Create a new app rule in your tru wallet. Use this after manually approving a charge to set up auto-approval for future similar charges. Supports spending limits (auto-approve up to $X per period), action permissions (allow/deny specific actions), and escalation thresholds (ask before charges abo...
AI agents use suggest_rule to create or update resources in Tru — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Tru environment.
| Parameter | Type | Required | Description |
|---|---|---|---|
label | string | Yes | Human-readable name for this rule (e.g. 'Auto-approve small purchases') |
app_id | string | — | Limit rule to a specific app (omit for global rule) |
rule_type | string | Yes | Type of rule: 'spending_limit' for auto-approve up to an amount, 'action_permission' to allow/deny specific actions, 'escalation' to require approval above a th |
action_name | string | — | For action_permission: the action to allow/deny |
action_allowed | boolean | — | For action_permission: true to allow, false to deny |
spending_period | string | — | For spending_limit: time period for the limit |
escalation_action | string | — | For escalation: 'ask' to prompt user, 'deny' to block |
spending_limit_cents | integer | — | For spending_limit: max amount in cents per period (e.g. 5000 for $50) |
escalation_threshold_cents | integer | — | For escalation: amount in cents above which to escalate |
Parameters from the server's own tool schema.
This tool creates or modifies rules that govern financial authorization and spending limits. While it doesn't directly move money, it configures automated decision-making for future financial transactions ('auto-approve up to $X per period').
From the tool's definition 'Create a new app rule in your tru wallet' — this creates a configuration object that modifies approval behavior for future charges. The tool establishes new rules that alter how payments are automatically processed.
Attacks that exploit this kind of access
Create a new app rule in your tru wallet. Use this after manually approving a charge to set up auto-approval for future similar charges. Supports spending limits (auto-approve up to $X per period), action permissions (allow/deny specific actions), and escalation thresholds (ask before charges above $X). Requires login first (use the login tool). It is categorised as a Write tool in the Tru MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
suggest_rule accepts 9 parameters: label, app_id, rule_type, action_name, action_allowed, spending_period, escalation_action, spending_limit_cents, escalation_threshold_cents. Required: label, rule_type. The full parameter table on this page comes from the server's own tool schema.
Register the Tru MCP server in PolicyLayer and add a rule for suggest_rule: allow, deny, rate-limit, or require approval. Point your MCP client at the PolicyLayer proxy URL and the rule is enforced on every call, before it reaches Tru. Nothing to install.
suggest_rule is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.
Yes. Add a rate_limit block to the suggest_rule rule in your PolicyLayer policy. For example, setting max: 10 and window: 60 limits the tool to 10 calls per minute. Rate limits are tracked per agent session and reset automatically.
Set action: deny in the PolicyLayer policy for suggest_rule. The AI agent will receive a policy violation error and cannot call the tool. You can also include a reason field to explain why the tool is blocked.
suggest_rule is provided by the Tru MCP server (tru-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Every MCP server has a record like this.
Type a name, get the same breakdown: verified identity, auth posture, risk grade, capabilities, recommended policy.
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