add_constraint · Chronos MCP: Risk & Policy

WHAT IT DOES

What add_constraint does on Chronos MCP

AI agents use add_constraint to create or update resources in Chronos MCP — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Chronos MCP environment.

WHY IT NEEDS A POLICY

Why add_constraint needs a policy

The tool name 'add_constraint' indicates creation or modification of constraint data within the knowledge graph system. This is a reversible data modification (constraints can be removed or updated), consistent with Write category. The empty description reduces confidence, but the naming pattern and context of sibling Write tools (add_event, remember) support this classification.

From the tool's definition Tool name 'add_constraint' suggests it modifies or adds a constraint to the knowledge graph. The sibling tools include 'add_event' and 'remember' which are clearly Write operations, placing 'add_constraint' in the same functional family.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

add_constraint Rate-limited

add_constraint stays usable, but capped — an agent stuck in a loop can't make hundreds of changes a minute. Everything else on the server is denied unless you say otherwise.

View as policy code

policy.json

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

LIMIT THIS TOOL →

Instant setup, no code required.

PolicyLayer is an MCP gateway: every tool call is checked against your rule before it reaches Chronos MCP, so you can run agents against it safely.

FAQ

Questions about add_constraint

What does the add_constraint tool do? +

add_constraint. It is categorised as a Write tool in the Chronos MCP MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on add_constraint? +

Register the Chronos MCP server in PolicyLayer and add a rule for add_constraint: 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 Chronos MCP. Nothing to install.

What risk level is add_constraint? +

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

Can I rate-limit add_constraint? +

Yes. Add a rate_limit block to the add_constraint 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.

How do I block add_constraint completely? +

Set action: deny in the PolicyLayer policy for add_constraint. 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 add_constraint? +

add_constraint is provided by the Chronos MCP server (synaptikal/chronosmcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.