Intended use & limitations
For: a local-first, best-effort PII detector for short, informal en/tr text —
scrubbing input before a third-party LLM, cutting PII in developer logs, a
privacy-conscious local utility.
Not for: a sole, compliance-grade safeguard. Redaction is a recall problem — a
miss is a leak — and on realistic out-of-distribution text this model misses a meaningful
fraction (concentrated on names, and on free-text entities in long or formal documents;
structured Turkish addresses are recovered by the grammar below). Do not make it the
only barrier before you log, store, or forward regulated data (GDPR / PCI / HIPAA). Use it
as one layer in defence-in-depth.
Scope: English + Turkish; short messages, not long documents; the nine types above.
Usage
from transformers import AutoModelForCausalLM, AutoTokenizer
model_id = "promptrails/piimask-qwen2.5-0.5b"
tok = AutoTokenizer.from_pretrained(model_id)
model = AutoModelForCausalLM.from_pretrained(model_id)
SYSTEM = (
"You are a PII detection engine. Extract every piece of personally identifiable "
"information from the user's text.\n\n"
'Respond with ONLY a JSON object of the form:\n'
'{"entities": [{"type": "<TYPE>", "value": "<exact substring from the text>"}]}\n\n'
"Valid types: PERSON, EMAIL, PHONE, NATIONAL_ID, IBAN, CREDIT_CARD, ADDRESS, "
"DATE_OF_BIRTH, IP_ADDRESS.\n"
"Each value must be copied verbatim from the text. If the text contains no PII, "
'respond with {"entities": []}.'
)
text = "Ben Ayşe Yılmaz, kartım 4111 1111 1111 1111, mailim ayse@firma.com"
prompt = tok.apply_chat_template(
[{"role": "system", "content": SYSTEM}, {"role": "user", "content": text}],
add_generation_prompt=True, tokenize=False,
)
ids = tok(prompt, return_tensors="pt").to(model.device)
out = model.generate(**ids, max_new_tokens=256, do_sample=False)
print(tok.decode(out[0][ids["input_ids"].shape[1]:], skip_special_tokens=True))
Checksummable types (EMAIL / IP / IBAN / CREDIT_CARD / NATIONAL_ID) pair with a
deterministic validation pass (format + check digit — Luhn, IBAN mod-97, TCKN) to maximise
precision on well-formed values. Turkish addresses — which have no checksum — pair with
the anchor grammar below instead.
Turkish addresses — add the deterministic grammar
The model learned one Turkish address format and misses street-first addresses
(Barbaros Hayrettin Paşa Sokak No:158 Daire:37 Konak/Adana). This small, order-invariant
regex grammar catches them by structure and recovers recall to ~1.0 — add its matches to
the model output. It fires only on Turkish structure, so English is untouched:
import re
_TR_IL = ("Adana Adıyaman Afyonkarahisar Afyon Ağrı Amasya Ankara Antalya Artvin Aydın "
"Balıkesir Bilecik Bingöl Bitlis Bolu Burdur Bursa Çanakkale Çankırı Çorum Denizli "
"Diyarbakır Edirne Elazığ Erzincan Erzurum Eskişehir Gaziantep Antep Giresun Gümüşhane "
"Hakkari Hatay Isparta Mersin İçel İstanbul İzmir Kars Kastamonu Kayseri Kırklareli "
"Kırşehir Kocaeli Konya Kütahya Malatya Manisa Kahramanmaraş Maraş Mardin Muğla Muş "
"Nevşehir Niğde Ordu Rize Sakarya Samsun Siirt Sinop Sivas Tekirdağ Tokat Trabzon "
"Tunceli Şanlıurfa Urfa Uşak Van Yozgat Zonguldak Aksaray Bayburt Karaman Kırıkkale "
"Batman Şırnak Bartın Ardahan Iğdır Yalova Karabük Kilis Osmaniye Düzce").split()
_L = "A-Za-zçğıöşüÇĞİÖŞÜ"
_IL = re.compile(rf"(?<![{_L}])(?:" + "|".join(sorted(map(re.escape, _TR_IL), key=len, reverse=True)) + rf")(?![{_L}])")
_ANCHOR = re.compile(r"\b(mahallesi|mahalle|mah|mh|caddesi|cadde|cad|cd|sokağı|sokak|sok|sk|bulvarı|bulvar|blv|meydanı|meydan)\b\.?", re.I)
_NUM = re.compile(r"\b(no|numara|kat|daire|blok|apt|d)\b\.?\s*[:.]?\s*\d|\bno[:.]?\s*\d|\d+/\d+", re.I)
def _start(text, a):
i = a
while i > 0 and text[i - 1] == " ": i -= 1
s = i
while i > 0:
j = i
while j > 0 and (text[j - 1].isalnum() or text[j - 1] in "çğıöşüÇĞİÖŞÜ"): j -= 1
w = text[j:i]
if w and (w[0].isupper() or w[0].isdigit()):
s = j; i = j
while i > 0 and text[i - 1] == " ": i -= 1
if i > 0 and text[i - 1] in ".,:;": break
else:
break
return s
def turkish_addresses(text):
spans = []
for m in _IL.finditer(text):
w0 = max(0, m.start() - 140)
anchors = list(_ANCHOR.finditer(text[w0:m.start()]))
if not anchors: continue
st = _start(text[w0:m.start()], anchors[0].start()) + w0
if not _NUM.search(text[st:m.end()]) and "mah" not in anchors[0].group().lower(): continue
spans.append([st, m.end()])
spans.sort(key=lambda s: (s[0], -(s[1] - s[0])))
out = []
for s in spans:
if out and s[0] < out[-1][1]:
out[-1][1] = max(out[-1][1], s[1])
else:
out.append(s)
return [text[a:b] for a, b in out]
Evaluation
Entity-level micro-F1, full piimask (the model plus the deterministic passes above)
versus Microsoft Presidio and the ai4privacy
DeBERTa PII NER (Isotonic/deberta-v3-base_finetuned_ai4privacy_v2).
Independent bilingual benchmark — a held-out, independently-constructed set of 400
short en/tr documents (some code-switched) with adversarial distractors (product codes,
reference numbers designed to trigger false positives):
Table with columns: System, micro-F1| System | micro-F1 |
|---|
| piimask (0.5B) | 0.81 |
| ai4privacy DeBERTa | 0.65 |
| Microsoft Presidio | 0.51 |
Turkish addresses are the clearest win. The raw model — like both baselines — learned
one address format and misses street-first Turkish addresses, recall 0.16; the
deterministic grammar above is order-invariant and lifts it to ~1.0, with no effect on
English. Presidio and DeBERTa score ~0.00 on Turkish addresses.
Other sets:
Table with columns: Eval set, piimask, Presidio, DeBERTa| Eval set | piimask | Presidio | DeBERTa |
|---|
| Realistic Turkish PII (held-out test) | 0.89 | 0.42 | 0.47 |
| piimb aggregate (en) | 0.65 | 0.55 | — |
| gretel finance docs (en, out-of-distribution) | 0.49 | 0.37 | 0.37 |
Read these honestly: the Turkish and bilingual numbers are on piimask's target domain
(short, informal text); the gretel English row is long, formal finance documents — fully
out-of-distribution and the most conservative, like-for-like number. Redaction is a recall
problem, and on long formal text the model still misses a meaningful fraction — so use
piimask in defence-in-depth, not standing alone. DeBERTa is not scored on piimb, which
overlaps its own training data.
License
Apache-2.0, inheriting the base model
Qwen/Qwen2.5-0.5B-Instruct
(Apache-2.0).