UltronCore Output Guardrails
Guardrails validate Claude outputs before they reach users or downstream systems — catching format violations, unsafe content, or business rule breaches.
Pattern 1: guardrails-ai (Python)
pip install guardrails-ai
from guardrails import Guard
from guardrails.hub import ValidLength, RegexMatch
guard = Guard().use_many(
ValidLength(min=10, max=500),
RegexMatch(regex=r"^[A-Za-z0-9\s.,!?]+$", match_full=False)
)
raw_llm_output = "Claude's response here"
validated = guard.parse(raw_llm_output)
# Raises ValidationError if constraints fail
Pattern 2: Manual validation layer
from anthropic import Anthropic
import re
client = Anthropic()
def safe_complete(prompt: str, max_retries: int = 3) -> str:
for attempt in range(max_retries):
response = client.messages.create(
model="claude-sonnet-4-6",
max_tokens=1024,
messages=[{"role": "user", "content": prompt}]
)
output = response.content[0].text
# Custom validation
if contains_pii(output):
prompt += "\nIMPORTANT: Do not include personal information."
continue
if not is_valid_format(output):
prompt += "\nReturn only valid JSON."
continue
return output
raise ValueError("Could not generate valid output after retries")
def contains_pii(text: str) -> bool:
patterns = [
r'\b\d{3}-\d{2}-\d{4}\b', # SSN
r'\b\d{16}\b', # Credit card
r'\b[A-Za-z0-9._%+-]+@[A-Za-z0-9.-]+\.[A-Z|a-z]{2,}\b' # Email
]
return any(re.search(p, text) for p in patterns)
Pattern 3: NeMo-Guardrails topical rails (YAML config)
# config.yml
models:
- type: main
engine: anthropic
model: claude-sonnet-4-6
rails:
input:
flows:
- check user message
output:
flows:
- check bot response
define flow check user message
if detect jailbreak
bot inform cannot help with this
stop
define flow check bot response
if response contains competitor mention
bot rephrase response without competitor
When to add guardrails
- User-facing outputs (PII, harmful content risk)
- Financial or legal content (accuracy requirements)
- Structured output pipelines (format enforcement)
- Multi-turn agents (prevent topic drift)
Related skills
security-hardening-checklist, auth-route-protection-checker, structured-output-extraction