List client contacts (people associated with clients). Filter by client_id to get contacts for a specific client. Returns contact details including name, title, email, and phone numbers.
AI agents call harvest_list_contacts to retrieve information from Harvest MCP Server without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool retrieves and queries contact information from Harvest without any side effects—it performs a simple listing/filtering operation to display existing data. There is no creation, modification, deletion, execution, or financial impact.
From the tool's definition Tool name 'harvest_list_contacts' and description 'List client contacts... Returns contact details including name, title, email, and phone numbers' indicates data retrieval with no modification or destructive capability.
Documented attack patterns abuse exactly the kind of access harvest_list_contacts gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Harvest MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for harvest_list_contacts:
{
"version": "1",
"default": "deny",
"tools": {
"harvest_list_contacts": {}
}
} harvest_list_contacts is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
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List client contacts (people associated with clients). Filter by client_id to get contacts for a specific client. Returns contact details including name, title, email, and phone numbers. It is categorised as a Read tool in the Harvest MCP Server MCP Server, which means it retrieves data without modifying state.
Register the Harvest MCP Server MCP server in PolicyLayer and add a rule for harvest_list_contacts: 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 Harvest MCP Server. Nothing to install.
harvest_list_contacts is a Read tool with low risk. Read-only tools are generally safe to allow by default.
Yes. Add a rate_limit block to the harvest_list_contacts 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 harvest_list_contacts. 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.
harvest_list_contacts is provided by the Harvest MCP Server MCP server (southleft/harvest-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Harvest MCP Server, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
Free to start. No card required.
21 Harvest MCP Server tools catalogued and risk-classified — across an index of 43,000+ MCP servers.