Recipes

Guard payments

For an agent that can move money, in 15 frameworks.

Last reviewed 2026-10-02

Small transfers run; anything over $100 waits for a person. The amount the rule reads is the one the model actually chose, because the adapter sends the call's real arguments.

The rule

{
  "name": "payments-guard",
  "effect": "require_approval",
  "priority": 10,
  "match_path": "/tools/transfer_funds",
  "conditions": [
    {
      "field": "amount_usd",
      "op": "gt",
      "value": 100
    }
  ]
}

Measured on production (2026-10-02, rule tester): the risky call below matches this rule and the safe one does not.

Risky	`{"amount_usd": 5000, "to_account": "acct-991"}`
Safe	`{"amount_usd": 25, "to_account": "acct-991"}`

Pick your framework

Framework	Tool name CAIN sees	Plugs into
Python (any function)	`transfer_funds`	the function that acts
LangChain	`transfer_funds`	your agent's tool list
LangGraph	`transfer_funds`	the tools your graph's nodes call
OpenAI Agents SDK	`transfer_funds`	function tools
CrewAI	`transfer_funds`	CrewAI's before-tool-call hooks
LlamaIndex	`transfer_funds`	FunctionTool
Pydantic AI	`transfer_funds`	an agent capability
AutoGen (agentchat)	`transfer_funds`	the callables you give AssistantAgent
Google ADK	`transfer_funds`	the functions in an agent's tools
Claude Agent SDK	`mcp__ops__transfer_funds`	PreToolUse hooks
MCP client (Python)	`transfer_funds`	any MCP client session
OpenTelemetry	`transfer_funds`	your existing tracing
Any other framework	`transfer_funds`	any Python callable
TypeScript / JavaScript	`transfer_funds`	any async function
HTTP (any language)	`transfer_funds`	your own call site

Try CAIN-42 on your own agents

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