PIIGhost¶

Transparent PII anonymization for LLM agents.

piighost is a Python library that automatically detects, anonymizes, and deanonymizes sensitive entities (names, locations, etc.) in AI agent conversations. It integrates via a LangChain middleware without modifying your existing agent code.

Features¶

• 4-stage pipeline: Detect → Expand → Map → Replace — covers every occurrence of each entity, not just the first
• Bidirectional: reliable deanonymization via reverse spans, plus fast string-based reanonymization
• Session caching: PlaceholderStore protocol for cross-session persistence (SHA-256 keyed)
• LangChain middleware: transparent hooks on abefore_model, aafter_model, and awrap_tool_call — zero changes to your agent code
• Protocol-based DI: every pipeline stage is a swappable protocol — detector, occurrence finder, placeholder factory, span validator
• Immutable data models: frozen dataclasses throughout (Entity, Placeholder, Span, AnonymizationResult)

Installation¶

uv add piighost

pip install piighost

Quick example¶

from gliner2 import GLiNER2
from piighost.anonymizer import Anonymizer, GlinerDetector

model = GLiNER2.from_pretrained("fastino/gliner2-multi-v1")
detector = GlinerDetector(model=model, threshold=0.5, flat_ner=True)
anonymizer = Anonymizer(detector=detector)

result = anonymizer.anonymize(
    "Patrick lives in Paris. Patrick loves Paris.",
    labels=["PERSON", "LOCATION"],
)

print(result.anonymized_text)
# <<PERSON_1>> lives in <<LOCATION_1>>. <<PERSON_1>> loves <<LOCATION_1>>.

original = anonymizer.deanonymize(result)
print(original)
# Patrick lives in Paris. Patrick loves Paris.

Navigation¶