Medium Risk

guardrail_create_policy

Create a reusable governance policy that guardrail_check evaluates deterministically (no LLM) on every call. Use this to define rules before calling guardrail_check — policies persist until deleted. Rules compose with and/or/not operators; applied by priority order (first match wins). Returns the...

Bulk/mass operation — affects multiple targets

Part of the Plith MCP server. Enforce policies on this tool with Intercept, the open-source MCP proxy.

plith/plith Write

AI agents use guardrail_create_policy to create or modify resources in Plith. 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 guardrail_create_policy repeatedly, creating or modifying resources faster than any human could review. Intercept's rate limiting ensures write operations happen at a controlled pace, and argument validation catches malformed or unexpected inputs before they reach Plith.

Write tools can modify data. A rate limit prevents runaway bulk operations from AI agents.

plith-plith.yaml
tools:
  guardrail_create_policy:
    rules:
      - action: allow
        rate_limit:
          max: 30
          window: 60

See the full Plith policy for all 14 tools.

Tool Name guardrail_create_policy
Category Write
MCP Server Plith MCP Server
Risk Level Medium

View all 14 tools →

Agents calling write-class tools like guardrail_create_policy have been implicated in these attack patterns. Read the full case and prevention policy for each:

Browse the full MCP Attack Database →

Other tools in the Write risk category across the catalogue. The same policy patterns (rate-limit, validate) apply to each.

What does the guardrail_create_policy tool do? +

Create a reusable governance policy that guardrail_check evaluates deterministically (no LLM) on every call. Use this to define rules before calling guardrail_check — policies persist until deleted. Rules compose with and/or/not operators; applied by priority order (first match wins). Returns the created policy object with id, name, rules, and priority. Duplicate names return an error. Free — no credits charged.. It is categorised as a Write tool in the Plith MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on guardrail_create_policy? +

Add a rule in your Intercept YAML policy under the tools section for guardrail_create_policy. You can allow, deny, rate-limit, or validate arguments. Then run Intercept as a proxy in front of the Plith MCP server.

What risk level is guardrail_create_policy? +

guardrail_create_policy is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.

Can I rate-limit guardrail_create_policy? +

Yes. Add a rate_limit block to the guardrail_create_policy rule in your Intercept 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.

How do I block guardrail_create_policy completely? +

Set action: deny in the Intercept policy for guardrail_create_policy. 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.

What MCP server provides guardrail_create_policy? +

guardrail_create_policy is provided by the Plith MCP server (plith/plith). Intercept sits as a proxy in front of this server to enforce policies before tool calls reach the server.

Let agents act without letting them run wild.

Deterministic policy on every MCP tool call. Per-identity grants. Full audit log.

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