Constraints

// WHEN AGENTS USE THIS TOOL

AI agents use Constraints to create or modify resources in Discourse. 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 Constraints 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 Discourse.

// RECOMMENDED POLICY

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

{
  "version": "1",
  "default": "deny",
  "tools": {
    "Constraints": {
      "limits": [
        {
          "counter": "constraints_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

See the full Discourse policy for all 4 tools.

// MORE DISCOURSE TOOLS

// WHAT CAN GO WRONG

These attack patterns abuse exactly the kind of access Constraints gives an agent. Each links to the full case and the policy that stops it:

• Data exfiltration via tool chaining
• Prompt Injection via Tool Results
• Privilege escalation via admin-only tools

Browse the full MCP Attack Database →

// OTHER WRITE TOOLS

Other write tools across the catalogue. The same approach applies to each: rate-limit and validate the arguments.

// RELATED READING

• Rate Limiting MCP Tool Calls: A Practical Guide
• MCP Security: Why Prompt Guardrails Aren't Enough
• The Case for Deterministic AI Agent Policies
• Why AI Agents Need a Control Plane

// FAQ