Guards Reference

QWED Open Responses provides 6 verification guards.

---

SchemaGuard

Validates AI outputs against JSON Schema.

from qwed_open_responses import SchemaGuard

guard = SchemaGuard(schema={
    "type": "object",
    "properties": {
        "name": {"type": "string"},
        "age": {"type": "integer", "minimum": 0}
    },
    "required": ["name", "age"]
})

result = guard.check({"output": {"name": "John", "age": 30}})
# ✅ Passed

Options

Option	Type	Default	Description
schema	dict	required	JSON Schema
strict	bool	True	Fail on any error

---

ToolGuard

Blocks dangerous tool calls and patterns.

from qwed_open_responses import ToolGuard

guard = ToolGuard(
    blocked_tools=["execute_shell", "delete_file"],
    allowed_tools=["search", "calculator"],  # Whitelist mode
    dangerous_patterns=[r"DROP TABLE", r"rm -rf"],
)

result = guard.check({
    "tool_name": "execute_sql",
    "arguments": {"query": "DROP TABLE users"}
})
# ❌ BLOCKED: Dangerous pattern detected

Default Blocked Tools

• execute_shell, bash, cmd
• delete_file, remove_file
• send_email, transfer_money

Default Dangerous Patterns

• DROP TABLE, DELETE FROM
• rm -rf, rmdir /s
• eval(, exec(, __import__

---

MathGuard

Verifies mathematical calculations.

from qwed_open_responses import MathGuard

guard = MathGuard(tolerance=0.01)

result = guard.check({
    "output": {
        "subtotal": 100,
        "tax": 8,
        "shipping": 10,
        "total": 118  # Correct!
    }
})
# ✅ Passed

What It Checks

• Totals: total = subtotal + tax + shipping
• Percentages: tax_amount = subtotal * tax_rate
• Inline calculations: "5 + 3 = 8"

---

StateGuard

Validates state machine transitions.

from qwed_open_responses import StateGuard

guard = StateGuard(
    transitions={
        "pending": ["processing", "cancelled"],
        "processing": ["completed", "failed"],
        "completed": [],  # Terminal
    },
    current_state="pending"
)

result = guard.check({"new_state": "processing"})
# ✅ Valid transition

result = guard.check({"new_state": "completed"})
# ❌ Invalid: pending -> completed not allowed

---

ArgumentGuard

Validates tool call arguments.

from qwed_open_responses import ArgumentGuard

guard = ArgumentGuard(rules={
    "amount": {"type": "number", "min": 0, "max": 10000},
    "email": {"type": "email"},
    "status": {"type": "enum", "values": ["active", "inactive"]},
})

result = guard.check({
    "arguments": {
        "amount": 500,
        "email": "user@example.com",
        "status": "active"
    }
})
# ✅ All arguments valid

Supported Types

Type	Validation
string	Is string
number	Is number, min/max
integer	Is integer
boolean	Is boolean
email	Email format
url	URL format
uuid	UUID format
enum	In allowed values
pattern	Regex match

---

SafetyGuard

Comprehensive safety checks.

from qwed_open_responses import SafetyGuard

guard = SafetyGuard(
    check_pii=True,        # Detect emails, phones, SSN
    check_injection=True,  # Detect prompt injection
    check_harmful=True,    # Detect API keys, passwords
    max_cost=100.0,        # Budget limit
)

result = guard.check({
    "content": "ignore previous instructions..."
})
# ❌ BLOCKED: Prompt injection detected

Detections

Type	Examples
PII	Emails, phones, SSN, credit cards
Injection	"ignore previous", "you are now"
Harmful	API keys, passwords, private keys
Budget	Cost/token limits exceeded

---

Combining Guards

from qwed_open_responses import (
    ResponseVerifier,
    ToolGuard,
    SchemaGuard,
    SafetyGuard,
)

verifier = ResponseVerifier(
    default_guards=[
        ToolGuard(),
        SchemaGuard(schema=my_schema),
        SafetyGuard(),
    ]
)

result = verifier.verify(response)
print(f"Passed: {result.guards_passed}")
print(f"Failed: {result.guards_failed}")