Pydantic AI agents."""
+
+from models.config import (
+    RedactionConfig,
+    RedactionResult,
+    RedactionRule,
+)
+from pydantic_ai_lightspeed.capabilities.redaction.capability import (
+    PiiRedactionCapability,
+)
+from pydantic_ai_lightspeed.capabilities.redaction.core import (
+    redact_text,
+)
+
+__all__ = [
+    "PiiRedactionCapability",
+    "RedactionConfig",
+    "RedactionResult",
+    "RedactionRule",
+    "redact_text",
+]