Add a custom security detection rule. Create custom rules to detect specific patterns in content. Rules use regular expressions for pattern matching and can be configured with different severity levels and actions. Args: - id (string): Unique rule identifier (lowercase, alphanumeric, underscores)...
Part of the Mund server.
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AI agents use mund_add_rule to create or modify resources in Mund. Write operations carry medium risk because an autonomous agent could trigger bulk unintended modifications. Rate limits prevent a single agent session from making hundreds of changes in rapid succession. Argument validation ensures the agent passes expected values.
Without a policy, an AI agent could call mund_add_rule repeatedly, creating or modifying resources faster than any human could review. PolicyLayer's rate limiting ensures write operations happen at a controlled pace, and argument validation catches malformed or unexpected inputs before they reach Mund.
Write tools can modify data. A rate limit prevents runaway bulk operations from AI agents.
{
"version": "1",
"default": "deny",
"tools": {
"mund_add_rule": {
"limits": [
{
"counter": "mund_add_rule_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}See the full Mund policy for all 23 tools.
These attack patterns abuse exactly the kind of access mund_add_rule gives an agent. Each links to the full case and the policy that stops it:
Other write tools across the catalogue. The same approach applies to each: rate-limit and validate the arguments.
Add a custom security detection rule. Create custom rules to detect specific patterns in content. Rules use regular expressions for pattern matching and can be configured with different severity levels and actions. Args: - id (string): Unique rule identifier (lowercase, alphanumeric, underscores) - name (string): Human-readable rule name - description (string): Optional description - type: Detection type (secret, pii, code_pattern, injection, exfiltration) - pattern (string): Regular expression to match - severity: Severity level (critical, high, medium, low, info) - action: Action to take (alert, block, log, quarantine) Returns: Confirmation of rule addition with rule details. It is categorised as a Write tool in the Mund MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Mund MCP server in PolicyLayer and add a rule for mund_add_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 Mund. Nothing to install.
mund_add_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 mund_add_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 mund_add_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.
mund_add_rule is provided by the Mund MCP server (@weave_protocol/mund). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 23 Mund tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
Free to start. No card required.
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