fleet_secrets_set

THE RISK

Medium Risk

Why fleet_secrets_set needs a policy

This tool creates or modifies secret key/value pairs, which is a reversible write operation. However, the severity is elevated to 'high' rather than 'medium' because secrets are sensitive security artifacts—misconfigured or injected secrets can compromise authentication, API keys, database credentials, and other critical infrastructure.

From the tool's definition Tool name 'fleet_secrets_set' and description 'Set a single secret key/value for an app' indicates creation or modification of secrets data. The Fleet server description notes 'age-encrypted secrets', confirming this modifies sensitive credential material.

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

POLICY

How to control fleet_secrets_set

PolicyLayer is an MCP gateway — it sits between your AI agents and Fleet, and nothing reaches the server without passing your rules. This is the rule we recommend for fleet_secrets_set:

policy.json

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

fleet_secrets_set 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.

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

LIMIT THIS TOOL →

Free to start. No card required.

EXPLORE

Related tools and policies

More Fleet tools

Execute fleet_audit_run Run an App Store compliance audit on a mobile app project via greenlight preflight. Execute fleet_deploy Deploy an app: build and restart Execute fleet_secrets_unseal Decrypt vault to /run/fleet-secrets/. WARNING: This overwrites any runtime changes that we Execute fleet_deps_scan Run a fresh dependency scan across all registered apps Execute fleet_git_push Push current branch to origin Write fleet_deps_fix Create a PR with dependency updates for an app (dry-run by default) Write fleet_audit_ignore Suppress a confirmed greenlight false positive from future audits. The finding is Write fleet_secrets_seal Seal runtime secrets back to the encrypted vault.

All 39 Fleet tools →

Write tools on other servers

M-Team MCP Server download_torrent YouTube MCP Server generate_video_title Android Forensics ADB MCP Server combine_reports 0xarchive web3_signup

Go deeper

The MCP Attack Database → Documented attack patterns against MCP deployments — and the policies that stop them.
Argument validation → Checking tool call arguments against schema and policy before they run.
Scoped token → Per-person credentials that grant a defined subset of servers and tools.
Rate Limiting MCP Tool Calls: A Practical Guide →
MCP Security: Why Prompt Guardrails Aren't Enough →

FAQ

Questions about fleet_secrets_set

What does the fleet_secrets_set tool do? +

Set a single secret key/value for an app. It is categorised as a Write tool in the Fleet MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on fleet_secrets_set? +

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

What risk level is fleet_secrets_set? +

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

Can I rate-limit fleet_secrets_set? +

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

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

fleet_secrets_set is provided by the Fleet MCP server (wrxck/fleet). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

Enforce policy on every Fleet tool call.

Start from Fleet, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.

CHECK YOUR STACK →