add_custom_credentials · Terra Config MCP Server MCP

WHAT IT DOES

What add_custom_credentials does on Terra Config MCP Server

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

WHY IT NEEDS A POLICY

Why add_custom_credentials needs a policy

Adding credentials is a reversible Write operation—it creates or modifies authentication data in the system. However, severity is elevated to 'high' because misuse could introduce malicious credentials, compromise integrations, or enable unauthorized access to health/fitness data sources. The empty description lowers confidence slightly, but the name and server context are sufficiently clear.

From the tool's definition Tool name 'add_custom_credentials' indicates creation/modification of credential data. Server context shows it manages 'provider credentials' and 'data source configurations' for the TerraAPI dashboard.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

add_custom_credentials Rate-limited

add_custom_credentials 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_custom_credentials": {
      "limits": [
        {
          "counter": "add_custom_credentials_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 Terra Config MCP Server, so you can run agents against it safely.

FAQ

Questions about add_custom_credentials

What does the add_custom_credentials tool do? +

add_custom_credentials. It is categorised as a Write tool in the Terra Config MCP Server 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_custom_credentials? +

Register the Terra Config MCP Server MCP server in PolicyLayer and add a rule for add_custom_credentials: 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 Terra Config MCP Server. Nothing to install.

What risk level is add_custom_credentials? +

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

Can I rate-limit add_custom_credentials? +

Yes. Add a rate_limit block to the add_custom_credentials 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_custom_credentials completely? +

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

add_custom_credentials is provided by the Terra Config MCP Server MCP server (tryterra/terramcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.