harvest_list_clients

THE RISK

Low Risk

Why harvest_list_clients needs a policy

This tool retrieves and queries client data without side effects, matching the Read category definition. The severity is low because listing clients poses minimal risk—it exposes non-sensitive structural information about the business that an AI agent cannot misuse to cause harm.

From the tool's definition Tool name 'harvest_list_clients' and description 'List all clients' indicate a retrieval operation with no modification or deletion. This is a read-only query.

Documented attack patterns abuse exactly the kind of access harvest_list_clients gives an agent:

POLICY

How to control harvest_list_clients

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_clients:

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "harvest_list_clients": {}
  }
}

harvest_list_clients is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.

Create a free account and register Harvest MCP Server — nothing to install.
Add this policy — paste it, or build it visually.
Point your MCP client (Claude, Cursor, anything) at your gateway URL.

CAP THIS TOOL →

Free to start. No card required.

EXPLORE

Related tools and policies

More Harvest MCP Server tools

Destructive harvest_delete_time_entry Delete a time entry. Use this to remove erroneous or unwanted time entries. Write harvest_stop_timer Stop a running timer on a time entry Write harvest_create_time_entry Create a new time entry Read harvest_compute_budget_performance Analyze employee performance based on budget adherence per project. Compares actual hours Read harvest_aggregate_time Aggregate time entries by various dimensions. Simple convenience tool for getting total ho Read harvest_compute_profitability Compute profitability metrics for a date range. Supports three modes: time_based (hours r Read harvest_compute_utilization Compute utilization metrics for a date range. Shows how much of available capacity is bein Read harvest_get_company Get information about the authenticated Harvest company/account

All 21 Harvest MCP Server tools →

Read tools on other servers

M-Team MCP Server get_torrent_detail YouTube MCP Server search_channel Android Forensics ADB MCP Server parse_browser_history 0xarchive web3_challenge

Go deeper

The MCP Attack Database → Documented attack patterns against MCP deployments — and the policies that stop them.
Data exfiltration → How read access becomes an exfiltration channel when chained with untrusted content.
MCP token cost → What connecting this server costs in context-window tokens on every request.
Rate Limiting MCP Tool Calls: A Practical Guide →
MCP Security: Why Prompt Guardrails Aren't Enough →

FAQ

Questions about harvest_list_clients

What does the harvest_list_clients tool do? +

List all clients. Note: Client contacts (people) are available via harvest_list_contacts tool. It is categorised as a Read tool in the Harvest MCP Server MCP Server, which means it retrieves data without modifying state.

How do I enforce a policy on harvest_list_clients? +

Register the Harvest MCP Server MCP server in PolicyLayer and add a rule for harvest_list_clients: 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.

What risk level is harvest_list_clients? +

harvest_list_clients is a Read tool with low risk. Read-only tools are generally safe to allow by default.

Can I rate-limit harvest_list_clients? +

Yes. Add a rate_limit block to the harvest_list_clients 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 harvest_list_clients completely? +

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

harvest_list_clients 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.

Enforce policy on every Harvest MCP Server tool call.

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.

CHECK YOUR STACK →